At present, with the high development of industry, it is almost impossible to find an object or product that could not be bought. Of course, the item received will fully comply with the most high requirements, but it will lose the special individuality and originality that wooden products made with their own hands can give.
Stages and tools for work
Let's decide what you may need to make handmade wooden products. The most important thing is the material from which the craft will be made. All logs are prepared in a special way, for this they are dried to 15% moisture, but experts say that the best option is 8-9%. It is important not to forget that wood differs in its strength and structure depending on the type.
To process the product, you will need a mounting table or workbench. Next, be sure to purchase an electric tool - a milling cutter, a circular saw and a grinder, as well as grooving and jointer.
A hand tool will also come in handy, which includes all kinds of planers, chisels, award hacksaws. In order to apply a pattern to a product, you can get drills and engravers.
Drawings of wooden products are also needed in order to understand what the finished object will be. It is advisable to independently develop sketches or borrow them from more experienced craftsmen.
Connection of products on sliding grooves
This is one of the simplest and most common types of bonding, so it is recommended for beginners. You will need to cut the same and straight strips, the width of which will be the same as the thickness of the workpiece, then insert these parts into each other.
Prepare two pieces of plywood or wood in the shape of a rectangle. In the middle, cut the grooves, the length of which is equal to half the workpiece. The width of such a fastener should be the same as the width of the part. The result is a strong and stable cross. If the grooves are cut in the corners, then it will be possible to create an angular solid figure. You can assemble four blanks in this way and get an excellent frame for a box or a rectangular shape for crafts. Such a connection is also perfect for creating round things, for example, a mill or a turbine wheel; production of souvenirs and children's toys; furniture production.
Stages of wood polishing
Primer. It is performed using a swab wrapped in a thin cloth and impregnated with varnish, which is applied to the product in different directions and impregnates it. This procedure is done in order to fill the smallest pores and cracks in the base of the tree. After drying, the surface is processed with fine-grained sandpaper, and then the coating is applied again in two layers one after the other. After drying, the product should be treated with the composition for the last time, diluting it one to one with polish. The prepared thing is kept in a closed cabinet for two days.
Polishing. To do this, polish is used, before working with which the swab is not wetted. large quantity vegetable oil. It is brought from the side, and the composition is distributed in smooth circular motions. All processes are carried out in three stages, and after each application, the surface is polished with fine sandpaper, then cleaned of dust. If everything is done correctly, then after the last layer has dried, a slight gloss will be obtained.
Polishing. It is carried out in order for the surface to acquire mirror shine. After all layers have dried well after polishing, the base is slightly treated with the finest sandpaper, which is pre-wetted in oil. Then a small amount of varnish is applied to the swab, and the surface is rubbed with the composition until a shine appears. In order to improve the strength characteristics of wood products, this procedure is repeated several times. On the last step the surface is wiped with a soft cloth soaked in water.
aged wood effect
In order for handmade wooden products to become exclusive, the effect of aging is used, which can be obtained in three ways.
The chemical method is only suitable for hardwood, since they contain tannins in their composition. To do this, the surface must be covered with ammonia, after which it will darken and acquire a characteristic gray tint.
Using the thermal method, you can age any breed. Initially, the surface is treated with a stain, and then it is singed with a soldering iron until a natural texture pattern appears on it. Then the soot is removed with a brush. Everything is varnished.
The mechanical method (often referred to as branching) is best for softwoods. For this method, you will need a metal brush, which needs to cut through the fibers of the tree - remove the soft layers, after which hard fibers will appear, which will give the material an aged look. Using this procedure, you can hide small defects that appear in the process. At the last stage, everything is varnished or painted.
Finishing Technology
Created with your own hands, after manufacturing they are covered with paint. Thanks to this, they will be especially beautiful and practical. This is done with a swab or a soft brush. Small surfaces, as well as wooden carvings, are best painted with watercolor thin brushes.
Before use, the stain is slightly diluted, after which it is easily applied in several layers, the amount of which will depend on the desired color. Since all parts of wood absorb paint in different ways, it is impossible to cover the product in one go. After each stage, the parts must be completely dried without fail, then you need to walk a little on the surface with sandpaper, remove dust and apply the next layer.
Care
In order for wooden products created with your own hands to look beautiful, they need special care. Steam and moisture easily penetrate inside, but just as easily evaporate. To protect the coating, it is best to use decorative wax. Humidity will not be able to harm products that are coated with such a composition. It is applied with a brush in several stages. This layer will be an excellent protection against minor mechanical damage. For application, you will need a tissue swab, with which the wax is rubbed with wide movements in the direction of the wood texture. For drying, it is necessary to withstand the product for one night at a temperature of +20°C.
Necessary equipment.
An approximate income plan for a mini carpentry business
Organization of a business for the manufacture of medium-sized wooden products.
Additional tools.
Woodworking is one of the oldest crafts known to the world. We, in Russia, attach special importance to this craft. A lot of wood products are decorated and decorated with the help of this particular craft.
The development of the art of artistic processing of wood in Russia was influenced by the development of the state itself, and the cultural development of the people. Therefore, the history of the promotion of wood crafts is divided into several main periods.
Very few original monuments of ancient Russian art of the 9th-16th centuries have come down to us. But based on ancient manuscripts, drawings in painting, information from guests who visited ancient Kyiv and Veliky Novgorod, they testify that even then the artistic processing of wood occupied definitely high positions in the life of the state and the people.
Housing was built from wood, furniture, dishes, city fortifications, workshops, outbuildings, ships, sledges, pavements, water pipes, machines and machine tools, tools and tools, children's toys and the like were made. All this was decorated with geometric patterns carved on them. The manufacture of spoons from ash, maple, birch on the tips of which various ornaments were carved was in special demand, one of the most popular was wickerwork.
The XV century brought the inhabitants of Russia liberation from rot Tatar-Mongol yoke and the founding of a centralized state centered on Moscow. Subsequently, folk arts, among which the artistic processing of wood, received freedom. Creative natures have received will in their craft. It was at this time that the greatest wood craft artists lived. Ancient Russia: Feofan Grek, Andrei Rublev, Dionysius who stood out for the integrity and harmony of their work.
Masterpieces of arts and crafts of the 15th century have become the objects of imitation for a generation of many craftsmen. Iconostases serve as an example, if you pay attention, they have a wicker ornament and gilding, which was inherent in the iconostases of artists of the 15th century.
A separate place worth noting is wooden interiors and wood products. Being in the room wooden interior it seems as if you are one step closer to harmony with nature. Your heart becomes calmer and you feel more cheerful. The tree not only brings you closer to nature, but also gives the home sophistication, sophistication, especially various carved geometric ornaments, in the details of which the craftsmen leave a particle of their soul.
|
|
Implementation of a mini carpentry business.
First you need to study the markets, visit exhibitions, wood industry fairs, in order to know what type of products are in demand by buyers. After collecting the information, create a business plan for your carpentry shop that can lead you to success.
