measuring wall thickness 2

[idanbrk]

hi,

i need to measure the wall thickness of a certain product , the product is made of ceramics and has an egg like shape which makes it very difficult to measure, in addition the wall thickness is not constant and varies along the profile . the average wall thickness is about 8.5 mm.
i tried using standard mechanical measuring tools (all sorts of big calibers and similar methods) , an ultrasonic gauge and i even found a kind of magnet based gauge but they all have the same problem- not accurate enough, i need an accuracy of at least +- 0.01 mm , if anyone has an idea on how to do it id love to hear it.

thanks

 

[byrdj]

do you have a cross sectional or any drawing you could attach?
the 0.01mm would be dificult even if a accesable with most micrometers

 

[rb1957]

"I wonder what the usage is that is sufficiently sensitive to thickness." ... i was wonderering the same thing ... 0.01mm accuracy over 8.5mm ... it's possible (just, maybe) that this is a feature of (bad?) design ... that this is trapped between two well controlled surfaces so excess thickness might cause something (the mechanism?) to bind.

in that case i'd've looked for something that would mould in place.

another day in paradise, or is paradise one day closer ?

 

[byrdj]

building an egg mic stand

 

[limey1]

http://gages.dyergage.com/viewitems...reach-direct-reading-min-wall-thickness-gages

 

[tbuelna]

With a part having a 400mm length you might be able to probe the inner surface from each end to the middle using a CMM with an extended probe. Or you could also cut the dimensional qual specimen into several short lengths.

Just out of curiosity, what process did you use to manufacture a 400mm long tubular ceramic component having a non-circular radial profile and a wall thickness tolerance of +/-0.01mm? Sounds like a pretty impressive piece of manufacturing work.

 

[hydroman247]

Just out of curiosity, what process did you use to manufacture a 400mm long tubular ceramic component having a non-circular radial profile and a wall thickness tolerance of +/-0.01mm? Sounds like a pretty impressive piece of manufacturing work.

A very very large chicken.

 

[idanbrk]

sorry, cant say what its for but the accuracy demand is necessary

 

[geesamand]

"how do i make a "non-bending" specialized micrometer that is at least 300 mm long and still light enough so a man can hold it while he is measuring? "

I'm picturing a dial indicator mounted to a flat surface on a "c" clamp. Zero the indicator on the opposing surface, lift the plunger to slip the C over the wall of the part, and read the result. If the C frame and surface are not too heavy it might work well.