I bought a Rabbit plotter off eBay over a year ago, and it worked most of the time - after going through many different signcutting programs but occasionally it would freak out and start cutting random lines all over the place there was no method to it, sometimes it would happen at the start of of a plot sometimes at the end, sometimes not at all, I just persevered and kept wasting vinyl until it cut what I wanted to cut.

That setup was;

Heng Xing Rabbit HX-720 (using built in serial-usb adapter)
Sign Cut X-2
13" Macbook (running XP under Bootcamp)

I came to the conclusion that the rabbits serial-usb adapter was bollocks and built a desktop PC and tried using a serial cable - same result. After sales support consisted of a Chinese Lady repeating Install the Driver. I then decided to buy a second hand Roland PNC 960 that I saw. I got it home only to discover that it had a 25 pin serial interface, so I bought a 25 - 9 pin adapter. In the mean time SC Pro X2 had been abandoned in favour of their new software Sign Cut Productivity Pro, Tried using the 25-9 pin serial adapter with both the 25 pin cable and the 9 pin cable that came with the Rabbit and couldn't get the Roland to go. Frustrated I decided to give th Rabbit another go, as soon as I plugged the serial cable in it started cutting eveything I had sent to the Roland. It worked perfectly for a few jobs, then the fault reappeared.

I had sort of lost interest when I decided I was going to install Ubuntu Linux on my box and thought hang on maybe there's a solution here, installed Inkscape
and Inkcut, fired up the Rabbit and cut a few things, the fault reappeared. Plugged in PNC-960 same thing cut a few times then random lines.

This fault has migrated two cutters, three motherboards, both the serial and usb interfaces on the Rabbit and two operating systems.

Does anyone know what causes this to happen? I thought maybe the cutters misinterpret HPGL commands sent to them.

Welcome buckton!

Hhhmm....I'm not terribly familiar with the workings of cutters in general, let alone the brands you have. Since this problem was happening before you ever installed Inkcut and Inkscape, we can logically eliminate them from the causes of the problem. And since it has happened on 2 different printers and OSs, we can eliminate them. To my sense of logic, that leaves only the files. So let's focus on the files.

Have you noticed whether it only happens on certain files? Anything similar about the files where the problem occurs? Has it ever happened on a file that previously or later cut properly?

I would sugggest saving the files where the problem occurs, and maybe some where it doesn't. And if you could make those files available for download, those of us who are knowledgeable about cutters/plotters can download and examine them for potential problems. (SVGs can be uploaded as attachments to messages here in this forum (look below Submit button); http://www.imgh.us/index.php is an image host that accepts SVGs; or I think most file-sharing sites accept SVGs, eg - Mediafire, et al)

Honestly, the first thing that comes to mind for me (as previously stated, not very familiar with cutter/plotters) is either a corrupt file(s) or a file(s) with a lot of disconnected paths (image may look fine, but paths aren't done properly for cutting). Are these all files that you created, or did you download and/or purchase them somewhere? I wouldn't be surprised to find a small percentage of corrupt files, or that aren't made properly for cutting, among a large package of downloaded files. (That's why I avoid acquiring files in this way, because typically you can't inspect them before purchase or download....and even if I were allowed to inspect them, couldn't possibly peruse every single one.)

Well anyway, unless you have some reason to think the problem is not with the files, I think that would be a good place to start (and hopefully finish, after your long nightmare)

if you have a known image that is bad and its one or two colors-

enlarge the image 3xs its size 10x10 change to 30x30 you will loose no detail if you enlarge it first

export as a png

bring it back into inscape

revector it

resize it

and if you still have problems it is not the file

Thanks for the replies guys, I work slowly and lost interest again, I bought a Centronics Printer - USB adapter cable and everything works fine with the old Roland.