To create a workshop you need: dry bright room size 50 square meters with ceilings up to 4 meters high. It also needs electricity. Then take on the collection of documents necessary for the tax and fire safety services.
Necessary equipment.
The next step is to collect necessary materials and purchase of machines for production. At your request, you can either buy completely all the necessary equipment, or 50 to 50. Make half yourself using Internet drawings, and buy the other half. It is not worth saving on materials and equipment, because half of the quality of your products depends on this. In short, you will need tools such as a circular or miter saw, a jointer, thickness gauge, power tools: a drill, a milling cutter, as well as kits hand tools: chisels, mallets, hacksaws.
Before buying equipment, you should carefully consider everything. What exactly will you produce, what tools and machines are needed for this, in order to avoid unnecessary costs for unnecessary equipment. It is also important not to forget about the people who will work with you, or for you. It is best to look not only for masters of their craft, but also for creative people who will put their soul into your products. If your product is original, the demand for it will never fall and it will bring a stable income.
What kind of wood products to make?
Wood products have their own character, which gives not only the apartment, but also the same office coziness and harmony. Therefore, the choice of products is very large from door handles to furniture of different categories. The carpentry business entrepreneur has a wide range of choices, the main thing is not to make a mistake.
|
There is a sea of wooden products among which are souvenirs, talismans, toys, amulets, they are one of those who are popular among buyers. Especially the amulet "Knock on wood." Its design is quite simple. They take a birch log with a diameter of 5 cm and a length of 10 cm, cut into two in length, cleaned from the bark. A wooden figurine of the spirit is placed at the bottom of the log, or the image of the spirit itself is carved. People say that by knocking on such a talisman you can contact the spirits of the tree, which will give you protection from evil forces and wickedness.
Lacquer is not applied to such a talisman; it is decorated with pieces of birch bark. The chip of the manufacturer of such amulets is the so-called instruction of knocking on wood. The people believe in all sorts of superstitions, so by printing instructions for communicating with spirits to your amulet, you will attract the attention of buyers. Such a product costs about 300 rubles.
Using the cheapest business slab material, you can make benches, tables, stools for cottages, and decorate with various geometric patterns. On the this moment such things are in demand and quite well valued in Moscow.
 |
The most common slab bench costs about 2,500 rubles, and by adding some kind of ornament to it, you can customize it for 3,500 rubles. During the summer, you will be able to manufacture and sell 25 pieces per month. Hot stands cost 25-40 rubles, and made from polished cuts up to 100 rubles, napkin holders from 150 rubles, but good original bread bins can cost up to 1000 rubles.
Mini business expenses and income.
The business plan expenses will include the following items:
. - rent of the premises itself up to $ 200, if you do not have your own;
. - room lighting up to $10-20;
. -materials up to 300 dollars. USA.
. -tools — $2500
 |
It will take about $3170 to open a small mini carpentry workshop. With a business efficiency of 23%, the net profit will be from $ 1000 per month, and the payback period will be up to 4 months. The carpentry business should be launched in time for the start of the construction season.
An approximate income plan for a mini carpentry business.
Subject to your premises:
Let's say your mini workshop makes the simplest joinery- doors. A master with no experience will be able to produce 10-12 doors per month. To do this, you need to purchase 1.5-2 cubic meters tree. The cost will be $270-360.
Price per door $120-130. $120*10 doors = $1200 income. Net income: $1200 - $270 = $930. Here the possibilities of a master without experience are pointed out, since usually a carpentry workshop with one employee manages to make large volumes in a month.
|
|
Organization of a business for the manufacture of medium-sized wood products.
The system for the production of window and door blocks can be divided into the following stages:
1. cutting lumber, checking its quality;
2. creation and processing of blanks;
3. construction assembly;
4. product grinding and coating.
For each step indicated above, you can buy a separate machine or choose a woodworking center that can perform all the above points. You can also kill two birds with one stone, that is, purchase a multifunctional installation that can combine several functions and work for 2-3 workshops at the same time.
When buying such units, you also save space in your premises, because one unit takes up less space than two or three, but includes the same functions. An example of such an installation is the D 300 machine, which can perform the functions of several types, such as: thicknessing, milling, grinding, planer shops.
Additional tools.
For high-quality and holistic work of your carpentry workshop, you need to buy the following tools:
Minimum locksmith tool kit;
. drill;
. screwdriver;
. jigsaw;
. Sander;
. moisture meter;
. roulette;
. calipers;
. electric planer;
. mains powered circular saws;
. tool for applying coloring, antiseptic substances;
. fan with bags for organizing sawdust removal.
  |
A small carpentry workshop can be set up on an area of 60 m2. Space savings can be achieved by combining all the equipment in a woodworking center. To achieve success in business, it is necessary to hire at least two professional carpenters, and also at the first stages of the publishing house, the director must be present in person at the manufacturing processes.
Feasibility study.
Capital investments (in rubles):
. purchase necessary equipment- 184,000 rubles.
. tool costs - 85,000 rubles.
. transportation costs - 50,000 rubles.
. purchase of raw materials - 400,000 rubles.
. registration of a business in the form of an individual entrepreneur - 21,000 rubles;
. other expenses (payment work force) - 15,000 rubles.
Total size investments in business: 755,000 rubles.
For each future product, a sketch is created separately. At first, this is done by hand, not on the scale of the future product. This is a sketch by eye, in which the author develops the idea of the product itself. After that, he coordinates this with the director of the enterprise, if he liked this development, then another drawing is created already beyond the scale, directly according to which future products will be made.
The designed product is depicted in three views from the top, front and side. Make a cut if necessary. If the part model is very complex, then it is divided into parts and each part is depicted separately. Each part receives its own number, under which it enters its specification. All drawings are made on paper, with a simple pencil, so that, if necessary, it is easy to correct the mistake made, or to introduce some kind of amendment, refinement.
Most use special paper - graph paper. This is paper that is divided into cells so that it is easier to calculate the scale and draw to scale.
In one step with the sketch, they think over the manufacturing system for this product. What kind of materials will be needed, what machines will be needed for this development, what tools will be used in the process of creating this product, the costs are calculated. They calculate everything to the last nail, in order to avoid a shortage of some materials in the future, and, of course, to ensure that production is organized.
Also during this period they are preparing the place of work of the master. Choose a workshop that is more convenient in size, which will correspond to the size of the products. They choose a convenient location of the drawings, the placement of materials in the workshop, from which future products will be made. Provide the master with free access to the machine, as well as tools. provide it comfortable conditions for work. Then the manufacturing system and the design of the future product are once again checked in order to avoid quality damage and various failures in the manufacturing process.
 |
1. THE ART OF WOOD CARVING. DECORATION WITH HOME-MADE FLOWERS OF PREMISES AND INTERIOR OBJECTS
Once in Russia, such a type of needlework as woodcarving , was one of the most widespread handicraft directions. Today the art of artistic processing wood blanks regaining popularity in our country. Moreover, if earlier this arts and crafts was mainly done by men, now many women are also engaged in making jewelry and handicrafts from wood. Fortunately, there is a large selection of tools with which you can easily and accurately carve, cut individual parts and solid figures from wood. Convenient models special knives-jambs, cutters, chisels and chisels allow you to quickly and efficiently process wooden blanks, create beautiful flowers, animal figures, and interior decorations with your own hands.
