Full Version: Need help and advice engraving Rowmark plastics,red core etc.
From: Larry B (PALMETTO) [#1]
30 Mar 2007
To: ALL
I have been working with some Rowmark engraving plastics with a red core and having some difficulties. The first one I tried was Rowmark 800 series textured. I started out engraving it at what the Epilog manual recommended for laserable plastic. I recall from memory that it was like 100spd/40pwr at 600dpi. That did not work at all on the first pass,didn't get through the cap.I finally figured out that particular product has an .007 cap instead of the more common .003. So, after several attempts, I finally got through it at 100/100. It was white/red and looked decent.
Next was some Rowmark Metalgraph Plus 316 Brushed stainless over red. This has an .003 cap. I'm expecting to get a nice red on the first pass with the recommended setting. No luck. So I increased power etc., slowed speeds etc and it finally showed me the red..it looked more pink than red. I definitely got through the cap and then some but the red was quite dull, no pop.
I need an outdoor material with red letters, for a sign I am making ,thus the selection of these products. My laser is a Epilog 40 watt Legend EXT. Could I get the benefit of the forum's experience with red core plastic and engraving of plastics in general. I have engraved a lot of plastics with rotary but I am new with the laser. I'm a bit frustrated with my results so far.
From: ab_laserart [#2]
30 Mar 2007
To: ALL
Hi Larry,
I'm not going to pretend to be the ultimate expert in Rowmark Metalgraph engraving, but I did stay at a Holiday Inn Express last night. Sorry, couldn't resist. I did engrave on brushed steel over black this morning and got some very pleasing results. My laser is 60 watts and I ran it pretty slow with pretty low power: 40% speed and 23% power. Interestingly I ran it with the factory mask still on and it worked great -- later I tried the same settings on some green over white Lasermark and it didn't work at all. Go figure.
HTH
Ron
From: Larry B (PALMETTO) [#3]
31 Mar 2007
To: ab_laserart [#2] 31 Mar 2007
Ron:
Thanks for the reply. I'm going to run a little test this morning using the color mapping feature of the driver. I have laid out 12- 1/2 x 1/2 squares on a sheet with different colors. The first 6 are the default RGB colors in the driver now. I am going to add six more to it. Then I am going to assign various settings to each and see what I get when I run the test on the material.
One question relative to your answer. If you ran at 40 speed and 23 power with 60 watts, would that mean that with my 40 watt would I run with 40 speed and 36 power? The logic being that your 60 has 20 watts more power or 50% more than my 40, thusly making me need to increase my power by 50% over yours? Does that logic apply? I know that lasers aren't linear with speed, does that apply to power also? I'll test that combination when I do my test anyhow.
From: Harvey only (HARVEY-ONLY) [#4]
31 Mar 2007
To: Larry B (PALMETTO) [#3] 31 Mar 2007
That logic will get you in the ballpark. Nothing is accurate on lasers. The tube power varies and the non linear curve for the speed vs power, and the percentage of power really delivered.
Add to that that the pulses may be a higher power on a high power but for a shorter time.
So it will give only ballpark settings. (A guess is that it will be within 10%, but might be as much as 20% off.)
From: ab_laserart [#5]
31 Mar 2007
To: ALL
I concur with Harvey -- it gives you a decent starting point but not much beyond that. The sad proof of that is the fact that the settings I quoted you for one Rowmark product didn't work on another Rowmark product (not even close really). One thing that I didn't mention was the resolution: mine is in metric so I'm not going to try to translate to dpi right now, but I ran the passes quite close together -- about 85% of the way to peak resolution.
Ron
From: Larry B (PALMETTO) [#6]
31 Mar 2007
To: ALL
Thanks guys!
I did the test I referred to earlier. I'm going to attempt to post it here. (haven't posted any attachments yet). I ran it on the Metalgraph Plus. I used color mapping in the driver to set up 10 squares-1/2 x 1/2 and ran them at the associated speeds and power at 400dpi and 600dpi. The results are pretty evident that on my machine I got a better result with this particular material at 600dpi and slower speeds, higher power.