Why You Should Use Plastic CNC Machining for Your Part Production

CNC machining is one of the most efficient machining processes, and the reasons for this are not far-fetched. One of such reasons is its ability to machine a wide variety of materials. An example of such materials is plastic. While plastic CNC machining might seem like a poor choice for machining, it is actually one of the best options.

If you’ll like to know how you can apply plastic CNC machining to the production of various parts, this article is a must-read.

Role of Plastics in CNC Machining

As mentioned earlier, machinists use CNC machining to machine a wide variety of materials, among which plastics is one of the widely used choices. This section will explain plastic’s roles in CNC machining ranging from its application, advantages and when you should consider it for parts production.


1. Medical Industry:

The use of plastics for parts production in various industries is a no-brainer for both machinists and clients alike. From its relatively affordable price to ease of machining, plastic is a favorite for application in industries such as:

Medicine is rapidly evolving, with the need arising for new equipment. Because of the unique properties certain plastics possess, they are better suited for medical applications where safety and sterilization are imperative. Also, the medical field requires a high level of purity with its equipment. This means they have to expose the equipment to extreme levels of sterilization regularly. Some CNC plastic materials are a perfect fit for this process as they can withstand autoclaving multiple times without degradation. Examples of medical equipment that uses plastic include imaging equipment, sterilization trays, endoscopic probes, surgical equipment, sterilization trays, etc.

2. Automotive Industry:

Automobiles require parts that can withstand various environments and levels of stress. With the machining of various high-performance plastics, the use of plastics in automobiles has greatly increased. Ranging from the car’s exterior to the chassis, machinists utilize different plastics in making components of automobiles. Also, plastic is a good source for prototyping new car parts to be integrated into cars. Due to their ease of machining, the cycle time will be faster, and the manufacturer can bring innovations to the market earlier. Examples of car parts that utilize plastic include air conditioner vents, gauges, dials, switches, etc.

3. Aerospace Industry:

The aerospace industry allows little or no chance for error as one small mistake could cause drag in some parts of the aircraft or increase wear of some parts. This is why they need prototypes in this type of industry most time. CNC plastic prototypes are an excellent way to test if these parts fit for inclusion into the aircraft. Apart from plastic prototyping, aircraft parts such as rudders, fuselages, ventilation ducts, etc., also utilize plastics.

4. Military and Defense Industry:

Plastic CNC machining also has a lot of applications in the military industry. Ranging from its use in their communication devices to parts of their transportation vehicles, plastic CNC machining is an indispensable process to the military and defense industry.  

5. Electronic Industry

Plastic CNC machining has virtually limitless applications in the electronic industry. This is because the industry encompasses a lot of products that involve the use of plastics. Machinists use plastics in products like switches, electrical insulation materials, mobile phones, etc.


Here are some advantages of using plastic CNC machining for your parts production:

1. Fast Prototype Turnaround

Plastic CNC prototypes are the best choice for anyone who needs a prototype to be made quickly. This is because there’s no need to make a mold. Therefore, the process is relatively faster, and the prototype will have a shorter cycle time.

2. Economical Process

For other processes like injection molding, you have to construct molds that normally take up many resources and time. However, plastic CNC machining doesn’t involve such. Therefore, the amount spent for part production is comparatively cheaper than other processes.

3. Hold Tighter Tolerances

For parts that require high tolerance measurements, plastic CNC machining is an excellent choice for production. This is because it can accommodate tight tolerance measurements. This is very important for parts that will be used in high-precision industries.

4. Greater resistance to corrosion and chemicals

CNC machined plastic products have this advantage over metal parts. Compared to metal parts which can easily rust after extended use, plastic parts are more resistant.

When to Consider Plastic Machining for Production

Choosing the perfect production method could be a difficult task for clients at times. However, if you fall into any of these categories, using plastic CNC machining is an excellent choice to make.

  • When you have a tight budget.
  • When you need a fast product or prototype turnaround.
  • If you have a low production volume.
  • If you only want to make prototypes (that do not necessarily require another type of material).

You could also talk to your machining company about the compatibility of CNC plastic machining for your part production. At RapidDirect, we give expert opinions to our clients about how their parts production can be optimized.

How to Create a Plastic Prototype with CNC Machining

The plastic prototyping process involves the use of plastics to make prototypes. Before machinists started using CNC machining for prototype production, metal used to be the go-to material for processes. This is because injection molding used to be the major plastic machining process before.

With injection molding, you’ll have to spend quite the sum to make the mold. The machinist also has to be very careful while making the mold. This is because errors in the process can lead to additional charges that even add to the project’s amount.

