Frequently Asked Questions

About WPC Treatment

No. The treatment doesn’t add or remove material which would alter important clearances and tolerances for your parts. Strictly speaking there is a dimension change however the dimension change is almost undetectable. For example on a hardened surface such as on a crank shaft journal the dimension change will be +/- 0.00004 inches. On softer materials such as piston skirts and bearings the maximum size of the dimples are less than 0.00008 inches. Q1

Yes. WPC acts in two ways to strengthen parts. First it adds an extremely high level of compressive stress at and near the surface. The second point is that WPC Treatment creates a Nano - Crystalline structure at the surface of the metal. Both of these mean that metal fatigue and crack initiation are both noticeably reduced. Q2

Yes, WPC treatment can be applied over coatings/platings as below.

  • PVD/CVD Coatings (DLC. CrN, TiN, TiAlN, TiCN, TiC, etc.)
  • Hard Chrome Plating
  • Electroless Nickel Plating
  • Nikasil® Plating (Nikasil® is a trademark of Mahle Corporation)
  • NiCom® Plating (NiCom® is a trademark of U.S. Chrome Corporation)
  • Plazma Splay, HVOF Some coating can be removed by WPC treatment.

Please note that if the adhesion of the coating/plating is not good or the coating/plating film is worn, the film might be peeled off.

Soft coating like Teflon® Molybdenum Coating (Teflon® is a trademark of DuPont) and graphite coating will be removed by WPC treatment. Q3

Yes, we can mask off the parts with special blast masking tape with masking fees. Rough surface, complex shape and small adhesion area might not be able to mask off. Q4

Yes, WPC treatment is an advanced/controlled micro shot peening process. Sometimes, it is called as below.

  • Fine Shot Peening (Fine Shotpeening)
  • Micro Shot Peening (Micro Shotpeening)
  • Micro Peening (Micropeening)
  • Controlled Shot Peening (Controlled Shotpeening)
  • Advanced Shot Peening (Advanced Shotpeening)
  • Micro Dimple Process(Micro Dimple Treatment, MD
  • Process, MD Treatment)
  • Fine Particle Shot Penning(FPSP)
  • Fine Particle Bombardment(FPB)
  • Fine Particle Bombarding(FPB) Q5

Yes, WPC treatment can be applied over cryogenic treatment to improve durability and oil retention of the parts. Treating cryogenic first and then WPC is recommended.

We provide Cryogenic treatment service in house. Q6

Yes, WPC treatment is an advanced shot peening process and gives high compressive stress under the surface. WPC can eliminate fretting corrosion and fretting wear without dimensional change. Q7

Yes, WPC treatment can be applied over polished, tumble finished, mirror finished, ISF® (Isotropic Superfinishing, REM® Finishing) processed parts to improve fatigue strength and oil retention. (ISF®, REM® is a trademark of REM Surface Engineering).

WPC treatment makes fine dimples on the surface so the original surface doesn’t need to be polished surface. Q8

Yes, WPC treatment is an advanced shot peening process and gives high compressive stress under the surface. WPC can improve metal fatigue strength more than conventional shot peening without dimensional change. Q9

Yes, WPC treatment makes fine crystal structure layer under the surface. WPC can eliminate stress corrosion cracking without dimensional change. Q10

Basically all parts need to be disassembled to get WPC treated. Chain, ball bearings need to be disassembled.

However most of taper roller bearings, needle bearings with retainer can be WPC treated in assembled state. Q11

Yes, WPC treatment can be applied on used parts as well. Please disassemble and clean the parts. Thick carbon buildup or gaskets need to be removed from the parts to get WPC treated. Q12

WPC treatment makes fine dimples on the surface and the dimples work as a oil retention pool to prevent wear. The dimples will flatten at hard contact area. Most of the cases, the dimples are observed under microscope even the surface looks shinny. If wear is much severe, the dimples might be gone. However WPC treatment does not only make dimples but makes harder and high residual compressive stress layer under the surface, which works to reduce wear. Q13

WPC stands for Wonder Process Craft or Wide Peening Cleaning. Q14

Currently we don’t license the process. Q15


It depends on the parts to be treated. Please see standard engine parts price list. Please request a quote for other parts. Q16


Please see order.

Our standard turnaround time is 4 business days. Please check Current Turnaround Time.

We have Expedited Service with fees Q18

No. There is no minimum order required. We offer builder discounts to qualified builders. Q19

WPC treatment service is provided only in Japan and here in the USA. Q20

Shipping address is as below

WPC Treatment Co., Inc.
2909 Oregon Court, Unit C2,
Torrance, CA 90503
United States
(310) 782-8647 Q21