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Views: 50 Author: Site Editor Publish Time: 2024-05-16 Origin: Site
While CNC machining is often associated with metallic workpieces, it's essential to recognize its extensive applicability to plastics as well. Plastic CNC machining stands as a prevalent process across various industries.
The widespread adoption of plastic machining stems from the diverse range of available materials. Moreover, the integration of computer numerical control has significantly enhanced precision, speed, and the ability to fabricate parts with stringent tolerances. Curious about plastic CNC machining? This article delves into compatible materials, techniques, and other pertinent aspects to aid your project.
Numerous machinable plastics cater to diverse manufacturing needs across various industries, chosen based on their unique properties. Certain plastics, like nylon, boast exceptional mechanical attributes, enabling them to substitute metals effectively. Here are the primary plastics favored for customized plastic machining:
Acrylonitrile Butadiene Styrene, or ABS, stands out as a lightweight CNC material prized for its impact resistance, strength, and exceptional machinability. Despite its commendable mechanical properties, ABS exhibits a notable vulnerability to various chemical solvents, including greases and alcohols. Moreover, its thermal stability, particularly in its pure form devoid of additives, is relatively low, leading to combustion even post-flame removal.
Pros:
Lightweight yet mechanically robust, ensuring structural integrity.
Highly machinable, making it a preferred choice for rapid prototyping.
Exhibits a low melting point, rendering it suitable for various rapid prototyping techniques like 3D printing and injection molding.
Boasts high tensile strength and durability, promising an extended service life.
Economical, making it a cost-effective option for diverse applications.
Cons:
Emits hot plastic fumes under heat exposure, necessitating adequate ventilation to prevent gas accumulation.
Low melting point may result in deformation due to heat generated during CNC machining.
Applications:
ABS finds widespread application across industries, particularly in rapid prototyping services, owing to its remarkable properties and affordability. It serves notably in the electrical and automotive sectors, contributing to the manufacture of keyboard caps, electronic enclosures, and car dashboard components, among others.
Nylon, also known as polyamide, emerges as a low-friction plastic polymer celebrated for its formidable impact, chemical, and abrasion resistance. With exceptional mechanical properties boasting high strength (76mPa), durability, and hardness (116R), it emerges as a prime candidate for CNC machining, further solidifying its role in automotive and medical part fabrication.
Pros:
Outstanding mechanical properties, ensuring robust performance.
High tensile strength enhances structural integrity.
Cost-effective solution for various applications.
Lightweight nature adds versatility to its usability.
Resilient against heat and chemicals, ensuring longevity.
Cons:
Exhibits low dimensional stability, impacting precision in some applications.
Susceptible to moisture absorption, necessitating protective measures.
Vulnerable to strong mineral acids, limiting its application in certain environments.
Applications:
Nylon finds extensive use as an engineering thermoplastic, particularly in prototyping and fabricating functional parts within the medical and automotive sectors. Its versatility extends to the production of components like bearings, washers, and tubes, underscoring its pivotal role in diverse manufacturing processes.
Acrylic, also known as PMMA (Poly Methyl Methacrylate), stands out in plastic CNC machining circles primarily for its optical attributes. Renowned for its translucence and scratch resistance, this plastic polymer finds favor in industries that prioritize such properties. Moreover, it boasts commendable mechanical characteristics, displaying toughness and impact resistance. Its cost-effectiveness further positions acrylic CNC machining as a viable alternative to materials like polycarbonate and glass.
Pros:
Lightweight nature enhances versatility in applications.
High chemical and UV resistance ensure durability in various environments.
Exhibits excellent machinability, facilitating precise fabrication.
Demonstrates noteworthy chemical resistance, expanding its utility.
Cons:
Limited resistance to heat, impact, and abrasion.
Susceptible to cracking under heavy loads.
Vulnerable to chlorinated/aromatic organic substances.
Applications:
Acrylic finds widespread application as a substitute for materials like polycarbonate and glass, particularly in the automotive industry. Its usage spans the production of components such as light pipes and indicator light covers. Beyond automotive, it serves diverse sectors, contributing to the fabrication of solar panels, greenhouse canopies, and more.
POM, also known as Delrin in commercial circles, stands out as a preferred choice in CNC plastic machining for its exceptional machinability and robust properties, including high strength and resistance to heat, chemicals, and wear and tear. Among the various grades available, Delrin 150 and 570 enjoy prominence across industries due to their commendable dimensional stability.
Pros:
Among the most machinable of all CNC plastic materials.
Exhibits excellent resistance to chemicals.
Demonstrates high dimensional stability.
