Using robot to automatically adjust frame

  • Hello,


    I'm working on two separate WaterJet systems with two wall mounted Fanuc M-20iA robots. One booth has R-30iA controllers and the other has R-30iB controllers.


    Both booths have turn tables that aren't repeatable and customer is not interested in fixing underlying problem so I'd like to try a different approach. When they swap out tools for different parts we always have to touch up the programs as they are usually a couple of millimeters off in both (X) and (Y) and most of these parts have 50 plus features that are being cut out. This is incredibly time consuming and with 2-3 swaps per 24 hour period on both sides of both booths this leads to substantial downtime. Only one frame is being utilized regardless of the part that we are running. They have routines for calibrating TCP but I was wondering if I could use this same method to update my user frame after tool swap to shift my programs into position to avoid doing touch ups? I've used touch sense before on mig welders but this is a water jet and that technology can't be used. I'm assuming this would utilize motor torque feedback as a sort of "touch sense" method like in the TCP_CAL subroutine. I've only used this method once to load a randomly picked metal dowel into a hole until it bottoms out. I would assume I could use the TCP_CAL style method to update my frame in the same manner as it works on the TCP_CAL.


    Has anybody written a routine that does this? Does anybody have an example program I could look at/use?


    Thank You

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  • Hi

    When you refer to "tool". Is that the EOAT or is the tooling (mold) of whatever you are cutting
    I know still takes time, but you can have the same UF a teach the 3 or 4 points every time they change the tool. You write a very simple procedure to teach the UF so you don't get a call a 3 am


    My concern with all these is that you could be the best programmer in the wold with the best most accurate robots in the world but you are never going to get it perfect if you're tooling is not repeatable.


    Is it possible that the customer could use locating pins to locate the table after the rotation ? This is a very standard method


    What are you cutting ?

    Retired but still helping

  • Thank You for your reply.


    I'm referring to the tool that is swapped out on the turn table. The water jet nozzle (TCP) remains the same regardless of parts. They have about 40-50 different parts that they cut on this system and it could be on either side of the turn table on either booth. We are cutting fiberglass. I understand shoring up the reliability of the turntable is optimal but the customer doesn't want to spend that kind of money. Dumb of them, I know. So I was trying offer a solution to mitigate downtime as much as possible. If I could develop a method of touching both sides of the (X) and (Y) side of the whatever tool they are running with the water jet nozzle to shift and rotate my frame that would be ideal.

  • The problem is is not only x, y , the tooling could be on a slight angle. Ho do you measure that ?

    Usually the tooling is dirty with left over or some fiberglass dust accumulation. If this happens where you are planning to do you x,y surface, it won't work.

    I tell you more, I bet your nozzle tip is shape as an hexagon. How do you know tip is exactly on the same location, it could be a bit tighter that before was removed and now you accuracy is useless


    You're cutting have to be so precise ( i guess under 1/2 millimeter), there is no way that you will achieve that on all the programs.


    FYI , my job between 1990 and 2005 was robot programming waterjet cells all around the world. Most of them for automotive industry


    I tell you ,Your customer is going to lose more money reprogramming than fixing the problem. They have to understand that what they are doing/thinking is wrong. It's not your problem. I know you need customer to keep your job but customer like that, I rather get rid of them. I hope they are not blaming you and they still pay for the time you waste

    Retired but still helping

  • I did waterjet cutting for 10 years. Your solution is positive location of the tool or fixture. I've worked on rotating walls too. Mostly working with soft parts or door panels which is another issue in itself. Fanuc does have software that will find your fixture and adjust the program. It involves touch sensing. It's different than the welding as it doesn't use a 24v circuit. It uses the feedback created on the motors. This tech was rock solid 20 years ago. We would run the touch sense program on a tool change and that would get us very close usually some minor touchups. The software is called cell finder. The cell finder software also included tcp which uses a plate with a hole. The program would touch the plate in several different ways to generate a TCP . You could also use this software to master the robot. All these things are important to maintain high accuracy cutting. In the end, it's all of maintenance and setup. Thing have to be done correctly or it's all a waste of time.

  • Never worked on a Waterjet, but here is my idea (may or may not work, other programmers can also comment).

    Use 2 distance sensors placed in 90 degree.

    For every tool make a reference program which gives variables (offset x and offset y) to be zero.

    After every swap run the reference program calculate the Distance and get the offset wrt reference value and add it into the TCP


    Its just an Idea an implementation and experiment may work as well.

  • I did waterjet cutting for 10 years. Your solution is positive location of the tool or fixture. I've worked on rotating walls too. Mostly working with soft parts or door panels which is another issue in itself. Fanuc does have software that will find your fixture and adjust the program. It involves touch sensing. It's different than the welding as it doesn't use a 24v circuit. It uses the feedback created on the motors. This tech was rock solid 20 years ago. We would run the touch sense program on a tool change and that would get us very close usually some minor touchups. The software is called cell finder. The cell finder software also included tcp which uses a plate with a hole. The program would touch the plate in several different ways to generate a TCP . You could also use this software to master the robot. All these things are important to maintain high accuracy cutting. In the end, it's all of maintenance and setup. Thing have to be done correctly or it's all a waste of time.

    Hello ROBOT_G

    I am interested in the Cell Finder software but I couldn't find any info about it in the net.

    Do you have a link where I can get some info?


    Thanks

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