hardware problems - PLEASE HELP

[wowhuh.mike]

okay, so last night I started cutting a 8' long piece of HDU "trim". It is two 2" thick pieces epoxied together. I have the stock aligned with the X axis. I roughed the stock along x axis and everything was fine. I then switched to my finish pass which I ran along the y axis. I am going to try to attach images of toolpath below.

So the problem was first noticed towards the end of the finish pass. At the beginning it was moving along just fine started at the top (z=4), rolled down the trim surface down to just about z=0, stepover y -0.100" then back up the surface to z=4, stepover y -.1", and so on down the length of the 8' stock. I walked into the other room preparing the next toolpaths, and when I came back in to the machine room it was cutting the same thing, still looked accurate, but after the stepover at z=4 and z=0 the tool would "lull" not move as quickly as it had when it started at the other end.

I felt like something had to be wrong, and I was really hoping it was something in the toolpath. Maybe there was something weird in my extruded surface that was causing problems on that end, that seemed unlikely it just had a hardware feel to it, but it was cutting the right shape, and I would have expected something to cut incorrectly with a feedrate change like that that wasn't intentional.

I finished one of the two pieces like that I had to cut. I left last night thinking I needed sleep and I would have to finish this evening with the other part after the day job. but I woke up this morning concerned, and fully aware that the day job is waiting on me to finish these parts and get the molds into production so I decided to start back up early this am. I started back up with roughing passes and prepared a finish pass that added loops to the stepover thinking that maybe the .100" stepover at 180ipm was maybe causing the problem.

Well I didn't get to the finish pass because 95% of the way into the roughing the tool stopped and said "TOOL STOP BUTTON IS ON". I certainly did not hit the E stop. Then I thought that I think this is like if you were to plunge the tool and it lost position. I have only done that once or twice and I think I just restarted SB control and hit reset and I was back in business. So I closed SB control and when I hit reset it didn't sound or feel right. A double-click in the relay and it wouldn't catch. VFD started to power up then back off again. reminded me of trying to reset a breaker that was bad.

The tool was not under a significant load when it stopped. 1/2" endmill .75" depth of cut engaged 45% in HDU. So I am guessing this is the sign of something more serious. Bad driver? bad motor? something in the closed-loop stepper system?

I am all strung out on stress and lack of sleep, and as much as I need to get these parts cut I want to let some of the community wisdom help guide me in what to do next. I am going to send this to SB support as well.

well nevermind on the pics, I guess I cannot figure out how to attach. It was just screen shots from CAM software.

Thanks in advance for any help you guys can give.

[wowhuh.mike]

okay, now it is letting me attach. I hope

[wowhuh.mike]

here is video I fortunately took before problem started

http://www.youtube.com/watch?v=pConx86GabA


here is video I took at the other end of the same toolpath after I noticed the change in feedrate

http://www.youtube.com/watch?v=JQ2fknZLgLg

[wowhuh.mike]

just pwered off control box to take a look at lights on the drivers. after the restart the reset button is working.

I am going to try to run the finish pass again, but still eager to hear anybody's thoughts

[myxpykalix]

check to see what the control software is showing for your "Move speed" or "jog speed" while th file is running you may have to go back and change that in the tool menu and resave the toolpath. Only it will probably start you at the beginning again.

[myxpykalix]

also open up 2 instances of whatever pgm you used to create your toolpath with the roughing and finishing toolpaths and look under the tool menu and see what the differences in feeds and speeds are. Thats what it looks like to me

[wowhuh.mike]

Jack- I have compared the toolpath code and there is no feedrate changes in the file, just an initial setting.

something caused the lag/chnage of feedrate.

I feel like the y -.1" stepover was too violent, and maybe this trippped the e-stop like if you crashed the tool. I also feel a little slop in the pinion gear, so that could have compounded it.

but how it kept going and kept it's position is what has me boggled. it seems as though it should have faulted out or lost position and wrecked the part. Neither of which happened.

I have been nursing it along all morning. It just randomly stops and has the tool stop button warning.

I have to shut down the control, turn back on and hit reset. if I don't power down control box the reset doesn't catch the relay.

Maybe I have bad contactors?

I hate intermittent problems, especially since I have a day job now and can't focus on the solution as I would like.

[dana_swift]

Most post processors insert a move speed command between tool paths. Your first set of 4 photos shows tool motion in one direction, then tool motion in the other direction. Look at the point in the SBP file where it finishes the first set of cuts, that is most likely where the MS command will be that is causing your problem.

Hope that helps-

D

[wowhuh.mike]

The problem happened mid-toolpath, and then got faster, then slower, then faster. I am certain there is no feedrate changes in that portion. I think you can see it in the youtube links. Speed was fine over the 3d surface but just after stepover the speed dropped then picked up again on the 3d surface, but kinda sloppy - like it is a mechanical lag not a programmed one. There is something deeper going on, it is not a CAM issue as I had hoped. I have been reusing the same toolpaths and not having a repeat of the same problem in the same area. I have not noticed slower movement since I added loops to stepovers, but I have noticed it is taking even longer than usual over the normal predicted machine times, so maybe it is running slower in areas.

[wowhuh.mike]

I seem to be losing steps in Y axis. After the last tool stop button warning, I restarted and had a misalignment in y after i picked back up. here are some pics