Below are the processes and tips for plastic CNC machining:

1. Tool Choosing

Although plastic has different properties compared to metal, the type of tools used on both are the same. It is only the force of cutting that differs. Examples of plastic machining tools used for plastic CNC prototypes include:

End Mills

End Mill

They are one of the most popular types of milling cutters, and they are quite similar to drills due to their ability to cut materials axially. There are different variants of the CNC machine tool. They differ in the number of flutes and the different types of noses they have. Some could have up to eight flutes or more. The types of noses include:

  • Flat: The flat-faced end mills is the general-purpose variant compatible with cutting out 2D features.
  • Ball nose: The ball-nose end mill is suitable for tasks like 3D contours and curves.
  • Bull nose: This variant has a flat end and rounded sides and is perfect for roughing and filleting.

Ball Cutters


You can quickly identify ball cutters due to their hemispherical cutting tip, which the cutter employs in making corner radiuses on perpendicular faces.

Hollow Mills

Hollow Mill

This mill has a pipe-shape and looks inverted in form. Machinists use hollow mills to create shapes like full points and form radii due to the mill’s cutting edge, which you can find on the inner part of the mill.

2. Machine Setup

In plastic prototype machining, setting up the tools intended for use is just as important as choosing the tools. This is because plastic is softer than metal, and it is easier to leave a mark on its surface. To avoid this and some other errors during production, here a few tips to note when setting up plastic machining tools:

  • There should be a soft pad between the materials and the cutting tool before machining starts. This will help to reduce the force with which the machine clamps down on the material. This way, you can reduce the occurrence of cutting marks on the material.
  • The machinist needs to keep an eye on the distance between the drilling place and the fixtures. This is because the drilling place always tries to pull the part up during the machining process. If the drilling place is far from the fixtures, the drill will easily pull up the material. This would lead to the bending or cutting of the material.
  • Lastly, the machinist should have a coolant placed directly at the point of the cutting tool. This will help cool down the temperature of the plastic during cutting and prevent melting.

3. Material Selection

Machinists utilize different plastics in plastic CNC machining. However, there are a few of them known for their excellent qualities in plastic prototype machining. Examples include:

1. POM (Acetal)

Acetal Rod

POM (Polyoxymethylene), also known as Delrin, polyacetal, or acetal, is an engineering thermoplastic renowned for its low moisture sensitivity, high resistance to chemicals, good electrical conductivity, high strength and toughness. Machinists use POM in the production of parts such as car locks, automotive clips, seatbelt adjuster, etc.

2. ABS

Acrylonitrile Butadiene Styrene Sheet

ABS (Acrylonitrile Butadiene Styrene) consists of different components which give it desirable properties. It is a popular choice for machining among machinists due to its chemical and thermal stability to its good toughness and strength. Machinists use ABS to produce parts such as control panels, pipes, refrigeration components, keyboard keys, etc.

3. Nylon

Polyamide (Nylon) Rod

Nylon (also known as polyamide) is a general-purpose engineering material that has different grades. It has good elasticity, is washable and dyeable, and can withstand high levels of heat. Machinists use it to fabricate parts such as cookware, parachute canopies, automotive parts, etc.

4. PC 

Polycarbonate Sheet

PC (Polycarbonate) is another plastic that machinists use for plastic prototyping due to its properties. It is a very tough plastic that can withstand heavy impact and high levels of heat. Machinists use it for parts such as baby drinking bottles, Blu Ray discs, swimming goggles, etc.

4. Surface Finishes

While metal has a wide variety of surface finishes choices, the same can’t be said about plastics. However, if the machining is done properly, the use of surface finishes might not be required. Examples of popular CNC plastic finishes include:

  1. Bead Blasting

Bead blasting involves using compressed air to blast an abrasive material against the surface of a plastic material.

2. Painting

Painting involves spraying paint onto the surface of the plastic part. It helps to improve the aesthetic appeal of a plastic part. It also offers protection to the plastic surface.


Machining plastics is a popular machining process that has various applications in different industries across the world. Using this machining process requires an expert machine shop’s services to help make your project a success. Using RapidDirect is an excellent choice you can make for your plastic machining projects.

RapidDirect Plastic CNC Machining Services

RapidDirect CNC Machining Services

Need a company to handle your CNC machining project? Look no further because RapidDirect has all the technical expertise you’ll ever need. With over two decades of manufacturing experience, we have experienced staff in all manufacturing processes.

RapidDirect understands that you want excellent service, and you don’t want to spend much to get it; therefore, we offer precisely that. With us, you will get the exceptional service you crave at a highly competitive price. Our service is affordable, and we don’t compromise quality at any stage.

With us, your plastic CNC machining job is safe. Our plastic CNC machining services covers the machining of various types of plastics. We also give expert recommendations to make your plastic machined part fit for its intended function. Our plastic machining services offers you top-notch services at a very affordable price point. Reach out to us today and get the best services for your machining project.


Q: What types of finishes are suitable with CNC plastic machining?

A: Finishes suitable with CNC plastic machining include bead blasting and brushing.  

Q: What advantages does plastic CNC machining offer?A: It is very cost-effective and offers turnaround time due to the absence of mold

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