Chapter 5 DESIGNS OF BASIC JOINERY AND CONSTRUCTION PRODUCTS 1. Types, purpose and methods of manufacturing formwork and inventory scaffolding During the construction of buildings and structures from monolithic concrete and reinforced concrete formwork is used. Formwork consists of forms in

Chapter 1 MANUFACTURE OF JOINERY PRODUCTS AND WOODEN STRUCTURES AT WOOD PROCESSING INDUSTRIES

Chapter 2 JOINERY AND INSTALLATION WORKS ON CONSTRUCTION 1. General information about installation and installation equipment Installation wooden structures is underway different ways: individual elements, parts or assembly units of structures. Method of installation of joinery

2. Preparing the surfaces of parts and products for finishing Carpentry preparation. Carpentry preparation includes sealing knots, cracks, removing dirt, cleaning the wood surface and subsequent sanding. Knots and cracks are repaired manually or using machines. Cracks in

3. Finishing the surfaces of parts and products with paints and varnishes and veneering. The prepared surface of the wood is coated with varnishes, paints or enamels. The varnish film gives the product a beautiful appearance and protects the surface from moisture. When opaque

Chapter 5 REPAIR OF JOINERY PRODUCTS AND STRUCTURES Repair of window units. Wood is used to repair window units coniferous species humidity for sashes, transoms, vents is 9 ± 3%, and for frames - 12 ± 3%. In window blocks, the bars mostly fail

Joinery and construction products are supplied to construction site with a finished surface protected from harmful effects rain and mud. Finishing is done by dipping, spraying and brushing. The surfaces of industrially produced doors and windows are treated using the dipping method. Spraying paint with a spray gun is associated with a large consumption of materials, but this method provides significant time savings compared to the brush method.

It is necessary to prime the end surfaces of the outer edges of door and window frames especially carefully. When choosing a primer, the main criterion is its compatibility with the coating during further processing of the product surface.

External installation of door and window units must be carried out especially carefully, since the quality and durability of the products depend on this.

Installation in new buildings begins only after the specified humidity has been reached. The building dries out depending on the construction method and atmospheric conditions. The slowest building to dry out is one built traditional way brickwork, due to the large number of seams and porous structure. The finished reinforced concrete parts are installed almost dry. After the plastered walls have dried, windows and doors begin to be installed. If the doors are inserted before this, the quality and durability of the joinery products are significantly reduced.

Between installation work in buildings constructed using traditional and industrial methods, there are certain differences. This is discussed in more detail in the following sections. assembly seams covered from the side and top, inside and outside with strips.

Finishing includes surface preparation operations: painting surfaces lined with natural veneer, priming and putty; varnishing, painting and printing wood texture patterns; polishing varnish surfaces. The composition and type of finishing is determined by the cladding material, the type of surface and the operational and aesthetic requirements for it, and costs.

In the furniture industry, sets of lines are used for printing texture patterns on the surface of plates (priming lines and intaglio printing lines), lines for varnishing the surface of panel parts with nitrocellulose and polyester varnishes. There are dyeing and priming lines. A special feature of finishing lines is that they include equipment for applying varnish or other material and drying installations.

Lacquering machines operate at high speeds - 60-140 m/min. The drying time for varnishes depends on the material and drying method. Drying plants are conveyor belts; the speed of movement determines the performance conditions. But as the speed increases, the length of the drying installations also increases. Typically, the length of the lines does not exceed 100 m (U-shaped configuration). The increased line length makes it difficult to fit them into existing production facilities.

Scheme of the MGP-2 line for intaglio printing of a textured pattern(Fig. 148, A). Printing is done on boards 200-900 mm wide and 400-2000 mm long. The line consists of a double loader 1, tilters 2 And 10, grinding machine 3, brush machine 4, 5 roller priming machines and 9, drying chambers 6 and cameras 7 normalization, two-section printing machine 8 and stacker 11.

Turner 2 turns the parts over when applying a pattern to the second face, and the tilter 10 turns the parts over after the first coating so that they are in contact with identical surfaces in the stack (with or without coating). This is necessary to protect surfaces from damage. Car 5 Applies tone primer to the surface of the shield, prepared on a special line. Car 9 will apply a protective varnish coating. Thermal radiation dryers; in the normalization chambers, the shields are blown with air at a temperature of 20-25 °C. These cameras are used for

cooling the surface of the board and removing volatile substances released from the varnish.

The composition of varnish lines depends on the brand of varnish used. If the varnishes are quick-drying, then tunnel-type dryers are used; in lines with long-term drying varnishes, the boards are placed on shelves loaded into chambers. Loading into shelves is done manually.

