Everything You Need to Know About Plastic Machining and How to Choose the Right Manufacturer

• Everything You Need to Know About Plastic Machining and How to Choose the Right Manufacturer
  • What are machined plastic parts?
  • Why do equipment manufacturers choose to customize plastic CNC parts?
  • Why choose CNC machining of plastics instead of injection molding to manufacture your project?
  • Advantages of Plastic Machining Technology in Prototype Product Development
  • The important role of 3D printing in the CNC machining of plastic prototype parts
  • Advantages of using machining processes to manufacture precision engineering plastic parts
    • 1. Reduce production costs
    • 2. High precision and strict tolerances
    • 3. Design flexibility
    • 4. Fast turnaround time
    • 5. Maintain material properties
    • 6. Small-batch production
    • 7. Good surface finish
  • When to use plastic processing services
  • When to avoid using plastic processing services
  • Key technologies in CNC machining of plastics
  • The difference between CNC plastic machining and metal machining
  • How to choose a high-quality plastic CNC machining service provider in China?
    • Conduct online research and seek recommendations
    • Inquiry and comparison of quotes
    • Do they possess the skills and abilities to effectively communicate project requirements?
  • Practical experience from Elimold, a plastic CNC parts manufacturing expert
  • Summarize
  • FAQ

Plastic CNC machining uses a Computer Numerical Control (CNC) system to precisely cut, shape, and drill plastic materials. This method ensures the accuracy and repeatability of the final parts and can handle different designs and shapes, making it ideal for manufacturing custom parts with complex geometries that are often difficult to achieve using traditional production methods (such as injection molding). Therefore, when equipment manufacturers are prototyping parts for small-batch production runs or manufacturing custom components, they often choose plastic CNC machining technology. More importantly, this technology not only accelerates production speed but also significantly reduces material waste, helping companies save time from equipment development to market and reducing R&D costs.

Now let’s get straight to the core considerations and explore everything about CNC machining of plastics and the key factors to consider when choosing a manufacturing partner.

What are machined plastic parts?

Machined plastic parts are components created through machining processes. Machining is a broad term, and CNC machine tools, short for Computer Numerical Control, refer to a modern technology that utilizes computer-controlled machine tools. This method provides unprecedented precision, flexibility, and repeatability in parts production, making it the cornerstone of parts manufacturing. Machining primarily involves controlled material removal processes. It encompasses a range of techniques, such as milling, turning, drilling, and grinding, to shape raw plastic materials into desired shapes or parts.

Why do equipment manufacturers choose to customize plastic CNC parts?

Custom-made plastic CNC parts offer advantages across various sectors due to their flexibility, affordability, and efficiency. The global plastic injection molding market is currently valued at $202.3 billion and is projected to grow at a CAGR of 22% between 2030 and 2035. This growth is driven by increasing demand from the automotive, healthcare, electronics, and consumer goods sectors.

Globally, equipment manufacturers choose custom plastic CNC parts primarily because they can tailor the shape, size, and characteristics of the manufactured components. Furthermore, plastic prototypes allow for rapid validation of equipment functional designs and facilitate the rapid manufacture of small-batch applications.

Furthermore, the rapid prototyping technology enabled by advanced 3D printing currently available on the market has reduced the development time of new equipment by 50%, thereby optimizing development time. Companies can now redesign products and complete production as quickly as possible within budget, and can also address complex and multifaceted application challenges.

Why choose CNC machining of plastics instead of injection molding to manufacture your project?

When you need to choose between CNC machining and injection molding to manufacture the parts you need, you only need to consider the unit quantity, delivery time, material characteristics, and cost factors.

For small to medium batch production, CNC machining offers excellent precision and flexibility in manufacturing plastic parts. It can create plastic parts with complex geometries without significantly increasing costs, especially if you need to quickly complete custom plastic parts, and each part must meet precise specifications. Choose plastic CNC machining services for these situations.

In contrast, injection molding is better suited for mass production of the same type of plastic parts. This is because it primarily leverages economies of scale to control project costs, meet project requirements, and support corporate marketing strategies. A characteristic of injection-molded parts is that once the quantity exceeds a certain threshold, the unit price drops significantly, but the required mold costs are extremely high. The versatility of this method is limited to using different types of plastics to produce parts of the same design. If you need to change the design, both costs and project time will increase because new molds must be made for each change.

Therefore, the choice between these two methods depends entirely on your project requirements. If precision and flexibility are key factors, then choose CNC machining for processing plastic parts; if you need low-cost, large-scale production of plastic products, then choose injection molding.

Advantages of Plastic Machining Technology in Prototype Product Development

Plastics machining technology offers numerous benefits throughout the product development process; it helps you quickly obtain validation parts, accelerates time-to-market, and improves the quality of the final product. Rapidly obtaining plastic prototype parts allows engineers to identify design flaws early, accelerating product iteration and saving time and costs associated with bringing new products to market.