Boasts high tensile strength and durability, ensuring prolonged usability.
Cons:
Displays poor resistance to acids.
Applications:
POM finds extensive applications across diverse industries. In the automotive sector, it contributes to the manufacturing of seat belt components. Within the medical equipment industry, it is instrumental in producing insulin pens. Similarly, in the consumer goods sector, POM is utilized for fabricating electronic cigarettes and water meters.
High-density polyethylene (HDPE) plastic stands out as a thermoplastic renowned for its remarkable resistance to stress and corrosive chemicals. It boasts exceptional mechanical properties, including a high tensile strength (4000PSI) and hardness (R65), surpassing its LDPE counterpart, making it a preferred choice for applications demanding such robustness.
Pros:
Exhibits flexibility as a machinable plastic.
Demonstrates high resistance to stress and chemicals.
Boasts excellent mechanical properties.
Cons:
Exhibits poor UV resistance.
Applications:
HDPE finds versatile applications across various sectors, including prototyping, gear and bearing production, packaging, electrical insulation, and medical equipment. Its suitability for prototyping stems from its ease of machining and low cost, facilitating the creation of multiple iterations swiftly. Moreover, its low coefficient of friction and high wear resistance make it an ideal material for gears, while its self-lubricating and chemically resistant properties render it suitable for bearing applications.
Low-density polyethylene (LDPE) emerges as a robust and pliable plastic polymer characterized by its commendable chemical resistance and tolerance to low temperatures. Particularly prevalent in the medical sector, LDPE finds extensive application in the fabrication of prosthetics and orthotics.
Pros:
Exhibits toughness and flexibility.
Demonstrates high resistance to corrosion.
Facilitates easy sealing through heat-based methods like welding.
Cons:
Unsuitable for applications necessitating resistance to high temperatures.
Exhibits low stiffness and structural strength.
Applications:
LDPE finds multifaceted utility in various industries, including the production of custom gears and mechanical components, electrical parts such as insulators and housings for electronic devices, and components requiring a polished or glossy finish. Its attributes, such as low coefficient of friction, high insulation resistance, and durability, render it well-suited for high-performance applications.
PTFE, commonly known as Teflon, stands out as a high-performance plastic material in CNC machining, renowned for its exceptional mechanical and chemical attributes that render it ideal for various commercial applications. This plastic polymer boasts a notably low coefficient of friction and exhibits resilience against chemicals, UV radiation, and fatigue. Additionally, its anti-adhesive properties make it a preferred choice for coating non-stick pans.
Pros:
Remarkable resistance to chemicals and light.
Low coefficient of friction enhances its utility.
Possesses anti-adhesive characteristics.
Cons:
Mechanical properties are comparatively inferior to other materials.
Limited availability in 2-inch-thick rods and plates, restricting the thickness of manufacturable parts.
Applications:
Teflon's anti-adhesive properties find practical application in the production of non-stick pans. Moreover, it is utilized in the fabrication of gaskets, semiconductors, and heart patches, showcasing its versatility across diverse industries.
PEEK, a plastic polymer, boasts distinctive mechanical attributes, including remarkable chemical, wear and tear, and heat resistance up to 260°C. Renowned for its lightweight nature, recyclability, and biocompatibility, it serves as a viable alternative to certain metals in part manufacturing.
Pros:
Exhibits outstanding mechanical properties.
Recyclable and biocompatible.
Lightweight and capable of withstanding harsh environmental conditions.
Cons:
Lacks resistance to UV light.
Unsuitable for marine applications.
High cost associated with its usage.
Applications:
PEEK finds application in part manufacturing necessitating plastic flexibility coupled with the mechanical properties of metals. Commonly produced parts include pistons, airplane engine components, and dental syringes.
Polycarbonate (PC) stands out as a robust yet lightweight plastic polymer endowed with heat retardant and electrical insulating properties, akin to acrylic, making it a viable substitute for glass owing to its inherent transparency.
Pros:
Superior efficiency compared to most engineering thermoplastics.
Natural transparency facilitating light transmission.
Excellent color retention capabilities.
High tensile strength and durability.
Resistant to diluted acids, oils, and greases.
Cons:
Degradation upon prolonged exposure to water exceeding 60°C.
Susceptibility to hydrocarbon wear.
Prone to yellowing over time with extended UV ray exposure.
Applications:
Leveraging its lightweight nature, polycarbonate serves as a glass alternative, finding utility in crafting safety goggles, CDs/DVDs, surgical implements, and circuit breakers.
