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Trimmers and Corner Rounders: The Finishing Kit
Laminating is half the job. The trim is what people notice, and it is where most home-produced work gives itself away.
Guillotine or rotary
Guillotine trimmers
A hinged blade that comes down on the sheet. Fast, and they cut a thick stack in one action.
The drawback on laminated work is that the blade can drag the film slightly as it closes, leaving a very slightly ragged edge. On thick pouches this is more noticeable. Guillotines also need a working blade guard — they are the more hazardous of the two by some margin.
Rotary trimmers
A circular blade running in a track along the cut line. Slower, and they take fewer sheets at once, but the cut is cleaner because the blade shears rather than chops.
For laminated items, a rotary trimmer gives the better edge, and the enclosed blade is safer. This is what most laminator kits include, and it is the right choice.
Leave the border
The commonest finishing mistake is trimming flush to the document. The sealed border is what keeps moisture out; cut through it and the laminate will lift at the edge within weeks.
Leave 2 to 3 mm of sealed film all round. It looks deliberate, and it is what makes the item last.
Why corners are rounded
Two reasons, both practical.
Square corners are where delamination starts. A corner takes the impact when an item is dropped or pushed into a pocket, and any lifting begins there and travels along the edge.
And square corners on 10 mil film are genuinely sharp. For anything handled by children, or carried in a pocket, rounding is a safety point rather than a style one.
Choosing a rounder
Corner rounders come in radii, commonly 3 mm, 5 mm and 10 mm. A 3 mm radius is subtle and suits cards; 5 mm is the general-purpose choice; 10 mm is a strong visual curve suited to signage and children’s resources.
Check the punch depth — a rounder rated for paper will struggle with 10 mil laminate. Look for one rated for laminated stock if that is what you are producing.
Blade care
Laminate film dulls blades faster than paper does. A dull rotary blade tears rather than cuts, which shows as a whitened, stretched edge.
Rotary blades are replaceable cartridges on most machines and are inexpensive. Replace rather than persevere — a torn edge cannot be tidied afterwards.
Guillotine blades can often be sharpened or reversed. Check the manual before assuming either.
Alignment
Use the grid and the backstop. Eyeballing a cut on a laminated sheet is harder than on paper because the surface reflects, and a cut that is 2 mm out of square is visible on a rectangular card in a way it is not on a document.
For a run of identical items, set the backstop once and cut them all against it rather than measuring each.
A sensible finishing order
- Print and let the ink dry properly.
- Laminate, sealed edge first.
- Let the item cool flat under a light weight — warm laminate cuts poorly and curls.
- Trim, leaving the border.
- Round the corners.
Cooling before trimming is the step most often skipped and it makes a visible difference to both the cut and the flatness.
Our Laminator Kits include trimmers and corner rounders alongside the machine. Ask us if you need a rounder rated for thick laminate.
