The unique characteristics of plastics make them well suited to a variety of use cases—at KT Tech, Inc., many of our medical device customers leverage plastics frequently for both parts and tooling that require gentle handling. We offer extensive plastic machining services, and our years of experience allow us to expertly handle these materials.
However, many of the same characteristics that render plastic so versatile can also create difficulties in CNC plastic machining. Learn why this process can be more complex and expensive than many buyers expect, and find out the alternatives we sometimes suggest to customers.
The Challenges of Machining Plastics
While many plastics are critical for certain parts and applications, in some cases designers choose plastic assuming that its pliability will enable simpler machining and lower prices. However, this is rarely the case—relative to metals, plastics are soft with low dimensional stability, low heat resistance, and high moisture absorption.
This profile creates several challenges that can reduce machining efficiency and potentially increase prices and lead times:
Precision Work Holding
Securing plastic is a very delicate balance. Too little pressure reduces machining accuracy; too much risks damaging the part. This issue can extend processing times and in some cases require specialized fixtures.
Brittleness and Chipping
Plastic machining services encompass a variety of types of materials, and some, like acrylics or Ultem, are particularly brittle. Even minor miscalculations in cutting tool selection or technique can result in chipping, especially as cutters exit the part.
Post-Machining Dimensional Changes
Materials like polypropylene and PTFE have very low dimensional stability after machining. Parts often require a 24-hour settling period before final inspection, as dimensions can shift significantly overnight. This extended process frequently impacts lead times.
Melting Risk
Plastics are significantly affected by heat, and parts can often be at risk of melting during machining—a concern that never arises with metals. This is particularly challenging in polycarbonate parts, especially those with thin-walled tubular designs and deep holes.
Tool Wear
Certain materials, particularly garolite and glass-filled resins, can wear tools more rapidly than metal. While glass reinforcement enhances material strength, it often leads to increased tooling costs and more frequent replacements.
Our Approach to Keeping Your Costs Low
At KT Tech, we believe in proactive problem-solving. When we identify potential design issues that could increase the prices of our plastic machining services, we offer design for manufacturing (DFM) suggestions such as:
Adjusting tolerances when possible
Modifying geometries to improve machinability
Recommending alternative materials that maintain functionality
However, if customers need the design and material as is, we are fully equipped to handle the most difficult designs. Our California machine shop combines advanced multi-axis machining with more than a decade of experience manufacturing complex plastic parts.
Partner With KT Tech for Plastic Machining
At KT Tech, our expertise extends far beyond plastic, and we always deliver exceptional results. From micro parts to low-volume Swiss machining, our range of capabilities can ensure success for your next project.
Request a quote today to discover how we can support your needs!
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