Polyethylene emerges as a formidable contender in the realm of plastic CNC materials, celebrated for its lightweight yet robust characteristics, encompassing impact resistance, stiffness, and flexibility. Notably, it boasts exceptional dielectric properties and presents in various grades tailored to specific applications, such as LDPE, HDPE, and UHMW PE.
Pros:
Lightweight while maintaining mechanical strength.
Exhibits high tensile strength.
Low moisture absorption rate.
Non-staining and non-toxic.
Demonstrates superior machinability.
Resilient against acids and alkalis.
Cons:
Emission of hot plastic fumes under heat exposure necessitates adequate ventilation.
Vulnerable to deformation due to its low melting point when subjected to heat generated by CNC machining.
Applications:
Polyethylene finds widespread utility across diverse sectors including pharmaceuticals, construction, chemicals, and food industries. It serves as a key material in the fabrication of various products and components such as squeeze bottles, wire and cable insulation, and toys.
Polyvinyl chloride (PVC) stands out as a prevalent choice in CNC machining, prized for its durability, versatility, and resilience against moisture, chemicals, and abrasion. Notably, PVC offers a seamless machining experience, effortlessly lending itself to cutting, drilling, milling, and turning operations to craft precise parts and components. Furthermore, its affordability renders it a cost-effective option across diverse applications.
Pros:
Exhibits high corrosion and chemical resistance.
Functions as an effective electrical insulator.
Boasts high machinability, facilitating intricate machining processes.
Characterized by a tasteless, odorless, and non-toxic nature.
Cons:
Displays limited heating stability.
May emit toxic fumes during machining processes owing to elevated temperatures, necessitating adequate ventilation.
Vulnerable to deformation due to its low melting point under the heat generated by CNC machining.
Applications:
PVC's chemical inertness renders it suitable for a multitude of industries, with its application varying based on its form. Flexible PVC proves ideal for crafting electrical wire insulation and flooring, while rigid PVC finds utility in manufacturing components like rings, rollers, pads, and pipe and valve components.
Should you require guidance in selecting the optimal plastic material for your CNC machining endeavors, do not hesitate to enlist the expertise of Zonze.
CNC plastic part machining entails employing a computer-controlled machine to precisely carve out sections of the plastic polymer, sculpting it into the desired product. Through this subtractive manufacturing technique, an array of parts characterized by tight tolerances, consistency, and precision can be fashioned. This is achieved through various methods, including:
CNC turning, a machining method employed in plastic manufacturing, entails securing the workpiece onto a lathe and rotating it against a cutting tool via spinning or turning motions. This technique encompasses various types, including:
Straight or cylindrical CNC turning, optimal for executing large cuts.
Taper CNC turning, suitable for crafting parts with conical shapes.
In plastic CNC turning, adhering to specific guidelines can enhance the process:
Employ cutting edges with a negative back rake to minimize friction.
Implement cutting edges with substantial relief angles.
Polish the surface of the workpiece to achieve improved surface finish and minimize material buildup.
Adjust the feed rate to enhance the precision of the final cuts (utilize a feed rate of 0.015 IPR for rough cuts and 0.005 IPR for precise cuts).
Customize clearance, side, and rake angles to match the plastic material being used.
CNC milling involves utilizing a milling cutter to eliminate material from the workpiece, shaping it into the desired component. This process utilizes various CNC milling machines, categorized into 3-axis mills and multi-axis mills.
A 3-axis CNC milling machine operates along three linear axes (side to side, front and back, up and down), making it ideal for producing parts with straightforward designs. Conversely, multi-axis mills can move in more than three axes, enabling the machining of plastic parts with intricate geometries.
To optimize plastic CNC milling, consider the following guidelines:
Employ carbon or glass-reinforced thermoplastics with carbon tooling.
Enhance spindle speed using clamps.
Create rounded internal corners to minimize stress concentration.
Implement direct cooling on the router to dissipate heat effectively.
Select appropriate rotational speeds.
Deburr plastic components post-milling to enhance surface finish.
Plastic CNC drilling entails the creation of holes in plastic workpieces using a drill equipped with a specific drill bit. The size and shape of the drill bit determine the hole's dimensions and facilitate chip removal. Various types of drill presses, such as bench, upright, and radial, are suitable for this process.
Consider the following guidelines for effective plastic CNC drilling:
Utilize sharp CNC drill bits to minimize stress on the plastic workpiece.
Select the appropriate drill bit based on requirements. For instance, opt for a 90 to 118° drill bit with a 9 to 15° lip angle for most thermoplastics (use a 0° rake for acrylic).
Ensure proper chip ejection by choosing a suitable drill bit.
Employ a cooling system to mitigate heat generated during drilling.
