Thanks, Tweakie. Will be waiting to hear more results from you guys.

Dan

This image is 106mm x 130mm and comprises entirely of laser dots on some scrap MDF. It took 80 minutes to complete but the interesting thing is that the same GCode could (theoretically) be used with an impact magnet and again it would take 80 minutes to complete. Higher resolution and larger images would, of course, take longer but I still have a bit of reserve as far as the speed settings are concerned. It is all a matter of putting theory into practice  

Tweakie.

EDIT. I have attached the .jpg / .bmp and GCode if anybody would like to try it.

Nice, Tweakie. Is it with that new program? When you say impact magnet do you mean using it with Art's plugin? A comparison with Art's plugin would be interesting.

Your earlier works using the plugin had much finer detail. I wonder how this new software would compare if you increased resolution.

Dan

Hi Dan,

Thanks for taking an interest in this and I am sorry if I don’t always manage to explain everything very well (there is a big difference between what is stored in my head and what actually manages to escape  )

The Mach plugin and the DotG program really operate in entirely different ways and I think it would be ‘apples and oranges’ to try and make a direct comparison mainly because each would be good at what it does best.
My earlier examples with the plugin were at 0.1mm stepover whereas the previous cat is at 0.4mm stepover. This has been done deliberately so that the dots are visible and can be compared with a subsequent magnet produced image (using the same GCode). The attached, enlarged, pic shows the dots better.

It is perhaps interesting to note that, as far as the professionals are concerned, it is usual when creating laser produced images from halftone to de-focus the beam so that the individual dots blend and produce a smooth result.
There is a quite lot of useful info relating to halftone on the PhotoGrav site if you are interested http://www.photograv.com/index.htm

Tweakie.

Hi Tweakie,

Thanks for the information.

Dan

Initially there was failure.
I mapped my B Axis direction pin to Output #1 (which is my spindle relay) and used the relay to fire the magnet. Unfortunately my version of Mach doesn’t like any Output # being repeatedly turned on and off rapidly as it introduces extra delays while it, presumably, catches up. This has caused missed pulses and ‘patterning’ indicating the repetitive nature of the problem and shown in the first picture.

Then there was success.
To be fair, Mach had never intended for an Output # to be cycled in this manner so I constructed a separate magnet driver circuit which is driven directly from the B Axis direction pin and this performed perfectly. The image produced is ‘dot-perfect’ to the laser produced image and was made from exactly the same GCode in exactly the same time frame of 80 minutes.

Tweakie.

.
Hi Tweakie

Brilliant as always.
this may sound like a dumb question but do you have any info on the workings of a impact magnet. I understand the gist of how they work but having searched for more detail on their workings found nothing. Do you have any detailed info?

Thanks Brian

Hi Brian,

My electromagnet was a gift from Andrea (Robotmar) http://www.robotfactory.it/Cnc_indexMain.htm (look under Micropunti) who had the first successful results using a magnet with the Mach Impact / Laser plugin. He shows the construction on his website or in this thread http://www.machsupport.com/forum/index.php/topic,16446.0.html but other than that I have no specific technical information relating to the field properties / iron saturation etc.

Hope this helps,

Tweakie.

Hi Brian,

My electromagnet was a gift from Andrea (Robotmar) http://www.robotfactory.it/Cnc_indexMain.htm (look under Micropunti) who had the first successful results using a magnet with the Mach Impact / Laser plugin. He shows the construction on his website or in this thread http://www.machsupport.com/forum/index.php/topic,16446.0.html but other than that I have no specific technical information relating to the field properties / iron saturation etc.

Hope this helps,

Tweakie.

Cheers, I will read and digest:)

Brian

Perhaps going a bit off topic but this halftone image was produced with the electromagnet although it could equally have been done with the laser by using the same GCode and for anyone old enough to remember them, the process sounds exactly like the old ASR33 Teletype’s although just slightly faster.

The GCode was produced with ‘DotG’ (http://dotg.weebly.com/index.html) and the image pre-processed with ‘Infanview’ (http://www.irfanview.com/) and the ‘Ximagic Gray Dither plugin’ (http://www.ximagic.com/) – All of these being free to download and use programs.

Like all halftones you need to be some distance from the image to get the best effect and the end result, shown here, is far from being perfect. It does, however, look exactly like the image shown in Infanview so now I have to experiment with different settings and gain some practical experience to produce an image and a group of settings that I am satisfied with. The final object of this exercise being an acrylic, edge lit display which contains a photographic image as well as text.

So far so good. 

Tweakie.