Messages

6761

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

« on: July 12, 2011, 11:34:53 AM »

Hi Sam,

I will try it but I am guessing that neat Bleach will destroy the dye in no time but there may be other alternatives.

Acrylic paint has been used successfully to fill the pores in laser'd glass so may work OK with glaze and if it does may resist a Bleach attack.
In a commercial process, low temperature glaze is applied over the top of screen printed ceramics and fired for a few hours this should work just as well with dye filled laser'd stuff.

There are also a few other things I need to try, just need more spare time. 

Tweakie.

6762

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

« on: July 12, 2011, 09:10:10 AM »

Good question Sir.

My machine is Class 4 radiation at a  wavelength of 10600nm and it only operates behind closed doors (there are no visitors). The workshop door is actually one of the interlocks which has to remain shut during use. I have a relatively high power, roof mounted, extraction system to remove toxic fumes and poison Bambi outdoors. I also have Halon (sales now banned in the UK, except for aircraft) fire extinguishers, just in case and my eye protection are goggles (intended for YAG) which are rated with a reduced OD of 7 at 10600nm but are adequate.

You can't take safety too seriously as it only takes one mistake. I have a number of friends in the woodworking industry and it seems to be a badge of office to have at least part of one finger missing - well I intend keeping all my fingers and eyes and etc.

In general CO2 lasers are a lot safer than lower powered diode lasers as far as eyes are concerned. A laser beam with a wavelength of 633nm when entering eyes will get focussed on to the retina and if any damage is caused it is permanent. A CO2 laser with a wavelength of 10600 will have to burn through the cornea first and this may be repairable damage but I would not want to put it to the test.

As a general statement to everybody and this applies to everything - If you have any doubts that you can keep yourself and others safe then don't do it.

Tweakie.

6763

General Mach Discussion / Mach Screen Question.

« on: July 12, 2011, 08:26:48 AM »

I suppose I should know the answer to this but I don't. 

What is the significance of the green rectangle surrounding the Cycle Start button and why does it sometimes flash on / off during the last few lines of a program ?

Thanks,

Tweakie.

6764

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

« on: July 12, 2011, 06:23:19 AM »

Again using the impact/laser engraving plugin some quite stunning results can be had with ceramic tiles. The laser produces micro-fractures in the surface of the glaze which are subsequently filled with a dye. This was one of my first attempts, using some left over’s from a tiling job, it’s not bad but I still have a long way to go before achieving results that I am fully satisfied with. Tiles marked this way are much more durable than I had first thought, they may fade with time but washing and cleaning have no effect on the dye once it has penetrated the surface.

In a way this serves to illustrate the stupidity of our patent system. Using a laser to mark the surface of ceramic tiles has been patented and technically I am not allowed to make or experiment with making such things as this (my comments will be written on the piece of paper which will be passed to the clerk of the court). And as you would expect it is not just limited to tiles – marking house bricks with a laser and marking Denim jeans with a laser have also been patented although half of Asia seems to be marking Denim with dis-regard to any patents. The list just goes on and on to the extent that I am surprised that a patent has not already been granted for just switching a laser on at the wall outlet.
I know that drug companies have been accused of patenting compounds and formulae they have no intention of using just to prevent a competitors research.

How, I wonder, would we all get on if a patent had been granted for machining a piece of material with a CNC machine ?
Not that much different in principle from marking a ceramic tile using a laser is it ?

Tweakie.

6765

General Mach Discussion / Re: Lost Steps

« on: July 10, 2011, 06:03:14 AM »

Glad you have a sense of humour S 


Tweakie.

6766

Tangent Corner / Re: Ooops !

« on: July 08, 2011, 01:07:20 PM »

Hi Mikee,

Don't worry about a thing - there is nothing that can't be sorted.

Have you worked out how to do it now ?

Tweakie.

6767

General Mach Discussion / Re: Noisy Axis problem.

« on: July 08, 2011, 12:50:12 PM »

Just from memory because it is a long while since I looked at the Xylotex instructions but if it has a PFD (percent fast decay) pot (adjacent to the current adjust pot) associated with each axis you could try a slight adjustment of this on the axis that is causing trouble.

Tweakie.

6768

Third party software and hardware support forums. / Re: Mach3 and Toshiba VFD spindle control question and some Help needed.

« on: July 08, 2011, 11:13:08 AM »

Take a look at Chris Humphris document here http://www.cjh.com.au//PWM%20Spindle%20Control%20using%20Mach3.pdf it contains a lot of useful information.

Tweakie.

6769

General Mach Discussion / DC-03 DigiSpeed GX V3

« on: July 08, 2011, 02:47:01 AM »

Darcy,

This is a pretty old thread but it is straightforward enough to connect the analog 0-5Volts to the laser PSU and it is again straightforward to setup the spindle control within Mach to output the PWM (do a search for PWM and you will find the details). This works just fine for vector cutting but if you decide to do raster work using the Impact/Laser Engraver plugin it all goes pear shaped.
There are more details in these threads (if you have a bit of time to spare  );

http://www.machsupport.com/forum/index.php/topic,16446.0.html

http://www.machsupport.com/forum/index.php/topic,12444.0.html

Hope this helps,

Tweakie.

6770

Tangent Corner / Re: Ooops !

« on: July 08, 2011, 02:35:40 AM »

Mikee,

Shielded cable is best to use for limit switches and only ground the shield (screen) at the controller end.

Tweakie.