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Reverse engineering with a CMM

metlmunchr

Diamond
Joined
Jul 25, 2004
Location
Asheville NC USA
I'm considering building some roll forming machines. We own examples of all the machines, so I have ready access to all the rolls.

A friend has a Zeiss CMM that's a couple years old. He's told me several times I'm welcome to use it anytime I want. So my question is whether the typical CMM is capable of generating the profile of these rolls, or if they're sorta limited to comparing a hard part to a drawing file that's been loaded into the computer? In his shop, they use the CMM pretty much exclusively in first article inspection, so he's not familiar with all its capabilities. Rather than asking him, and having him spend a bunch of time learning about something he wouldn't actually use, I figured there might be some people here who already know whether or not this is a common CMM capability.

FWIW, these are machines considered commodities in certain trades, in production for over 60 years, so I'm not looking for a solution to copying someone's new technology. There are a couple domestic manufacturers, both of whom seem to have adopted the attitude that there's no upper limit to the prices they can charge. On a per pound basis, 50% more than the per pound price of live tool, subspindle, Y axis lathes is the current norm. As a result, this has created a fairly large market for Asian import copies which aren't real great from a quality standpoint.

The imports are functional, but the price level of the domestics tends to support prices on the imports that make them a very poor value for the dollar. Sales of the imports tends to be tied up by a couple national sellers at what I'd suspect is a very high markup. I know for a fact dealer margins on the domestic brands is very slim, so there's no great loyalty among them to the manufacturers. In conversations with a few of them, its more like they sell the machines just to have a full line to complement their other sales to the same trades. It seems there's a lot of room for someone to build some machines here at a realistic price while maintaining a reasonable profit, pick up the interest of some regional dealers around the country, and perhaps create a few jobs in the process. These machines are used by trades that cannot be outsourced, so there's a market that's not going to disappear tomorrow.
 
I use mine for that, and I'm sure it's primitive compared to your Zeiss. It will find the radius, centerpoint and roundness of arcs, and the angle of edges, that should be all you need, right? The tricky part on contours is determining where the arcs start and stop, I use the roundness number to decide whether or not I have it. On complicated curves, you can break it up into many arcs and stitch them together in CAD. If you are really fortunate, it will be a Zeiss scanning CMM, which will allow you to just drag the stylus along the curve rather than taking a point cloud.
 
Thanks Mud, it sounds as if it should do what I need. Think he said about $40K when he bought it as a factory rebuilt and updated unit, so maybe it will do the scan thing. Then again, maybe not since 40 grand don't go as far as it used to :D

Sending you a PM about another subject.
 








 
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