The authoritative public forum
  for Metal Finishing since 1989
-----

Reflective pre-finish needed for stamped parts

I have an 0.075" stamped part that needs to have a reflective or bright finish that won't fade over time. This application uses an infrared sensor to detect the movement of a gear train. The sensor works most reliably with a reflective surface below the gear. I would prefer a coating that could be provided pre-finished in the coil to reduce costs by eliminating secondary operations. Any suggestions would be greatly appreciated.

Kevin Kezar
Product Design Engineer - New Paris, Indiana, USA
February 25, 2010

---

Hi, Kevin. What is the substrate . . . mild steel? Nickel plating is corrosion resistant, durable, reasonably reflective, and available. There are better reflective surfaces like chrome, or rhodium, but more expensive and less available.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 26, 2010

---

First of two simultaneous responses -- March 1, 2010

If you are going to do anything but shear the material, it would have to be fairly thin and ductile. Also, radii would need to be quite generous or the plate will crack or chip or peel.
If I were to guess, I would try an electroless nickel that is ductile. Optimum is a solution designed for this and maintained in very tight tolerances. It can be tweaked to provide a very bright deposit, but it would need to be on polished or very smooth metal because the thickness is minimal.
Somewhere, there is an optimum, but it might not be that much cheaper than a secondary operation. Lots of homework.

James Watts
- Navarre, Florida

---

Second of two simultaneous responses --

Yes, the base material is mild steel.

Kevin Kezar
- New Paris, Indiana
March 2, 2010