Last month we talked about why wheat starch successfully removes thin conformal coatings. But this mild abrasive is great for other delicate applications, like deburring black PEEK.

A Quick Demo

A video says more than we can about deburring black PEEK. Take a look:

About this Part

We designed and machined this part in our shop. We deliberately gave it a lot of burrs for this demo. We also made sure it had sharp edges, rounded lines, and intricate features that attract inconsistent burr formations. These characteristics are representative of the kind of PEEK parts that come in for sample testing.

What is Black PEEK?

PEEK (PolyEtherEtherKeton) is a colorless organic thermoplastic polymer. It is used across industries, but primarily in challenging environments because it is so durable.

Benefits of PEEK in Part Design

  • resistant to harsh chemicals, high temperatures, and wear
  • lightweight and easy to fabricate
  • elastic modulus similar to bone

Black PEEK is either carbon or graphite filled. PEEK is used extensively in the aerospace, medical and semiconductor industries because it is a great material for small, intricate parts that must stand up to extreme conditions. Unfortunately, cutting tools leave burrs on PEEK parts during the upstream manufacturing processes, and these burrs often change size and location part-to-part.

Risk: Discoloration and Roughness

Most PEEK parts can be quickly and safely deburred using sodium bicarbonate abrasive. It is soft enough that it will not change the dimensional integrity of a part, but its particle has a monoclinic shape that effectively removes a burr at its root.

However, sodium bicarbonate tends to discolor and roughen black PEEK. Wheat starch is one of our mildest abrasives. We decided to test it and found that it deburred successfully without causing discoloration or surface roughness.

black PEEK before and after - discoloration from deburring with sodium bicarbonate

Before (L) and after (R) deburring black PEEK with sodium bicarbonate. Note discoloration and roughness in the after image. 

Black PEEK - before and after deburring with wheat starch

Before (L) and after (R) deburring black PEEK with wheat starch. Note the smooth surface and clean edges in the after image.

Again, What is Wheat Starch?

  • Composition: crushed and polymerized wheat starch
  • Hardness: 2 on the Mohs scale (really mild)
  • Shape: blocky and crystalline with shard-like edges (provides gentle abrading power)
  • Risk: low, a great starting point in many sample tests
  • Bonus: water soluble and biodegradable
100-micron wheat starch

100 µ wheat starch particles (50x)

Similar Materials to Black PEEK

These materials also benefit from deburring with wheat starch:

  • Nylon
  • Polypropylene
  • Delrin
  • UHMW
  • Torlon
  • TecaPEEK
  • Vespel
Torlon- before and after deburring with wheat starch

Torlon: before and after deburring with 100-micron wheat starch

TecaPEEK- before and after deburring with wheat starch

TecaPEEK: before and after deburring with 100-micron wheat starch

Dig Deeper


Pat Byrne, Sales and Marketing Manager

Ready to test wheat starch on your application?

Email me or give me a call at 800-796-6626.