Full Version: Vector cut problems - ridges in all materials
From: Upacreek [#1]
9 Mar 2005
To: ALL
Hi. I bought an Epilog Mini 45-watt back in August.
With every material I vector cut, whether thin wood, acrylic, leather, rowmark laser plastic, paper, you name it, there are ridges along the edges like you would feel on an quarter or dime.
The horizontal cuts produce lighter ridges, while the vertical cuts are more prominent and the rounded cuts are the most prominent. I need to take sandpaper to the Rowmark plastic to smooth the edges.
I have sent samples to Epilog twice now (Nov & Feb). Today they have finally responded with basically a "deal with it" attitude. My Epilog Sales Rep has been non-existent since the sale was completed.
Is it true that I should have these ridges on all my vector cuts (doesn't matter how fast or slow I go)? The Epilog manual certainly states different - that Acrylic should "produce an almost flame polished edge" and that "Laser cutting produces very nice edge quality without the need for polishing or secondary clean up."
Michel
From: Harvey only (HARVEY-ONLY) [#2]
9 Mar 2005
To: Upacreek [#1] 9 Mar 2005
I have a ULS/NH machine and the only time I get that is if I try a material that is too thick for the machine. (25W and 1/2" acrylic with multi passes.)
I get a faint set of lines that can only be seen by getting a reflection off the edge with 1/4" acrylic. Even that can be reduced by exact settings.
The only advice I can give is generic for a well operating machine. Try increasing your pulses per inch. If it is pulsing, that will help, if it is beam shape or power it will not. The description of the edge of a quarter is a good one. (Even on the over-thick pieces, that appears only near the bottom of the piece, the first 1/4" is smooth.)
[What creek is that which you are up?]
From: Upacreek [#3]
9 Mar 2005
To: Harvey only (HARVEY-ONLY) [#2] 9 Mar 2005
Thanks for the response.
This is happening with Rowmark Lasermark, Lasermax, Laser thins, etc (and everything else). These are all far less then 1/8" thick so thickness is not an issue as the 45-watt laser easily cuts it.
I've tried changing the frequency from low to high and tried auto-focus instead of manual focus.
These ridges show up all the way through. The ridges do not change if I turn off air assist.
These ridges show up with just a simple rectangle, line or oval created in Corel 12.
Michel
From: Harvey only (HARVEY-ONLY) [#4]
9 Mar 2005
To: Upacreek [#3] 9 Mar 2005
I wonder if you have a tube problem, or maybe a tickle problem.
It sounds like you are not getting the firing the way you should.
If you can post the wattage+%, the speed+%, and the type of acrylic that you use for 1/4", I can check that against my settings and see if there is a big difference. If you seem to need a lot more power than I do for the same product, it may indicate a firing problem.
These settings should be just enough to go through the 1/4" plus about 15% for a guaranteed cut through.
From: Upacreek [#5]
9 Mar 2005
To: Harvey only (HARVEY-ONLY) [#4] 9 Mar 2005
Thank you.
It's an Epilog Mini 45-watt with their lastest print driver on Epilog's site.
Latest plastic has been the Rowmark Lasermax about 1/16" thick (.0625). I've tried it at 40 speed, 100 power and 5000 frequency. Slowing it to 20/100/5000 produces too much burnt area but less prominent ridges.
It was REALLY evident with an oval cut (like the shape of a Peterbilt logo), but it also evident with a square/rectangle with or without rounded corners.
Not sure if this is related, but my raster images also produce fine lines if I engrave a black square on acrylic, plastic, etc.
Michel
Forgot to add.. I don't have any 1/4" acrylic on hand...
EDITED: 9 Mar 2005 by UPACREEK
From: Engravin' Dave (DATAKES) [#6]
9 Mar 2005
To: Upacreek [#1] 9 Mar 2005
Upacreek,
Your frequency settings appear to be way to high for laserable plastic. I do not have an Epilog manual for a Mini, but I would anticipate that the recommended frequency setting should be closer to 500, than 5000. I base this comment on what my experience has been and that a 45 watt Legend EX has recommended settings of 40 speed, 30 power, 500 frequency for laserable plastics.