AT recent times some interior designers have begun to use more handmade wood flowers for decorating platbands, stairs, furniture , walls (in the form of panels or compositions within), as well as individual crafts in the form of bouquets of flowers carved from wood.
From hard rock It is rather difficult to make various volumetric and geometric crafts on trees, and mainly experienced professionals who are fluent in the technique of wood carving are engaged in such work. But from such soft tree species as linden or wild apple, carving flowers and various figures is not so difficult. Even a novice master, after a few lessons on the technique of processing wooden blanks, will be able to make an elegant rose with his own hands. , big sunflower or other flower. 
There is a very simple way to make petals from shavings (from a pencil sharpener) of branches, and then make pretty roses out of them. Even a child can handle this job. Below you will find a master class on making such flowers from wood with your own hands at home. You can do with your child stylish topiary of such roses, which will decorate the interior of a children's room.
What woodcarving tools will be needed when making flowers (photo):
Stages of making flowers and other wood crafts with your own hands:
Preparatory stage.
As in any business, first an idea is born, an idea appears. You must clearly imagine in your mind what a fully created craft will look like.
After that, you need to make a pencil outline on a piece of paper. If the flower is not very complex and detailed, then you can limit yourself to a schematic sketch in several projections. And if the figure carved from wood is complex, then try to draw a sketch on the sheet indicating all the main proportions;
Sculpting a flower model.
Now you can mold a craft model, guided by sketches or a sketch. Many masters at this stage additionally draw a diagram in 2 or 3 projections. You will need drawing paper, pencil, polymer clay or plasticine, flexible copper wire to form the frame, stacks;
Rough cutting of a piece of wood.
We saw off a piece of wood with a saw with a middle tooth perpendicular to the central axis. Through the center of symmetry we draw 2 lines perpendicular to each other. First, we remove the excess from the projection, which requires deep processing;
Cutting a figure into 4 faces.
On the side, front and back faces, we cut out the figure of the craft, focusing on its outline, which is applied to the workpiece according to the created sketches;
Cutting a figure into 8 faces.
We cut off the corners of the formed blanks. There are 8 edges in total. At this stage, it is important to take into account the relief of the future flower, cutting narrower on convex areas, and wider on concave and sloping ones;
Detailing crafts made of wood, rounding.
Now tools such as jamb knives, chisels with different curvature, and ceramics will be used.
We work out small details, remove unnecessary faces, give shape to the flower petals;
Sanding.
The ideal option is to use a drill with nozzles from different sandpaper. If you will process the surface of a wooden craft with your own hands, then choose fine-grained emery material on a fabric basis (corundum or glass);
Flower carved from wood.
Processing with special means and finishing of the product is necessary to protect against external influences environment. The decoration of the flower made of wood helps to emphasize the creative intent of the master.
Tips for beginners:
√ don't choose soft rocks trees, if you plan to cut a craft with a lot of small details and perform fine carving;
√
large flowers (roses, chrysanthemums, lilies) are best made from tree species such as wild apple, linden;
√
if you are a novice craftsman, then first learn how to cut a triangle out of wood using a joint knife. Knowing how to cut even only this figure, you can make simple wooden crafts with your own hands. If you have already learned how to process wood well with different tools, then try to cut a simple three-dimensional or geometric figure out of soft wood;
√
To protect wood, various impregnations and varnishes are often used. But if you cover wood crafts with these products, the surface may turn yellow and become less expressive. Therefore, it is best to use wax to treat and protect the structure of the carved wood.
2. HOW TO MAKE YOUR HANDS TOPIARY WITH ROSES FROM WOOD
Step by step master class. This is a pretty tree of happiness even a child can do it by hand. Flowers for decorating a tree are made using a regular pencil sharpener. As a material, you can take branches of any tree (but not too old and brittle).
photo instruction
3. MASTER CLASSES FOR MANUFACTURING CRAFTS FROM WOOD WITH YOUR HANDS
Master class number 1:
HOW TO CUT A BEAUTIFUL VOLUME FLOWER FROM WOOD FOR DECORATION OF INTERIOR OBJECTS. STEP LESSON FOR BEGINNERS. SUCH ARTICLES CAN BE MADE BY SCHOOLCHILDREN AT THE LABOR LESSON IN THE WORKSHOP WHERE THERE ARE TOOLS SUITABLE FOR CREATIVE WORK.
Master class number 2:
ORIGINAL WOODEN CRAFTS FOR INTERIOR DECORATION. WE CUT OUT WITH OUR HANDS FROM A SOFT WOOD CHAMBER (you CAN TAKE A WILLOW) GEOMETRIC FIGURES AND WE COLLECT A FLOWER IN THE FORM OF A SUNFLOWER FROM THEM. YOU CAN WORK A LITTLE ON THE CRAFTS AND TURN IT INTO A SUN WITH A FACE.
Master class number 3:
WE LEARN WOOD CARVING. THIS PHOTO INSTRUCTION WILL HELP YOU UNDERSTAND THE PRINCIPLE OF WOOD CUTTING AND EDGING.
Master class number 4:
Wood sanding is very milestone when finishing furniture. You can’t do without grinding before painting, you won’t get a high-quality and beautiful product. I must say right away that I use a whole set of power tools for grinding. These are grinders, a grinding disc, a drum with a replaceable skin, SHLPS - a belt grinder. There are also nozzles for a drill and a manual belt grinder - a machine. And with all this set, manual grinding still takes a lot of time.
O homemade devices I wrote a post. Grinding electric tools greatly reduce the time of work, and in many cases give a better result than grinding by hand. But sanding isn't just for flat surfaces. Corners, edges, milling, other places where you can’t get with a large tool still have to be sanded by hand. And most importantly, buying a set of tools for home use is expensive, and sometimes there is simply nowhere to place it.
Perhaps everyone knows the main device for grinding by hand, this is a wooden block wrapped in sandpaper. Such a bar is used for sanding flat surfaces. Usually the skin is nailed with small nails on the sides. But sandpaper is a consumable item, it often has to be changed. Each time tearing off nails and nailing on a new one is not enough pleasure. A specially made bar will help here, more precisely, not just a bar, but a block with elements holding the sandpaper.
There are several options for attaching the skin. A fairly simple way to fix the sandpaper with wooden wedges on both sides of the skin. For this in wooden block two gashes are made, and for these gashes it is necessary to make or pick up wedges. Moreover, the cuts themselves and, accordingly, the wedges can be of very different shapes.
