Y shift while running finishing pass on large 3D files

[nick]

I seem to have problems with the finish pass programs on large 3D files of over 100000 lines.

The picture is being cut from right to left and 3 quarters the way finished, the tool shifts in the Y direction. This is the second part that I wasted because of this. I can re run the file...it may or may not happen, and If it does happen...it's at a different location.

My computer has 256 megs of ram, and is kind of old...can this be my problem?

Thanks





6500

[bill1]

The file may be to big, you may need to split the file. Just in case this is the problum you can find the file splitter at the link below.

http://www.shopbottools.com/LabFiles/FileSplitter.htm

[knight_toolworks]

did you compare the file to whats the machine is doing? if they match it's not the machine.

[magic]

Can you program a slightly larger dish - (looks like you have a 20% angle on the slope) - offset the vector, then just clean up the dish?

if you only need one relief, this might work.....for today.

[myxpykalix]

I have cut 3d blanket chest lids that were far bigger than that with no problem. My laptop is about 2 yrs old and i don't recall how much ram it has. Do you have any other processes going on with the computer that runs the bot?

Very often with older computers they don't manage their memory very well and don't empty their "cache" even after you stop running the programs. One thing i would suggest is that if you use it for other tasks before you use it to run the bot is to shut it down, turn it off for 60 seconds or more then start it up and run the bot. Chances are you only have a fraction of that 256 megs at your disposal and that might be the problem.

[nick]

Jack,

I did suspect that memory might be hogging the PC so I restarted the computer, went to task manager and shut down all tasks that I thought would cause a problem and started SHOPBOT to run my program.

Maybe I have a old program such as a printer or something that was assigned to a USB port that is still running in the backround, and every so ofter, it sends a signal out to communicate and gets confused.

Do you think splitting my programs would help or buy a newer computer.

Thanks

[myxpykalix]

This sounds like a good excuse to go buy a new computer to me. This way you can eliminate that aspect as being the problem if it persists.

[tkovacs]

I have never run any 3d files but it seems to me that the only way this could happen is if the bot was being run in relative mode (as opposed to absolute mode) or the motors missed some steps. Running in relative mode with a big file seems like a problem waiting to happen. Is relative mode normal for 3d files? If you move to zero after this happens do you get back to zero or is there an offset? If you are in absolute mode and there is an offset then the motors missed some steps and you probably need to slow down or adjust some other parameters.

[nick]

OK...so what I thought was spuradic is very predictable. My Y shift in this matter seems to only happen on large files...even while I split them. And only on style B DISH carvings purchased from vector art 3D.

And it has happened before...and in the same locations.

Really strange...

Now...shopbot said it is the PC...but that was out me telling him that it is in the same location. Does the computer fix work still...if so...I'm getting the fasters computer...gotta be better that scraping work daily.

[Gary Campbell]

Nick...
How much ram on the control computer? You may be getting the Y glitch on a ram dump.
Gary

[nick]

The computer that runs SB3 has 256meg...

[Gary Campbell]

Nick...
I dont know what is actually recommended, but I run 2 Gig on the SB3 computer, because it doesnt have to do much. I did notice an improvement in performance when I upgraded from 1 Gig. I personally would never use less than that on an XP machine, nor less than 4 Gig on my Vista design computers. When 64 bit software is readily available (SB3) I will be happy to use XP 64 with 8 Gigs. Ram is like money... ya really cant have too much.

You might want to air cut that file near the spot where you have experienced the glitch with Windows task manager running to monitor your resources. You can see how much ram and processor are being utilized. I dont think I would start shifting processor priorities when actually cutting a file.
Gary

[nick]

WOW...so I'm WAY under...

I'm getting a new PC and starting their...

Good idea with the aircut...will do.

Thanks

[Gary Campbell]

Nick...
Try running the whole file, but pay special attention in the timeline where you lose the Y. It may be happening by diverting resources on a read/write to the page file. With lower ram amounts you will experience more page file use.
Good Luck, Gary

[nick]

Gary,

I bought a new PC with 2 gigs of ram and it didn't resolve my issue...althought it did run faster...my Y shift still appears...and in different locations.

I air cut this part...checked my zero before and after and the only thing that was off was the X by .050 but I found some slop on the right X axis motor which I'll have to call SB about.

It's always something.

At this point...I'm really at a lost for words...

I've had my bot for 6 months for practice...got some business in finally, and now...I have serious cutting problems.

We'll, at least I know my PC is ok now...

[Gary Campbell]

Nick...
Without a doubt, get the slop out of the machine. Many of the lost step and/or position problems have been attributed to issues of grounding. Actually the lack of them. Get your pinions in the rack, make sure everything is tight, and read this: http://shopbotwiki.com/index.php?title=Grounding_your_ShopBot
Gary

[erik_f]

Depending on how big the job is maybe someone can cut it for you until you get things squared away. The problem with being the engineer, service guy, machine opps guy, sales guy, packaging guy, accountant...and so on and so on...is when something goes wrong its about the last thing I want to do, is chase down what the hell is going on...I feel your pain Nick.

[gerryv]

Nick,
Have you had anyone else use your file as-is to run a physical part on their machine?

[nick]

Gary...I found my slop...my XII motor will turn under power and my XI motor will not.

I guess my motor is shot and I need to get a new one. Have no idea how this happened...since I'm not hard on my machine.

Back to my Y shift problem...I actually cut another part just smaller than first one.

5.5 x 20. No problem at all...even with the slop.

I'm going nuts...Does the SB warrantry cover this?

Good I hope so.

[Gary Campbell]

Nick...
A phone call to Durham is in order. (assuming new machine) They will be able to tell you right off how to troubleshoot the motor. Have you checked (push/pulled/wiggled) the motor connectors? Try the connector thats by the motor and the one into the driver.
Gary

[nick]

I will place a call in the AM.

Thanks.

[rookie432]

Nick,
I had the exact same problem with large files. I also noticed my control box acting a little wacky... (stop in the middle of a file, lose zero). My box tends to get dirty so I have been blowing it out regularly and still problems now and then.
Upgraded to the 4G recently with the bigger power supply and no problems in the last couple of weeks. Enclosed the new control box to avoid dust and some humidity.

The offset just started happening one day and I had previously done plenty of 3d carvings.
I have a cheap Wal-Mart e-machines computer to run the Bot and it cant handle a ton but it handles large Bot files just fine.

It had to be in the control box.
Sounds like you've narrowed it down to everything but.. and this worked for me.

[jsfrost]

Nick,
I have had success fixing cutting errors with a sharp carving chisel followed by careful sanding. The right answer is a real fix but this could save the material.

The toolpath is a raster scan left to right? Was the start at the bottom or top? Is the center correct as the photo suggests, with errors only on the top and bottom edge. In many ways, the signature looks much like slipping pinions.

Jim