Commonly used are aluminum profiles and die-casting aluminum alloys. Among them, aluminum ingots with purity above 92% are used as the main raw materials, and metal elements such as carbon, magnesium, silicon and sulfur are added to form a multi-element "alloy".
1. 1 aluminum profiles: aluminum profiles are often used as screens and windows. It adopts extrusion molding technology, that is, after aluminum ingots and other raw materials are melted in the furnace, they are extruded into the mold by an extruder for outflow molding, and profiles with different sections can also be extruded. The main properties, namely strength, hardness and wear resistance, meet the national standard GB6063.
Advantages: the weight is only 2.8, it does not rust, the design changes quickly, the die investment is less, and the longitudinal elongation exceeds10m. The appearance of aluminum profiles can be divided into two types: bright and matte. The treatment process adopts anodic oxidation, and the surface treatment oxide film reaches the thickness of 0.12m/m. The wall thickness of aluminum profiles is selected according to the optimization of product design, not the thicker the better in the market, but according to the requirements of cross-sectional structure, which can be uneven in 0.5 ~ 5 mm Laymen think that the thicker the tougher it is, it is actually a mistake.
Disadvantages: warping, deformation, black line, convex-concave line and white line. If the designer's level is high and the mold design and production process are reasonable, the above defects can not be obviously avoided. The inspection of defects should be carried out according to the inspection method stipulated by the state, that is, the sight distance is 40~50CM to identify defects. Aluminum without oxidation treatment is easy to "rust", which leads to the decline of performance and the longitudinal strength is not as good as that of iron products. The wear resistance of surface oxide layer is not as good as that of electroplating layer, and the cost is higher.
1.2 die-casting aluminum alloy
Compared with the processing method of profile, the equipment used for die casting alloy is different. Its raw materials are aluminum ingots (purity about 92%) and alloy materials, which are melted in a melting furnace and molded in a die casting machine. Die-casting aluminum products can be designed like toys with different shapes, which is convenient for connection in all directions. In addition, it has high hardness and strength.
2. 1 ferrous metal parts
Mainly refers to iron products.
Advantages: deformation resistance, extremely high strength, good wear resistance, high hardness, low price and long service life. It belongs to carbon-iron alloy and is divided into high carbon steel, low carbon steel and medium carbon steel. Divided into round tube, square tube, angle steel and steel plate. The round tube is mainly used for chair products; Square pipes are used for beams and supports; Steel plates are mainly used for baffles, mesh plates, pendants, handrails, metal cabinets, doors, etc.
Disadvantages:
1, easy to rust
2, the volume is heavy
3, afraid of humidity
The methods to solve the above defects include electroplating, spraying, blackening and bluing. )
There are many ways to process and shape hardware: bending, punching, drilling, welding, cutting and stamping. In short, it is processed according to the design requirements or product requirements.
2.2 Nonferrous metal parts
Refers to all metal parts except iron products, such as aluminum, copper, zinc and stainless steel. It has a characteristic that it is not easy to rust, and its strength is worse than that of ferrous metal. Widely used in furniture: aluminum plate, aluminum strip, stainless steel tube, stainless steel plate, copper plate and zinc plate.
Stainless steel parts: Stainless steel parts can be divided into stainless iron and stainless steel: "430" is often called stainless iron and "304" is pure stainless steel. One way to distinguish them is to test with a magnet that "430" can be attracted by magnets, but "304" can't. The proportion of stainless steel is slightly higher than that of iron products, but the price is four times higher than that of iron products. So only high-end products are used.
Copper products: Copper products are divided into pure copper and copper alloys. Pure copper, also known as red copper, has poor strength and hardness, but good toughness. Brass is widely used in furniture in copper alloys, and it is an alloy copper mainly containing zinc. The price of pure copper is slightly 30~40% higher than that of "304" stainless copper, and the price of brass is 20% lower than that of pure copper. The hardness and strength of copper alloy are slightly higher than that of stainless copper, but it is easily broken and brittle. The copper parts used in furniture are mainly handles and embedded screws. In order to prevent "rust", pure copper can only be used after electroplating, but brass is not used, and there are fewer products widely used in furniture.
Zinc products: Pure zinc products are rarely used, mainly combined with zinc alloy or steel. Such as galvanized sheet, electrolytic sheet, etc. It is less used in furniture because the strength of zinc products is poor. Zinc alloy fittings, such as eccentric buckle, connection point of structural parts, etc. The specific gravity of zinc alloy is slightly lower than that of iron by about 6.8, and its price is between steel and aluminum alloy. Most zinc alloys produce furniture accessories in the form of die casting.
Titanium zirconium alloy: this expensive metal is used in furniture, mostly in the form of electroplating, and is used in high-grade handles, hinges and high-gear exposed connectors or hotel furniture. Its electroplating cost is about 40% higher than that of chromium plating, but its appearance is high-grade similar to that of gold and silver products, with good wear resistance and no rust.
2.3 Cast metal
There are many castings used in furniture hardware products, such as handles and door hinges. In 2007, there were many popular casting production methods in the market, such as precision casting, die casting and casting. The casting materials are brass, stainless steel, zinc-tin alloy and aluminum alloy. Features of casting products: exquisite, special shape, etc. The disadvantage is that the single piece cost is high, and the process cost of different castings is different. From high to low, the cost of precision casting and die casting is from high to low: die casting and precision casting. The disadvantages of casting products are: the production cycle is slightly longer, the products have to go through 2~3 processes to make qualified parts, and the parts have to be decorated by electroplating, polishing, wire drawing, sandblasting and oil spraying according to different requirements.
(3) Rubber and plastics
3. 1 plastic parts
Plastic products are widely used in furniture. There are many kinds of materials: ABS, PP, PVC, PU, POM, PA, PMMA, PE, PS and PC. Different materials have different application ranges.
ABS: commonly known as engineering plastics, it can be used for connectors, chair backs and seat boards. It is the main raw material for plastic electroplating (water electroplating).
PP: common name polypropylene, used for five-star feet, handrails, foot pads and connectors with low strength requirements. Disadvantages: poor wear resistance and low surface hardness.
PVC: commonly known as polyvinyl chloride, mainly used for edge sealing and insertion conditions. It is suitable for extrusion molding. At the same time, PVC material belongs to non-combustible materials in plastic parts, and its processing and molding temperature stability is poor, especially its color stability is not good.
PU: commonly known as polyurethane. Mainly used for handrail (foam) fittings.
POM: The common name is Sai Gang. Mainly used for wear-resistant parts such as foot pads, casters, door hinges, hinges and so on. Wear resistance and pressure resistance, but poor dimensional stability.
PA: commonly known as nylon. Mainly used as foot pads, five-star claws, casters and other places with wear resistance and high life requirements. Features: Wear resistance, pressure resistance, high strength and long indoor service life. Some models, such as PA66, are resistant to high temperature of 2200, but the disadvantages are variability, easy breakage and poor sun and weather resistance.
PMMA:: plexiglass (commonly known as sub-afterburner). There are five transparent materials in plastics, and PMMA is one of them. The workpiece smells of acetic acid when it is cut, and it is easy to deform when it is processed. Soaking in boiling water can shape and bend. Disadvantages: the surface is easy to scratch, the hardness is low, the bending is easy to crack, and the price is more than 20% higher than ABS.
PC: commonly known as polycarbonate. This variety is also a transparent material with high surface hardness, scratch resistance, strong impact resistance, high strength and good weather resistance (that is, not afraid of sunlight). Screen partitions and sun panels in furniture are made of this material by hollow extrusion. Features: high cost, about 40% higher than PMMA.