I use not only smooth bars. For sanding bent parts, I make the sole of the bar of the appropriate shape. Often, the concave part of the part cannot be sanded out by anything else. In the old carpentry manuals, it is suggested that files be used to finish curly parts. But I don’t use files, they clog quickly, and it’s difficult to clean them.
For sanding curly edges, where it is difficult to climb even with my hands, I use the same skins. For finishing, instead of a file, I take large skins 25-30 No. I pick a long bar desired shape e.g. round, flat, oval. I wind the sandpaper and process the details like a file. It is possible to make such a device for permanent job. For example, as in the picture, the skin is fixed on the working part of the tool, and if necessary, it is easy to change.
In the pictures you see options for bars with different working surfaces. For sanding grooves, straight and rounded. Most use wooden wedges to fix the skins. But you can attach skins in other ways. Sandpaper is fixed with special spring paws with teeth, as, for example, on the same grinders. I even saw such devices in stores. You can choose and make for yourself any option, any shape and size.
Another option is the skin is attached between two platforms, upper and lower. In this case, the sites must be included in each other.
Try to sand along the fibers, when sanding across, deep scratches remain, which then need to be sanded again.
Start sanding with large sandpaper, I use #20-25.
After leveling and sanding the parts with coarse sandpaper, finish grinding with fine sandpaper No. 12 or No. 10. I rarely use finer sandpaper. An overview of the power tool in the article.
Manufacturing wooden parts, assembling units and finishing in mass production are woodworking operations. The technological process here is built according to a complete cycle, starting with the drying of lumber or blanks and ending with the finishing of the units.
CHARACTERISTICS OF THE TECHNOLOGICAL PROCESS
The technological process of manufacturing wooden parts of tools is generally homogeneous with the process of manufacturing products of carpentry and mechanical industries and consists of: drying lumber (or blanks); cutting lumber and plywood; processing blanks to obtain parts of exact dimensions and shape; assembling parts into units; subsequent processing of nodes with their preparation for finishing; internal and front finishing of knots.
Each stage is a complex of sequential operations, the implementation of which requires appropriate jobs, equipment, cutting tool, fixtures and skilled workers.
The mechanized process of manufacturing and assembling parts is carried out on the basis of the use of standard and special high-performance equipment, assembly clamps, various devices and high-quality cutting tools.
Mass production requires the interchangeability of parts, without which the mechanization of assembly operations is impossible.
§ 2. MATERIALS FOR MANUFACTURING PARTS OF THE BODY, GROUND AND INPUT CHAMBERS The raw materials for the manufacture of wooden parts of reed instruments are products of sawmilling and plywood production in the form of boards, blanks and plywood glued, planed and peeled (veneer). The quality and grade of both lumber and plywood must meet the standards (GOST) and republican standards (RST). List of applicable tree species limited mainly to birch, maple, beech, linden, alder, spruce, fir and cedar. In some cases, non-ferrous plywood is used as a facing material.
Currently, the enterprises receive both sawn timber (boards) and blanks. The initial moisture content of the boards is 80-100%, the blanks are 40-70%. It is advisable that enterprises receive only cutting blanks with a moisture content of 22 to 25%.
In production conditions, when almost all parts are processed in blanks that are multiples of length and width, the supply of dried blanks is very economically profitable: smaller drying facilities are required and there are no cutting departments. It is also advisable because drying wood at sawmills, which have a large amount of cheap fuel, is cheaper. Transportation costs are also reduced, since the transportation of waste, which makes up at least 40% when cutting boards into blanks, is excluded. That is why the supply of enterprises with dried billets produced by sawmills on special orders should become very widespread in the near future.
Storage of timber. Timber arriving at the enterprise, as a rule, is not immediately sent to production, but is stored in a timber warehouse. Softwood lumber is usually stored in stacks, hardwood lumber and all types of blanks are stored under sheds, and plywood is stored in closed warehouses. The norm of the area for storing lumber here is similar to the norms for furniture factories (for 1 m3 of lumber in stacks during mechanized laying, 1 m2 of storage area is required, for 1 m3 of lumber stored under sheds - 2 m2 of shed floor area).
When storing lumber in a warehouse, measures must be taken to prevent it from spoiling. You should strictly adhere to the rules for atmospheric drying and storage in warehouses of softwood lumber, regulated by GOST 3808-62, and hardwood, regulated by GOST 7319-64.
Standards for the stock of sawn timber. These standards are determined by the volume of production, terms of delivery and the need to dry lumber in a timber warehouse to an air-dry state. Lumber usually arrives at enterprises with a high initial moisture content, reaching up to 80-100%. Drying lumber with a high initial moisture content to a final moisture content in the range of 8 to 10% causes an overload of the drying chambers and practically does not provide a uniform content of the desired moisture content in a batch of dried lumber, especially hardwood. Uneven humidity of individual parts in a batch inevitably leads to marriage. Therefore, it is necessary to keep lumber in the warehouse to an air-dry state, i.e. to a moisture content of 20-22%. Such moisture content is acquired in the warehouse for different periods depending on the species and thickness, climatic conditions, time of year.
According to GOST 3808-62 and 7319-64, the territory of the USSR is conditionally divided into four zones according to the conditions for drying lumber, and the active drying period in natural conditions is defined as six months (April - September). Depending on the assortment, lumber entering the warehouse during this period reaches a moisture content of 20-22% in 20-75 days. On average, with a uniform supply of sawn timber throughout the year, the stock standards for their stock in the warehouse can be taken as follows: for sawn softwood - 4 months, hardwood - 6 months, plywood - 2 months.
Drying lumber. In industries engaged in wood processing, lumber is dried to a moisture content at which the parts. can no longer change their shape in the assembled product. Lumber can be dried both in boards and in blanks. The advantages of one or another type of drying must be carefully analyzed for each specific case. Drying lumber in boards allows more economical use of wood, as well as wood waste. Drying in blanks allows more economical use of drying chambers. Considering that, on a national scale, the economical use of wood has more importance than the best use of drying chambers, drying in boards should be preferred. In our case, we should recommend drying in boards at sawmills to a moisture content of 20-25%, cutting the dried boards into blanks, supplying blanks to enterprises and drying the blanks to a predetermined final moisture content. The type of drying chambers depends on the volume of production and the range of lumber used. For the production of accordions, button accordions and accordions, which uses a large assortment of lumber in small batches, the most effective drying chambers periodic action of small capacity, with high-speed reverse air circulation of the TsNIIMOD type.
Drying modes are set depending on the range of dried wood from among the normative recommended by the All-Union Conference on Wood Drying.
Cutting lumber. When lumber enters the enterprises in the form of boards, after drying, they must be cut into blanks of the required length, width, and sometimes thickness. Usually, one or two of the four cutting methods are used: transverse-longitudinal (first, the boards are cut across into cuts equal to or multiples of the length of the workpiece, and then sawn along the width of the workpiece); longitudinal-transverse (first, the boards are sawn along the width of the workpiece, and then the sawn long segments are cut into workpieces of the required length); cut according to the markup (the boards are first drawn into blanks, and then sawn according to the first or second method); cut according to the marking with preliminary planing of the board (before marking, the boards are planed on one side, and then they are marked and sawn into blanks).
