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Reducing the cost of HDPE plastic parts with CNC machining

CNC (computer numerical control) machining is a manufacturing process that uses computer-controlled power tools to shape plastic, metal, foam and other raw materials into finished custom parts. In CNC machining, the cutting tools are attached to programmable machines like lathes, mills and routers. These machines follow coded instructions that direct their precise movements to cut, drill and grind material away from a solid block to form a part.

CNC machining is an excellent option for creating plastic parts needed for prototypes, custom fixtures and low to medium production runs. It offers many cost benefits compared to other manufacturing methods like injection molding. This article will discuss the various ways CNC machining can significantly reduce the costs of plastic part production.

HDPE anti-collision block

How CNC Machining Reduces Plastic Production Costs

CNC machining plastic parts is a very fast and economical process, especially for small batch sizes. Here are some of the major ways it yields faster and cheaper plastic part production versus traditional molding:

  • Faster production times - With CNC machines, plastic parts can be machined rapidly, often in just hours or days. This compares favorably to the weeks it can take to produce injection molds. Faster production means reduced labor costs and faster time to market.
  • No injection molds - CNC machining avoids the high cost of creating steel or aluminum injection molds which are required for mass production molding. Molds are slow to manufacture and can easily cost thousands to tens of thousands of dollars.
  • Lower setup costs - The setup time and costs for CNC machining are much lower compared to molding. You can simply mount your plastic stock material and provide the CNC program file to the machine.
HDPE guide bar

Cost Benefits of Using CNC for Plastic Part Manufacturing

In addition to the time and mold cost benefits, using CNC machining processes for plastic parts can yield significant advantages in production costs and flexibility:

  • Easy part modifications - With CNC machining, programming can be easily changed to create design iterations. New molds are not required every time a change is needed, providing huge time and cost savings.
  • Low start-up costs - Beginning manufacturing of a plastic product via CNC machining has far lower start-up costs compared to injection molding or other techniques that need mold tooling.
  • Reduced material waste - Machining plastic components from stock rods or blocks results in less wasted material than molding processes. The excess plastic can be recycled after machining.
HDPE Mould

Reducing Plastic Mold Costs with CNC Machining Services

For prototyping injection molded plastic parts, CNC machining can avoid the high cost of custom mold tooling altogether. Even for short-run production, CNC machined molds can save significantly on costs:

  • Prototype part molds - Getting prototype molds CNC machined from aluminum, for example, can be done without the need for an expensive steel production mold.
  • Lower cost molds - For short injection molding runs, CNC machined mold tooling can cost a fraction compared to hard tooled production molds that can take weeks to produce.
  • Faster mold turnaround - Lead times of 1-2 weeks on CNC machined prototype and bridge tooling can allow faster testing of new plastic part designs before committing to full hard tooling.

Comparing CNC Machined Plastic Parts vs Injection Molded Parts Pricing

How do costs actually compare between CNC machined and injection molded plastic parts? Here is a look at some key cost factors:

  • Lower start-up costs - The start-up costs for CNC machining a new plastic part design are much lower compared to injection molding that requires expensive mold tooling.
  • Part cost crossover point - Analysis of per-part tooling, material and production costs typically shows CNC machining with a lower overall price point for quantities up to 500-5000 units, at which point injection molding becomes more cost effective for higher quantities.
  • Time savings - The faster turnaround of machined plastic prototypes and parts can get your product to market significantly sooner, providing major cost advantages.
Machined parts for lathes

Tips for Lowering Plastic Fabrication Expenses with CNC Machining

To maximize cost benefits for your plastic parts produced by CNC machining, consider the following advice:

  • Use affordable plastic materials - Opt for plastics like acrylic, ABS or polycarbonate. Avoid pricey engineered resins unless the material properties are absolutely necessary.
  • Take advantage of CNC prototyping services - Rather than purchasing your own CNC mills or lathes, use a plastic machining service for prototyping and short runs.
  • Design parts for machinability - Avoid thin walls, deep ribs and other features that make machining difficult or increase fixture requirements. Keep contours gradual.


With its elimination of high mold costs, fast turnaround times, flexibility to modify parts, and competitiveness for short runs, CNC machining is an excellent way to reduce expenses for plastic parts. Sourcing CNC machined plastics for prototyping and before committing to injection molds can save untold amounts of time, money and headaches. By understanding machining processes and designing parts strategically, you can maximize the significant cost benefits CNC plastic fabrication provides.

Let me know if you would like me to modify or expand this blog post draft in any way. I aimed to incorporate the relevant keywords naturally throughout the article.

Green HDPE matting strips
If you are interested in using HDPE Plastic in your project or want to know more information, welcome to harass us. We are a professional supplier and manufacturer of all kinds of plastic custom processing and production, with a professional team of engineers and precision equipment, we can provide you with customized plastic solutions that meet your specifications and budget. We are happy to serve you and help you fulfill your needs. Do you need a free quote or help with any questions or materials?
Our website: www.BeePlastic.com
Click to contact: Custom HDPE Plastic
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