We are doing a short run project for a company. We are a stamping factory. They want to stamp out a flat "V" shaped retention spring out of 0.018" thick steel and measure 0.010" flatness,
unrestrained. I usually deal with material that is thicker than this. Anyone have any ideas?
I would try to measure it directly on the granite, but with a probe angle important (like A80, for example, to limit the force.
You could also decrease the trigger force and the upper force.
About 0.5 mm f steel shouldn't be too soft (IMO).
If you can find an "APOLLO" probe, it will be ok, the probing force is close to zero !!!!!
Do you need to measure a lot of these? If not id suggest just leveling it out with some adjustable legs and run an indicator over it.
No. Most likely 30 pieces for a capability study on flatness.
Honestly, that was my thought as well with stands and an indicator rather than a CMM. I just wanted to know if anyone has done anything like this on an automated piece of equipment.
put three 1" gage blocks on a surface plate with magnets on them.
Place part on gage blocks, side you want to measure touching the gage blocks (upside down, so to speak).
Put indicator tip UP and measure the part's underside for flatness. The underside. Measuring the top is parallelism.
I don't work with sheet metal, so I don't know how I'd hold the part from moving without risking distorting it on the CMM, but the probe angle definitely needs to be minimized as Jefman said if you go that route.
For .010" flatness, I'd definitely want to run it on the CMM as it is run and forget, but I don't know how I'd hold it without restraining it...
Extremely wasteful, but you could lay down some dental mold on the part then flip it onto the CMM plate and let the mold cure. You might distort the part removing the mold though. A release spray maybe. You'd have to mold each one individually. I'd never do this for .010" flatness, unless .010 is hard to hold and I had to. I might be seeing .010 and thinking that is huge sloppy and can't be missed when in sheet metal stamping it is tight and miserable to hit.
Did they build in the cost of burning through pounds of dental mold to inspect the parts, though, when they quoted, I'm guessing no since people rarely seem to consider inspection during quote.
You can get dental mold that is different viscosities from almost water to paste. I'd pick a medium or light body for this, were I to do it. I only do machining, so I don't need any release, the parts won't distort pulling the mold off. You might need a mold release.
Optical comparator doesn't really check 3D features. In this case the best tool is vision CMM with laser beam. But few places want to spend $$$ on machine like that. I've been clamoring at my place to buy one of those for almost 5 years now. They got me one but Keyence instead.
