Paper Creasing.....Why?

[JMugs]

Typical flat out and a streaming cold, but all was going smoothly until......
Printing steins for a commercial order, never have a problem, but today I do.

Stein, image, silicon sheet. Pop in heat press, take out....paper had sort of scrunched up a bit, thus a crease, thus a blow out, and so it goes on. Now got them all printed but what a faff.

Never had this problem before....any ideas?

Janners

[Andrew]

Could be a slight barrelling on the mug and as they are taller it affects them a bit more. Excess paper around the narrower areas then crease would be my best guess without seeing the whole thing in action. Steins are usually quite good though on straightness. Any sign of paper not touching the mug in areas when taped on?

[JMugs]

Problem identified, a Lemsip and Andrew's comment helped. The steins aren't overly straight. They are slightly waisted as opposed to barrelled.