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Offline Tweakie.CNC

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Re: Impact engraving plugin
« Reply #180 on: August 19, 2011, 02:12:29 AM »
Hi Obal,

Thanks for posting the video link - that has given me something to think about.  ;)

Tweakie.
PEACE

Offline Tweakie.CNC

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Re: Impact engraving plugin
« Reply #181 on: December 02, 2011, 08:01:07 AM »
Over the past 3 months I have received a number of emails about Impact Engraving and how it has been made to work with Mach3. I certainly had many difficulties to start with so thought I should try to explain the principal for the benefit of others that follow.

The credit must all to go to Andrea for discovering ? that an electro-magnet can be driven directly from one phase of a bipolar stepper motor driver and the, perhaps obscure, principal that advantage can be taken from the fact that electromagnets, just like stepper motors will stall when pulsed too fast.

In operation and when at rest, a stepper motor shaft is locked but when that same stepper motor is pulsed too fast it will stall and then the shaft is free to rotate, in either direction, quite easily by hand – the energy within the coils is not transmitted to the iron core of the rotor or at least if it is transmitted then it is in complete balance and cancels itself out.
It is the same with an electromagnet – in operation and when at rest, it is energised but when it is pulsed too fast it will effectively ‘stall’ and drop out. As the pulse rate is reduced, a threshold is reached and at that point the electromagnet will again be energised and this is the way in which the impact engraver can be used.
The actual needle impacts with the work are made only on the ‘overshoot’ of the return or spring stroke and the Z height has to be precisely adjusted to take advantage of this. Setting up is perhaps easier the second time around but once mastered is extremely easy to reproduce.

There is still some work to be done here and I am perhaps lagging behind on updating the pdf document (Engraving.pdf   http://www.cooperman.talktalk.net/Engraving.pdf) which so far attempts to cover Laser but not yet Impact – it is on my ‘to do’ list and will be completed as and when.

In the meantime if anyone else has any experiences with Impact Engraving I would be extremely please to hear them.

Tweakie.
PEACE
Re: Impact engraving plugin
« Reply #182 on: June 25, 2012, 05:03:51 AM »
Hello!
I made a controller for engraving, but do not know what gives the plug-in mode of engraving.
how to control the force of impact?
if you can tell me in detail.
Thank you.
P.S. Sorry for bad English. translated in google.

Offline Tweakie.CNC

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Re: Impact engraving plugin
« Reply #183 on: June 25, 2012, 05:32:37 AM »
Hi Josaami,

The earlier post http://www.machsupport.com/forum/index.php/topic,16446.msg111240.html#msg111240 explains the magnet construction that both I  and Andrea use and the next post http://www.machsupport.com/forum/index.php/topic,16446.msg111241.html#msg111241 shows how it is driven by one phase of a standard stepper motor driver circuit and also details the Mach3 configuration for it's use.

Another approach could be to make a dedicated controller such as this http://hobbycncart.com/_fr/1/3711394.jpg

I hope this helps.

Tweakie.
PEACE
Re: Impact engraving plugin
« Reply #184 on: June 25, 2012, 06:39:22 AM »
Thank Tweakie.CNC!!!!
Re: Impact engraving plugin
« Reply #185 on: June 28, 2012, 04:02:37 AM »
Hello
Can anyone describe in detail how mach engraves shades of gray, ie what information it gives to the LPT port??
Mach changes the pulse duration or frequency, or simply the density of the shocks or something else then?? For me, this question remains a mystery.
Help please someone who can. I would really appreciate it!!
If you can draw a timing diagram.
Thank you!

Offline Tweakie.CNC

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Re: Impact engraving plugin
« Reply #186 on: June 28, 2012, 06:49:40 AM »
Hi Josaami,

Perhaps my pdf for the plugin may help  http://www.cooperman.talktalk.net/Engraving.pdf

Tweakie.
PEACE
Re: Impact engraving plugin
« Reply #187 on: June 29, 2012, 05:33:26 AM »
Thank you Tweakie.

You write that the frequency of the pulses on the LPT depends from the feeding and from of the frequency of kernel.
Question: each pulse is a blow head (I use to engrave a drum head)?
P.S. I really do not speak English, Sorry.

Offline Tweakie.CNC

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Re: Impact engraving plugin
« Reply #188 on: June 29, 2012, 06:26:02 AM »
Hi Josaami,

No worries about your English.  ;)

Yes, each pulse on the Digital Trigger (LPT Output) is an impact.
The frequency of these pulses (set by feed rate) is related to the transducer you are using. For example ; the maximum I have achieved with an electromagnet is 21Hz http://hobbymaro.puhasoft.hu/Tweakie/Impact1.wmv and an air operated solenoid around 5Hz.

Something else you may wish to consider, which can produce similar results but in an entirely different way is DotG.  http://dotg.weebly.com/
This software is free to download and use - it produces Mach3 compatible GCode and English translations of the manuals are available from their website. (Perhaps Google Translate may be useful in your deciphering of these documents).

Tweakie.
PEACE
Re: Impact engraving plugin
« Reply #189 on: June 29, 2012, 07:24:05 AM »
Thank you Tweakie.