Sofa structure
According to the shape of the sofa, the sofa is currently divided into two major types: classical and modern. Classical sofas generally use some traditional styling elements and traditional craft structures, so the structure is relatively complex. The exposed parts of this type of sofa are often decorated by carving, inlaying, painting, and painting. The production process is long and the technical requirements are high. The production process of modern sofas is relatively simple, and modern new craft materials are widely used. The production process is short and easy to mass produce.
The sofa is mainly composed of three parts: frame, filling material, and fabric. (1) The frame constitutes the main structure and basic shape of the sofa. The frame materials are mainly wood, steel, artificial board, medium-density fiberboard, etc., and medium-density fiberboard is currently the main material. The frame must mainly meet the shape requirements and strength requirements. (2) The filling material plays a decisive role in the comfort of the sofa. Traditional filling materials are palm fibers and springs, and now commonly used are various functional foam plastics, sponges, synthetic materials, etc. The filling material should have good elasticity, fatigue resistance, and long life. The filling material of different parts of the sofa has different load-bearing and comfort requirements. The performance and price of the filling material vary greatly. (3) The texture and color of the fabric determine the quality of the sofa. At present, there are a wide variety of fabrics. With the advancement of science and technology, the variety of fabrics will become more and more abundant.
The general structure of a traditional sofa (from bottom to top): frame - wood strips - springs - bottom gauze - palm mat - sponge - inner bag - outer cover.
The general structure of a modern sofa (from bottom to top): frame - elastic band - bottom gauze - sponge - inner bag - outer cover. It can be seen that the production process of modern sofas omits the time-consuming and labor-intensive process of fixing springs and laying palm mats compared to traditional sofas.
The process flow of sofa production
The characteristics of sofa production are that the materials used are of various types and the materials vary greatly. Wood, steel, artificial boards, paint, decorative parts, etc. are used to make the frame; sponges, foam plastics, elastic bands, non-woven fabrics, springs, palm mats, etc. are used for filling; cloth, leather, composite materials, etc. are used to make the outer cover. The processing technology spans a wide range, from woodworking, painting, sewing to furnishing. According to the principle of professional division of labor and improving work efficiency, sofa processing is divided into 5 sections: frame section, mainly making sofa frames; exterior section, mainly making exposed components of sofas; lining section, preparing various types of sponge cores; outer cover section, cutting and sewing outer covers; general assembly (leathering) section, assembling the semi-finished products of each section with auxiliary materials into complete sofa products.
Different sofa manufacturers have different process flows. The process division lines of small enterprises are relatively rough, and the process division lines of large and medium-sized enterprises are relatively detailed. Professional division of labor is conducive to improving work efficiency and ensuring the stability of product quality.
Introduction to production process
Ingredients process
Most of the materials used for sofa frames are boards. Straight boards are cut with cutting saws, while small enterprises use circular saws and band saws to cut curved boards. Medium-density fiberboard can be used for sofa frames because medium-density fiberboard has the advantages of large format and high yield, which is particularly significant for curved parts. At present, the performance of various fasteners and connectors that match medium-density fiberboard is very good. There are still many formaldehyde-sealing and formaldehyde-capturing chemical products on the market. Spraying on the surface of the MDF frame can get rid of the trouble of formaldehyde. For the frames, handrails, and decorative parts made of solid wood, these parts have high surface quality requirements and complex processes. Some of them need to bend solid wood, and some need special process treatment. These parts are basically consistent with the processing of solid wood furniture, so they will not be discussed.
Clear and correct ingredient lists, layout drawings, and templates for curved parts are the main measures for reasonable material use and improved work efficiency.
