Messages

5731

G-Code, CAD, and CAM discussions / Half-Tone techniques.

« on: December 20, 2011, 05:04:41 AM »

Over the last week or so I have been looking at ‘free of charge’ options for CNC production of half tone images. The first one I found (DotG) uses a ‘dot-dithering’ technique (similar to half tone) with the GCode that is produced being eminently suited to dot impact or laser use and I posted details in this thread http://www.machsupport.com/forum/index.php/topic,12444.msg141147.html#msg141147

Another software (DXF Halftone 2.1) is more true to the half tone technique and is best suited to varying depth V bit drilling. Although this drilling function is incorporated into other commercial software, this program, which is free to download and use (under the GNU Public License) has many advanced features and the inbuilt post-processor produces fully Mach compatible GCode. For those that are interested this can be downloaded from the Finnish website here http://www.students.tut.fi/~syvajar3/

I hope this information is useful to old hands as well as those just starting out into the world of CNC - We can never have too much free software  

Tweakie.

5732

General Mach Discussion / Re: Breakout Board Recommendation?

« on: December 19, 2011, 06:47:54 AM »

Hi Jay,

Nice looking machine you have there.

It is an expensive route but CNC Doctor have all the information and parts required for the conversion http://www.cncdoctor.co.uk/index.html

Tweakie.

5733

General Mach Discussion / Re: Connecting a printer

« on: December 18, 2011, 11:08:00 AM »

Hi Jim,

If your CNC is all running OK then don't risk the printer connection.
Why not use a memory stick or something similar to transfer a copy of the program to another computer which is connected to a printer ??

Tweakie.

nb. If you don't have another computer - It's Christmas time 

5734

General Mach Discussion / Re: Spindle moving slowly from right to left

« on: December 18, 2011, 05:28:52 AM »

Hi Ben,

VFD's are notorious for producing electrical noise.
Check that you have no 'earth loops' and that your VFD is only earthed at one point.
Re-route your spindle cable away from any signal cables.
Check that you have no 'GND loops' in your wiring layout.
Use shielded cable for your limit and estop switches and only connect the screen at the controller end.

Just a few things to try,

Tweakie.

5735

General Mach Discussion / Re: Spindle moving slowly from right to left

« on: December 18, 2011, 04:37:47 AM »

Hi Ben,

Could well be electrical noise. Are you using a VFD with your spindle motor ??

Tweakie.

5736

General Mach Discussion / Re: Single Line Fonts (Stick Fonts).

« on: December 17, 2011, 08:53:41 AM »

Hi Dave,

I must be the lucky one because all my engraving is functional rather than decorative and although my customers get to specify the finished size of the notice they get what they are given when it comes to font. 

Tweakie.

5737

General Mach Discussion / Re: Single Line Fonts (Stick Fonts).

« on: December 17, 2011, 08:41:03 AM »

Thanks Guys,

Now I have purchased Vectric I have all the fonts I need but I still remember when I first started out just how difficult it was to find a (free) single line typeface so, just like you, I hope this posting helps some newcomers to the CNC world of engraving. 

Tweakie.

5738

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: December 15, 2011, 12:13:10 PM »

Hi Dan,

Yes I think it is slower than the plugin but the jury’s still out on this one for the moment because it does not make any unnecessary line scans or unnecessary increased length of scan lines. More comparative testing is necessary before I know for sure.
As far as magnet impact is concerned it should be a lot faster but I think Andrea will have more information on this.

Yes I am using the B Axis direction signal and only the F1500 is being used from those other commands.

Tweakie.

5739

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: December 15, 2011, 10:58:37 AM »

Hi Dan,

The image has to be pre-processed until it is essentially a 1 bit halftone which is really just a collection of dots. DotG then scans this image in raster fashion and creates the GCode as a series of ON or OFF instructions for the laser or impact magnet.
For some time now I have used the B Axis as my laser control with B1 to turn the laser on and B0 to turn the laser off  and for me, this has two major advantages. Firstly the on or off commands can be synchronised with the start or finish of axis movement and secondly the G01 federate can be used to control the laser burn time.
I have attached the GCode used for the previously posted image which you will see is pretty basic stuff with just two lines per dot (or dash). I haven’t quite got my post-processor right yet so the code is still a bit messy but this can only improve  

Tweakie.

5740

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: December 15, 2011, 08:27:52 AM »

Those of you that have been following this (never ending) thread will know that between Andrea in Italy and myself in the UK we have spent quite a lot of time putting the Mach Impact / Laser engraving plugin through it’s paces. Although there are still some improvements that could be made to the plugin and it still has a lot of mileage left in it, the legacy issue of it’s requirement for a parallel port are starting to show and it is perhaps time to start looking at alternatives.

In the Eastern European countries, for many years, it has been common practice for black marble monuments and remembrance plaques to display an engraved ‘photographic style’ of image and this has inevitably prompted the development of CNC software to complete the task. One such software is “DotG” a Hungarian program which has just had an English translation version released. It is completely ‘free of charge’ and can be downloaded from here http://dotg.weebly.com/download.html

DotG works in an entirely different way to the Mach plugin insofar as it creates GCode from a pre-processed 1 Bit image and although I haven’t quite got my postprocessor completely sorted everything looks extremely promising so far.
It is early days yet but I will keep you posted of my experience with this software as I learn more.

This example image of Audry Hepburn with the glamour of the 1950/1960’s was laser cut into some scrap MDF whilst I was testing various settings and it would, I think, look quite stunning cut into some mirror tile (project awaiting).

Tweakie.