According to research, for furniture enterprises, if the useful yield of the workpiece by the first method is taken as 1, then the yield for the rest will be 1.03, 1.08 and 1.12, respectively. Therefore, according to the fourth method, the useful yield of blanks is 12% higher than according to the first one. In the production of accordions, button accordions and accordions, where blanks are intended for the manufacture of small parts (neck and bars of entrance chambers, linings, thrust bars, valves, etc.), i.e. with a large multiplicity in length and width, cutting is usually done according to the first way. For more critical and large parts (body walls, walls of fur frames, neck parts, wedges of inlet chambers, etc.), boards are cut into blanks according to the fourth method.
Two types of circular saws are usually used for cross cutting boards. In machines of the first type (pendulum), the saw, mounted on a swinging frame above the work table, is pulled over the material being cut by hand. Machines of the second type (with rectilinear motion) are the most convenient, since the saw moves on the material parallel to the surface of the desktop. In machines of this type with automatic feed, the advance of the saw and its return are carried out automatically at the touch of a button. The productivity of these machines is high and amounts to 10,000 cuts per shift. For longitudinal sawing of boards, circular saws are used with both manual and mechanical feed. The productivity of machine tools with mechanical feed is on average 10,000-12,000 running meters. m per shift. When reconstructing existing or designing new workshops for cutting boards into blanks, as well as with a significant amount of production, a semi-automatic line should be recommended.
A semi-automatic cutting line, especially for hardwood lumber, should include pre-gouging and marking boards. Such a line usually consists of a hydraulic lift, which receives boards from the cooling room of the drying department, roller tires, roller conveyors with pusher rollers, a thicknessing machine, trimming and cutting machines (for transverse and longitudinal sawing) and a belt conveyor.
Cutting of plywood is carried out on a circular saw with manual feed, and peeled and planed plywood is made on guillotine shears.
The output of blanks when cutting boards is determined technical requirements and therefore depends on the grade of lumber. Most rational use lumber of I, II and partially III grades in the following ratio: I grade - 40%, II grade - 40%, III grade - 20%. With the indicated ratio of lumber grades and cutting of blanks for the largest and most important parts according to the fourth method, the output of blanks from lumber is 50-60% on average.
Workpiece sizes. With regard to production conditions, where small wooden parts predominate with a multiplicity of blanks from 2 to 100, the dimensions of the blanks are set mainly based on the convenience of their further processing. However, in each individual case, the dimensions of the workpieces should be selected so that, with the minimum laboriousness of their processing, the maximum yield of suitable parts is obtained.
The thickness of the workpiece (board) is determined from the conditions of the current assortment of lumber, the thickness of the part in cleanliness, the allowance associated with the drying of wood, allowances for primary and subsequent processing, and more efficient use of raw materials with the intended technology. The length and width of the workpiece are set depending on the dimensions of the machined parts, the more appropriate multiplicity of parts, the allowances indicated above and the accepted method of processing, taking into account the maximum yield of parts. Usually the length of the blanks is in the range from 700 to 1000 mm, and the width is from 40 to 50 and from 80 to 110 mm.
The allowances associated with the drying of wood should take into account the change in the size of sawn timber and blanks due to the drying of wood from initial to final moisture content. At the same time, the shrinkage value for sawn timber up to 15% moisture content is given in GOST, and the allowance for this shrinkage is given for boards for sawmills.
Shrinkage of lumber from 15 to 8% moisture is very insignificant and is usually not taken into account, as it is covered by the processing allowance. If it becomes necessary to dry the workpieces with a moisture content of more than 15%, then allowance for shrinkage should be taken into account (for coniferous species in accordance with GOST 6782-67, for hardwood - with GOST 4369-72). When drying blanks of hardwood with a high initial moisture content, especially from beech, the appearance of end cracks is inevitable, which must be taken into account in the length reserve. For workpiece lengths from 700 to 1000 mm, the length allowance for end cracks is taken into account in the range from 15 to 20 mm (for two ends).
Allowance for primary processing. The processing of the workpiece to give it the correct geometric shape begins with leveling by planing one wide face and one edge with the formation right angle between adjacent edges. Two faces adjusted to a plane and a right angle are basic for processing the remaining faces of the part. The third face of the workpiece is usually processed by planing along the thickness of the part, and the fourth by sawing along the thickness. In addition, the workpiece is trimmed along the length of the part. The size of the allowance for the thickness and width of the workpiece depends on the transverse and longitudinal warping, on the deviation in nominal dimensions, on the dimensions of the workpiece and the multiplicity of its width and length.
All of these factors are found in production in various combinations, so the allowance cannot be a simple algebraic sum of all the deviations encountered. The rational value of the allowance for a given production is usually established by conducting experimental work. The observations carried out at the time by the laboratory of the Krasny Partisan factory over experimental batches of blanks made it possible to establish the following allowances.
The length allowance depends on the defects of the ends of the workpiece, i.e., on the perpendicularity of the ends to the longitudinal edges of the workpiece, as well as on the size of the end cracks and the multiplicity of the workpiece along the length.
Allowances for further processing. These allowances take into account the formation of parts during their processing before and after assembly into units, as well as specific features of the technological process. The establishment of rational allowances for subsequent processing is carried out on the basis of a thorough analysis of all factors affecting their value (process flow diagram, processing requirements, equipment used, cutting tools, fixtures).
Allowances for subsequent processing should take into account: subsequent processing of parts on milling and other machines before giving them the final shape; sawing parts with multiple dimensions of the workpiece; dimensional milling of cases and fur frames to remove sagging and give an accurate shape.
TECHNOLOGICAL PROCESS DIAGRAM
To consider the technological process of manufacturing wooden parts and assembling the body, neck and entrance chambers, the bayan was mainly chosen as the most common and characteristic type of instrument in the entire subgroup.
According to the nature of the technological steps and their sequence, woodworking operations are divided into: drying-cutting - for drying and cutting plywood and lumber into blanks; machine tools - for the production of parts of exact sizes and shapes from blanks; assembly - for assembling bodies, necks and entrance chambers and finishing - for internal and front finishing of instruments.
Usually all these operations are combined in the woodworking shop of the enterprise.
In addition, this workshop also includes auxiliary departments: a tool room with the functions of caring for a cutting tool (point, editing, installation, operation); gluing - for centralized preparation of glue and varnish-preparatory - for preparing working solutions of primers, varnishes and polishes.
We have already considered the features of drying and cutting operations.
Both universal and special woodworking equipment are used to process bar body parts, neck and other components. Universal equipment and methods of working on it, as well as the fixtures and cutting tools used, do not differ from those used in carpentry and mechanical production. These issues are very widely covered in the literature on woodworking and therefore it is inappropriate to repeat them. To show the features of the technological process, examples are given that characterize the use of special equipment, special types of equipment and specific working methods.
