Supplier's First Run had Plating Problems - Can they Strip, Re-Plate and PPAP them?

[Golfman25]

Most commercial plating standards are .0001-.0002. Any more, and they are wasting thier own money. They generally won't do that - thier incentive is to skimp on plating. Recently, for the first time in 15 years, we had an over plating issue which caused out of spec parts. They had .001 of plating. We thanked them for the extra zinc and had the parts stripped and re-done. Good luck.

[vardar3]

Do your prints call out the plating thickness, or is that something figured out from the weight?

[Golfman25]

In Reply to Parent Post by vardar3

Do your prints call out the plating thickness, or is that something figured out from the weight?

Generally, they do not call out a thickness. Sometimes they reference a standard. Sometime they just say "zinc plate." Plating houses I am familar with have the ability to check plating thickness using some type of "magic machine." As I stated, plating thickness has very rarely been a problem.

[bobdoering]

Another point is whether or not stripping and replating is going to be an approved rework process, to be included in the process flow when necessary. It is always better to spell out rework processes ahead of time.

[fujow17372]

In Reply to Parent Post by Golfman25

Generally, they do not call out a thickness. Sometimes they reference a standard. Sometime they just say "zinc plate." Plating houses I am familar with have the ability to check plating thickness using some type of "magic machine." As I stated, plating thickness has very rarely been a problem.

Zinc phosphate is a compressible coating and can only be accurately measured by performing a weigh-strip-weigh analysis. Unlike electroplating, phosphate "grows" into and on the surface of the part. The surface finish and material type, along with pretreatment and bath chemistry, will determine the thickness of the coating. Test panels - or representative parts - should be prepared with the production parts and sent to the plater for process validation and final testing. You will find that some specs will give an estimate of coating thickness based on weight, but it is only an estimate. Crystal size will impact the thickness v weight of the coating and no two processes will create identically sized crystals.

The "magic machines" you are thinking of are typically x-ray fluoroscopes and eddy current measuring devises.

[Jim Wynne]

In Reply to Parent Post by fujow17372

Zinc phosphate is a compressible coating and can only be accurately measured by performing a weigh-strip-weigh analysis. Unlike electroplating, phosphate "grows" into and on the surface of the part. The surface finish and material type, along with pretreatment and bath chemistry, will determine the thickness of the coating. Test panels - or representative parts - should be prepared with the production parts and sent to the plater for process validation and final testing. You will find that some specs will give an estimate of coating thickness based on weight, but it is only an estimate. Crystal size will impact the thickness v weight of the coating and no two processes will create identically sized crystals.

The "magic machines" you are thinking of are typically x-ray fluoroscopes and eddy current measuring devises.

Welcome to the Cove.

Excellent first post! Thanks for helping.

[JaxQC]

I want to re-point to Bobdoering's post on approved re-work.

I'd use the opportunity to include in your PPAP the data related to re-worked parts. Take samples (strip & re-plate) and include their data as well showing they are no different from the correct (first run) material. It may be just dimensional or whatever your other criteria is (torque to failure, hardness, appearance etc). Submit your Flow as showing both with supporting data and your covered for the future.