pinchvalve
pinchvalve GRM+ Memberand UltimaDork
11/13/12 1:33 p.m.

Math and Geometry are not my strong suits, so I am looking for some help. I have to put a sticker onto something that is roughly shaped like a doughnut. The issue is that it is not a flat surface, it is curved.

Imagine replacing the straight "veho360" with a sticker that goes all, or part of the way around. Not only is it circular, it also slants down at a specific angle.

How do I print something flat, then apply it to that so that it matches the contour? What shape would the flat strip have to be to match?

Sky_Render
Sky_Render HalfDork
11/13/12 1:42 p.m.

A flat surface will never apply to a curved one without "bubbles" or "folds."

ransom
ransom GRM+ Memberand SuperDork
11/13/12 1:47 p.m.

Yep the only way that's going to work is if the diameter is large enough that the curve is gradual enough for the stretchiness of your sticker material.

Apart from that, you'd have to figure out how to cut a bunch of wedges in it, but I have a hard time believing you'd ever get an acceptably smooth application (though "acceptable" is obviously up to you...)

Giant Purple Snorklewacker
Giant Purple Snorklewacker MegaDork
11/13/12 1:48 p.m.

In reply to pinchvalve:

You use ink or paint. Alternatively you can use a stretchable material like vinyl or make it more than one decal in a small enough width to cope with the curve.

wearymicrobe
wearymicrobe Dork
11/13/12 1:54 p.m.

Just use an inflatable paint transfer screen print and be done with it.

nderwater
nderwater UberDork
11/13/12 2:30 p.m.
pinchvalve wrote: Imagine replacing the straight "veho360" with a sticker that goes all, or part of the way around. Not only is it circular, it also slants down at a specific angle. How do I print something flat, then apply it to that so that it matches the contour? What shape would the flat strip have to be to match?

Cover your target area with small strips of masking tape, trim around the edges to get looking nice, then peel off carefully to obtain the crescent-ish or ring shape your sticker will need to be. The narrower the shape is relative to its length, the less stretch the decal will need to keep from deforming. If the decal needs to go the full distance around, consider segmenting it into 2/3/4 pieces for easier application.

stafford1500
stafford1500 GRM+ Memberand New Reader
11/13/12 2:45 p.m.

If I read the issue correctly, you need to make a patten that will keep maintain a level around a cone shaped (or roughly so) part. The flat pattern for something like that is described in the following link:
Cone flat pattern
You might also try searching for 'cone flat pattern' or other similar phrase.
Here is an interactive site: Cone flat pattern dimensions
As long as the 'doughnut' shape is reasonably flat and smooth, a cone will be your first approximation. If you are trying to print a logo for the shape, you will have to curve it to the shape of the flat pattern for the cone segment.

pinchvalve
pinchvalve GRM+ Memberand UltimaDork
11/14/12 9:17 a.m.

So the answer is that it can't be done because it defies the laws of physics. No wonder I was having such a hard time figuring it out! I will look at making a smaller label, that has some stretch or silkscreening it.

Thanks all!

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