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Author Topic: Impact engraving plugin  (Read 358302 times)

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Offline Dan13

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Re: Impact engraving plugin
« Reply #210 on: October 06, 2012, 02:52:53 PM »
I am curious what are you using for current control? Is it an Op Amp?

Also what do you mean by the frequency divider?

Dan
Re: Impact engraving plugin
« Reply #211 on: October 08, 2012, 03:52:14 AM »
Hi, Dan
Now i use an opamp for constant current control, but
soon I will make a PWM control .
Frequency divider because isnt possible to drive electromagnet with frequency output of plugin...
...it's too high.
Of course, part of informations of the scan , will go down.
Anyway I would be happy to see your system used, for comparison .
« Last Edit: October 08, 2012, 04:11:09 AM by patter »

Offline Tweakie.CNC

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Re: Impact engraving plugin
« Reply #212 on: October 08, 2012, 04:58:03 AM »
Hi Pasquale,

I don’t know if this will be of any help to you but I recently made a small change to the Engraving.dll to add an option (primarily for my laser use) to alter the formulae by which the pixel dot density is calculated. This may be of benefit with your slower axis speed.

Details of this change and the latest .dll are here. http://www.machsupport.com/forum/index.php/topic,12444.msg157668.html#msg157668

Tweakie.
PEACE

Offline Dan13

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Re: Impact engraving plugin
« Reply #213 on: October 08, 2012, 07:53:34 AM »
Hi Pasquale,

I don't have a working system. I attempted to build an electromagnet for this purpose some time ago but not completely understanding the physics behind it and wrongly assuming that it ought to be powerful to be able to engrave, I built a strong one. Then I saw that the plunger was too heavy and the coil had to much inductance and I couldn't drive it any fast.  I reduced the plunger and the coil but it still was not enough. Haven't touched it ever since.

Not sure why you said PWM. I was asking about the practical current control in the circuit. What component will be controlling the MOSFET gate voltage? Only way I know of in the configuration you laid out is an Op Amp. But I built such a circuit and found it struggling to pulse the MOSFET at frequencies higher than about 10Khz. I think that possibly the specific Op Amp model was not suitable although it was 1Mhz band width I think.

Regarding the frequency divider, I think that Tweakie and Andrea were getting good results without this. So again not sure why you need it.

Dan
Re: Impact engraving plugin
« Reply #214 on: October 08, 2012, 10:45:20 AM »
Thanks Tweakie, i missed this update. I will try soon. Another thanks .
Ok Dan.......sorry for your problems...
My idea is make a constant current source with PWM control.
About the frequency divider, my experience is this, but can be wrong.
Re: Impact engraving plugin
« Reply #215 on: October 13, 2012, 03:39:17 AM »
Hi Tweakie,
I have tested your impact engraving release, but the result did not improve.
Of course this is due with my electronic interface , that distorts and changes
the grayscale compression.
Thank you for help.
« Last Edit: October 13, 2012, 03:41:51 AM by patter »

Offline Tweakie.CNC

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Re: Impact engraving plugin
« Reply #216 on: October 13, 2012, 04:06:00 AM »
Hi Pasquale,

Thanks for reporting back on your results and I am sorry that the Greyscale compression did not help you.

I have not yet tried it with my impact magnet set-up but as soon as I get a bit of spare time I will.

Tweakie.
PEACE
Re: Impact engraving plugin
« Reply #217 on: September 14, 2013, 02:44:19 PM »
Hi,
news about impact engraving on my blog ....
Thank you.

Offline Tweakie.CNC

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Re: Impact engraving plugin
« Reply #218 on: September 15, 2013, 02:40:03 AM »
Excellent write-up and excellent work Pasquale, a feed-rate of 3500mm/min + is a great achievement indeed.

Tweakie.
PEACE
Re: Impact engraving plugin
« Reply #219 on: September 16, 2013, 02:48:30 PM »
Thank you Tweekie.
I have did your name for your the exellent  correction of the  plug in.