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What is Polypropylene (PP)? CNC Machining

CNC Machining

Polypropylene (PP) is a tough, rigid and crystalline thermoplastic. It is the second most widely produced plastic after PE and is harder and more heat resistant. For UK engineers and product designers, CNC machining Polypropylene (PP) is a reliable route from prototype to finished part.

It is lightweight, chemically stable and will not rust, with good insulation and low thermal conductivity. Common examples are packaging, consumer products and medical applications. Its quoted tensile strength of around 33 MPa gives a useful guide when sizing parts. Our team can advise whether Polypropylene (PP) is the right fit for your design, or suggest an alternative.

Parts are CNC milled or turned and available in white or black. Its high thermal expansion should be considered for tight-tolerance parts. Get an instant online quote for Polypropylene (PP) CNC parts and have them delivered to your door in the UK.

Material

Polypropylene (PP)

Description

Strengths

Lead time 10 business days. Light, chemically resistant and low cost, with good impact resistance and insulation.

Weaknesses

Low heat resistance; can deform

Colour & Finishes

White / black

Mechanical properties

Ultimate tensile strength

33 MPa

Yield strength

32 MPa

Modulus of elasticity

1.6 GPa

Elongation at break

8–12%

Physical properties

Density

0.90–0.91 g/cm³

Hardness

102 HRR

Melting point

171°C

UK equivalent

Thermal properties

Maximum service temperature

130°C

Thermal expansion coefficient

17 × 10⁻⁶ /°C

Thermal conductivity

0.27 W/(m·°C)

Electrical properties

Electrical insulation

Good

Post treatments

Post-processing

Deburring / bead blasting

Recommended finish

As machined

Common applications

Packaging

Consumer products

Medical applications

Chemical-resistant parts

Values shown are typical supplier figures for Polypropylene (PP) and may vary with stock condition. Please confirm critical properties before production.

Frequently asked questions

Is Polypropylene (PP) easy to CNC machine?

Polypropylene can be machined, but it is soft and flexible and can deform from heat, so sharp tools and careful fixturing are needed.

What tolerances can be held on Polypropylene (PP) parts?

Plastics are softer and expand more with heat than metals, so very tight tolerances and thin walls need extra care. Achievable tolerances depend on part size, geometry and features, so mark any critical tolerances on a 2D drawing with your upload and they will be reviewed and confirmed in your quote.

What finishes are available for Polypropylene (PP)?

PP is usually supplied as machined, deburred or bead blasted.

What is Polypropylene (PP) used for?

Typical uses include packaging, consumer products, medical applications and chemical-resistant parts.

Should I choose polypropylene or polyethylene?

Both are light and chemically resistant. PP has a slightly higher service temperature and stiffness, while PE is tougher at low temperatures and has excellent weather resistance. PTFE suits harsher chemical environments.

How long does it take to make Polypropylene (PP) parts?

The typical lead time shown for Polypropylene (PP) is 10 business days from an approved order. Quantity, finishing and any heat treatment can affect this, and your quote confirms the date before you order.

Polypropylene CNC Machining