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stefan karlsson
10-15-2012, 8:46 AM
Hi, This is my first post here so donīt be mad if I write in wrong post :)

I tried to engrave a sign on a acrylic sheet and the results are BAD. Do anyone know why this happens ???

I have cleaned the mirrors and lens. And also the rails. 243280

Thank you !!

Mark Bowman
10-15-2012, 9:07 AM
Are you using cast or extruded acrylic?

Scott Shepherd
10-15-2012, 9:09 AM
Isn't it obvious? You should have been engraving "Manchester United" :p

What machine do you have? It's fairly common. I've seen it many times.

Reduce your power greatly and change the black to 80% black or 90% black, take the machine out of focus by .030" or so (lower the bed, making it .030" away from from laser).

stefan karlsson
10-15-2012, 9:59 AM
I will try with Manchester Logo :)

I am using a China laser 80W (Thunderlaser) Itīs cast acrylic. Idonīt know howe to change the black settings, I am just using Corel to "make" the job and then export it to a program called PH Cad.

Donīt understand why its just some times :(

Thanks for the quick answers.

Scott Shepherd
10-15-2012, 10:07 AM
It's not just you, that's a common problem.

In Corel, click on the graphic or parts of it,one at a time, if you need to, and instead of black, pick the color "85% Black" or "90% Black". It's actually a color you can pick from a dropdown box when you pull up the color dialogue box.

Reduce the power and take it out of focus.

Scott Shepherd
10-15-2012, 10:13 AM
Should look something like this :

243282

Ross Moshinsky
10-15-2012, 2:56 PM
I've engraved a lot of acrylic, 100% black has never been an issue for me.

What does the artwork look like? It's it one color artwork or is it multi-color artwork? If it's a multi-color version, you should either convert it to a one color version or look into processing the artwork so that it creates the proper half tones using the Gold Method or something similar. I wouldn't trust the Chinese software to do that for you.

Scott Shepherd
10-15-2012, 3:49 PM
or look into processing the artwork so that it creates the proper half tones using the Gold Method or something similar. I wouldn't trust the Chinese software to do that for you.

That's exactly what converting it to 90% black is going to do, that's why I suggested it.

Ross Moshinsky
10-15-2012, 5:23 PM
That's exactly what converting it to 90% black is going to do, that's why I suggested it.

Actually it's not. You're counting on the Chinese software to convert it to "half tones". Would you trust Chinese software to do that properly?

walter hofmann
10-16-2012, 7:01 AM
hi there
you should never use the halftone dithering with PHcad. I do alot of acrylic engraving even picture for edge lighting and PHcad can not work with half tone actually the whole dithering process in PHcad does not work well at all. I use ether corel photo paint to convert and send the picture to phcad or from corel draw.

just finishe the work in corel and use the phcad as driver to the machine.

what version of the thunder you are using??
do you use PHcad 4.47 or have the latest 2012 version

greetings
walt

Ross Moshinsky
10-16-2012, 7:48 AM
From a bit of experience, there is absolutely no reason you should be engraving a logo like that in full color anyway. That should be engraved as a one color logo. If you do a Google image search you'll find that Arsenal themselves use the one color logo very often. There are times when you have to look at using a full color logo but most of the time, you want to use the one color logo. Any time you try to start doing full color logos, you have to do a bit of experimenting to make sure it's going to look right. That can take time and cost money.

For experimenting, absolutely try getting a result from messing around with full color logos. There will be a day where you are required to engrave one and it's better to have some knowledge then no knowledge. Just know on a day to day basis, it's more practical and the results are better if you stick with one color logos. I'd say well over 95% of the logos we engrave are one color logos. It simply works better and frankly, it's the industry standard.

stefan karlsson
10-16-2012, 7:58 AM
Hi,

I am using v.4.47, How do I get the new version ?? I dont use dithering from PHCad. The arsenal logo sometimes turns out good and some times bad. I engrave Iphone shells to and the result is the same here :(


Best Regards

stefan karlsson
10-16-2012, 8:05 AM
243396This is the result when engraving on aluminium :(

Ross Moshinsky
10-16-2012, 8:43 AM
You're ignoring the artwork element.

I've attached what the artwork should look like for engraving as per what Arsenal uses themselves. If you want to use the full color version, you're going to need to do something like the Gold Method to get it to engrave right. Your Chinese software will never do a good enough job.

Kees Soeters
10-16-2012, 10:14 AM
Just tested a few things.. I took a color logo from the internet, scaled it to ~3cm (~1.2") high with 300dpi, inverted it and converted it to 1bit with dithering (in that order)..
For this i didn't use scripts like Goldmethod or PhotoGrav.. Just converted it from color to 1Bit..
Imported this picture in PHCad, asigned it to 250mm/s 40% power 0,07mm scangap and pushed the button on a piece op anodized scrap aluminum..
No strange behaviour on my Thunderlaser controler..

Kees

walter hofmann
10-16-2012, 3:36 PM
Hi my friend
you are out of luck thunderlaser does not provide any update or newer version of PHcAD.
WHAT ARE YOUR MANUFACTURER SETTINGS?? the laser frequency should be at 20,000 , set it on precission cut .
what format has the logo? is it bmp? with BMP you should trace it in coreldraw with color selection black and white and safe the trace with a new name
and send this over to phcad.
maybe this helps.
gretings
walt

paul mott
10-17-2012, 6:17 AM
Stefan,

From your first picture it would appear that you have severe horizontal banding which is usually caused by variations in the tube’s output power density.