From: Rodney Gold (RODNEY_GOLD) [#7]
9 Mar 2005
To: Upacreek [#1] 9 Mar 2005
Ridges can be caused by multiple factors
1) Loose motion system (fine lines sound like the y axis might need adjustment?)
2) Too low a PPI
3) The design package is not doing curves properly
4) Curve interpolation in the driver is set too low (if it has this)
5) Not getting the melt the laser produces being ejected at the back sde of the cut (use a cutting grid)
5) Incorrect air assist pressure - resulting in a rapid cooling of the material.
6) Problems with an encoder in one or both axes (ie its not sensing position correctly.
7) A problem with the laser source
8) incorrect focus
This is not a "live with it" type problem , it's a real problem that affects functionality of the machine and you need to get it sorted out - I don't have the machine you do , but would never accept it on mine.
Try vector engraving a set of closely spaced concentric circles , IE not cut but just engrave , and try this at various speeds , espcially low speed (just drop the power)
if the quality of the circles is very good , it rules out anything to do with the design package and most likely rules out motion system problems and you can investigate further.
In terms of air assist , you want to back off till flaming occurs and then whack it up a bit to stop flaming but to get a smooth melt.
If you arent using a cutting grid , do so
As to your driver an PPI , I cant help as Im not at all familiar with your machine
The laser source might also be struggling when being asked to deliver higher powers for some reason or another , your tech dept should help there.
As to focus , if you have a 2" lens , then the distance to your workpiece from the bottom of the lens should be as near to 2"s as possible
Hope some of this helps
From: Upacreek [#8]
9 Mar 2005
To: Rodney Gold (RODNEY_GOLD) [#7] 9 Mar 2005
Thank you for the input Rodney. It is greatly valued.
For this test, I used Rowmark Lasermax plastic. The Epilog Mini uses speed/power/frequency for vector cutting
I ran several circle vector cuts with both 600 & 1200 dpi and the results were nearly identical.
Running at slower (at 1/1/500 & 1/1/5000) produced a cleaner cut, yet there are still faint ridges visable when the laser changed directions in the lower right & upper left of the curves. The faster it was run, the more the ridges appeared (with both 500 & 5000 frequency)
Air Assist appears to be working okay and I do use a vector grid. (No difference if I elevate the plastic off the grid or not.)
I'm using the 2" lens and according to the instructions, the focus distance is correct too.
Just for grins and giggles I raster engraved several black squares at 600 & 1200 dpi with both the "clip art" and "photograph" dithering options at different speeds. The fine horizontal lines remained the same on all the black squares.
Michel
From: Rodney Gold (RODNEY_GOLD) [#9]
9 Mar 2005
To: Upacreek [#8] 10 Mar 2005
Try vector (NOT raster) engraving the circles , Ie use a high speed and little power , and then drop the speed and the power accordingly , the quality of the vector engraved circles will tell you a lot , perfect circles at all speeds will eliminate the motion system (well it should) and the driver or circle interpolation.
Regards
From: Harvey only (HARVEY-ONLY) [#10]
10 Mar 2005
To: Upacreek [#8] 10 Mar 2005
On the circles with ridges, (like Ruffles), are the ridges appearing to be a movement of the beam or is it a wider opening and then a narrower opening? Wide and narrow relates to a power problem, zig-zag, like a record is a motion problem.
From: UCONN Dave & Lynn too (DANDL48) [#11]
10 Mar 2005
To: Upacreek [#5] 10 Mar 2005
I would call Epilog back and insist in talking to Peck who is the head of Tech Support. I'm really surprised on their attitude, we've never had a problem.