Rice. 148. Finish lines:

A- MGP-2 intaglio printing of textured pattern; b- varnishing of layers, double-sided; V - MPP-2 polishing of polyester coatings

Line diagram for double-sided finishing of panels with polyester varnishes(Fig. 148, b). The line consists of a loading roller conveyor 1 and an unloading 15, brush machines 2 And 10, heating chambers 3, paint filling machines 4, 6, 11, 13 gelatinization chambers 5, 12, blocks of drying chambers 7 and 14, including convective and infrared dryers, transferor 8 and tilter 9. First coating applied by machine 4 And 11 dry for 5-7 minutes until gelatinous. After applying the second layer of coating on machines 6 (13) the varnish dries for 15-20 minutes until completely dry. A group consisting of shields is simultaneously processed on the line various sizes, stacked in a 3500 X 1800 format, which complicates the process of mechanizing the loading and unloading of the line. The use of group finishing increases the coefficient

Line usage rate. When processing single panels, this coefficient decreases, since mechanisms designed to pass parts maximum size, process parts that are significantly smaller in area.

Scheme of the MPP-2 line for polishing polyester coatings(Fig. 148, V). The line consists of a loader 1 and unloader 6, unified with the MGP-2 line, grinding machines 2, conveyor 3 for quality control of grinding, six-shaft polishing machines 4, normalization chambers 5. These lines have modifications of the U-shaped configuration.

The considered finishing lines can be used for processing parts of built-in furniture and door panels.

Painting of timber parts of joinery and building structures. This operation is carried out by jet pouring (Fig. 149, A). Bar 1 on the conveyor 4 with shaped rollers fed through paint filling machine 3 and enters the transfer position. The block acts on the limit switch SQ1 and when the fork 8 will be in the required position, the switch will be pressed SQ2, the starter is triggered KM1 and the electric motor turns on M1 transfer mechanism drive. Disc 5 turns counterclockwise, lever 2 rises, grabs the block and transfers it to the fork 8, installed on conveyor 7. When the disc comes off 5 from the initial position NO contact SQ3 closes, the relay turns on KM2, which will prepare the relay circuit KM3. It will work when disk 5 returns to its original position (SQ3 will be pressed). Normally closed contact KM3 will turn off the starter KM1, engine M1 will turn off and the switch will take its original position. The bars are fed through conveyor 7 into the drying chamber 6.

Lattice structures (chairs, window units) are varnished or painted in the field high voltage. The line diagram is shown in Fig. 149, b. Monorail 1 carriage 2, on which the separated products are hung, are moved by load-carrying conveyors 3. The carriage, deployed along the movement, passes to the area for hanging and removing products - cameras 4 applying an electrically conductive composition and 6 - coating application. Before entering drying chamber the carriage rotates 90°. In the drying chamber 7 the carriage is disengaged from the main load-carrying conveyor 3 and is advanced by an auxiliary conveyor 8, having low speed and small step between grips. At the exit from the drying chamber, the carriages are picked up again by the main conveyor. The route layout can be much more complex, since one chamber for applying an electrically conductive solution can provide several painting chambers, drying chambers can consist of several parts, and the coating is applied in several passes.

6. Installation of built-in wardrobes

Built-in furniture (cabinets, mezzanines) is installed after laying the floors in the room, performing plastering and sanitary work.

Cabinets are assembled from ready-made elements on the floor. They are attached to the floor, ceiling, walls with nails, screws and bolts. Cabinet elements are attached to the walls using wooden corks, into which screws are screwed or nails are hammered. The cabinet elements are assembled together using bolts or screws.

The rigidity of the cabinet is ensured by the strong connection of the walls with the door blocks, as well as with the bottom and top parts wardrobe (mezzanines, etc.). The cabinet elements are connected with bolts or screws only after checking the correct installation. The verticality of the installation is checked with a plumb line and a square.

In the closets, after they are installed, shelves or rods for dresses are installed in place. Types of connections for built-in wardrobe elements are shown in Fig. 126 a B C. The cabinet elements adjacent to the floor, i.e. the bottom of the cabinet, are covered with a plinth. The junction of the cabinet with the walls is finished with slats or platbands. Depending on the size, the gaps between the ceiling and the top of the cabinet are closed with a strip or a special cornice.

The shelf separating the mezzanine door from the cabinet door is attached tightly to the side walls of the cabinet, the remaining shelves are made removable, and the shelves are placed on under-shelf bars, metal or plastic shelf holders. To make cleaning the lower part of the cabinets easier, a polish is applied (Fig. 126, G).

Cabinet doors are hung on hinges or card hinges. Card hinges protrude from the outside of the door, so it is more advisable to use special hinges (Fig. 126, d, f).

Rice. 126. Connecting elements of built-in furniture: a – rear and side walls using a block; b – side wall c door block; c – rear wall with intermediate wall; d – details of the lower part of the cabinet; d – loop; e – hanging doors on hinges; 1 – side wall; 2 – screw; 3 – block; 4 - back wall from chipboards; 5 – block door frame; 6 – door leaf; 7 – intermediate wall made of solid wood fiber boards; 8 – floor (bottom) made of plywood or hard fiberboard; 9 – floor boards; 10 – plinth; 11 – card loop, console, chrome-plated.

Handles are used to open cabinet doors. The cabinet doors are closed with latches consisting of an aluminum body and a latch mounted into it. The latch has a button for movement. Doors are hung so that they close tightly and do not spring when opening and closing. Door leaves and other cabinet elements covered with valuable wood veneer are finished with varnish, and if the cabinet elements are made of plywood, solid fiberboard or particle boards without veneer, they are painted with nitro enamel or oil paint to match the walls. In some residential buildings the surfaces of the cabinets facing the room are covered with the same wallpaper as the walls, and internal surfaces covered with drying oil or oil or enamel paints.