Assembling the frame
Combine the prepared plates, bent parts, and square materials into a frame, and seal the bottom plate. It is necessary to frequently collect and summarize the fasteners used for sofa frame assembly, and cleverly select fastener information, which can achieve twice the result with half the effort for assembling the frame. The quality of the sofa frame should be paid attention to, and the frame size of mass production should meet the requirements. The error of the size will cause trouble to the general assembly (skin palpation) process. The strength of the frame must meet the requirements. At present, the frame structure of the sofa is based on experience. In fact, through optimization, the frame material can be reduced or the strength can be further improved. The processability of the frame structure should also be paid attention to, and it should be convenient for the operation of subsequent processes. The surface of the frame should be smoothed, burrs and sharp corners should be removed to avoid hidden dangers in subsequent processes.
Sponge preparation
According to the specifications and sizes required by the material list, the sponge should be marked and cut. For sponges with complex shapes and need to be cut, a material list and template should be attached to facilitate construction.
Pasting the frame
Nail elastic bands on the frame, nail gauze, and glue thin or thick sponges to prepare for the leather-touching process and reduce the workload of the leather-touching process. In this process, there must be corresponding requirements for the specifications, quantity, tension value, and cross order of the elastic bands. These parameters will affect the comfort and durability of the sofa.
Coat cutting
According to the requirements of the ingredient list, cut according to the sample. Check the natural leather one by one to avoid scars and defects. Artificial synthetic materials can be cut in stacks with electric shears, and precious natural leathers can be used reasonably, and materials should be selected according to the materials to prevent oversized materials from being used for small purposes. Coat cutting is a control point for production costs.
Outer cover sewing
The cut outer cover is sewn into outer cover, cushion cover, etc. on different sewing equipment according to different process requirements. There are many types of sewing equipment at present, and the seams of sofas are also constantly developing and changing.
Assembly (leathering)
The pasted frame, processed inner and outer cover, various decorations and accessories are assembled into a sofa. The general process is to nail the inner cover on the frame with sponge, then put on the outer cover and fix it, then install the decorative parts, nail the base cloth, and install the feet.
Inspection and warehousing
After passing the inspection, the product can be packaged and put into storage.
Sofa production technology improvement measures
Modular technology can be used in sofa production
Although the sofa shape varies greatly, by analyzing and classifying, determining the basic elements, we should establish the concept of standardization and serialization, and try to reduce the number of specifications of parts in production. Change the situation that a model of sofa is equipped with a set of parts ( from frame to cover ) , which cannot be interchanged one by one. Realize the organic composition of basic parts and optional parts, the basic parts remain unchanged and can be interchanged within a series, and the optional parts change with the sofa model. Improve the degree of specialization in sofa production . At present, the degree of specialization of sofa hardware is very high. Professional factories can manufacture various hardware such as connectors and fasteners according to the various needs of sofa factories. The solid wood decorative parts of the sofa and the exposed solid wood frame can be produced by professional factories, which is conducive to improving the overall quality of the sofa frame and improving the degree of specialization of the sofa factory. Improve the mechanization level of sofa production . At present, the professional machinery used for sofa production includes elastic belt tensioning machine, filling machine, cutting machine, leather palpation workbench, etc., but their variety, scale and quality cannot meet the needs. Sofa manufacturers can cooperate with furniture machinery manufacturers to develop professional sofa equipment. In fact, sofa machinery is also a large market. Developing software for sofa production At present, various software can be used to draw modeling and structural drawings for sofa appearance design, but the unfolding and layout of the sofa cover and the determination of the margin size of the sponge are still completed by the layout master based on experience. The accuracy of the layout is generally poor now, and the fullness of the sofa is often controlled by test correction, filling foam sponge and touching the leather. Due to the inconsistency of products caused by the operator's gestures, the accuracy of each process in sofa production should be gradually improved to eliminate uncontrollable factors and achieve controllable production. Developing componentized sofas In the general assembly ( touching the leather ) process, the operator has to constantly turn over the heavy sofa, change different workstations, and always work at low workstations where he can't do anything. The labor intensity is high, the work efficiency is low, and long-term work is harmful to the body. Using a lifting and rotating multifunctional workbench is one method. At present, some sofa manufacturers are experimenting with componentized production of sofas. Componentization is more conducive to sofa production, assembly, storage and transportation, which is a breakthrough in sofa production.
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