Test Pattern uploads

General discussion of laser machines

Test Pattern uploads

Postby dcassyc1 » Fri Mar 02, 2012 1:54 am

Hi all
I have uploaded a zip file containing 9 raster test patterns. The file contains 3 raster images in resolutions of 72, 200 and 500 dpi each. Would someone please run them on a laser engraver to see if they work out OK.
The largest image is 2 inches wide, and the staristep and multuburst images are 1 inch high.
If you can get them to run on your laser engraver, please let me know so that I can attempt to get my laser engraver working. I have been unable to ge my DSP version 2 board to control the laser current which exceeds 20 MA at each try. It cuts vectors OK, but engraving is not working for me.
cheers,
Denis
Attachments
test.zip
(1.13 MiB) Downloaded 787 times
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Re: Test Pattern uploads

Postby twehr » Fri Mar 02, 2012 12:04 pm

Forget about rasters or anything else until you get your power control issues figured out. You are killing your tube at over 18ma.

Show us with a drawing exactly how you have things wired up. The DSP is very good and easy to use for power control so it is eith wiring or misunderstanding how to run the software.
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laser current readings during cutting and scanning

Postby LeonS » Fri Mar 02, 2012 1:03 pm

I second Tim's advice.

Also, the reason you are seeing a difference in current is because you are reading the average current over a period of time. During cutting the laser is on steady so you read current reasonably close to the working current of the tube. During raster scanning the current is 0 part of the time so the average goes down.
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Re: Test Pattern uploads

Postby dcassyc1 » Sat Mar 03, 2012 9:37 pm

Hi Guys

and thanks for the reply. Believe me, I am well aware that I'm killing this laser tube by overdriving it. Thanks for the warning and the acknowledgement. It's good that we are in agreement on this overdriving issue and I, for one, don't think we have to mention overdriving the laser tube in the future. I am sure that when it finally engraves properly. it can be controlled to never exceed 18 MA. Im tje meantime though, I sure ain't gonna stop trying to get it to engave and if It exceeds 20 MA while I am trying to get it to run, well I guess I'll just have to halt the run and most likely try another scheme, AKA getting back on the horse.

Please take the time to answer the four questions that I've raised which are all preceeded by a 'Q' . I'm trying to get the correct directions. Charging the issue with emotion probably won't help. I'm upset too. I'm not going to " Forget about rasters or anything else " either, because as you can see, without trying to test the engraving functionality, I'll never know if I have power control issues. It's sort of a catch 22, or a circular argument. Please help me to get the engraving functionality working. I'd appreciate if someone would send me a small file. If the laser current goes to maximum when I try to run it, I will halt and try another wiring/config/etc strategy, until I get it working. I'm diligent enough to halt the run if the laser current is flat out at 20 MA. Once again, thank you for the warning.
I hope we can drop the overdriving warning.

This reason I originally posted, was to pony up some raster images so that someone could run them on their machine to confirm they do in fact work OK , and then maybe they can email their toolpath to me so I can set up my rig to engrave like theirs. Maybe that's not a reasonable plan. The images are small but likely large enough for testing the DSP/laser chain, biggest dimension is 2 inches. There are 10 step grayscales, and an indian head test patterns in three sets of resolutions. Here's the reasoning: I'm here with a pile of hardware ( K40 rabbit ) which might bear some similarity to other user's setups. I don't know if the config or wiring is correct. Besides that, I'm not sure I've got a good toolpath to run. However, If I had a good toolpath that was proven on another similar machine, that would eliminate at least one variable, and then perhaps I could set up my machine like the test machine and mine will work too.

Q1. Is that a sensible approach to getting my K40 laser to engrave pictures or raster images?

I don't see any area on this fourm where I could download that sort of test tool file containing these 4 parts: 1 orignal, 2 engraved, 3 toolpath, 4 config file and 5. wiring diagram.

I will try to explain it another way: here's an original subject picture, here's a shot of the laser engraved original picture, here's the code (or toolpath) that produced that engraving, and here's the config files and wiring diagram used to set up that particular test engraving machine. If there was a standard picture, engraved picture of orignal, toolpath and config files or settings available then I could download all, and wouldn't have to go through all of this. But I haven't seen it. And I think someone just recently, raised a concern about or suggested a need for ' test patterns ' , but it was late at night when I read it, so I probably misunderstood. Perhaps these files that I uploaded could be used for test patterns, why not look at them and let me know.. Please note also, I never ran them and can't vouch for their merits. They have resolution and 10 step grayscale features that are easy to see, and because they were used to setup B&W TV raster cameras from days of old, they might be good tools to quantify performance.

Q2 What's you opinion of the subject matter? Are they garbage, maybe they are good - would someone please take the time to look at them and advise?

Q3. Are these laser engraving machines doing rastering when engraving?

I am attaching a picture of the wiring diagram and pictures of the installation too. I've tried several wiring schemes, none of which had produced positive results.

The laser current does ramp up and down when a potentiometer is connected to the Power Supply, so I conclude that the PS is controlling the laser current in response to analog input control voltage. The current will ramp up from 0 MA to >20 MA smoothly, tracking the 0 to +5VDC analog control voltage.

Q4 Based upon this analog test procedure, does the Laser Power Supply test OK?

