View Full Version : Need help with laser settings

Robert L Stewart
07-15-2010, 12:38 AM
Hello all,

I read the threads on this forum everyday and have learned a lot but I have light years to go. Thanks to you for all your knowledge and experience and for forums like this :D

I am rastering and cutting "plumbing valve labels" on my 45 watt Epilog mini 24. They have text only, Arial 23 pt. and are 3.75" x 2.25". The material is Romark Metalgraph Plus brush copper on black .060.

My settings are:
600 DPI
Raster 70 speed, 50 power.
Vector 20 speed, 50 power fc 500

I did not mask for the vectoring so there is a slight burr on the surface. The burr is acceptable as these are seldom handled. Is there a way to eliminate the burr besides sanding or filling?

Clean up is quick with go ole DNA. Took me a while to understand what DNA was when I first discovered this forum.

The issue is with the rastering, The black is not very black, almost has a chaulky look when the light hits it just right. Not much contrast the way it is now. Is there anything I can do to make the black darker like the core or is this normal?

Just guessing that my setting could be off.


Mike Chance in Iowa
07-15-2010, 1:57 AM
I haven't worked with that material yet, but I have to ask the obvious question. Have you tried rastering a 2nd pass at different speed/power?

Robert L Stewart
07-15-2010, 2:10 AM

Yes I did. Rastered the same piece again once with the same setting (70/50). No change.

Rodne Gold
07-15-2010, 2:49 AM
Use spray n cook on the label after lasering for a darker black - it doesnt last forever but will make the label look a lot better for a while.
Ps you could probably use 300 dpi and 1/2 the time of engraving for this application.
Try 300 dpi with the laser EVER so slightly out of focus.
Buy a cheap deburring tool at any engineering supply house , the one with a rotating blade and you will be removing those burrs in seconds and give the label a slight bevel where you have done so - will look a lot more professional.

Mike Null
07-15-2010, 7:44 AM
Rodney is absolutely right about the setting. I would recommend 400 dpi but 300 should work. Run at full power and increase your speed a little.

I would increase the ppi, (frequency) if you have that setting on the cutting part of the job.

I normally clean with dna but when I run into the gray problem I use mineral spirits. It doesn't last a long time but it will darken the image.

At some point you will need to buy a beveler; assuming you plan to do a lot of these. Almost all that I do must have the edges beveled for a better look.

You can get paid for it.

Joe Pelonio
07-15-2010, 8:02 AM
I have a 45 watt Epilog, and have used the copper often.

I agree with the others on the dpi, 400 should work fine. Also, I'd be running it at 100 speed 50 power for the engraving. If you need slower speed and more power then something may be wrong, warped material not laying flat, focus or dirty lens/mirror problem.

For cutting I run that material at 22 speed, 44 power, 600 frequency, so you are close to that, but I get nice clean edges. Are you using air assist?

Ross Moshinsky
07-15-2010, 8:38 AM
I disagree with the change in DPI. I've run several tests on plastic and there is a discernible difference between 400dpi and 500dpi. 500dpi to 1000dpi, the difference was not discernible. The edges at 400dpi were definitely not crisp enough for me.

If I had to guess, your raster issue is from you being too hot. Sounds like the black base plastic is melting. You should be just burning off the top layer of plastic. Not melting the base material.

As for the vectoring, are you using air assist? Vector, pin, or honey comb table? I'd also guess this setting is too hot by your description. 1/16" material cuts pretty cleanly. Worse case scenario is I run the edges on a block sander which takes about 20 seconds per piece.

Robert L Stewart
07-15-2010, 10:38 AM
Thanks Rodney,

I will try your setting when I can get back on the laser, will be out of town for a day. Will have to look for some "spray n cook" concoction here locally. Will also take a stab at "out of focus" settings. I work in a building with a "metal shop" and have been eyeing his deburring tool for ages. No doubt nows the time to own one.

Robert L Stewart
07-15-2010, 10:43 AM
Thanks Mike,

I do have the ability to change the cutting DPI and will try that. Will also put that gal can of Minerial Spirits to use. I am getting paid for this first experience and I like the idea of having a deburring tool.

Robert L Stewart
07-15-2010, 10:48 AM
Thanks Joe,

I seem to have plenty of power as my laser has seen little action in it's first year of service. So far I have only used it for wood.

Will try your vector setting. The edges look clean and smooth and I am using the air assist.

Robert L Stewart
07-15-2010, 11:00 AM
Thanks Ross,

My first though was that the black core was melting. I will try rastering at full speed. Now that it's daylight here I can see that I have engraved way to deep into the core.

I am using the air assit, no pin jig just the honey comb table. Cutting edge looks ok to me but then I have nothing to compare the end result to. Will also try the edge sanding. My day job is cabinet making so I have plenty of good grit at hand.

I have a case of "Countertop Magic" from back when I did plastic laminate counter tops. Will give that a try.

Scott Shepherd
07-15-2010, 11:08 AM
I'll just throw something out there to try, try less power. Many of the products from Rowmark take very little power to get through the top cap. On my 45 watt, I can get through the top cap with as little as 17 power on some materials and most of them in the low 20's on the power. I have found that too much power can cause all sorts of weird finishes and patterns to appear in the engraving.

Might not work in this case, but I'd try less power if you're just playing around.

Mike Null
07-15-2010, 12:49 PM
I don't think a deburring tool is the tool you need for this kind of work. The proper tool is the beveler. You can make smooth straight edges as well as beveled.

Randy Digby
07-15-2010, 2:44 PM
Something I picked up here when we converted to laser - When I do equipment labels, I draw and raster a box around the perimeter of the label which makes the label appear to have had the edges beveled. I typically draw the box and make the lines .050" wide with the outside of the lines on the cut line. This is not the same as beveling but it sure looks better than nothing.

Rodne Gold
07-15-2010, 10:31 PM
We dont even use a deburring tool in my workshops on most straight cut stuff - just the inside edge of a pair of scissors (the flat bit ).
Deburring tool works better when there are curved bits.
Rastering a border can make a job take a huge amount longer - rather use a multiline contour with overlaps and vector engrave it and then cut using the outermost contour.

John Noell
07-15-2010, 10:45 PM
On the MG+ vectoring, I use a the max freq of 5000 - the edges are nicer.

Robert L Stewart
07-17-2010, 1:45 AM

Thanks for taking the time to respond.

Your idea of using a multiline contour with overlaps and then vectoring is interesting. Not sure I understand what that means or how to do that in Corel Draw. I can see the savings in time by not rastering a border around the outside edge as Randy suggested, I think I would like that look though.

I will try to post a file. Perhaps you have a sample image/file or you can show me what you mean in Corel Draw.


Robert L Stewart
07-17-2010, 5:12 AM

Excuse my spelling of your name :). Thanks for the quick help with doing attachments. The file I spoke of earlier is encluded. Will appreciate any tips. I have only played with the contor tool so far. Not very clear on how to use it sometimes.

Dan Hintz
07-17-2010, 8:16 AM

It's actually Rodney, be he prefers to play with our minds ;)