In addition, prototype parts manufactured by plastic machining can very accurately simulate the appearance, feel and function of the final product; and prototype products are crucial in stakeholder demonstrations and user testing, and machined plastic prototypes can help decision-makers select appropriate materials and manufacturing processes for their expected products.

Custom-made parts produced by plastics machining not only meet design requirements but also exceed customer expectations for equipment performance. If you are currently choosing the best method for manufacturing custom plastic parts, you should consider the factors mentioned above to improve and ensure that the relevant quality standards met for the procurement projects you are responsible for are met.

Only through practical methods can the success rate of a project be ensured, thereby reducing the risk of failure in the implementation phase due to a lack of practice, and thus promoting your company’s creativity and market share.

The important role of 3D printing in the CNC machining of plastic prototype parts

The advent of 3D printing has dramatically changed the manufacturing process and efficiency of CNC machining for plastic prototyping. The combination of these two technologies provides a fast, inexpensive, and flexible method for plastic prototyping. This combined technology allows designers and engineers to create models more quickly for shape, fit, and functional testing before moving on to the machining process for the plastic parts.

With our innovative technology, equipment manufacturers can easily modify designs and obtain the necessary parts for verification in the shortest possible time, regardless of the type of custom parts required, thereby accelerating product iteration and significantly shortening the time to market for new products. It also allows for testing more complex product and part designs without investing too much capital.

In addition, we often use 3D printed prototypes to help verify whether a customer’s part design can be manufactured using CNC machining technology, thereby ensuring that the design is optimized for CNC processes before actual production, thus bridging the gap between the conceptual design stage and the final manufacturing point.

Advantages of using machining processes to manufacture precision engineering plastic parts

Below, we will explore the main advantages of choosing plastic processing over other services such as injection molding.

1. Reduce production costs

One of the best reasons to use CNC plastic machining is cost savings. Compared to other processes, plastic machining can produce large quantities of plastic parts with minimal error.

2. High precision and strict tolerances

Plastics machining is popular due to its high precision, especially in industries with stringent tolerance requirements. Because most machining is automated by CNC systems, machines can achieve extremely precise dimensions when processing plastic parts.

3. Design flexibility

The biggest advantage of CNC machine tools is that they can be programmed to machine any desired shape or geometry. Thanks to computer-aided manufacturing (CAM) software, these machines can optimize any toolpath, thus machining designs of any complexity.

4. Fast turnaround time

If speed is critical to your production, then plastics processing services will be a powerful asset. With CNC automation, most parts can be easily produced in the required quantities with extremely high precision.

5. Maintain material properties

Another important reason for using plastics processing services is that they can preserve the properties of the materials being processed. This is because these machines are more energy efficient and better able to maintain the inherent properties of plastic materials.

6. Small-batch production

Another significant difference between plastic processing and other alternatives such as 3D modeling and injection molding is that it is capable of handling very low to medium batch production.

7. Good surface finish

One of the biggest advantages of plastic processing is its ability to achieve very smooth and desirable surface finishes. Depending on the desired surface finish, CNC machine tools can produce a variety of effects, from smooth polished surfaces to textured matte surfaces.

When to use plastic processing services

As you can see, plastics processing services can bring many benefits to manufacturers. But like anything else, it must be used at the right time and in the right process.

Here are some situations in which you should use plastic processing services:

• When you need to produce small batches (few parts) or customize one-off parts.

• When prototyping different part designs before mass production.

• When dealing with parts with very complex geometries and features.

• When you need parts with strict tolerance requirements, that is, when near-perfect dimensional accuracy is required.

• When your materials are limited or you want to reduce material waste.

• When you need fast processing turnaround time and good surface finish.

When to avoid using plastic processing services

Despite the many advantages and applications of plastic processing services, it is not always the best choice.

Here are some situations where you should avoid using plastic machining services:

• When you need to produce in large quantities , the unit price of injection molding will be lower.

• When you need a simple part design with a wide tolerance range.

• When the required part size is too large, processing methods such as welding and thermoforming may be more suitable.

Key technologies in CNC machining of plastics

When manufacturing custom plastic parts, there are many different types of CNC machining technologies to choose from. How do you determine which technology is best suited for your parts? Below is a summary of important technologies in plastic CNC machining.

