Bernie Daraz

Spotweld Locating for sheet metal parts

Discussion created by Bernie Daraz on Jul 19, 2017
Latest reply on Jul 20, 2017 by Bernie Daraz

This is less a Solidworks use comment than it is advice I would like to share from my 40 years in manufacturing.

 

In my years in producing precision sheet metal I had encountered a vast number of tools that I had no idea were available. Wilson Tool is one of the premier tooling manufacturers for turret tooling among others.

 

I was working at one very progressive place more than 25 years ago, and they used Wilson tooling to produce these ‘locaters’ for spotwelding brackets and precisely locating them. Previously I have made locating fixtures, some of you may know how tricky they can be and do add handling time to the process. Sometimes they also get warm and you need another fixture or you might have ‘timed’ the process so the fixture could cool.

 

This progressive place used this tooling and had two sets, one slightly larger. They had to be defined correctly in the programs and they had names, WELD01, and WELD02. WELD02 being the larger one. WELD02 also had to be set ‘higher’ to clear the half shear from WELD01.

 

We would put at least two of these on mating parts for location during spotwelding. It was easy for the guys to just pop one part over the other and spotweld without any further clamping or fixturing. We also never used the locators in a manner where the individual parts could be located 180 degrees out. They were always offset in such a manner to be 'crooked or slanted'. The visual would indicate to the spotwelder that he had the parts orientated incorrectly.

 

Well, one day the turret guy made a mistake and swapped the tools. The parts would not locate and I was called over. My simple solution for this lot was to just ‘force’ them together using the PEM machine and two flattening tools. I think the issue added less than two hours to the job. To this company, that was a loss.

 

I looked at the tools and decided that we would use the ‘form up punch’ of the larger tool (.125 diameter) and the ‘form upper tool” of the smaller (.121 diameter) tool. The upper tool being the ‘die’ and ‘creating a form’ of .123 diameter.

 

Now instead of using two tools in the turret we only used one set with no height set requirement as long as it appeared to be about half of the material thickness.

If you’re thinking how can you use a die smaller than the punch? You know more than the average person. Much more. Since the tooling never punched a through hole, why not.

 

So, I reordered another set from Wilson and then received their rejection. I was directed to call their tooling ‘genius’ and we had the discussion, first he telling me that you cannot have a punch larger than a die and must always have a clearance. I countered with, why? I’m not punching through. It’s a half shear according to your description. OK, so now I have his attention.

 

I did discuss that I had expected extra wear on the tooling set and we would monitor for that. It all worked very well, eliminated the need for a second tooling set and the potential for errors. All good I would say. Eventually we had three turrets and had three sets of this tooling.

 

The image below is from Wilson's website and while not an actual picture it does represent what to expect from using the tool set. Try to imagine a punch being performed from the bottom of the material roughly half way through. This one tool set was used on many thicknesses and materials without concern for die clearances.

 

WT Image Half Shear Round.JPG

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