finishing

[AgeOfEmpire]

Hi all friends,

I need to learn something about finishing.Could you give some information about this sentence ?
" The bore should be finished by techniques known to produce approximately 12rms "

Thanks for your interest

 

[CorBlimeyLimey]

It's not so much finishing you need to learn about. You need to understand the manufacturing processes which can achieve the desired surface "texture".

http://www.engineersedge.com/surface_finish.htm

Helpful SW websites FAQ559-520
How to get answers to your SW questions FAQ559-1091

 

[tomwalz]

Bore as in "rifle bore"

RMS is one way to measure smoothness. There are others.

What it appears that someone wants is a means to finish bores so they achieve a certain smoothness. This could be very smooth cutting. It could be honing (sanding, polishing, other finishing) after cutting. It could be chemical or electrochemical finishing.

Assuming a rifle barrel as an example. It is drilled. Then the lands are cut. Smoothness can be achieved by burnishing.

We do a final finish chemically in our work..

When achieving smoothness be aware that other characteristics are important as well. A smooth barrel that is out of round may not be desirable. Changing the chemistry or physical properties may be desirable or undesirable.

Our approaches to achieving smoothness vary. On our ceramic tipped tools it is done by the grit size in the grinding wheels. On applications such as rile barrels, automotive cylinders, etc. is it done by applying a layer of ceramic forming material and creating a layer of metalo-ceramic (e.g. ferrosilicate) bonded with an intermetallic to build up the low areas.


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

 

[Goahead]

ASM defines Finish as the Surface condition, quality, or appearance of a metal.
In your context it means some fine machining by use of fine mesh abrasives to perform operations like honing, lapping, superfinishing, polishing etc.
rms stands for root mean square, an accepted method to express numerically the measure of roughness or of smoothness of a surface.

http://www.welding-advisers.com/

 

[Cockroach]

The statement refers to machining with high RPM and low feeds. I highly doubt you can get this manually off a lathe, probably not even a CNC, usually 32 Ra are obtained.

12 RMS is typically some sort of surface grind and polish. So your statement is more of manufacturing processes which would hold a surface finish to a mirror polish.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[diamondjim]

Do not know if a balling technique
would cold work the surface to that
fine of a finish. What is the length?
Possibly a drill and reamer would do it.

 

[AgeOfEmpire]

these information was useful for me.Thank you very much friends

 

[ornerynorsk]

cockroach, 12 is not a mirror finish.

Ageofempire, the answer you are looking for is burnishing, ballizing, honing, or jig grinding; depending on the diameter, depth, and whether or not it is a blind hole. Reaming will not generally produce better than 16 to 20, repeatedly.