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Author Topic: The Laser Project.  (Read 806561 times)

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Offline Tweakie.CNC

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Re: The Laser Project.
« Reply #260 on: October 30, 2010, 07:49:16 AM »
That's a thought Dave - thank you - I think that may work.

De- focusing a little may also have the same result of smoothing things out a little I suppose but it has become a real challenge now and I have just got to find the actual cause of this phenomenon.
It is so strange that, in the laser world, everybody seems to know about it, nobody admits to it and the cause has just not been defined. If this was the plot for a book it could be a best seller.  ;D

So far, I have checked my Y axis for backlash / slack and also for unequal step size (looking at the line scan spacing under magnification shows no problem). I have measured the time taken to complete each line (feedrate) from the X axis direction signal and they are as equal as I can measure on a chart recorder. I have recorded the incoming mains voltage and there is some fluctuation, but not much, certainly not in steps like the images show however I have a UPS voltage conditioner coming for a trial. And finally, for the test sample, I have matched the vertical image size and stepover exactly to the number of vertical pixels.

The saga continues.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline budman68

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Re: The Laser Project.
« Reply #261 on: October 30, 2010, 07:52:49 AM »
Can't say you're not "trying" !  :D

Good luck, my friend-
Dave
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Just because I'm a Global Moderator, don't assume that I know anything !

Dave->    ;)
Re: The Laser Project.
« Reply #262 on: October 31, 2010, 04:38:57 AM »
Does the banding consist of only one line or is it several lines next to each other? Wonder if the result would be the same if you applied some force to your x and y axes like a spring or a wire running over a wheel and a weight in the end of the wire so that a force is applied to the axes. Then any backlash would be ruled out completely.

Offline Tweakie.CNC

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Re: The Laser Project.
« Reply #263 on: October 31, 2010, 11:33:03 AM »
The banding I am referring to consists of many lines and can probably be seen best in this image http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=22163;image which consists of just two shades (black & white).

Not sure if I should show this because it may confuse the issue but the image below is a good example of color depth banding (similar but not the problem I am referring to) where the background consists of more shades than the eight which the Mach plugin can handle. As a result the background is stepped into bands that best match the true shade. The dithered image itself is unaffected by this procedure.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline Tweakie.CNC

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Re: The Laser Project.
« Reply #264 on: November 10, 2010, 03:17:22 AM »
I think that the ‘Banding’ issue is going to have to go on the back burner for a while – it is not going to be easy to find the answer to this. After much checking and testing I am now convinced that it is not a mechanical thing which leaves software and electrical still to be investigated. I have had bit of a setback on the UPS voltage conditioner which, due to some regulation or another, has had to be shipped without it’s batteries so this is turning into bit of a drama.
I will find the solution to this banding issue - just not today.

Meanwhile, I have been fortunate to have some help from Dar303 who has shared the design for his RF laser controller.
From his layout, schematic and PIC hex dump I have made the PCB, programmed the PIC and tried it out with my Synrad J48. Excellent work Daniel you have done a really good job there.

I still have some more testing to do with regard to ‘pulse width’ and ‘pulse repetition frequency’ which both seem to affect power density in a similar way but each have a different effect on the work piece. Once this is complete I will have a better understanding of exactly what is required to get the best results from the RF tube under Mach control.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: The Laser Project.
« Reply #265 on: November 11, 2010, 05:12:59 AM »
Hi Tweakie

Have you see the new Laser/impact Engraving plugin that Art insert on this message?
 http://www.machsupport.com/forum/index.php/topic,16446.msg111335.html#msg111335

You had realized that there was an error in the old DLL?

You saw the description I made for the construction of the solenoid?
What do you think, very simple is not?

You remember that some time ago I have asked about this?

Andrea

Offline Tweakie.CNC

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Re: The Laser Project.
« Reply #266 on: November 11, 2010, 06:09:20 AM »
Thank you for the update Andrea.
I have not seen or heard about the latest DLL, I am still using various 'workarounds' with the old version.
I have downloaded and will try the new one.

I will look at you solenoid next.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline Tweakie.CNC

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Re: The Laser Project.
« Reply #267 on: November 24, 2010, 07:30:22 AM »
Another little circuit board - this one is for the development of the PIC microprocessor program and circuit for the 'Pulse Repetition Frequency' and 'Pulse Width Modulation' part of the RF laser control unit.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: The Laser Project.
« Reply #268 on: November 24, 2010, 07:50:58 AM »
Sweet, I have a couple of boards I need made, any chance your for hire? ;)

Offline Tweakie.CNC

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Re: The Laser Project.
« Reply #269 on: November 24, 2010, 08:10:11 AM »
I will do your boards if you do my tree trunks.  ;D

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.