Dave
From: old man (OLDMAN) [#12]
10 Mar 2005
To: Harvey only (HARVEY-ONLY) [#10] 10 Mar 2005
I also have a 45 watt Epilog mini. Do alot of plastics such as 1/8" acrylics , Rowmark laserMax ect ect . You will never get a cut that is perfectly smooth . There will always be some ridges left behind but from what you say it sounds like a tech problem with your machine . Try and call the tech people at Epilog . Their # is in your users manual . Talk to Peck , the head tech guy.
I had a few problems with my mini and he was of great help . If you want you can send me a small sample of your plastics " ridges" on a piece of Rowmark and I can compair it to the output from my machine . Not to tell you that if there is a big problem that I can solve it but might be nice to see where you stand
Hope that is of some help
A J Palik
Photon Graphics
From: Upacreek [#13]
10 Mar 2005
To: ALL
Rodney, The circles I ran earlier were vector cuts. The higher the speed the worse the ridges appear. The slowest speed of 1/1 still produced a few ridges when the laser changed direction on the x-axis.
Harvey, I'm a little fuzzy at the moment. I'm not 100% certain if it's zig-zags or thickness. I think it may be a combination of both on the circles. On the raster squares I did it appears to be thickness as the lines taper at the ends - it's like looking at woven fabric.
Dave, Peck is the only tech support person I have dealt with. My Sales Rep, Phil Tucker has yet to respond. My corncens about his slow response time prior to the purchase have proven to be valid.
From: Upacreek [#14]
10 Mar 2005
To: Upacreek [#13] 10 Mar 2005
Thanks for the response AJ.
What settings are you using to raster engrave and vector cut your lasermax? Ours should be the same settings.
Michel
From: Harvey only (HARVEY-ONLY) [#15]
10 Mar 2005
To: Upacreek [#13] 10 Mar 2005
Can you take a close up digital shot and crop it to a small area. Post the remaining area at at least 4" width and we should be able to see exactly what is up.
If you have Corel Paint you can Resample to 150 DPI and set the width to 4". Then when you save it as a JPG you increase the Compression to where it just starts to show degradation, then back off a bit. Set the Rounding to 0 for best clarity.
From: Upacreek [#16]
10 Mar 2005
To: ALL
Hi. Here's some pictures. The lighting/focus isn't the best, but you get the general idea.
The acrylic was raster engraved with a solid black background. Not sure if you can tell, but the lines are broken up and taper at the ends. I get the same effect with Rowmark laser plastic.
The ridges are on a piece of Rowmark Lasermax plastic. This was a rectangle about 6" long. The whole thing is like this.
Epilog has seen the posts and have contacted me and are requesting more samples on all forms of laser material.
Michel
From: sprinter [#17]
10 Mar 2005
To: Upacreek [#16] 10 Mar 2005
From: Rodney Gold (RODNEY_GOLD) [#18]
10 Mar 2005
To: Upacreek [#16] 10 Mar 2005
What are the manufacturers asking for samples for? Tell them to fix your machine chop-chop and to stop dickering around!!!
From: Harvey only (HARVEY-ONLY) [#19]
10 Mar 2005
To: Upacreek [#16] 10 Mar 2005
That appears to be uneven firing of the tube.
On laserable acrylic I get a white faintly grainy, (dot grainy), result from the fine grain in the acrylic. Those are really lines, laser problem, not material aberrations.
The edge also looks like firing at different powers in an uneven manor. My gut feeling is that the tube is not firing when it should.
From: old man (OLDMAN) [#20]
10 Mar 2005
To: Upacreek [#14] 10 Mar 2005
Here is a few settings that work on my 45 watt Mini
LaserMax Raster speed=100 Raster power=35
Vector speed=28 Vector power=75
Freq.=500
1/8" cell cast acrylic Raster speed=100 Raster power=45
Vector speed=10 Vector power=100
Freq=5000
Hope that puts you in the ball park. Took a look at the pics that you posted and you DO have a problem. My edges have slight ridges in them---YOURS HAS HILLS AND GULLIES.
As I posted eariler---Call tech support at Epilog
A J Palik
Photon Graphics
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