I'm tasked with developing a new robotics lab. I have experience with CNC machining, but I'm new to robotics. My company is planning to acquire most likely a KUKA robot that we will experiment with many different applications in a lab environment before implementing tasks within our production facility. I would like to setup a station for machining wood & other soft materials. Does anyone have experience with building a vacuum table for this purpose? Or know of a manufacturer of such a thing? I'm thinking that the workholding table will be designed with devices for defining the origin, calculating tool length, etc....
Workholding / Vacuum Table
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cuarchitect -
February 22, 2017 at 6:12 PM -
Thread is marked as Resolved.
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Try Googling "CNC Vacuum table." That's where most of the information will be.
For myself, I'm fond of ones like this:Basically, the rubber gasket strip allows you to make a "border" around the section of the table you're using, and keep the vacuum limited to that area. You'll need to be able to valve the vacuum selectively to the different ports through the table, of course.
The gasket strip needs to be just big enough to completely fill the "slot" in the table and stick up just a bit, so that the work piece "squashes" it down when the vacuum pulls on it, but not so thick that the work piece ends up "floating" on rubbery surface rather than being held against the machined surface of the grid. Quite a few people make their own to save money, especially if they need large areas or intend to let the top of the vacuum board be sacrificial for full-depth cuts.
For registering to the origin and doing tool length, you could probably use a Triple Edge Finder from http://www.themakersguide.com/ or something similar. You'd have to wire the probe to one of the KRC's Fast Inputs and use low-speed, Interrupt-based search motions to find the corner, but once you have that debugged, it would be a nice time saver.
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Awesome! Yeah, it looks like I'll be machining my own plenum from MDF or a sheet of plastic with 4 or 6 "zones" & a spoil board on top. I would like to at least have a 4'x8' table that can handle a sheet of material & the machined aluminum ones that I've seen on the internet can get VERY expensive, especially for this project that's still in the "experimentation" phase.
I've seen other CNC router accessories similar to the Triple Edge Finder. I'm glad to hear that using such a tool with a KRC won't be too difficult!
Thanks for your help!!
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Just remember that MDF likes to warp over time/humidity/temperature, so you may have to re-face your MDF vacuum board periodically to keep it level (and eventually replace it). So to increase its lifetime, you may want to start with it being extra-thick so it can survive multiple re-facings.
Also, if you're gong to use a robot for CNC-type work, be prepare for a lot of frustration. It can be done, but a robot will never be a CNC machine, any any motions that change tool orientation, or cause an axis to reverse mid-motion, will cause visible departures from your ideal tool path. You will need to optimize your cutting paths to work with the robot kinematics, which are much more complex and much less rigid than any CNC machine.