The walls of the floor of the buildings. The workpieces are fed to a planer for leveling one face and one edge, then to a planer for planing the second face, i.e. for gouging to size in thickness. Then they are transferred to a circular saw for longitudinal sawing along the width of the part, then pa? circular saw for cross cutting along the length of the part.
The next operation is cutting the spikes. This operation must be carried out with great precision, as it affects the interchangeability of parts. Therefore, it is advisable to cut the spikes simultaneously from both sides of the housing wall. As universal equipment to perform such an operation is not, then a special double-sided tenoning machine with mechanical feed is used.
In the absence of the specified machine, one-sided cutting of spikes is usually carried out on a milling machine with a bracket adapted for heavy work. A pack of walls is placed in a husk and is fed manually along the guides to rotating slotted cutters, reinforced with spacer rings on the machine spindle. The selection of the fold and the profiling of the edge of the wall are performed on a conventional milling machine.
To eliminate the wavy surface formed during the processing of parts with rotating cutters, as well as to remove burrs and scuffs, the body walls are ground. The inner surfaces of the parts are ground before assembly, the outer surfaces - after the assemblies are assembled. Belt sanders are usually used for grinding. grinding machines with bottom location sanding belt.
Accompaniment overlay. Sheets of plywood are cut on circular saws, first into strips along the width of the lining, and then into strips along its length. Given that mechanical properties of wood depend on the direction of the growth layers, the accompaniment overlays must be cut in such a way that the long side of the overlay is in a plane perpendicular to the direction of the annual layers of plywood shirts. According to the specifications, this overlay should be glued on both sides with celluloid. Details about the mode of gluing wood with celluloid and the adhesives used will be discussed below. The accompaniment overlay, pasted over with celluloid, after an appropriate exposure, is sent to a drilling machine for drilling holes. As already mentioned, in the overlays of full bayans and accordions, 100 or 120 holes are drilled, placing them in five to six rows, 20 in each, on a special 20-spindle drilling machine with constant pitch between drills.
From the electric motor 1, through a belt drive 2, a worm gear 3, twenty spindles 4 with drills 5 are driven into rotation. detail 11. At the same time, the rocker arm 12 presses the button of the magnetic starter 13, which turns on the electric motor 1. Such machines are introduced at the Leningrad factory "Red Partizan", the Rostov bayan factory, etc.
Decks. Sheets of plywood are cut into circular saws in width and length of decks with an allowance for further processing. Here it is also necessary that the long side of the deck is in a plane perpendicular to the direction of the annual layers in the plywood shirts. It is advisable to drill cylindrical holes on multi-spindle drilling machines of the type used for processing the lining, and oblong holes on copy-milling machines. In the absence of such special machines, holes in the deck are drilled on a conventional single-spindle drilling machine with the help of a plume. A pack of 6-8 dec is placed in the sous lag, which are processed simultaneously. They drill along the lower conductor, which fixes the location of the holes on the deck, and the catcher, mounted on the machine table.
The next operation is planing the deck along the contour (along the perimeter) until its exact width and length are obtained. The operation is performed on a milling machine using a device (sulagi) with upper cylindrical catchers. A pack of 8-10 decks is put on with extreme holes on catchers, which are basic, i.e. defining given distances between the axes of symmetry of the holes and the edges of the deck. Sulagu lead, pressing against the thrust ring. As a cutting tool, a multi-knife milling head or a smooth-cut milling cutter is used. The next operation is the grinding of two deck planes on a belt sander.
The grooves are sawn on a special horizontal multi-saw machine. A set of saws with spacer rings are fixed on the shaft, which determine the pitch of the cuts in the bar.
The workpiece is fixed in the carriage 3, which moves along the guides in the direction perpendicular to the plane of rotation of the saws, as well as in the vertical plane.
entrance chambers. Wedge. As already mentioned above, it is possible to mill a wedge to form cells (nests) for each vocal plank separately both along and across the direction of the annual layers of wedge wood. Although the technology for making a wedge when milling cells along the annual layers is longer, it is preferred, since when milling across the annual layers, a significant percentage of rejects is obtained during the production process. As an example, below is the technological process of manufacturing a wedge of the melody inlet chamber when milling cells along the annual layers.
After cutting, the workpieces are fed to a jointer to align one face and two edges. The sequence of further manufacturing operations is shown in fig. 128: 1 - blanks are fed to the thicknessing machine for planing the second layer in thickness; 2 - gluing boards (700X700 mm) from the resulting plots; 3 - after planing two layers, the shields are cut into planks; 4 - trimming the strips along the length into two parts; 5 - sawing each plank into two wedges; 6 and 7 - milling a wedge into a cone in height and thickness. The next operations 8 and 9 are milling of cells and air channels.
These operations are performed on a special horizontal milling machine. circuit diagram such a machine does not differ from that shown in Fig. 122. Instead of saws, a set of smooth cutters with spacer rings is fixed on the shaft, which determine the pitch of the cells (nests), i.e. their location on the wedge. This machine is also used for milling nests in the bodies (combs) of harmonicas.
In addition to the schemes of technological processes for the manufacture of bar parts recommended above, when they are transferred from one machine to another during processing by conventional vehicles (trolley, forklift), recently automatic lines have been widely introduced in the woodworking industry. Such a line usually consists of universal equipment general purpose and special Vehicle and loading devices that allow you to automate the process of loading parts into a line, feeding from machine to machine and transferring parts from longitudinal to transverse movement; line capacity is about 4000 linear meters. m parts per shift.
In industries where lumber is used in small quantities, and the range of parts is very large, the introduction of an automatic line for processing bar parts is economically feasible for a production volume of at least 50,000 button accordions per year in the manufacture of case walls from lumber.
The line for processing bar parts (body walls, neck bars, details of inlet chambers, etc.) is shown in fig. 129.
GLUE AND ASSEMBLY OPERATIONS
All wooden parts of the body, neck and entrance chambers are interconnected with glue, and some of them, for greater strength, are also fastened into a tongue, into a spike or screwed on with screws.
If there is a metal deck in the semi-hull, it is connected to other wooden parts with screws.
The parts are glued together with collagen and synthetic adhesives, including polyvinyl acetate emulsion.
Since the characteristics of these adhesives, the methods of their preparation and modes of application are well known in the literature on woodworking, and the presentation of these issues is also provided for in the material science course, the following is only the main mode of gluing wooden parts with synthetic glue with heating the adhesive joints to 110-120°C.
The bonding of parts is made up of the following items: preparing the surfaces to be glued, applying an adhesive layer on them, connecting the parts to be glued and pressing. The surfaces to be bonded must be clean and dry, free from grease and other contaminants, well adjusted to each other and slightly rough. The quality of the preparation of the surfaces to be bonded has big influence for adhesive strength. Glue is applied to both surfaces to be glued in an even layer with bristle or bast brushes. After joining the surface, the parts are lightly rubbed to distribute the adhesive more evenly and to expel air bubbles from it, and then hydraulic, pneumatic, eccentric or screw clamps are applied.
