Discover AIP’s process of machining PPS plastics in this informational polymer machining guide.

1. Machining PPS: A Plastics Guide
AIP Precision Machining | Daytona, FL

2. Machining PPS: A Plastics Guide
An Informational Brief on Polymer Machining
Did you know that PPS (or Polyphenylene sulfide) products offer the broadest
resistance to chemicals of any high-performance thermoplastic? It’s no surprise that
this makes them a popular choice for industrial (link to Specialized Industrial)
applications such as wheel bushings, chemical pumps, and compound clamp rings
for semiconductor wafers.
What goes into machining this thermoplastic, however, and how does it differ from
metal machining, injection molding, or 3D printing?
With Machining PPS: A Plastics Guides, AIP provides you with a guide to this
material and its machining process. First, let’s start with the basics: thermoplastics
vs thermosets.
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3. Machining Thermoplastics vs Thermosets:
We’ve already said that PPS is a thermoplastic, but what does that mean exactly?
All polymers can more or less be divided into two categories: thermoplastics and
thermosets. The main difference between them is how they react to heat.
Thermoplastics like PPS, for example, melt in heat, while thermosets remain “set”
once they’re formed. Understanding the technical distinction between these types
of materials is essential to CNC machining them properly.
What type of thermoplastic is PPS in particular? It’s a semi-crystalline, high-
performance thermoplastic that has an extremely stable molecular structure.
The chemical resistance of PPS is often compared to PEEK and fluoropolymers.
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4. Properties & Grades of Machined PPS
There’s a lot to like about PPS’s material properties. As we mentioned before,
PPS has exceptional chemical resistance that makes its bearing grades especially
favorable for the chemical industry or caustic environments. In particular, its
resistance to acids, alkalis, ketones and hydrocarbons lend PPS stellar structural
performance in harsh chemicals.
Additionally, PPS materials are inert to steam as well as strong bases, fuels and
acids. Combine that with a low coefficient of thermal expansion and zero moisture
absorption, and you get a material that is ideal for continuous use in corrosive or
hostile environments. PPS has replaced stainless steel for a lot of industrial
applications for this reason.
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5. Properties & Grades of Machined PPS
Most impressively, PPS will not dissolve at temperatures below approximately
200 °C, no matter what solvent is used. In fact, all grades of PPS share UL94 V-
0 flammability ratings, without requiring flame retardant additives, resulting in an
excellent material for aircraft where flame resistance is paramount.
Some grades of PPS that we regularly machine at AIP Precision Machining
include Ryton®, Fortron®, TECHTRON®, TECTRON® HPV, TECATRON PVX
and TECATRON CMP.
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6. Machining PPS:
Annealing PPS
The process of annealing and stress-relieving PPS reduces the likelihood of
surface cracks and internal stresses occurring in the material. Post-machining
annealing also helps to reduce stresses that could potentially contribute to
premature failure.
AIP’s special annealing process for PPS is designed to take the specific properties
of PPS into account, and we advise anyone working with PPS to hire a
manufacturer that understands its unique demands.
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7. Machining PPS:
Machining PPS
PPS is a fantastic material for machining. Its low shrinkage and stable dimensional
properties make it easy to machine to incredibly tight, precise tolerances. A unique
characteristic of PPS is that when dropped, it sounds just like a piece of metal hitting
the floor.
PPS, like many other thermoplastics, is notch sensitive, so take care to avoid sharp
corners in design. We recommend carbide tipped cutting tools for working with PPS as
they provide an ideal speed and surface finish.
We also suggest non-aromatic, water soluble coolants, such as pressurized air and
spray mists, to achieve optimum surface finishes and close tolerances. Coolants have
the additional benefit of extending tool life as well. No known coolants attack nor
degrade PPS.
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8. Machining PPS:
Preventing Contamination
Contamination is a serious concern when machining polymer components for
technically demanding industries such as aerospace. To ensure the highest level
of sanitation down to the sub-molecular level, AIP Precision Machining designs,
heat-treats and machines only plastics, with any sub-manufactured metalwork
processed outside our facility.
To learn more, read our article “Three Ways to Ensure Sterilization in Your
Plastic Machined Medical Applications.”
PPS Machining Guide: Supportive Information
Chemical Resistant Materials Guide Energy Sector Materials Guide Aerospace
Sector Materials Guide
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9. Let’s get started.
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Any Product Puzzle.
Any Customer Challenge.
AIP is the niche that you need for all of your plastic parts.
724 Fentress Boulevard, Daytona Beach 32114
+1 386.274.5335
AIP.Sales@AIPprecision.com
AIPprecision.com
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