Hello, I’m attempting to etch a pattern in some hard white plastic that is curved in one plane. I have been successful in getting it to cut without burning the surrounding plastic, but with the curvature and the fixed focus (3 mm below the protective cowling) I’m not getting a consistent pattern except at the middle where I set the focus at. It curves down about 1 mm at the edges of the 15 mm lens. I was thinking of setting it at 2.5 mm, but that sounds like the wrong rabbit hole to go down. Are there more forgiving on the focus lasers out there?
Thank you!
Depth of field is entirely controlled by the lens… Shorter focal length, smaller dot but more shallow depth of field, larger focal length larger dot and more depth of field.
I think you will be pretty restrictive…
I’d advise you measure it yourself and determine if it’s possible get what you want.
Using one of the ramp focus tests you can pick the focus range you want. Or it might not be able to produce in that range…
Looked at your machines advertisement, but getting something like depth of field is tough with co2 and nearly impossible with a dpssl like yours.
Wish I had better advise, but dpssl are not usually used like this, I think, because of the shallow depth of field…
Maybe someone with yours or a similar machine has better news for you…
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Thanks for the info Jack! Would a CO2 laser do a better job?
Thanks again!
Ed
There are so many variables here, I’d hate to make the call either way… I hate to see you invest in something that may not do what you need to be done.
The problem is the curve of the object… A co2 with a long lens would definitely help, but there must be other solutions that are more cost effective…
Can you rotate it in a rotary? If you can follow enough of the curve in a rotary, that might be lower cost. You’d have to figure out how to hold on to it…
The problem is going to be the same for any laser… does it have a long enough focal length to handle the change in focus…?
I’d suggest you do a ramp test and you can measure the depth of field for your lens… How far from the focus point does the lens have to cover? It sounds like you are following the process, setting focus to mid point…
A CO₂ laser will certainly put more power on the plastic, which may not be desirable if you’re going for a shallow mark.
Also, because the laser wavelength will be different, the resulting surface finish and color effects will also differ.
The only way to find out is to try, but you’d definitely want to do that with somebody local in order to minimize the fiddling around required to align it properly and get the settings tweaked for decent results.
Thank you for your insight Jack and ednisly! At a dollar per hour it sounds like this would be a million dollar job. I was pretty certain that I had ruled everything out and you guys confirmed it for me, thank you. I’m going to get a CNC engraving machine to do the job.
Thanks again!
Have a great day!
Ed
Let us know how it works out… love to see the end product, no matter what you use…
Good luck … Take care
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