Could you help an ignorant engineer.
We purchased a used KR 120 R3900-K, it showed up at our facility and it's an Ultra K variant. Un fun surprise when the bolt patterns didn't match our existing 120s. I'm struggling online to find out what the difference is between these two robots, I see the power delivery on top of axis 3 but other than I'm lost. The price was good and the lead time better, but I'm trying to understand what the differences are and if it's going to create problems in the future.
Posts by Solideon
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regardless...
not sure how would that work without previous knowledge of the
precise location of it. and i would like to avoid need for CMM/laser tracker measurement or similar. i would prefer to make it completely standalone (robot only).
I'm not sure what you're getting at? You can do an XYZ 4-point with any arbitrary addressable point within the robot reach on the pendant. No fancy lasers or feedbcak needed. In this case you are using a ring, or as you mentioned better yet a dome that is the exact imprint of your tool, To act as a sharp point to find the center of your spherical tool.
Place your Ring/hemispherical divot tool on your work surface. perform XYZ-4 point, get the spherical tool to fit snug in the hole, take a point, repeat 4x and check your error on your calibration. You're done. Next time you calibrate you can tape it to the wall, the floor it doesn't matter you're still performing a 4 point calibration the same.
The other way to do this, is if you had a tool holder (I'm thinking like a ball nose end mill or CMM probe) you could make a tool that had the same length but was machined to a sharp point you could touch up there and transfer over or measure the difference between the points and offset/input your TCP. Assuming the tool isn't easily removable or they won't give you the budget to have a custom insert made the ring/divot method would work just fine. -
you can create a machined ring that is just slightly larger than the diameter of the sphere. You can then touch off the inside of the ring and get a good TCP depending on the amount of error you can allow in your process.