Visual System Checks during Assembly. 1

[SDETERS]

We are having a discussion on how to communicate areas of a part, that is used for our vision systems, to the supplier, so that the supplier will not "modify this area" because it has an impact on the vision system in assembly.
For Example we had a part, and the parts thickness was over spec. The supplier ground the parts to get them back into thickness spec. As a result the vision system rejected these parts because the surface know was ground VS as pressed. It was a reflectivity issue with this surface.

It was suggested to put a note on our prints that points these areas out.

I am looking for suggestion on how to handle critical vision system surface and communicate these back to the supplier.

Thanks

 

[drawoh]

SDETERS,

It sounds like you need to specify some sort of surface finish. This this an optical component?

--
JHG

 

[SDETERS]

Drawoh
No this is not an optical component. We use castings, Powder metal, some plastics.

we are using a Vision camera system in assembly to determine if the correct part is assembled onto the unit. For Example we have two different covers, each cover has different rib patterns. These rib patterns can be picked up by our vision system camera. Now if the surface reflection changes, for example being ground on, or a different shade, the camera system will fail the unit in assembly.

The Goal is to communicate to the Die caster supplier, which surfaces we are using for our assembly Vision testing to accept and reject units during assembly. This way the supplier will know not to rework these areas (Grind, Sandblast) which could make the vision system fail the unit, for having the wrong part installed onto the unit.

 

[Nescius]

Surface finish control seems like a good start. Beyond that, it could be difficult to objectively describe the acceptable state of your parts. Things could go off the deep end...trying to define a range of acceptable color or how reflective something is seems like juice that isn't worth the squeeze. I'd expect the supplier to charge more for the parts with the new requirement, whatever that may be.

How about some alternatives?

Casting in a physical identifying feature in a safe spot? It probably wouldn't have to be much. A couple of dimples or something?
Mark the parts in some other, more crude, way? Big dab of white paint, etc.
Improved vision system?

 

[3DDave]

Most would work with their machine vision supplier to accept more variations to the cover finish.

Other than that, add a note that says - LEAVE AS-CAST and indicate the surfaces that are important to the process.

 

[SDETERS]

Great inputs thanks. Sure these will help as we move forward with this discussion.

 

[DraftingMan]

SEDETERS,

Why not use the "Material Removal Prohibited" surface finish symbol, example "d" in the attached.​

John H. Dunten, CD
Certified Drafter

 

[SDETERS]

That is great idea also. I was thinking of surface finish but did not think of doing this. I always think of surface finish of removing material.

 

[mkcski]

SDETERS:

I would also be concerned about "handling" damage to the surface(s) that would cause issues with the accuracy of the vision system. I would recommend notes as well so the supplier has some understanding of why the surface(s) cannot be "machined" of damaged.

Certified Sr. GD&T Professional

 

[dgallup]

So you think the supplier should have scrapped the oversize parts rather than reworking them?

I'm with 3DDave, the vision system programing needs to be improved so it does not reject an acceptable part. Sounds like it's looking for the wrong things.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[SDETERS]

dgallup. Good question I do not know the detail. I talked to the ME today and he mentioned after the ground those gears it was like looking into a mirror. So the reflectivity was an issue.

I do not know the details of the vision system, when we discuss this again I will try to get the type of vision system we are using.

Great inputs thanks again.