We are having trouble cutting small holes. The lack of roundness being the issue. It looks like adjusting some servo schedules could help with our accuracy. I'm reading that software called Small Circle Accuracy is whats needed to gain the servo schedules. I've been told, but have not read, that this software is not supported by our handling tool version.
1) Does anyone have knowledge of compatibility? If our Handling tool version is too old, can it be updated to support Small Circle Accuracy?
2) How much do I have to spend?
3) dose anyone know if it will work as advertised?
We have Handling tool v6.4076
Shape Generation
R-2000ia/125L
RJ3iB
Small Hole Accuracy
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popbot -
April 4, 2017 at 1:30 PM -
Thread is marked as Resolved.
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1 & 2) Not sure
3) I have used Shape Generation on a V8.2 HandlingTool robot for trimming and cutting heavy plastic with a horrible abrasive mixed in as a filler material. The small circle accuracy worked quite well if I didn't push the cutter too hard. If I tried to cut too fast, the accuracy of the circles would drop off pretty quickly. I can see this option being even more useful for processes that don't require contact: water jet, laser, plasma cutting, etc.Shape Gen is really nice for programming a number of different shapes as you pick out a center position and a couple of other dimensions for the shapes and the controller generates a program for you. This is a big time saver.
I know Shape Gen was upgraded from a previous version and I'm pretty sure you have the older version on your V6.4 controller. I'd give Fanuc Spare Parts a call to see what is possible/available.
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HandlingTool V6.40 lists 'Small Circle Accuracy' as Option J644
Doing small circles requires very good calibration and then a very accurate TCP. I would verify both and adjust if necessary before spending the money.
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Thanks for the 6.4 info, Skooter. Building on your thoughts, I would also suggest verifying the capabilities of the option on the older controller because I think the older version does not include program generation. I understand small circle accuracy is the goal here, but having a complete understanding of the capabilities might help to make the decision to buy a bit easier.
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This is the typical result when i try to cut holes. Sometimes worse. Am I expecting too much from this 125L ?
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Can you shed some light on your process? Material being cut, thickness, max cycle time allowed, feeds, speeds, cutter type, horsepower, etc...
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I had s similar issue with water jet cutting, which turned out to be the TCP was taught correctly in the wrong location.
The TCP was taught at the nozzle, however the nozzle was spaced 13mm from the part.
As the wrist re-oriented the water stream pivoted 13mm above the part rather than on the part. All the points were in the correct location, it was how I got there that was the issue.... -
This is not the cutting we are using but the one we use is very similar. I'm cutting at about 10000rpm and 10 to 13mm/sec feed rate. I would like to travel faster but with faster cutting speed come less accurate holes. At the current parameters, the cuts feels and sounds good. it does not seem to be bogging down at all.
One test I did was to cut a hole undersized, then come into the same hole a second time to trim it out to size. Hoping to reduce the load on the arm. Even tho the trim cut was very slight, I still got the same exact flaws.
Thanks Tony, already thought of that too.
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What is the hole diameter, do you have to do different size holes? What material is this?
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One of our hole cutting processes was eventually replaced with a hole saw (tool change) as we were unable to achieve the required accuracy.
It would be interesting to see what different servo tuning could do for your process. -
I was thinking the same thing as fastfingers. If you can get a cutting tool the same diameter as your hole, you just have to plunge. That usually works well, depending on your material.
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It looks like you're cutting plastic?
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Recently had an ArcMate 100iA that had a slight wandering in a straight weld. Traced it to J5 motor - you could hear a slight variation in it that synced with the motor revolutions. Changed J5 motor (had bad front bearing) and variations disappeared. Since this is not a new robot and you have tight tolerances, I suggest you take a very good look at the mechanical.
I like the moving the TCP to where the work is being done as suggested by tony gast and the other suggestions too. The 125L may also accommodate a second motor to drill holes. You could build it/them into the fixture and come up from the bottom and save some cycle time, just have to manage the scrap. Seen it done with bathtubs.
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Another thing to try in order to improve hole cutting accuracy is to increase the number of positions around each circle. I have programmed 1.38" dia. circles with 100 or so points around the circumference using shape generation and the automatic program generation in Roboguide. I played around with the CNT values and made some descent progress on the hole quality. This could be manually programmed without the option installed on the controller and would take some time, but might be of use.
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I’m cutting into material that is vacuum formed acrylic backed by fiberglass. The 1.5” hole I posted is the most common size but I need twenty or so assorted sizes. @ fastfingers, I would love to see an example of the hole saw setup you described. Is it capable of cutting fifty hole on a row without jamming up? Also, not sure how the shape generation works. I know the reference CUT_CIR job points cannot be adjusted. I tried to fudge them around a little, wouldn’t let me. Although I never tried to add more point. I can’t view the SGCIRCLE job used to calculate the circle so I can’t see how it works. Will it handle extra points in the reference job?
Here is one way to manually program a circle. I would love to see other ways of doing it. I’m in a programmer desert here.
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I don't have any pictures of the setup. The hole saw we are using looks very similar to the stamped steel hole saws you can buy in sets from MSC, Grainger, etc. except there aren't any teeth on this one. It is a fabricated piece and is diamond coated in order to handle the abrasiveness of the material to be cut. We are doing 50+ cuts without difficulty.
Things get pretty complicated with 20 different sizes. You could run a tool changer and swap out tools, but at 20 different tools, you'll most likely run out of mechanical unit reach to pick all the tools and run out of money as well.
Acrylic doesn't sound too bad. A carbide toothed hole saw would probably be good here. I saw an image you posted earlier that showed a burr cutter. Is this getting gummed up during the process?
One issue you might run into with a hole saw is making sure the slug you cut doesn't get lodged in the cutter. One option would be to use a hollow motor shaft with an ejector rod/cylinder to expel the slug. Pretty tough to implement though. Personally, I'd rather program around this issue and make sure the slug doesn't get caught in the saw. You can hold the saw at a slight angle to the piece to prevent the saw from breaking through the whole circle simultaneously. In other words, let the saw break through in one quadrant of the circle and then angle the tool toward the opposite quadrant and finish the cut. This should help keep the slugs out of the tool. The absence of a pilot drill on the hole saw will also help to keep the slugs from hanging up in the saw.
I am not familiar with the programs CUT_CIR or SGCIRCLE. I would suggest writing a new program so you can verify if adding points to your circles would be beneficial or not. It might be a bit time consuming, but worth the effort. You could do something similar to your sample code in the jpg image where you do the math for the positions and write them into pos regs. Automatic program generation is where Shape Gen shines.
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I have a R2000i/165F cutting holes in FRP backed vacuum formed acrylic with no problems... I generate my circles using the method you have shown in your photo, I use a 10HP router running an Onsrud 60-252 bit 12000RPM @ 30mm/s
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That's good to hear. Do you use any special servo tuning or just run the standard tuning?
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Now that's what I want to be doing!
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TitusLepic Can you tell me more? How thick is your product? What kind of tolerance can you maintain? How old is your robot?
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