I'm not ragging on anyone or bitching. I'm trying to get this K40 rig to engrave since abandoning the project in frustration last September.
I have shipped this DSP back to Marco and he produced a video of it engraving, which I could not duplicate. So, I shipped it to King at Thunder laser in Hong Kong, and he had it engraving successfully also.
Now, if I had wired this board exactly the same as these 2 gentlemen had wired it, and the test procedute for the Power Supply current control is OK, can someone give me any suggestions to get it engraving.
By the way, King's power supply was identical to mine.
The attached wiring diagram is the most recent, I've tried them all, and there's no difference in the performance - maximum laser current always on engrave.

Cheers,
Denis
Attachments
DSC_5197.JPG
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Re: Test Pattern uploads

Postby dcassyc1 » Sat Mar 03, 2012 9:42 pm

here's the wiring diagram, I botched the attachments.
cheers


Denis
Attachments
DSC_5197.JPG
DSC_5198.JPG
DSC_5200.JPG
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Re: Test Pattern uploads

Postby lasersafe1 » Sat Mar 03, 2012 11:21 pm

I have uploaded the image I created for the Black Granite Einstein engraving in my gallery entry. This was a compilation from 4 separate images. I would have uploaded the coreldraw file that I actually launched to engrave, but .cdr is not an allowed format for upload. It has been 1bit dithered at 300dpi.
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Re: Test Pattern uploads

Postby twehr » Sat Mar 03, 2012 11:52 pm

I have used your test image of the Indian head. I'll make the following observations which you are welcome comment on or to ignore as you wish.

1. The images you provided are indexed color or rgb.
2. I don't recall you mentioning if or how you may have dithered them.
3. The wiring you show is not standard. You don't need the jumper from pin 5 of the L1 to pin 1 of L1. You are tying that to ground. In the Minimum Connections documentation (attached) from Light Object, pin 5 is not connected at all.
4. You board appears to be exactly the same as one of mine. I am using L1 pins 1,3,4 (three going to the TTL input). The others just as you have them. If you are using TTH, then you want pins 1,2, 4 as you have them, but without the jumper between 5, and 1.
5. You comment that you are getting nothing but solid burns, means you will never get good results until you get your wiring correct. (Seems you have already rejected the idea of fixing that first, but if you can't control the output, how do you plan to get usable results?)
6. Don't recall you mentioning what material you were trying to engrave on.
7. I don't think you need additional test files. The one(s) you have are fine. If you can't engrave them, you won't be able to engrave anything else either.

(EDIT- I had the TTL vs TTH incorrectly annotated in Tim 4 above. Now corrected. )

Here is your Indian head file, cropped to the head only, 2" wide. It was engraved at 100mm/s, 30% (works out to 10.9 mA on my setup). Dithered by LaserCAD (or probably PHCad, in your case) at .04, with a scan gap of .04. It is done on Baltic Birch craft plywood.

IndianHead.png


The first thing I would (again, you are welcome to do as you wish) is to disconnect pin 5 on the Laser 1 output of the DSP. Then try your file again.

I also ran your full IndianHead test pattern file, scaled down to 2" wide. Ran it the same as the above settings, but dithered at .10 and a scan gap of .10. Considering how small the image it, it turned out pretty well too.

IndianHead2.png
Attachments
DSP TYPICAL MINIMUM OPERATIONAL CONNECTIONS.pdf.pdf
(2.72 MiB) Downloaded 843 times
Last edited by twehr on Sun Mar 04, 2012 12:59 pm, edited 1 time in total.
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Re: Test Pattern uploads

Postby twehr » Sun Mar 04, 2012 12:16 am

lasersafe1 wrote:I have uploaded the image I created for the Black Granite Einstein engraving in my gallery entry. This was a compilation from 4 separate images. I would have uploaded the coreldraw file that I actually launched to engrave, but .cdr is not an allowed format for upload. It has been 1bit dithered at 300dpi.


John,

Where's the uploaded file? Never mind - I found it. Thought it was supposed to be attached to this post, not your other one.

(Would you send me the CDR. I'd like to play with it. tim dot wehr at gmail dot com)
tim
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Re: Test Pattern uploads

Postby dcassyc1 » Tue Mar 06, 2012 3:13 am

Hi all,
I'm glad the test patterns worked out OK
Sorry I can't do anymore wiring interfaces. Believe me, I have tried them all. Besides, I had it wired exactly the same as Light Object and Thunder Laser who both had this particular board engraving. I went to the hassle of sending both firms this particular board and the I used their wiring schemes and config settings explicitly, and never got control of the laser current on engraving. I read about other people's experiences too, and relaize it's my turn in the barrel. I simply cannot proceed any further. I figured if I threw enough at the wall some of it would stick - wrong.
I pulled out all the parts, it says:
PHcad Ver 2.0, there's a control panel, connecting cable, USB stick.
If you're interested in buying this setup, let me know because it's going cheap, and if you can give any advice on how to sell it off please contact me at
fprckq@shaw.ca
I'm out $200 for duty charges alone not including shipping, absolutely bizzarre.
I sent an email to Marco yesterday but no reply so will phone him tomorrow.
This stuff must have some value for someone.
Thanks for your time.
Denis
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Re: Test Pattern uploads

Postby twehr » Tue Mar 06, 2012 11:18 pm

Hate to see you give up.

You never did say whether you were dithering the images or not. If not, that will make any photo look terrible, as the auto dithering (your model) does just turns anything <50% gray to white and anything >50% gray to black. The newer version seems to use a better algorithm so the default is at least presentable. I have seen lots of people forget (or not know) to dither before running the job when importing anything > 1 bit images. Of course you can do the dithering externally and then it is just an import and run operation.
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