Heating of the adhesive layer. Gluing wood at a normal temperature of 16-25 ° C continues quite long time, the production cycle of adhesive units is stretched and requires large production areas, as well as a lot of gluing equipment and fixtures. When gluing knots without heating, more than 85% of the cycle time is held. It is known that the rate of curing or polymerization of the adhesive depends on its temperature. Heating the wood being glued to 110-120°C significantly reduces the holding time of the parts in the pressed and free state.
To heat the parts to be glued, high-frequency and low-voltage electro-contact heating is most often used.
High-frequency heating should be used when gluing parts of considerable thickness (more than 6 mm) with multi-layer gluing, as well as in all other cases when adhesive joints are in places that are hard to reach for contact heating (thorn joints of the body walls). It should be borne in mind that during high-frequency heating, the adhesive seam, due to its increased dielectric constant, absorbs more electrical energy and therefore heats up much faster than wood. This position contributes to a noticeable acceleration of the gluing process and a decrease in specific consumption electricity. Electro-contact heating gives good results when gluing the soundboard to the body plates, the back of the neck to the end bars, the top of the neck to the main bar, rosettes to the wedges of the inlet chambers, etc. The introduction of high-frequency and contact heating of the glued parts opens the way to the organization method on conveyor lines.
For high-frequency heating of the adhesive layer, it is recommended to use lamp generators. At present, there is still no high-frequency lamp generator specially designed and manufactured for heating wood. Therefore, relatively easily adapted universal generators are used in the woodworking industry.
In the production of accordions, button accordions and accordions, good results were obtained using a high-frequency tube generator of the LGE-3b brand. Such a generator usually serves two glue clamps. While the parts are glued and held in one haym, the parts for gluing are laid in the other. Depending on the type of parts to be glued, three or more clamps can also work from one generator. You can also use the LGD-10 generator.
For electric contact heating of wood, heating elements (copper, steel and aluminum tapes) are used, powered by step-down transformers. Such transformers are connected to a common power network with a voltage of 220/380 V. The output side of a step-down low-voltage transformer is within 2-3 V. It is advisable to centrally supply electricity to glue clamps located in a certain area. Depending on the bonding area and the thickness of the parts to be bonded, one 3 kW transformer can operate from four to eight bonding clamps.
Assembling the body and fur frame. The assembly of the walls of the right or left semi-body of the button accordion, as well as the fur frame into the box, consists in dipping the straight, flat and through spikes and lugs with glue, connecting the vertical and horizontal walls at a right angle and compressing them. For streaming organization assembly work, as well as gluing, it is necessary to introduce a system of tolerances and fits, and to intensify gluing, use synthetic quick-hardening adhesives, and in this case the adhesive layer is heated in the field of high-frequency currents. Clamps with pneumatic clamps are also required. The walls of the semi-body and the fur frame are assembled in an assembly clamp.
In a two-position hayme, nests L and B are located in the same way and are designed so that if gluing is performed in nest A, then the glued knot is removed in nest B and the details of the next one are laid. The bed 15 of the clamp is equipped with rigidly installed base beams 12 and 13 and adjustable power crossbars 2, 9 and 16.
The crossbars 9 and 16 are equipped with pneumatic cylinders 10 and /7, to the rods of which pressure shoes 8 and 14 are pivotally attached. The crossbar 2 is equipped with two pneumatic cylinders 4 and 16 with pressure shoes 3 and 7. clamping shoe tips. In addition, regulation of the position of both the pneumatic cylinders in the crossbars and the crossbars themselves is provided using screw mechanisms 11, 18. a value sufficient for the free laying of parts. For more convenient insertion of parts and removal of the assembled housing, each of the clamp positions is equipped with a lifting pallet (from a separately located pneumatic cylinder) with spring part holders (pallets with pneumatic cylinders are not shown in the diagram). Vaima has a device for high-frequency heating of glue joints, consisting of a set of electrodes 5, connected to a lamp generator of the LGE-3b brand.
To protect the worker from burns and injuries, the wyma is equipped with an automatic protective device connected to the starting device for turning on the lamp generator. Pneumatic cylinders are controlled by an air distributor, which ensures their subsequent switching on and automatic switching off by a time relay command, which operates according to a regulated regime. Vaima can also work with an unregulated rhythm. To do this, the following conditions must be met: during crimping and drying of the semi-body in socket B, the electrodes are connected to a lamp generator; at this time, the finished half-body is taken out of slot A and the details of the next half-body are placed in it. When loading parts, the electrodes are disconnected from socket A from the lamp generator, the pallet is in the upper loading and unloading position; they are installed in the pallet holders along the edges of the body walls, the spikes and lugs of which are lubricated with glue (the spikes must match the lugs).
At the end of the laying of parts and the expiration of the exposure time of the semi-hull in the nest, usually determined by light or sound signal, press the air distributor pedal, in connection with which the following cycle operations are automatically performed sequentially: the tray of the nest A with the laid parts is lowered to its lowest position; Pneumatic cylinders 4 and 17 are switched on, compressing the semi-body on socket A; the socket electrodes are disconnected from the lamp generator at the same time raise the fence of this socket and lower the fence of socket A; the electrodes of socket A are turned on and at the same time the pneumatic cylinder for lifting the pallet of sockets B is turned on. At the end of these operations, the semi-body is removed from socket B and the details of the next product are placed here, after which the cycle is repeated.
The performance of such a clamp is determined by the duration of the cycle of gluing the floor of the hulls. Typically, the hourly output of a vayma is 40 semi-corps. With two-shift operation, the productivity of the wyma, taking into account the gluing of fur frames, will also be 70-75 thousand sets per year. After gluing and appropriate curing, the semi-body is transferred for further processing to a milling machine. Here, he is given dimensions in height and at the same time eliminates the sagging of the edges that have arisen during gluing. To do this, two saws are fixed on the spindle of the milling machine, between which there are intermediate rings. The distance between the saws corresponds to the height of the semi-body; the latter is put on the template and sawn off along the thrust ring.
Gluing parts into a semi-body. Details such as lining, deck, neck bars, thrust bars, etc., are glued using templates that exclude marking of gluing places. To clamp the parts to be glued, various devices are used, which are quite well known in woodworking. It is expedient to glue the soundboard to the facings by the electrocontact method in a pneumatic clamp.
After gluing all the parts, the semi-body enters the area for subsequent machining. Depending on the required shape of the semi-hull and the method of its manufacture, the nature of the subsequent machining is different and may include such operations as removing sagging in the corners of the walls by grinding, planing or milling, rounding corners, shaping milling of corners and ribs, selecting cutouts for meshes, finishing surface grinding, etc. To perform all these operations, standard woodworking equipment, conventional cutting tools and fixtures adopted in wood processing are used. If necessary, local puttying and surface grinding are carried out, after which the semi-hulls are transferred to the finishing (cladding) department. The cleanliness of the wood surface is characterized by dimensional indicators of irregularities, as well as the presence or absence of hairiness or moss on the treated surfaces. In accordance with GOST 7016-54, 10 cleanliness classes are established depending on the magnitude of surface irregularities. Hairiness and mossiness on the surface of wood of the 6th, 7th, 8th, 9th and 10th classes are not allowed. The cleanliness of the wood surface in the drawings is indicated by the class number, preceded by the letter d (wood) and an equilateral triangle with its apex facing the surface to be treated (for example, dd7).
