When designing non-standard automation equipment, when it comes to the selection of materials, it is reasonable to not know what material to choose. With the improvement of engineering requirements for machinery and parts and the continuous development of material science, the rational selection of materials has increasingly become an important means to improve the quality of parts and reduce costs. Especially when designing a set of non-standard equipment, it often includes many kinds of materials. How to choose materials reasonably has become a very important link in non-standard design. Therefore, next, we will introduce the materials commonly used in non-standard design.
- Stainless steel
- Aluminum
- Steel
- Copper
- PU
- POM
- PMMA
- PF
- NYLON
- PTFE
- PEEK
- PP
- ABS
Steel material:
Steel: refers to the general term for iron-carbon alloys with carbon content between 0.02% and 2.11%. Because of its low price and reliable performance, it is the most widely used and used metal material. The most widely used steel materials in non-standard mechanical design are: Q235, 45# steel, 40Cr, stainless steel, die steel, spring steel, etc.
Classification of low carbon steel, medium carbon steel and high carbon steel: low < medium (0.25%~0.6%) < high
Q235-A: Low carbon steel with carbon content < 0.2%, indicating that the yield strength is 235MPa, its plasticity is good, and it has certain strength but not impact resistance. In non-standard design, it is generally used for welding structural parts, such as square pass, welding block, large frame plate, angle steel, etc. of welding frame. When surface treatment, the structural parts are generally sprayed or painted, and the boards are usually chrome-plated or blackened for rust prevention. (The steel grades suitable for blackening are only carbon steel and low alloy steel. The principle is to coat a dense iron oxide film on the surface of the steel parts.)
45# steel: medium carbon steel with carbon content of 0.42~0.50%, its mechanical properties, cutting properties are excellent, and welding properties are poor. In the non-standard design, it is generally used as a large frame of the frame, structural connectors, shafts with low strength requirements, etc. 45 The hardness of quenched and tempered (quenched + tempered) steel is between HRC20~HRC30, the quenching hardness generally requires HRC45, and the strength stability cannot meet the requirements after the hardness is too high.
40Cr: belongs to alloy structural steel. After quenching and tempering treatment, it has good mechanical properties, but the weldability is not good and cracks are prone to occur. Can be used to make gears, connecting rods, shafts, etc. After quenching, the surface hardness can reach HRC55.
Stainless steel SUS304, SUS316: Both are low carbon steels with carbon content ≤ 0.08%. It has good corrosion resistance, mechanical properties, good stamping and bending hot workability, and standard SUS304 is non-magnetic. However, many products are magnetic due to segregation of components during smelting or improper heat treatment. If non-magnetic is required, it should be explained in the engineering drawing. SUS316 is more resistant to corrosion than 304, especially in high temperature and harsh environments. At present, there are many 316L on the market. Due to the lower carbon content, its welding performance and processing performance are better than SUS316. Sheet metal is generally used as a mounting seat for standard parts such as cover and sensor of small parts in non-standard design, and sheet metal can be used for parts connection.
Stainless steel SUS420J2: After heat treatment, it has high strength and wear resistance, and is suitable for manufacturing plastic molds that can withstand high loads, high wear resistance and corrosive media. In addition, because of its high polishing performance, it is a better decorative material.
Die steel CR12: It is the national standard name, corresponding to the JIS name SKD1. Because of its excellent comprehensive performance and low price, it is currently widely used cold work die steel. It has high strength and good wear resistance, but has poor impact toughness and is prone to brittle cracking. It is mainly used for dies and punches with low impact load and high wear resistance.
SKD11: It has good hardness and wear resistance, and its toughness is higher than that of Cr12 steel. It can be used to manufacture various molds and tools with large cross-section, complex shape and large impact load.
DC53: It is a new type of die steel improved on SKD11. After tempering, the hardness can reach 62HRC. The strength, wear resistance and toughness are better than SKD11. The machinability and abrasiveness are also better than SKD11. Reduce processing procedures, and will fully replace SKD11 in the field of general and precision molds in the future.
S136: Plastic mold, used for anti-corrosion and mirror polishing occasions. After long-term use, the surface of the mold cavity can still maintain the original smooth state, and the quenching hardness can reach HRC52. It is suitable for molds and wear-resistant parts used in weak acid and humid environments.
65Mn: poor weldability, high wear resistance, used in various springs, circlips, clutch reeds. In non-standard design, it is mostly used to make railway rails, shrapnel, etc.
Cast iron
It is mainly composed of iron, carbon, silicon and other metal elements. It is an iron-carbon alloy with a carbon content of less than 2%. The carbon content of industrial cast iron is generally 2.5%~4%. Because of its good fluidity, it is used for casting complex internal structures. parts. The mechanical properties of ductile iron are the best, and gray cast iron is poor. However, due to its low price and good castability, wear resistance and shock absorption, gray cast iron is the most widely used cast iron, followed by ductile iron. Gray cast iron (HT150) is widely used, and is often used in gear boxes, machine tool beds, boxes, hydraulic cylinders, pumps, valve bodies, bearing caps, etc. It is used to make complex parts or fixtures in non-standard equipment.
