Surface smoothness achievable by grinding/machining. 3

[vvvipin]

What is the maximum surface smoothness that can be achieved by simple grinding? Can a finish of 12.5 microns be achieved by grinding with a grinding wheel or is it necessary to use a lathe machine? How does one measure the surface smoothness? Are there any instruments which can give surface roughness readings?

Virtually an assault of questions! Can someone direct me to codal provisons. An (overzealous) inspector is raising these uncomfortable questions and I have to prepare a reply.
This is an SOS call.

Regards

V.V.Vipin

 

[PAN]

Grinding could give the roughness high 0.1 to 1.6 microns for average application.

 

[joedem]

A profilometer is used to measure surface roughness. See below for description of computerized profilometer. Non-computerized profilometers are also available.

The profiler is a computerized, highly sensitive surface profiler that measures roughmess, waviness, step height, and other surface characteristics in a variety of applications. It features the ability to measure micro-roughness with up to 0.5 Å (0.002 µin.) resolution over short distances as well as waviness over a full, 60 mm (2 inch) maximum scan length.

 

[kyong]

I think there are three types of grinder or grinding machine. One is simple machine which can called hand grinder. Second is mounted type which a two wheels on both sides. I can say all fabrication shops have these type of grinder in their shop. Third is quite different. It is normally more expensive and gives more higher level of accuracy than lathe. Of course the purpose is different form that of lathe. I might be wrong but I suppose that "vvvipin" means the first type and "joedem" means the third one.

Measurement of smoothness should be regarding for small area. So if the vvvipin's inspector wants only smoothness, hand grinder can do with very fine wheel or wheel with rug. But streghitness, roundness, size etc would be not accurate. If these measurements are also important, the third type of grinding machine would be necessary. Depending on the shape of the object and accuracy required, lathe of other machins, i.e. milling machine, could be used.

kyong

 

[joedem]

Surface roughness is interpreted in accordance with ANSI B46.1, and applied per ANSI Y14.36

 

[ctchong]

What is the maximum surface smoothness that can be achieved by simple grinding? Can a finish of 12.5 microns be achieved by grinding with a grinding wheel or is it necessary to use a lathe machine?
12.5 micron of what meterial? carbon steel, tools steel or high speed steel? heat treatment to what hardness? Hrc 58? or no heat treatment?

softness --> carbon steel < tools steel < high speed steel

if your work pieces are round then lath machine can do this kinds of finishing surface for carbon steel in the proper rpm and feed rate. you have to choose the right tools to cut it, normaly we use carbide insert for hard steel, but carbon steel you can use normal tools


How does one measure the surface smoothness? Are there any instruments which can give surface roughness readings?

find some template that demo the surface finish by compare this sample to you work pieces then you can get the rough feeling of what finishing you have get .


Virtually an assault of questions! Can someone direct me to codal provisons. An (overzealous) inspector is raising these uncomfortable questions

You have to look for the books cover Machine Shop practice to get all this info. this is experinece from people. Do not propose the expensive solution to these question.



and I have to prepare a reply.
This is an SOS call.

Hope you have your answer.

 

[ctchong]

What is the maximum surface smoothness that can be achieved by simple grinding? Can a finish of 12.5 microns be achieved by grinding with a grinding wheel or is it necessary to use a lathe machine?
12.5 micron of what meterial? carbon steel, tools steel or high speed steel? heat treatment to what hardness? Hrc 58? or no heat treatment?

hardness --> carbon steel < tools steel < high speed steel

if your work pieces are round then lath machine can do this kinds of finishing surface for carbon steel in the proper rpm and feed rate. you have to choose the right tools to cut it, normaly we use carbide insert for hard steel, but carbon steel you can use normal tools


How does one measure the surface smoothness? Are there any instruments which can give surface roughness readings?

find some template that demo the surface finish by compare this sample to you work pieces then you can get the rough feeling of what finishing you have get .


Virtually an assault of questions! Can someone direct me to codal provisons. An (overzealous) inspector is raising these uncomfortable questions

You have to look for the books cover Machine Shop practice to get all this info. this is experinece from people. Do not propose the expensive solution to these question.



and I have to prepare a reply.
This is an SOS call.

Hope you have your answer.

 

[vvvipin]

The material is ordinary carbon steel. The Indian Code is IS:2062 and the equivalent is ASTM A36.

Thanks for all the suggestions and tips. The response is really overwhelming.

Regards

V.V.Vipin

 

i need examples of finish specs 8g to 12g on .100 thick alum. surfaces, asap

 

[Abrasive]

The issues raised here are discussed in a new book by David Whitehead -Surfaces and Their Measurement (see a posting at

http://www.abrasivesmall.com/bksurfin.htm)

You may be able to find his older book Handbook of Surface Metrology at a library somewhere. The limits of surface finishes for grinding depend upon how you define grinding. Current work at 3M pushes the use of coated abrasives(sandpaper)into the nanometer range of finishes used in semiconductor manufacturing. Chemcial Mechanical Planarization processes use loose abrasives to produce similar results. For more traditional definitions of grinding, surface grinding machines properly adapted can produce micron and submicron finishes.

 

[hammaad]

i think that with simple grinding machine 5 micron surface roughness could be achieveable.

 

[loboy]

A list of surface textures by process can be found in the Machinery's Hand Book on page 705. This particular page number is out of the 23rd Edition. As it states on the bottom of the graph, &quot;Higher or lower values may be obtained under special conditions.&quot;