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Rotary engraving: stretched designs, slipping rollers and seams that miss
A design that comes out squashed, stretched, or does not meet where it should is nearly always a circumference number or a slipping roller. Neither needs new hardware.
Check your job time →1. Measure the diameter where the engraving goes
Tumblers are not cylinders. They taper, and they have a lip. If you measure the widest point but engrave 40 mm lower, the circumference your software is using is wrong and the design stretches or compresses to fit. Measure the diameter at the exact height of the engraving band, and re-measure for each new product - not each new order of the same product.
2. Roller rotary vs chuck rotary
A roller rotary turns the object by friction from below: simple, fast to load, and it depends entirely on the object not slipping. A chuck rotary grips the object and turns it positively, so slip is not a failure mode, but setup is slower and very light items can be crushed. If you engrave many tapered tumblers, the chuck removes a whole class of problem. If you engrave straight-sided items in volume, rollers are quicker.
3. Fixing slip
Slip shows up as a design that is fine at the start and drifts or overlaps by the end. Slow the rotary down - acceleration is what breaks traction. Add weight over the rollers, or a rubber band around the drive roller for grip. Make sure the object is not resting against anything that adds drag, and that the rollers themselves are clean; polish and finger grease both reduce friction.
4. Calibrating steps per rotation
Engrave a line, rotate exactly one full turn, and engrave again. If the two lines do not land on top of each other, the steps-per-rotation figure is wrong. Adjust and repeat until a full rotation returns to the same place. Do this once per rotary, not per job - and write the number down, because a firmware update can reset it.
5. Framing, origin and the seam
Rotary jobs are unusually sensitive to origin mode. If framing does not return to where it started, the design will not close at the seam. Use a consistent origin setting, frame before every job, and mark your start position on the object with a pencil so you can see whether it actually returned. For wrap designs, leave a small tolerance at the seam rather than trusting a perfect meet.
Rule of thumb: Diameter first, then slip, then steps per rotation. Most 'broken rotary' posts are one of those three, and all are free to fix.
Open the calculator →FAQ
Why is my tumbler engraving stretched?
The diameter entered does not match the diameter at the engraving band. Tumblers taper, so measuring at the widest point and engraving lower down gives the wrong circumference and stretches the design.
How do I stop my rotary slipping?
Slow the rotary down, since acceleration is what breaks traction, then add weight or a rubber band on the drive roller for grip. Clean rollers grip better than polished, greasy ones.
Roller or chuck rotary - which is better?
Chuck rotaries turn the object positively so slip cannot happen, which suits tapered tumblers. Roller rotaries load faster and suit straight-sided items in volume.
How do I calibrate steps per rotation?
Engrave a line, rotate one full turn, engrave again. If the lines do not coincide, adjust the steps-per-rotation value and repeat until a full turn returns to the same place.