Key Technology	Brief Explanation	Primary Purpose
CNC Milling (Plastics-Specific)	Uses sharp, high-rake cutters and optimized feeds/speeds to prevent melting, burrs, and surface tearing.	Machining complex 3D plastic parts with tight tolerances
CNC Turning	Applies low cutting forces and controlled chip formation to avoid deformation of plastic rods and tubes.	Producing cylindrical and rotational plastic components
High-Speed Machining	Utilizes higher spindle speeds with proper chip evacuation to reduce cutting load and improve surface finish.	Efficient machining of soft and semi-crystalline plastics
Tool Geometry Optimization	Employs polished flutes, large chip gullets, and positive rake angles designed specifically for plastics.	Minimizing heat buildup and surface defects
Thermal Management	Controls heat through air cooling, mist cooling, or intermittent cutting to prevent melting and dimensional instability.	Maintaining dimensional accuracy and material integrity
Chip Evacuation Control	Uses air blasts and vacuum extraction to remove stringy or powder-like plastic chips during machining.	Preventing re-cutting, tool clogging, and surface damage
Precision Fixturing	Applies soft jaws, vacuum fixtures, or low-clamp-force setups to avoid part distortion.	Securing flexible or thin-walled plastic parts
Multi-Axis CNC Machining	4-axis and 5-axis machining reduces setups and improves accuracy for complex plastic geometries.	Manufacturing complex, high-precision plastic components
Post-Machining Finishing	Includes deburring, flame polishing, vapor polishing, and fine sanding depending on plastic type.	Improving surface quality and aesthetic appearance
Process Parameter Control	Fine tuning of feed rate, spindle speed, step-over, and depth of cut for each plastic grade.	Ensuring repeatability and consistent machining results

The difference between CNC plastic machining and metal machining

The main difference between CNC plastic machining and metal machining lies in cutting mechanics, thermal behavior, and process control requirements. Engineering plastics typically have lower hardness and strength, and much lower heat resistance and stiffness. Therefore, machining engineering plastics requires the use of sharp, large rake angle tools, higher spindle speeds, smaller cutting forces, and strict thermal management to prevent melting, sticking, or dimensional deformation.

Metal machining, due to the robust nature of metal materials, requires stronger cutting tools, higher cutting loads, and sufficient coolant to control heat. In addition, plastic machining may involve developing specialized fixtures to avoid deformation of parts during manufacturing, as well as carefully designing chip removal paths to handle filamentous or powdery chips. Furthermore, due to the creep and thermal expansion that plastics may undergo during machining, tolerance control is relatively difficult. Metals, under similar CNC machining conditions, offer greater dimensional stability, easier-to-control tolerance ranges, and more predictable surface finishes.

How to choose a high-quality plastic CNC machining service provider in China?

The procurement of plastic parts often faces numerous challenges, including varying supplier capabilities, complex and risky pricing structures, and project delays due to inconsistent quality. Many buyers tend to focus only on the initial price, neglecting key factors such as technical capabilities, quality management systems, and long-term reliability.

As a professional engineer at Elimold, I will now share how to effectively and quickly find suitable plastic CNC parts manufacturers. These comprehensive criteria will help you quickly determine if a manufacturer is suitable for your project, thus ensuring your project’s success from the outset.

Conduct online research and seek recommendations

Begin your selection process by conducting comprehensive online research. Google can help you identify potential Chinese plastic CNC machining service providers, while leveraging your professional network for recommendations. If you know someone with positive experience in a particular area, their recommendation can be valuable. Also, be sure to explore the websites of plastic CNC machining service providers for further insights.

Inquiry and comparison of quotes

Once you’ve shortlisted some potential plastic CNC machining companies, the next step is to request quotes. You can determine if a company is suitable for your project by providing project quotes and actually meeting with their engineers. Of course, during this process, be sure to provide as much project detail as possible to obtain an accurate estimate. Additionally, take the time to compare quotes from different suppliers. Remember, consider not only price; you should also consider their communication quality, expertise, and expected timeline.

Do they possess the skills and abilities to effectively communicate project requirements?

When communicating project details with plastic CNC machining suppliers, please be as detailed as possible. Explain the purpose of the parts you need, providing 3D models or drawings if available, and specify all important parameters such as material, tolerances, and surface finishes. Remember, clear and comprehensive communication is crucial to ensuring your project is understood and executed accurately. If, after you and the company’s engineers have clearly communicated all project details, the company still cannot provide adequate customer service or manufacturing capabilities, then find another manufacturer to avoid wasting time and money.

Practical experience from Elimold, a plastic CNC parts manufacturing expert

Currently, the Elimold manufacturing team has over fifteen years of extensive professional experience providing custom parts for high-end manufacturing industries such as aerospace and precision medicine. Experience in machining over 500,000 complex parts has laid a solid foundation for our technical system.

Our production system strictly adheres to the ISO 13485 medical device standard, ensuring full compliance with medical-grade production environment control and operating procedures. In terms of technological innovation, we actively combine the advantages of additive manufacturing (AM) with traditional CNC machining, overcoming the limitations of traditional processing through hybrid manufacturing technologies. Adhering to a philosophy that emphasizes both standardization and innovation, we have improved our processing efficiency by over 35% and maintained a product qualification rate of over 99.5% for many years.

Furthermore, Elimold has built a complete CNC machining process library through the accumulation of massive amounts of machining data. Therefore, our team can combine authoritative standards and practical experience to ensure that every technical suggestion helps customers solve practical machining problems and improve manufacturing levels.

Summarize

Plastics machining services combine speed, precision, and versatility, which will undoubtedly change the operating models of many manufacturers.

Understanding when to use plastic machining services and how to determine if a manufacturer is suitable for your custom plastic parts project will help you make informed decisions, optimize your production processes, and ultimately achieve your manufacturing goals.

FAQ