movable jig/fixture/tool for veirfying tapering issue in rectangular/square sheets

[dkgpune]

Hi,

I'm looking for solutions (movable jig/fixture/tool..) for veirfying tapering issue in a rectangular/square sheets.

Any pointers.

Thanks,
-Deepak GUPTA

 

[MintJulep]

Quantify the size of the items being checked.
Quantify the amount of tapering that is being encountered and allowed.
Quantify the accuracy of measurement required.

 

[dhengr]

Dkgpune:
What do you mean by taper? Do the sheets taper in thickness? Are they out of square at one or all four corners? Does the cut edge taper from face to face, so it is not perpendicular to the faces? How big are they and in what position are you inspecting them? What are the normal industry stds., tolerances for these conditions?

 

[dkgpune]

tapering in thickness. Usually one or two corners are out of square. Size could be 15mm x 15mm to 1200mm to 600 mm.

Attached is a picture of tapered piece. We have thousand of such pieces hence a solution (low cost) to quickly verify the tapering is required.

 

[3DDave]

1) Hire someone cheap
2) Set up a machine vision inspection system

On the second option check OpenCV. You could probably build a working solution based on a back-light screen and a smart phone.

http://help.ptc.com/creo_hc/creo30_...ntals/fund_six_sub/About_Layer_Display_1.html

 

[dhengr]

Dkgpune:
I think there must be something lost in the translation here. There isn’t much about your photo that shows the sheet/piece tapers in thickness or isn’t square. It does appear to show that your supplier didn’t make the edge cut in line with the stamped pattern. You have to get with your supplier and tell him what you want, and have him do his own inspecting and rejecting. Then you just do random testing/inspecting to keep him honest. Pieces like that are often hemmed or edged with a stiffening frame of some sort and some minor variations can be hidden by this framing, and some final squaring can happen/be hidden at that stage. When you are talking about sizes varying from 15mm to 1200mm, and then various cross dimensions, for squares or rectangles, one simple jig or fixture might not be the answer.

 

[tbuelna]

I'm with dhengr. The photo provided shows what appears to be the sheared edge of a piece of expanded/flattened metal mesh. I don't know how you would check for a taper in thickness along the sheared interface given the fact that the sheared edges are not contiguous or uniform in cross section. And if you wish to check the sheared material for parallelism/perpendicularity of its perimeter, this would also seem to present some difficulty since the perimeter is not contiguous, and there will likely be some displacement of the unsupported wire ends during the shearing operation.

The best approach to aligning the material for shearing would be to make a fixture that has a pair of dowel pins that fit into the mesh holes. This would ensure that the sheared edge is aligned with the mesh, rather than the edge existing on the raw material supplied.

 

[tomwalz]

Are you fighting with a vendor / supplier on this?

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[IRstuff]

" Size could be 15mm x 15mm to 1200mm to 600 mm."

Is it the same mesh size for these different sizes? What tolerance did you give the supplier for misalignment of the mesh?

Is the "taper" always contiguous?

If the mesh is always the same sized pattern, I could see an electrical way to do this: a single straight edge with separate spring-loaded electrical contact points + a jig that the mesh fits on, and moving the mesh to the first electrical contact to the mesh, and then the last. The difference in position is the amount of taper or other non-straightness of the edge.

TTFN
faq731-376

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