Any ideas on why this is happening?

Yeah, it's a head strike. The mat'l isn't laying totally flat for you and the head is subsequently rubbing that raised-up ridge. Try adding another pinch roller if you have them (my 540 has several extras but I'm not sure about the 300). Also, you may try lowering the heat to keep the mat'l from buckling like that.

 

Looks like head strike to me. Is there a way you can adjust the level of your print heads?

Checkers

 

Another vote for the headstrike. Convex is such a thick material you have to keep an eye on it. Try to avoid this or you will be replacing your heads ($600+ part).

 

I've had that occur a couple times at the begining of a print as the vinyl heats up and it kind of puckers or gets wavy across the width. It's never happend to me other than in the first few inches of a print. For me, adding pinch rollers hasn't helped. After it feeds across a little further it seems to straighten out, but I've also just stopped the print and sheet cut a few inches or a foot and that seems to flatten out the vinyl.

 

You gotta babysit it while it prints, Id adjust the vaccum too so it keeps the material snug against the platen

 

I don't think you can adjust head height on the SP300

 

You cant

 

What profile are you using for the convex on the SP300v.
Thanks

 

Just feed out about 10 inches of material before you start printing..I know, it seems like a waste of material,,and it is..but this will solve it.
ken

 

I had the same problem too with certain banner material when the material was being tugged from behind so all I did was roll out material behind the machine and make sure it never needs to be 'pulled' through

Hope this helps too

 

I had the same problem with my sp540. I also found that by rolling out the material behind the machine helped. Since doing this I haven't had any head strikes.