CNC Machining | the Characteristics and Uses of Plastic Materials

Plastic is a common non-metallic material, which has good insulation properties and low cost advantages. Plastic materials are commonly used in the manufacture of electronics, appliances and auto parts. When selecting plastic materials, it is necessary to consider factors such as physical properties, mechanical properties, temperature resistance and processing properties.

We have selected and launched a number of plastic materials suitable for CNC machining, this blog will focus on the above optional plastic materials, for everyone to choose as a reference basis.

1. ABS

ABS is a terpolymer of acrylonitrile, butadiene and styrene, which is the most widely used polymer. It combines the various properties of PS, SAN and BS organically, and has excellent mechanical properties of tough, hard and rigid phase balance.

Features:

ABS has the common properties of three components:

A Make it resistant to chemical corrosion, heat resistance, and a certain surface hardness. It is not affected by water/inorganic acid/food acid and base, can be used for -50 to +70℃, good impact resistance at low temperature, good shape and dimensional stability at warm temperature;

B to make it highly elastic and ductile. High mechanical strength and rigidity, not easy to scratch; High tensile strength, chemical wear resistance and surface strength;

S makes it have the processing and forming characteristics of thermoplastics and improves electrical properties. Easy coloring, easy processing, electroplating, with excellent chemical properties and electrical insulation properties.

Disadvantages:

Intolerant to weathering and susceptible to weather conditions; Limited acid and rot resistance, soluble in ketone solution, softening in chlorinated hydrocarbons \ fat \ aromatic compounds \ aldehydes.

Application:

Modeling materials, such as building models, hand models, food industrial parts, electronic parts of the phase industry, refrigerator refrigeration industry, etc. In the field of electronics and appliances, ABS can be used to manufacture components such as antenna sockets, coil frames, patch boards, converters, speakers and connectors.

2. POM

POM is a thermoplastic engineering plastic with high melting point and high crystallinity. It is the hardest in thermoplastics, and it is one of the varieties with the mechanical properties closest to metal in plastic raw materials, commonly known as steel.

Features:

Resistance to organic solvents, insoluble at room temperature, good low temperature, thermal deformation temperature and PC/PTFE nylon similar, higher than PVC/PS/PE; High compression strength, second only to glass fiber; Excellent wear and creep resistance, high rigid mechanical strength and hardness, high size and shape stability, and maintain toughness at minus 400℃; Good sliding, no water absorption, wear resistance and hydrolysis resistance, lazy nature, suitable for contact with food, good machining.

Disadvantages:

No acid, especially not resistant to mineral acid, not resistant to ultraviolet light, no self-extinguishing, not close to fire, not resistant to impact.

Application:

Suitable for the production of sliding parts, precision mechanical parts and water-resistant parts, dimensional stability of precision parts, a large number of parts for mechanical equipment. Such as: bearing, gear, impeller, CAM, washer, bushing, guide rail, handle, handle and other fixture materials. The use of industries throughout the automotive, electronic, medical, food machinery and other fields.

3. Bakelite board

Bakelite board, also known as rubber board and phenolic laminated board, is a board made of bleached wood paddle paper soaked with phenolic resin.

Features:

Good electrical performance at room temperature, good machining performance, specific gravity 1.45, warpage ≤3‰, with excellent electrical, mechanical and processing properties. At the same time, it has intermediate electrical insulation, no water absorption, no conduction, no static electricity, wear resistance and high temperature resistance.

Disadvantages:

Bakelite products molding due to heating molding, processing time is longer than ordinary plastic, mold wear greater requirements for steel.

Application:

It is suitable for motors and electrical equipment with high mechanical properties as insulation structural parts, and can be used in transformer oil. It is also suitable for PCB drilling, silicone rubber mold, fixture, switchboard, electrical appliances, mechanical parts, communication equipment, electrical insulation accessories, etc.

Economic benefits:

Bakelite raw material price is nearly 50% of ABS price. Although bakelite products molding due to heating molding, processing time is longer than ordinary plastic, mold wear is larger on the steel requirements, but because of its dominant position of raw material prices, it is still the preferred substitute for many plastic parts.

