manufacturing process to obtain surface finish of Rz100

[Dieguy300B]

Hello, I'm hoping to find some advice on what type of manufacturing process is required to produce a surface finish callout of v- Rz100 on a hole diameter? I currently have a stamped part 8.0mm thick with a hole diameter of 8.0mm in it with this surface finish callout.
Thanks in advance for your assistance.

[Kelly_Bramble]

Welcome to EE!

"Rz" or do you actually mean "RT"? I'm not familiar with a Rz roughness scale... The Rt 100 is equivalent to CLA of 1000 and a Ra of about 1000 micro-inches which is very achievable using stamped blanking manufacturing.

[Dieguy300B]

Thanks Kelly, the callout is definitely Rz100 and it points to the diameter of the hole. I'm getting speculation from various engineers that the hole requires a shave and a burnish operation, although there is no shave callout or minimum true diameter callout.

[Kelly_Bramble]

Ok, I found the specification. Rz is defined within ISO 1302 and ISO 8785 as the maximum height of the surface roughness profile. Rt is the Total height of the surface roughness profile.

So, as I understand it the surface finish which is normally given as Ra which is an arithmetic mean deviation of the surface finish profile and Rz would be the maximum height of the surface profile element.

If the units are in mm, 1000 mm converts into .03937 or .040 inches, which should be achievable by conventional stamping operations.

[Cragyon]

See these links on Engineers Edge.

ISO Surface Roughness Symbols and Terminology

Surface Roughness Conversion

[Dieguy300B]

Thanks for your help guys. I've recently been told by the manufacturing engineer in charge of the project that piercing this hole in a normal stamping die operation with 6% die break will meet this criteria.

Thanks again.