Annoying twitch

[matt_raymond60]

When my ShopBot first drops into the material to start a cut created in ArtCam it makes a little jog and then begins the cut. Unfortunately it jogs into the piece instead of away from it so I end up with a a very small (1/8" or so) notch in the corner of the workpiece. All the rest of the cut is perfect. Obviously this is not always going to be something that I can hide. I don't seem to have any play in the machine and it doesn't do this when I use Partworks. Can anyone help me figure out why it is doing this?

[Gary Campbell]

Matt...
Does the little jog happen just before or as the machine begins to move in the X,Y direction?

There are only a couple things that will cause this. One is a long or flexible bit coupled with a plunge speed that is too fast. The other is play in the machine. Please understand that the majority of people with play in the machine dont think there is play, or they woud have fixed it already.

I am not sure why this would happen in artcam and not PartWorks if the plunge speed for the bit is set the same. If you can post the file or your move and plunge speeds it might be easier to diagnose.

[billp]

OR if you HAVE to use Artcam for the job, create a " lead in" ( more than 1/8"outside) tool path so your plunge occurs outside of your tool path and THEN enters the desired cut path. Yes it's a workaround rather than a fix, but in the end it will get the job done until you CAN find the solution....

[matt_raymond60]

It plunges down in the workpiece, then makes the little twitch which ends up where it started, then starts cutting in the x and y axis. It is a very definite quick little jog when it does it.

[bleeth]

A couple of specific questions:
1. What version of AC do you have?
2. Have you sent a sample file to your reseller?
3. Post or send the SB file (as GC asked).

[Gary Campbell]

Matt...
That would have been my guess.

What model machine are you using?
What is your bit & plunge speed(s) if different between AC & PW
How long since you have tightened pinion/rack & adjusted V rollers on the X, Y and Z?
How about spindle or router mounting bolts?

[jerry_stanek]

have you tried ramping into the cut?

[RickWyatt]

Matt, I have also found little glitches now and then when I have had "open vectors" and/or small fragments of vectors found from tracing a bitmap.

Just a thought...

[MogulTx]

I'm no Artcam guy, but can you look at the text for the file in Artcam? If so, is it using a "template" to start the files? (Are there preset parameters that are loaded into the beginning of every file?) If so, you may have some little line of code that pops up for every file and that may be a pre-set ramp into a cut or something....

You know: like the automatic start height. The automatic line to return to 0,0 before starting the file. Auto run for the spindle or router and maybe vac system. It would be peculiar to the set up of the software and what it expects to preload.

I don't know how to do it yet, but I want to learn to set up templates in PartWorks 3.0 and use them- and I can see that something like that might make for a disaster if the wrong data is being applied every time. This can be especially problematic if this is a used machine that was set up that way for a specific purpose or if you made an error (created this command to be automatically inserted) and didn't know you did it.

Good luck. I think this one will prove to be pretty simple to figure out if you can see the code and see what is different if you code it in Partworks and then in Artcam and see what it does differently to start the file.

Monty

[gc3]

have you looked at the .sbp file in the sb editor? you should be able to find that line and edit or delete it

[jimboy]

I agree with Gene, edited it out in the Job. For whatever reason it is seeing vectors that you can't.
Jim

[garyb]

Matt
Without seeing your .art file and you're .sbp file everything here is pretty much a guess.
A couple of things to ponder, if it happens with one file and not the other then you can usually rule out machine. I would then compare the tool paths more than likely thats where the difference will be.
it looks like the start point is in the corner and your are getting bit flex on acceleration. So are both start points & direction of cut the same.

Doubt you have any additional open vectors underneath since ArtCam will throw a tool path error if they are all selected. Also I don't think you will find this in the sbp code to edit unless this issue is with your vectors or post.

If your reseller is unable to help you can send me your .art file and I will check it out for you
Gary

[matt_raymond60]

Just got back into town so I can get to my machine again. I will take a look at the files and see if there are any hidden issues in the beginning that may be throwing it off.

I believe that my Z speed is .5.

Thanks for all the suggestions!

Matt

[jimboy]

Let us know how it works out
Jim

[matt_raymond60]

Didn't see anything funky in the cutting code. Starting to think that there may be some flex in the router setup. I am in the process of buying a genuine Shopbot router clamp and new router from someone here on the forum, I am going to see if that helps the problem once I receive it and get it installed. My Bot just has a router base that is welded to a chunk of metal which in turn is bolted to the Z axis and it seems that it may have just a touch of flex if I really pull up on the front edge of it. This is the only Bot I have ever seen so am not too well versed in what works or doesn't. I bought it used from a guy who did signs, maybe it was strong enough for that but not for cutting melamine without flexing a bit. Or I am taking too big of a bite with it initially. But I would think that would show up in other places as well.

[gc3]

set up ramping lead ins in you toolpaths...

[matt_raymond60]

I will give that a shot as well. Also, just bought the newest version of ArtCam Insignia yesterday, looking forward to receiving that hopefully next week. I have been using Insignia 3.1 as that is what came with my machine when I bought it used. It will be nice to have a version that can run on our better computers and screens. Stand by for questions!

[jimboy]

Fire when ready Matt.
Jim