2012 DSP Feature Request : PPI

[Gadroc]

Marco,

I have posted this in other forums but thought I'd repost the feature request here.

Some other commercial laser have the ability to set a pulse rate when cutting. This is usually talking about in terms of Pulses Per Inch (PPI). This would mean instead of turning the laser on and leaving it on the laser would be fired that many times per inch. For example if my machine was stepping at 1000 steps per inch and I set a cut job to 200 PPI the laser would fire every fifth step instead of just turning the laser on and stepping. This allows for much greater control of heat put into a material.

Ideally this would be another cut parameter we could set along with power and speed under the layers properties.

Here is an example of someone implementing it via adding an external control by watching the stepper pulses.
http://www.buildlog.net/forum/viewtopic ... =300#p6989

Here are some other links referring to this behavior
http://www.rowmark.com/mark/laser_guide/pages/intro.asp
http://www.inlay.com/cnc/laser/index.html

Thanks,
Craig

[Tech_Marco]

I'll forward it to the programmer see if he can do it

Marco

[baccus61]

Sounds interesting.
One other thing I would also like is the ability to set up pre-ignition for a glass tube.
Apparently it increases the life of the laser tube and also enables it to engrave a lot better.

On a previous request for the Z axis limit to be able to be stopped, could you set it up in hardware to, say, a zero amount for the soft limits to NOT take effect so you can drive the table up or down when you like and not have to change the limit direction in software and then do a reset to drive the opposite way?.
I know you have said before the limits are hard coded into the board but that might be an easier way around it. It's just a dream of mine.

The U axis setup that Tim has put up doesn't seem to work with this board. I might need to try again and select U axis in software and play around with the settings. I do forget some things sometimes.

[Tech_Marco]

Craig, per programmer, he said that the PWM frequency is desgined for that purpose. You may give a try

[Gadroc]

I don't think they do the same thing. It was my understanding that the PWM Frequency affected the PWM that is used for the Input pin of the laser. This changes the speed of the square wave generated for setting laser power. This is not varied per material it is set once to a compatible setting for your power supply.

I'm asking for a similar control of the TH/TL pin outputs during a cut job. It makes cutting look closer to engraving where I don't bring the TH/TL pins to on setting and leave it there while I move the X/Y Axis. Instead I turn the laser on and off while the X/Y Axis moves. For a PPI of 200 the TL pin would be brought low once every .005 inches of movement in the X/Y plane.

[twehr]

I'm asking for a similar control of the TH/TL pin outputs during a cut job. It makes cutting look closer to engraving where I don't bring the TH/TL pins to on setting and leave it there while I move the X/Y Axis. Instead I turn the laser on and off while the X/Y Axis moves. For a PPI of 200 the TL pin would be brought low once every .005 inches of movement in the X/Y plane.

Marco,

You may remember that on the early versions of the controller, the software allowed you to engrave, cut, or fire dots. You could set the spacing of the dots. It was cool for making dot-to-dot drawing for kids (one dot every 1 inch, for example). It is basically that concept that they are looking for, specifying the number of "dots" per inch of cut path to fire the laser.

I don't know why it was removed when the version 2 controller came out, but maybe it is something that could be added back in rather easily, based on the old behavior.

[baccus61]

I have seen some settings/3d graph for the PWM controls for a CO2 laser and they are used for cutting or engraving different materials. Wood might engrave very nicely at 2,000KHz PWM but glass might engrave a lot better at 10,000KHz PWM. You can hear the difference with the glass tubes when cutting by setting different pulse rates. The buzzing noise changes frequency with the change in pulse rate. I could never hear this audible change with my FR laser.

I must look into posting the PWM chart up here for you to look at.

My understanding is that a low signal pules of around 1KHz is used on the RF lasers to ALMOST ionise the gas in the tube so it keeps it in a ready state for the initial ionisation pulse when the laser is fired. Apparently it makes the engraving process a lot quicker as the gas is ready for a pulse so the rise time is lowered dramatically and it increases the lifetime of the tube due to less shock on every thing. I may be wrong as it's been a while since I read all about it.
Rich.

[Engineerable]

I second the desire for a PPI functionality. The ability to set the number of laser pulses to the TH/TL pins per unit of distance traveled would be very useful.

Thanks!

[twehr]

Craig, per programmer, he said that the PWM frequency is desgined for that purpose. You may give a try

I ran tests this weekend. Varying the PWM frequency on glass tubes does not have any affect. Also, on the 2011 model, the minimum frequency is 5000. To do the kind of work the PPI does for you, you need to be about to get down to 200 and up.

[baccus61]

One thing I would like also is a persistent timer so it stays on the LCD display when the job finishes. When I engrave a mirror or a large item it typically can take between 2-4 hours and I go off and do something else while it engraves but when I come back and the job is finished the timer has stopped and is cleared when the system reverts back to the start so another file can be processed.

Can you set it up to reset the timer when the next job starts so the timer is always visible.

I usually use the timer to be able to cost the job accurately and now if I am not there when the job finishes I have to estimate it.

I do a rough calculation by measuring how long it takes to do 20mm then multiply that by the height of the job. It's not accurate but it is relatively close.

Rich.

[Tech_Marco]

The programmer is working for a new software after the V5.77 and it will show job time on the software. It will give an estiamted completed time and I hope this is what you guys want. He said that the software should be ready in next 7~10 days.

Regarding the PPI, I need to discuss it with him as he seems don't understand what exactly you guys want. May be someone can setup an example and I'll talk to him see if he can add that to the new software before he roll it out

Marco

[twehr]

The programmer is working for a new software after the V5.77 and it will show job time on the software. It will give an estiamted completed time and I hope this is what you guys want. He said that the software should be ready in next 7~10 days.

Regarding the PPI, I need to discuss it with him as he seems don't understand what exactly you guys want. May be someone can setup an example and I'll talk to him see if he can add that to the new software before he roll it out

Marco

Marco,

Here is a drawing that should help to understand what is needed. The idea is to modulate (pulse) the TH and TL lines at a specified frequency.

[wctx1977]

I'll be very glad to see this new features added to the new soft upgrade but I still have a question. Will the new version work or will communicate directly with coreldraw x5 just like x4 does to sent the final job to laser cad? hopefully this is gets added.

[Tech_Marco]

Guys:

I just talked to the programmer and he said that he could add this function to the LaserCad. But he was wondering what's advantage to have PPI included? In what suitation is the PPI most significant? What is the densitty of the PPI wanted? He want to understand it completely before adding this new feature to the card. Both software and hardware need to updated (through patch)

Please response to me asap as he is waiting for my reply for the feature.

CorelDraw X5 will be support on next version. Possible in about 2 weeks per programmer.

Isn't it a good Christmas Gift to you folks?

What about me? Where is my Christmas gift


Marco

[wctx1977]

Thanks Marco!! We are gladly waiting for that Christmas gift!
And for you, our best wishes for a better year in busyness, hugs and kisses