X-axis troubles

[TMC-GSO]

I am just going to start my own thread. We have a PRS standard. The problem is that the x-axis will lose its coordianates to the point that the files come out a little bit off or it will jump track completly.

Another thing is every time I power the shopbot down the next morning I start it back up and try and move it using the keys, it will jump track right away.

The machine is second hand and I am trying to decide if I have to compleltly disassemble the machine and redo it to ensure its completely square and level. I would really rather not do that so does anyone have any ideas/solutions to try?

[paul_z]

It sounds like you are missing steps on the x axis and it may be due to binding on the X axis. I'd disconnect the X motors from the drivers and make sure that you can move the gantry the full range of travel without any binding. Moving the gantry by hand with the motors connected to the drivers is a "no-no" even if the power is off. If the bot has been moved, I'd also do the same for the Y and Z axis.

I'd then disengage the x drive motors and reconnect the motors to the driver. Then power up and make sure both motors are actually rotating using the keyboard command.

Paul Z

[wberminio]

Follow Paul's advice to rule out only other issues-
What are your move and jog speeds?
Try slowing them down.You might be going too fast for your standard and are losing steps

[jerry_stanek]

Also when the motors are disconnected try wiggleing the wires to see if you have a broken one

[TMC-GSO]

Both motors spin and work together. My move speed is 2 and jog speed is 3.5. I still have to try moving it while disconnected from the drivers. I will try this and see what happens.

[gc3]

computer issues.....

i have a old pr and can jog/cut at max speeds 6ips x/y for my software version. 4gig of ram on control computer and no other software just sb v 3.4.27

[TMC-GSO]

Our PRS is still jumping track. I took off the motors and switched them around that did'nt help the problem. Once you put them back on track you can run for awhile before it jumps again but if you turn off the control box then turn it back on as soon as you go to move on the x it jumps.No problems with the y or z.

[jimmya]

When you say 2 is that inches per minute or inches per second? If it’s inches per second, slow it down to 1.7 and see if that helps. I have the same machine, if I go to fast it will do the same thing as yours.

Jimmy

[bleeth]

Cameron: You need to check your x axes for level and parallel. The tolerances for this are very slight. Disconnect your motors and drop them from the pinions. Slowly roll the gantry up and down the rails. If they bind anywhere you have probably found the problem. If while doing it you see that all 4 wheels do not stay centered on the rails you have found the problem. It could also be that the gantry is not square to the x rails. Gary Campbell wrote a paper on squaring the PRS gantry that is very helpful. Here is a link to it:

http://www.shopbotblog.com/index.php/2008/12/tuning-up-the-prs-gantry/

Getting the whole framework properly tuned can be a tedious job and take a good day or two of tweaking before it is all good. Regardless of any other issues though this is absolutely necessary.

When you engage the x motors to the pinions they should be good and tight but having them too tight can also cause some real issues. I heard of one guy using clamps to pull them up tight and he blew out his drivers.

IF all is verified to be parallel and square and you are still having this issue then it could be communication speed from the computer to the control box.
This is easy to check by using the speed test in tools in the SB control software. This topic comes up regularly and the cure is a powered high speed USB Hub added between your computer and control box.

You could also be having a grounding issue. Another recent thread has covered that very well along with a sketch of proper grounding systems.

Let us know the results of your work with these fixes. We have all been there and many have found that what they thought was defective equipment was actually improper alignment and/or installation. Your tool should be comfortable jogging and cutting much faster.

[TMC-GSO]

Our problem was our X1 driver was bad. The led was still on and it would work intermittently. Which was why our problem was so hit and miss. For the future is there a way that a driver can be tested to check its effectiveness. It sucked that a shopbot tech had to come out here and figure it out in 15 minutes.

[bleeth]

The intermittant short is the worst there is. I just hate them. I just had a file run screw up twice (lost steps in X) today for no apparent reason and then ran fine since. Maybe I have the same thing! You can switch drivers by switching wires and run tests. You need to go into the Variables input file (VI) and reasign the drivers correctly after you switch the wires. I'd be interested in how to check with a meter. I've also got Gecko's although mine are an older series than yours.
At least you're back in business!