Aluminum
AL6061, AL7075, 7075 aluminum sheets are super hard aluminum sheets, and their hardness is higher than 6061. But the 7075 is much more expensive than the 6061. It can be processed by natural anodizing, sandblasting, hard anodizing and nickel plating. Generally processed parts are anodized with natural color, which can ensure the finishing size. The sandblasted oxidation appearance is more ornamental, but it cannot guarantee high precision. To give aluminum the look and feel of steel, nickel plating is available. Some aluminum parts that are in direct contact with the product, such as adhesion, high and low temperature resistance, and insulation, can be plated with Teflon.
Copper: brass, red copper, bronze, beryllium bronze.
Brass is an alloy composed of copper and zinc, which has strong wear resistance and strong wear resistance. Among them, H65 brass is composed of 65% copper and 35% zinc. Because of its good mechanical, technological, cold and hot processing properties, and golden appearance, it is widely used in non-standard industries. It is used in wear resistance and appearance requirements. high occasions.
Red copper: Red copper is a simple substance of copper, its stiffness and hardness are weaker than that of brass, but its electrical and thermal conductivity is better. Used in applications with high thermal conductivity requirements. For example, the welding head part of the laser welding part.
Bronze: Adding tin or lead to red copper, bronze has good castability, wear resistance and stable chemical properties, and is suitable for casting various appliances, mechanical parts, bearings, gears, etc. Bronze is also harder than pure iron, tin bronze is often used for oil-free bushings, and high-strength brass is often used for oil-free bushings inlaid with solid lubricants, but its hardness is higher than tin bronze, and its bearing capacity is better than tin bronze copper bushings , but not as wear-resistant as tin bronze.
Beryllium bronze: containing 1.7% to 2.5% beryllium and a small amount of nickel, chromium and other elements, beryllium bronze has high strength, hardness, good thermal conductivity, electrical conductivity, wear resistance, corrosion resistance, often used as important elastic components, wear-resistant parts Wait, the price is higher.
Non-metal materials
POM:
High hardness, high rigidity, high melting point, wear resistance, impact resistance, organic solvent resistance, but not acid and alkali resistance, high insulation. In the non-standard design, it is generally used as a jig, a jig bottom plate, a belt support plate, etc., and it is easy to deform when the processing length is too large.
PVC:
It is a low-end general-purpose plastic with moderate mechanical properties, heat resistance and price, and strong applicability.
Nylon (PA):
It belongs to engineering plastics, and its mechanical properties, heat resistance and price are much higher than that of polyvinyl chloride; it is usually used for heat-resistant and wear-resistant materials.
PF：
The chemical name is phenolic resin, which has high mechanical strength, brittleness and brittleness, good insulation, heat resistance and corrosion resistance. It is often used in electrical materials, and some companies in non-standard equipment use it to make electrical installation boards, fixtures, etc., processing deformation and easy generation of dust should be considered.
PU：
It is a common material for equipment, because of its excellent elasticity, it is often used for buffering on non-standard equipment. For example, the jig on the conveyor belt, the cylinder, the limit buffer of the single-axis module, and the glue on some rubber-coated rollers is also a polyurethane material.
PTFE：
Polytetrafluoroethylene, resistant to strong acid and alkali corrosion, good insulation and extremely low friction coefficient. Therefore, some materials plated with Teflon have the functions of anti-scratch products, anti-sticking and insulation.
ABS：
A terpolymer composed of three monomers, acrylonitrile (A), butadiene (B), and styrene (S), is a common plastic with high mechanical strength and good overall performance. The outstanding point is the surface Can be electroplated and painted. ABS is easy to absorb moisture, dimensionally stable, easy to form and process, and widely used.
PC：
It is the best impact-resistant plastic variety, with good mechanical properties, stable dimensions, acid and alkali resistance, low water absorption, but poor wear resistance, products are easy to crack, and the price is high. For small load, low speed wear parts, such as gears, worms, bushings, etc.
PP：
Odorless, non-toxic, low density, strength, stiffness, heat resistance, transparency are better than polyethylene (PE). Easy to age, easy to burn, poor toughness, poor cold resistance. The chemical properties are stable and generally can only be corroded by concentrated sulfuric acid and concentrated nitric acid. Used in wet, corrosive environments in non-standard industries
PEEK：
Chemical resistance, flame retardant, wear resistance, radiation resistance, not resistant to strong nitric acid, concentrated sulfuric acid, with superior mechanical properties. Non-standard designs are generally used in occasions requiring non-metal, corrosion resistance, and high strength, but they are expensive.
PMMA：
Acrylic sheet has good transparency and chemical stability, and is often used in non-standard designs to be matched with aluminum profiles as machine covers.