4. PMMA

PMMA, also known as acrylic sheet, is an important plastic polymer material developed earlier.

Features:

Gloss high energy surface polishing, transmittance 92% refractive index 149 compared to the best optical glass. Stable shape at warm temperature, suitable for -40 to 90℃ range, UV resistance, weathering resistance, resistance to inorganic acids and alkalis, lipid hydrocarbons and cleaning agents, tear resistance is better than other plastics. It has good electrical and dielectric properties and excellent mechanical strength.

Disadvantages:

Stress incision is easy to damage, chemical resistance and impact resistance is poor, fragile, mechanical is short-term effective, long use needs to be less than 1500psi in the tensile requirements will not be brittle, impact resistance is low, toughness decreases with the temperature, vulnerable to chlorinated hydrocarbons, aromatic/ester/ketone erosion.

Application:

Machine covers and accessories, clock dial plates, fan pieces, relay covers, windshields, electrical medical devices, transparent models, specimens, ornaments, dentures, advertising nameplates, etc.

5. PP

Features:

It has high stiffness, high hardness and high surface strength, but the notched impact toughness is general, and the PP material withstands tensile stress and is easy to weld. Heat resistance, operating temperature from +5°C to +100°C without deformation, good chemical stability, excellent electrical performance.

Disadvantages:

Oxidation resistance is general, wear strength is general, embrittlement at low temperature, notch impact toughness is general, PP material to withstand tensile stress, but not high frequency welding, bonding paint is general, easy to be limited by weather conditions.

Application:

Pump valve parts, drinking water and sewage pipes, seals, spray carriers, electroplating process, toy parts, dental catheters, etc.

6. FR-4

FR-4 is a grade of fire-resistant material code, which means that the resin material must be able to self-extinguish after combustion.

FR4 epoxy board is a kind of high performance and multi-functional insulating material composed of high temperature resistant composite material and glass fiber.

Features:

Electrical insulation performance is stable, good flatness, smooth surface, no pits, thickness tolerance standard. It has high dielectric property, heat resistance and moisture resistance, good machinability and structural stability, and the most notable feature is its high flame retardant

Application:

It is applied to the products with high performance electronic insulation requirements and the parts of insulation structure in motors and electrical equipment, such as FPC reinforcing board, PCB drilling pad, electrical (electrical) equipment insulation board, electronic switch insulation board, etc.

7. PA6

PA6, also known as nylon 6, polyamide 6, is a highly analytical compound. It has the most superior comprehensive properties, including mechanical strength, toughness, mechanical shock absorption and wear resistance, and is often used in the manufacture of mechanical structure parts and maintainable parts.

Features:

Hard and small coefficient of friction, wear and pressure resistance; The size is stable without water absorption, and the ductility and toughness increase after water absorption; Temperature resistance, good heat stability; High toughness, sub-zero toughness, with high tensile strength and elastic modulus; It has good sliding and energy cushioning properties, and has good chemical resistance to many fats, tallow and mineral oils; Good inductance, easy processing, easy gluing and welding, insulation.

Disadvantages:

The water absorption speed is fast, and the tensile strength and rigidity decrease with the increase of temperature and humidity.

Application:

Widely used in chemical machinery, anti-corrosion equipment gear and parts blank, wear parts, transmission structure parts, household electrical parts, automobile manufacturing parts, screw mechanical parts, chemical machinery parts, chemical equipment and so on.

8. PC

PC is an amorphous, odorless, non-toxic, highly transparent five-color or slightly yellow thermoplastic engineering material, known as transparent metal.

Features:

High polymer low crystalline plastic, excellent impact resistance, toughness, creep resistance, mechanical strength and dimensional stability, transparency/ductility, weather and high temperature resistance, suitable for -150 to +120°C. Flame and radiation resistance, good insulation hard steel strength, good electrical insulation.

Widely used in safety glass, slide projection equipment components, mechanical and electronic, automobile, construction, daily necessities, handboard model materials and other high-tech fields. At present, it has been used as windscreen, bulletproof glass, instrument observation window, patch board, fixture, model and so on in aviation, electronics and machinery.