Go No-Go Guage for Ring

[yutaini]

Hi How can i ensure correct ring size in mass production environment? How to sort mixed ring?

Ring Size as follow:
ID x Thickness x OD (mm)
25 x 3 x 35
25 x 2.94 x 35
25 x 3 x 34

Thanks

 

[GregLocock]

How about a 34.5 inch hole and a 2.97 inch slot?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Cheddarcaveman]

I guess it rather depends on what sort of tollerences you are looking for and what quantities you are producing.

For small quantities, hand operated, a couple of simple go/no-go guages would work fine.

A 24.9mm rod mounted "through" a 35.01mm (or 34.01mm for the other size) hole would sort out the OD/ID. If the ID is OK but the OD is too big they would catch on the "hole" and if the ID was no good they would either not go over the rod or again would catch on the "hole". Then as GregLocock says, two slots, one for each thickness.

If you are talking large numbers then it would start to get expensive. You'd need an automatic system similar to that in a coin operated machine, that checks what coin has been put in and sorts them.

 

[MintJulep]

How they are produced is a factor.

 

[MadMango]

Since you mention "mass production", I think you may need to find more information on some sort of vision system. The difference between 3mm and 2.94mm thickness is so small, I doubt this could be detected with any hand-held Go/No Go gauge.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[NickE]

Do the ID and OD need to be concentric? That's a whole nother thing thats hard to check with just go-nogo,

You basically need to logically set up your steps to make the proper decisions at each test to catch all the parts.

You might be able to check the thickness with well built parallel plates. Although hopefully you aren't expecting modern sheet/strip steel to hold 0.0024" (0.060mm)

Sandvik, Hitachi, Eberle, and possibly Paturle can, but Ive only seen it in flapper valve grades. In the usual steels on the secondary market, 0.1157" and .1181" are basically the same thickness.

(and dont spin the micrometer)

 

[MikeHalloran]

I see 'em rolling down a trough, and being sorted for thickness with an air gage, kicked into one of two other troughs, and being sorted for od by falling out one side or the other of the 'thick' trough.



Mike Halloran
Pembroke Pines, FL, USA

 

[MintJulep]

Mike,

I thought I knew about most obscure pneumatic control gadgets, but I've never heard of an air gage as I imagine it in your context above.

Could you explain what it is, and how it works?

 

[MikeHalloran]

Imagine a trough a little wider than the thickness of the thickest ring. Arrange a pair of low pressure air jets entering the trough opposite each other, fed by a fixed pressure supply through an orifice.

Now, if a thick ring passes by, the backpressure on the air gage, measured between the jet and the limiting orifice, rises.

If a thinner ring passes by, there's more clearance between the ring and the jet, hence less backpressure.

I'm actually a little fuzzy on the internal details, but I think that's the essence of how they work. We used them at Ford in the sixties to measure bearing diameters on axle shafts. They can easily resolve 'tenths' of difference from the master they're set with. I don't think they have a large measuring range, and they may not be linear, but in an application like this, you don't care. All you're sorting for is 'is it 3 mm thick, or a little less'.

There was actually no stated requirement to measure the absolute value of any of the provided dimensions, only to detect differences so as to discriminate and sort a flow of similarly sized but distinct pieces.



Mike Halloran
Pembroke Pines, FL, USA

 

[MintJulep]

Got it. I've seen the concept used for gross detection of an object. Didn't know that degree of resolution was possible.

 

[xnicke]

Mike, that was a nice solution.. Just curious, any problem with noise with such a device?

 

[Cheddarcaveman]

Hey Yutaini - please answer some of the questions posted here to try to help you. It's no good posting a problem and then ignoring it!

 

[sbozy25]

Well one of my companies main products is retaining rings. Here is how we check them at a production level.

We have a Datamyte system that has electronic calipers hooked to it. Then one in every 5-10 parts is pulled out and the operator measures the key dimensions. These dimensions are put into the Datamyte and voila... it gives you a nice histogram showing the Cpk of said dimensions. As long as you are getting a good Cpk, the parts are fine. A go no go gauge is ok, but it does at times become time consuming to use for rings because of their small nature.

 

[sbozy25]

Oh... I didn't see the mixed ring sort part....

I agree with a statement above that it depends on the manufacturing process. I would hope these rings would be produced on seperate machines, or the same machine at different times. By looking at such a small difference in size, I would think this would be way to large of a potential for contamination. This could be a real problem in your PFMEA.

Just an idea, but you could also go by the weight of a part. Since the smaller part would weigh less have a sensor that they pass over detect the weight and then sort accordingly.

 

[MikeHalloran]

Air gages don't make a lot of noise. The flow is just barely sufficient to keep grinder coolant out of their apertures. In a metalworking shop, you couldn't hear them.


Sometime in 1967, I attended a tryout party for an engine assembly machine. It measured incoming piston assemblies for OD at several locations on the skirt, and shuffled them into one of maybe six queues, based on size. It measured the bore of each cylinder and inserted a piston from the appropriate queue to get just the right clearance. That was just one module; the complete machine was bigger than my house. Later that week it would be knocked down and reinstalled at the customer's site.

No computers, no PLCs; all relay logic.

Highest tech component:
The station for cleaning incoming blocks had a fire- hose sized fluidic oscillator for blasting chips out of the cooling cavities. A quick demo got everyone wet.





Mike Halloran
Pembroke Pines, FL, USA

 

[ischgl99]

Here is a link that shows what Mike was describing.

http://www.westerngage.com/extgageframe.htm

Air ring gages are used in bearing manufacturing to test for size as well as concentricity. The beauty of these gages is you do not have to have a perfect sample to set them up, just know what the measurement of the control piece is to calibrate the gage. The indicator then shows variation from the item used to set it and the piece being measured, so if too much variation, reject it.

 

[MikeHalloran]

Yeah, like that. We had hundreds of air snap gages.



Mike Halloran
Pembroke Pines, FL, USA