To prevent damage when removing the CNC drill, ensure the drilling depth is limited to three or four times the drill diameter. Additionally, reduce the feed rate as the drill nears completion of the drilling process.
Apart from CNC plastic part machining, there are alternative rapid prototyping processes available. Some common alternatives include:
Injection molding stands as a favored method for mass-producing plastic components. In this process, a mold is crafted from aluminum or steel, chosen based on factors like durability. Molten plastic is then injected into the mold cavity, where it cools and solidifies into the desired shape.
Injection molding finds utility in both prototyping and actual part production. It offers cost-effectiveness and is adept at handling parts with intricate or straightforward designs. Additionally, components produced through injection molding typically necessitate minimal post-processing or surface treatment.
Small-scale businesses commonly rely on 3D printing as their primary prototyping method. This additive manufacturing process encompasses various technologies like Stereolithography (SLA), Fused Deposition Modeling (FDM), and Selective Laser Sintering (SLS), which are adept at working with thermoplastics such as nylon, PLA, ABS, and ULTEM.
In each of these technologies, 3D digital models serve as the foundation for constructing parts layer by layer. This process resembles plastic CNC machining but with reduced material wastage and without the requirement for tooling. Moreover, 3D printing excels at producing parts with intricate designs.
Vacuum casting, also known as polyurethane or urethane casting, utilizes silicone molds and resins to replicate a master pattern. This rapid prototyping technique is adept at producing high-quality plastic replicas. Additionally, these copies are invaluable for visualizing concepts and identifying potential design flaws.
Plastic CNC machining finds extensive application owing to its advantages in accuracy, precision, and tight tolerance. It is commonly employed across various industrial sectors for:
At present, CNC plastic machining is utilized in the production of medical machined components, including prosthetic limbs and artificial hearts. Its exceptional accuracy and repeatability enable it to adhere to the industry's rigorous safety regulations. Additionally, the process offers a wide range of material choices and facilitates the creation of intricate shapes.
Plastic CNC machining serves both car designers and engineers in crafting automotive components and prototypes efficiently. Its versatility finds ample use in the automotive industry for manufacturing custom CNC plastic parts like dashboards. The lightweight nature of plastic aids in reducing fuel consumption, while its corrosion resistance and durability are advantageous for automotive components prone to wear and tear. Moreover, plastic's malleability allows for the creation of intricate shapes with ease.
Precision and tight tolerances are paramount in aerospace part manufacturing, leading the industry to rely on CNC machining for designing, testing, and fabricating various aerospace components. Plastic materials are favored for their ability to accommodate complex shapes, lightweight properties, and high resistance to chemicals and heat, making them well-suited for the demands of aerospace applications.
High precision and repeatability make CNC plastic machining a top choice in the electronic industry. This method is extensively employed for crafting various electronic components like wire enclosures, device keypads, and LCD screens with exceptional accuracy and consistency.
Deciding on the ideal plastic manufacturing process from the options available can pose a challenge. To aid in this decision-making process, here are several factors to consider that can help determine whether plastic CNC machining is the optimal choice for your project:
CNC plastic machining stands out as the preferred method for producing parts with stringent design specifications necessitating tight tolerances. Utilizing a standard CNC milling machine enables the attainment of remarkable precision, with tolerances reaching approximately 4 μm.
The CNC machine provides a superior surface finish, rendering it ideal for projects that don't require additional surface finishing steps. This sets it apart from 3D printing, where layer marks are often left behind during the printing process.
Plastic CNC machining offers versatility in producing parts from various plastic materials, including those with unique properties like high-temperature resistance, strength, or chemical resistance. This versatility makes it well-suited for crafting prototypes with specific and specialized needs.
CNC machining relies on easily modifiable 3D models, facilitating iterative changes during the testing phase. This flexibility enables designers and manufacturers to swiftly produce functional plastic prototypes for testing and identifying and addressing design flaws.
Similar to alternative manufacturing techniques, plastic CNC machining offers a cost-effective solution for producing parts. Compared to metals and composites, plastics are generally more affordable. Additionally, the precision of computer numerical control enhances cost-effectiveness, particularly for intricate designs.
Selecting the appropriate machining method can pose a significant challenge, often prompting the need to engage a plastic CNC service provider. Zonze specializes in offering tailored plastic CNC machining services, crafting various parts for prototyping or practical applications according to your specifications.
Our array of plastic materials is well-suited for CNC machining, meticulously curated through a rigorous selection process. Moreover, our expert engineering team stands ready to furnish you with professional guidance on material selection and design recommendations. Simply upload your design today to receive prompt quotes and complimentary DFM analysis, all at a competitive rate.