On construction sites, cabinet elements have to be manufactured on site from particle boards 16 or 19 mm thick. In accordance with the working drawings, the dimensions of the cabinet elements - walls, doors, shelves - are applied to the sheet, after which they are cut out with a circular electric saw, hacksaw, etc. In those elements in which it is necessary to install wooden trim on the edges, select a groove on the edge of the plate, in which a wooden lining with a comb is inserted onto the glue. The lining of the shield elements is made flush with the plane of the shield.

1. Types of wood finishing

Joinery products are finished with paints and varnishes that protect them from environmental influences. Painted products have a good appearance, are easier to keep clean, and their durability increases.

Types of finishing can be divided into the following main groups: transparent, opaque, imitation, etc.

With transparent finishing, the surface of the wood is covered with colorless finishing materials that preserve or further reveal the texture of the wood. It is used for finishing furniture and high-quality construction products: windows, doors, panels made from valuable wood.

Transparent finishes are achieved by varnishing, polishing, waxing and coating with transparent films. When finishing by varnishing, varnishes are used that contain film-forming substances in organic solvents, solvents, etc.

Most often, polyester, nitrocellulose and urea-formaldehyde varnishes are used for finishing wood, and less often - oil and alcohol varnishes. Nitrocellulose varnishes dry well, produce a transparent, elastic, durable and fairly weather-resistant film that can be sanded well. Varnishes based on urea-formaldehyde resins form a film with a shiny surface that is quite transparent. The film formed by oil varnishes is elastic, durable, weather-resistant, but not decorative enough; alcohol varnishes produce a film with insufficient strength, weather resistance, and low gloss. Depending on the degree of gloss, coatings are classified into glossy, semi-glossy and matte.

When waxing, i.e. applying a mixture of wax and volatile solvents (white spirit, turpentine) to the surface of wood, a transparent film is also obtained, formed by a thin layer of wax (volatile solvents evaporate during the drying process). The wax coating is usually applied to porous wood (oak, ash). The wax film is soft, so it is covered with an additional layer of alcohol varnish. The wax coating has a matte surface.

With an opaque finish, a film is created on the surface that covers the color and texture of the wood. Opaque finishes are used in the manufacture of school, kitchen, medical, built-in and children's furniture, doors, and windows.

To obtain an opaque coating, oil, nitrocellulose, alkyd, perchlorovinyl, water-based paints and enamels are used.

When painting with enamels with a large content of film-forming substances, glossy coatings are obtained, with a smaller amount - semi-gloss, and when painting with oil paints - matte.

Imitation finishing improves the appearance of products made from wood, the texture of which does not have a beautiful pattern. The main methods of imitation finishing are deep dyeing, pressing of textured paper with a pattern of precious wood, finishing with veneer, films, and sheet plastic.

Surface finishing using the airbrush method involves applying paint with an airbrush gun and creating a pattern (using a stencil). Using airbrushing, designs with planar (ornaments) and three-dimensional images can be applied to surfaces.

Lamination is one of the types of imitation finishing and consists of lining chipboard or fiberboard with paper impregnated with synthetic resins. When pressing boards covered with paper between metal spacers at a pressure of 2.5–3 MPa and a temperature of 140–145 °C, a smooth and shiny surface is obtained on the boards.

The performance qualities of paint and varnish coatings must have a number of physical and mechanical properties: adhesion to wood, hardness, heat, light and water resistance. These properties are of significant importance in the operating conditions of the products. They are determined by the quality of paints and varnishes, the conditions of their application, and drying of coatings.

Adhesion refers to the strength of adhesion of the paint coating to the surface of wood, while hardness refers to the resistance of the paint coating to the penetration of a harder body into it.

Water resistance is the ability of a coating to withstand the effects of water on the surface of a product. It plays a very significant role in the operation of carpentry products (window blocks, external doors) in conditions of variable humidity.

To finish the surface of panel parts (boards, doors), an LM-3 paint-filling machine is used (Fig. 196). Using this machine, nitrocellulose and polyester varnishes and enamels based on these varnishes are applied to the panels. The varnish filling machine is a frame on which a conveyor for feeding panels, varnish feeding installations and vertically adjustable heads, and a machine control panel are located.
The panels are placed on a conveyor, which evenly moves them under the heads, forming a varnish curtain. Passing through this curtain, the shields are coated with varnish.

More on the topic § 78. Equipment for finishing carpentry and construction products:

1. SURFACE FINISHING OF JOINERY PRODUCTS
2. DESIGNS OF BASIC JOINERY PRODUCTS
3. REPAIR OF JOINERY PRODUCTS AND STRUCTURES
4. MECHANIZATION AND AUTOMATION OF PRODUCTION OF JOINERY PARTS AND PRODUCTS
5. MANUFACTURE OF JOINERY PRODUCTS AND WOODEN STRUCTURES AT WOOD PROCESSING ENTERPRISES