Full Version: Vector cut problems - ridges in all materials
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
From: Upacreek [#21]
10 Mar 2005
To: ALL
Thanks everyone for the input. Since I haven't seen other's laser engraving it's hard for me to compare what is correct or not.
When I talked to Tech Support today, I was informed that they look at some of the forums too, but that I can't expect to see the same results as others who have different machines then I do and that I should not rely on any comments other then what Tech Support tells me. Even though you guys are doing it for a living, they know best.....
I sent full size pictures (no cropping or editing smaller) and Peck said he couldn't see the horizontal lines in the acrylic example I posted. Also that I can't expect acrylic to laser as well as other plastics.
I had Peck confirm that I was focusing correct, and that my settings were acceptable (similar to their manual recommendations) so I do not see how it can be user error. (Which I am fully willing to accept - as long as I'm told how to correct my errors!) I even offered to put the machine on the floor to rule out any type of microscopic table wobble!
I have already done an alignment test to all 4 corners (several times) and I have already leveled the table in Nov. (the right side was 2 clicks lower then the left). I clean the machine regularly.
I feel the request for more samples is another stall tactic. I was a computer monster in my former life doing the full gamut from teaching, troubleshooting, documentation, testing, tech support & building the junk (er, software & equipment) for about 20 years and I know what stalling is. (I'm not that old! I started full-time IT work while in Hi Sch.) Requiring more samples on all laser material is a waste of time & product, but they are unwilling to pursue anything until I send more samples.
I'm tired and grumpy so I better stop before effin this and effin that starts showing up.
Oh and sorry, "what creek am I up" ... those are the personalized plates on my CJ5 (Jeep). For those who don't get it. Jeep + Mud = you eventually .... get stuck .... which means "You are up a creek without a paddle"...
AJ - I'll try your settings and see if there is any difference. Thank you.
Michel
From: old man (OLDMAN) [#22]
11 Mar 2005
To: Upacreek [#21] 11 Mar 2005
send me your address and I will send you a sample off of my machine---that way you can compair the outputs----could epilog be stalling as they have never seen this problem before???
aajj at comcast dot net
EDITED: 11 Mar 2005 by OLDMAN
From: bobkat [#23]
11 Mar 2005
To: old man (OLDMAN) [#22] 11 Mar 2005
From: old man (OLDMAN) [#24]
11 Mar 2005
To: bobkat [#23] 12 Mar 2005
I get good results from my 45 watt Epilog Mini. The corners are as smooth as the rest of the cut. The Mini is a new machine and JUST maybe the demand outstripps their ability to test the machines before they ship them.
Hopefully they will get it right soon as word can spread real fast about problems with production. I paid about $15k for mine and that is alittle more than pocket change where I live.
A J Palik
Photon Graphics
From: bobkat [#25]
12 Mar 2005
To: old man (OLDMAN) [#24] 12 Mar 2005
From: UncleSteve [#26]
12 Mar 2005
To: bobkat [#25] 12 Mar 2005