Bonding of entrance chambers. Gluing the parts of the inlet chamber in the manufacture of a wedge by milling is reduced to gluing the top plate and rosette to the wedge, the thrust bars to the rosette, and cleaning the assembly from dust. When constructing an inlet chamber with a composite wedge, it is necessary to additionally glue the partitions to the wedge and saw them in length and width. Finished inlet chambers are sent to the area for mounting voice strips.
Gluing the fur frame. The fur frame is usually glued into a blank 4 times in width, similar to a semi-hull, which is then sawn in width into four fur frames. This is followed by operations: rounding the corners and profiling the walls, after which the frames are sent to the fur manufacturing area.
The use of synthetic adhesives in combination with heating the glued wood to a temperature of 100-120 ° reduces the duration of holding the parts in the pressed state to 1-2 minutes, which creates conditions for organizing a flow process.
Selection and calculation of pneumatic clamping devices. Recently, various pneumatic clamping devices have been widely used in industry. They are used for clamping parts during their processing on woodworking and metalworking machines, as well as for clamping parts in the process of gluing them in clamps. Since these issues are not sufficiently systematized in the specialized literature, it is necessary to dwell on them in some detail. The advantages of pneumatic clamping devices in comparison with others, characterized by the time factor, can be seen from the following data from TsNIIMOD and NIIDREVMASH.
Pneumatic clamping devices compare favorably with others by their high efficiency, simplicity of device, reliability in operation and ease of use. The use of high-speed pneumatic clamping devices eliminates the disadvantages inherent in manual operations (incomplete clamping, application of significant efforts by workers, long clamping time) and creates opportunities for regulation, control, automatic control, and along with the characteristic feature of a pneumatic drive - the constancy of the clamping force - allows you to work with increased modes and increased accuracy.
There are three types of pneumatic clamping devices - piston, hose and membrane.
Piston clamps are used in cases where a significant clamping force is required with a relatively large piston stroke, when gluing the walls of the case, the walls of the fur frame, etc., when the distance between the clamping bar and the parts to be glued is more than 30 mm.
Hose clamps are usually used with a small clamping force and when the distance between the clamping bar and the parts to be glued is less than 30 mm, for example, when gluing plates or thrust bars with a deck, rosettes with wedges, etc.
Membrane clamps are very compact, consume little air, but have a limited clamping force, usually not exceeding 600 kg, and a stroke of no more than 15-20 mm; they are used mainly for clamping parts when processing them on machine tools.
The piston clamp is a metal case, consisting of a cylinder 1 and two covers - front 3 and rear 14. The cylinder is made of steel, and the covers are made of cast iron. The cylinder and covers, connected by a tight fit, are equipped with lead sealing gaskets 15 and are additionally tightened with studs 7 with nuts 5 and lock nuts 6. Both covers have channels 2 through which compressed air fed into the cylinder. Fittings 4 cylinders are connected to the air line using a flexible hose. A cast iron piston 20 is placed in the cylinder, moving as compressed air is supplied. The piston has two sealing leather cuffs 18, pressed against the piston by rings 17 and 19, which are fixed with screws 16. The piston rod 10 passes through the sleeve 13, pressed into the opening of the front cover and having a seal in the form of a leather ring 11, pressed by the flange 12. At the end of the rod an eye 8 is screwed on, which, together with the pin 9, forms a swivel clamp of the clamp.
By turning the handle of the air valve, air is allowed to enter one of the fittings and at the same time air is released through the other fitting. From the above, it can be seen that the clamping force depends on the air pressure in the network and the piston diameter. The air pressure in the network should be 5 kgf / cm2, but for calculations they take p \u003d 4 kgf / cm2. Usually used pneumatic cylinders with an internal diameter of 30, 40, 50, 75, 100, 150, 200 and 300 mm. The rod diameter is usually 0.2 piston diameter.
The basis of the hose clamp is a rubberized hose 1 (Fig. 134). The ends of the hose are connected using fittings 2 with flexible air ducts through which compressed air enters. Hose 1 and spring 5 are placed between a fixed bar 3 and a movable bar 4, connected by a spring 5. The parts to be glued are placed on the base 6 of the clamp and rest on a fixed bar 7. Until the press is applied, i.e., before the compressed air enters the hose, it occupies the position shown in Fig. 134, a, where the letter x denotes the distance that the hose occupies between the fixed and movable bars. The hose diameter commonly used in these clamps is 75mm and the hose thickness is 3mm. In position a, distance d: \u003d 3-2 + b where X is the gap between the walls of the hose, which is assumed to be 2 mm, i.e. l: \u003d 3-2 + 2 \u003d 8 mm. After the moment of applying the press, the hose takes the position indicated in fig. 134b.
Based on experimental work, it has been established that the largest clamping force is achieved at a value of x equal to 0.4 of the hose diameter, i.e. in our case, l: = 0.4-75 = = 30 mm. With a further increase in the x value (from 30 to 75 mm), the clamping force will decrease accordingly, and with x equal to the diameter of the hose, i.e. 75 mm, the clamping force will become equal to 0. Thus, the hose clamping force turned out to be somewhat greater required effort, which indicates its compliance this species works.
The membrane clamp has a rubber membrane sandwiched between two cast iron hemispherical covers 4 and 9. In the center of the membrane there is a hole into which the stem shank 12 enters, connected to the membrane by two steel washers 2 and 14 and a nut 5. Cover 9 has a tide, in the hole of which is pressed cast-iron bushing 13, which is a guide for the rod. Two through holes 8 in cover 9 serve for free passage of air inside the hemisphere formed by this cover. The other hemisphere formed by cover 4 is hermetically sealed and can change its volume under the pressure of compressed air supplied from the network through fitting 5 screwed into the opening of cover 4. When the tap is opened, the compressed air squeezes out the rubber membrane and it transmits movement to the stem 12, which has a hinged joint 10 with a clamping bar 11. The rod is returned to its original position by a rubber membrane 7, which contracts when air is removed from the hemisphere formed by cover 4. The membrane clamp is attached to the machine using a bracket 6 and bolts 7. With a membrane diameter (along the contour of the clamp) D equal to 230, 200, 75 mm and a design pressure in the network p = 4 kgf / cm2, the membrane clamp accordingly develops forces Рg equal to 450 -500 kg, 350-400 kg and 50-60 kg; at the same time, large forces correspond to smaller ones, and smaller ones correspond to a longer stroke length of the rod.
Loading...