Messages

8291

Show"N"Tell ( What you have made with your CNC machine.) / Re: My first attempts at laser engraving.

« on: June 26, 2009, 07:37:48 AM »

Just a word of consolation - my laser won't melt butter either.
However if somebody ever produced black butter the laser would surely cut it !.

Tweakie.

btw. These low power lasers have to be focussed to a dot the size of a pin point to have any affect on anything - do you have a good lens ?.

8292

Share Your GCode / Re: CNC "rackmount" pizza box server plans for MiniITX mobo, PSU and dual 3.5" H

« on: June 26, 2009, 07:22:31 AM »

Wow !

Tweakie.

8293

Tangent Corner / Re: trying to help my grandpa set up cnc machines

« on: June 26, 2009, 03:30:46 AM »

Just a regular parallel port is the minimum requirement for Mach operation. A breakout board is good to have and essential for some types of CNC driver boards although not required for Gecko and some other drives.

Your Grandpa will have endless hours of fun.

Tweakie.

8294

Tangent Corner / Re: Y Axis problems ?.

« on: June 26, 2009, 03:23:36 AM »

Of course, the flood defences - bit like the wall alongside your workshop. 

Tweakie.

8295

Share Your GCode / Re: CNC "rackmount" pizza box server plans for MiniITX mobo, PSU and dual 3.5" H

« on: June 26, 2009, 03:20:44 AM »

Well presented project - must have taken you a lot of time to compile.
Can't help thinking that you have some shares in an acrylic company though. 

Tweakie

8296

Show"N"Tell ( What you have made with your CNC machine.) / Re: My first attempts at laser engraving.

« on: June 26, 2009, 02:47:17 AM »

I underline the points about the toxic fumes.
Good posting John.

btw. Have you tried cutting acrylic with a laser - what sort of surface finish do you get at the edges ?.

Tweakie.

8297

Share Your GCode / Re: CNC kids toy project..

« on: June 24, 2009, 12:53:22 PM »

Another great project John.

Tweakie.

8298

Tangent Corner / Y Axis problems ?.

« on: June 23, 2009, 02:54:19 AM »

The Highways Dept. have really screwed up this Y Axis (or is it the Z Axis ?).   

Tweakie.

8299

Tangent Corner / Re: New Here!

« on: June 23, 2009, 02:11:07 AM »

Hi Dom,

An chance you could post a couple of pictures ?.

Tweakie.

8300

General Mach Discussion / Re: How do i setup Mach3 to control a laser with TTL input?

« on: June 13, 2009, 10:13:06 AM »

Hi Borge,
The laser TTL spec is usually <0.5volts for off and >2.0 for on. Providing it does not draw any appreciable current this input can be connected to the Z axis direction pin  on the BOB so that it turns the laser on for -Z moves and off for +Z moves. I disable the Z axis so that the laser focus is not disturbed and use the Z axis DRO scale factor to control the 'laser bite time' (which varies from material to material). If the laser operation is reversed then change the direction active low under ports and pins.
Although I have used this method quite successfully I now favour a simple shutter system to switch the laser beam on and off, again using the Z axis direction signal as I believe that longer laser life will be achieved by using a soft start when it is turned on from cold.

Tweakie.

There is some further information here :-

http://www.cooperman.talktalk.net/index_files/Page4549.htm