I don’t know if this is any help but I initially had a similar problem which was traced to variations in the incoming mains voltage level. This in turn was traced to a thermostatically controlled workshop heater and the auto-start shop air compressor which when re-wired on to a different circuit to the laser completely cured my problem.

Paul.

Kees Soeters
10-17-2012, 11:58 AM
the laser frequency should be at 20,000
Hi Walt, can you explain why? i have set mine to 50,000 and have no complaints...Thought it would be better to get higher resolutions... but if 20,000 gives better results for a reason, i will switch over... (how to test??)

Kees

walter hofmann
10-17-2012, 4:29 PM
Hi kees
any CO2 lasertube can only take a maximum frequency because of the inertia of the corona parts . the manufacturer max frequency should be up to 25,000.
I personaly use exclusivly 20,000. the PWM powersupply usually can not provide stable output of more then 40,000 .
the lower the frequency the more stable the beam.
you could test it if you engrave a line with around 80 mm/s and the same power about 15% then change the frequency after each run and note it then compare.
greetings
walt

stefan karlsson
10-18-2012, 4:22 AM
Hiiii.

I will check the settings today. I have some other questions about the different options in software/hardware and I hope that you will/can help me :)... And please forgive my speeling (Im just a sweed) ;)

walter hofmann
10-18-2012, 6:07 AM
no probleme you can send me a PM at a542002@hotmail.com.
greetings
walt

stefan karlsson
10-18-2012, 6:18 AM
Hi :)

First of all I want to say thanks for all the help I have received. It really means a lot to me..

Here is a picture of my settings. What does FOCAL LENGTH AND FOCAL MULTIPLE means???

243532243534


Thanks :=)

stefan karlsson
10-18-2012, 6:33 AM
Hi Kees,

what strength do you have on your tube ? I have tested to vector the image and BMP Too, I do the BMP in Corel and the DPI is 500.

stefan karlsson
10-18-2012, 6:43 AM
Hi Ross, I just saw your picture you sent me, I'll try it. Thank you for your help.

Kees Soeters
10-18-2012, 6:52 AM
you could test it if you engrave a line with around 80 mm/s and the same power about 15% then change the frequency after each run and note it then compare.

Hi Walt, Thanks for the answer... I tried this morning. First i engraved a wide box an a small image on a piece of acrylic with 50.000Hz Then the same with 20.000 and even a set with 5.000HZ.
In between i switched off and on the entire macine to be sure this parameters where active (some only become effective after a cold-boot)
Even with a magnifying glass i really cant see any difference so i left it at 20.000..

@ Stefan: What i have read somewhere: Focus does add some extra to where your auto focus sensor is triggered.. So if you enter a value of 10, your bed will lower 10mm after triggering the autofocus sensor.

Kees

stefan karlsson
10-18-2012, 7:39 AM
Thank you Kees, That makes sens :)

stefan karlsson
10-19-2012, 5:56 AM
Iīm back with more noob questions :) 243573

Can you tell me what this is ? I donīt understand the Software manual :(

Rodne Gold
10-19-2012, 8:21 AM
If you change your motherboard/controller and lcd panel , cost around $4-500 , you can run better software..I think PHcad was a forerunner to RDcam and laserworks..
a new controller will work with your tube and motion system and stepper motors and stepper drivers..might be a little fiddly to wire compared to your old motherboard/controller
The pic you just posted of actual vs expected is most likely to compensate for mechanical errors , that is , lets say you draw a line of 10cm and it actually measures 9.8cm on the engraved item , the software will correct it so you get 10cm engraving for a 10cm designed line.

Kees Soeters
10-19-2012, 10:55 AM
Can you tell me what this is ? I donīt understand the Software manual :(


There are probably several manuals..
This is a calculator to calculate your pulse unit..
Say you have a pulse unit 0f 1.00 for the X-axis. When you want to draw a box of 200 x 200 mm and the laser only draws one of 63 x 63 this is obvious too small:
You expected one of 200 but you got actual 63.. When you enter 200 in the Expected field and 63 in the Actual field and press OK, you will see the value of Pulse Unit alter..
If you draw your box of 200 x 200mm you will probably get one of 200x200, or at least very close to that..

Kees

stefan karlsson
10-25-2012, 11:57 AM
Thanks for all the help friends,

I have bought a UPS power battery and I can say it help allot, I have 2-3 machines on same switch and the UPS makes the AC power stable all the time.

BIG recommendation to buy, Only costs about 200USD In Sweden. Here is the link:http://www.trust.com/products/productpictures.aspx?artnr=17679

Best regards Stefan

Shane McGinley
10-25-2012, 12:31 PM
I am having a similar problem with the lines within the cast acrylic once engraved, especially when engraving pictures. Could this be caused by power fluctuations?

paul mott
10-25-2012, 12:46 PM
Thanks for all the help friends,

I have bought a UPS power battery and I can say it help allot, I have 2-3 machines on same switch and the UPS makes the AC power stable all the time.

BIG recommendation to buy, Only costs about 200USD In Sweden. Here is the link:http://www.trust.com/products/productpictures.aspx?artnr=17679

Best regards Stefan

Good choice Stefan. I hope this resolves the banding problem.

Paul.