Messages

8631

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

« on: May 04, 2009, 12:00:03 PM »

Hi Dave,

I am only too pleased to share any info I have. All I know about CNC has come from you guys sharing your info.

Another piece of information - When the laser is operated at 2 Volts it produces a faint beam which is ideal for focusing because there is no loom and the beam can be adjusted to the smallest spot then it only lases when the voltage is increased to 5 Volts - pretty similar to the operation of the laser cross hair pointers we use for the tool positioning.

Couple more pics. - The Mach write wizard allows GCode to be created without Z moves which is ideal for experiments - This little laser cuts through 4mm high density foam (the stuff I use to protect RC servos and receivers) too easily, in fact it scored the surface during the fast G00 moves. It also makes short work of pvc electrical tape too.

Tweakie.

8632

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

« on: May 04, 2009, 07:21:50 AM »

Hey Guys,

I am still learning about this process and don't know all (hardly any really) of the answers myself yet.

The laser I have used was bought last year from Virtual Village, one of the Chinese retailers, and came with its own constant current power source (picture attached) which just requires a standard 5 Volts regulated supply. It cost around £35 (GBP) plus the shipping cost.

The laser is used in CW mode (continious operation) and my GCode file was edited to delete all the +Z moves completely and replace the -Z moves with G4 P3 to give a dwell before moving off from each new starting position. When the G0 moves are made they are too fast for the laser to bite therefore focus was set once, at the start of the job and without any subsequent Z moves using a feedrate of F20 (mm/min) and G0 inbetween the results were as you can see in the initial photos. Increasing the feedrate thins the line width and reducing the feedrate thickens it. (I guess the whole process must be very similar to plasma cutting requiring pretty much the same disciplines).
I did modify the laser to add a focus ring (the clear acrylic part on the front) but all this does is allow me easy focusing adjustment without using any special tools.

This laser does focus well even though it has plastic optics (min. 30mm - max. the length of my workshop) and was originally purchased as an allignment tool for a larger YAG laser which I have been slowly constructing for the last 6 Months or so (not sure if I will ever get it finished though). It was just by chance that I fitted it to my CNC to see how it would cut vinyl. Now it is a whole new ball game and I have so much learning to do (all the laser engraving machines I have seen so far use fast raster scan and pulsed laser operation) CW operation and vector drawing is just like conventional engraving and well suited to relatively slow moving CNC machines such as mine.

Thanks Guys for the interest - I will post more info and pics as things develop.

Tweakie.

8633

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

« on: May 03, 2009, 02:40:47 PM »

One important thing I forgot to mention is that protective glasses or goggles are essential and must be worn at all times that the laser is powered on. 150mW doesn't seem like much power but focussed to the size of a pin point its reflected image is pretty powerful and harmful to the eyes. 

Tweakie.

8634

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

« on: May 03, 2009, 02:20:27 PM »

Hi Dave,

A moron like me managed it OK.

Its a standard 150mW diode laser from China mounted to the Z axis. You can draw any vector graphics on relatively dark colored, thin, materials and woods in the same way as engraving with a cutter but at a much, much lower feed rate (too fast and it doesn't mark the surface, too slow and it cuts right through thin stuff)
Although it cuts the dark vinyls well the edges of the cuts are slightly raised where the material has melted so only 'so so' for bumper stickers and the like (drag knife cutting of vinyls is better).

What do you need to know ?.

Tweakie.

8635

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

« on: May 03, 2009, 01:14:57 PM »

Not bad for a first attempt but I still have a lot to learn about vector laser engraving. The feed rate and dwell time at the start of each cut are all important and of course there is no Z axis movement.
Here I have used a low power (150 mW) red laser with a 650 nm wavelength fitted to the Z axis.

Tweakie.

8636

Tangent Corner / Re: Metal shredder

« on: May 03, 2009, 05:55:19 AM »

They are certainly some machines Hood has posted the video of.

Tweakie.

8637

General Mach Discussion / Re: Laser Cutter Contest

« on: April 22, 2009, 02:38:38 AM »

Nice design - Good Luck with the contest.

Tweakie.

8638

General Mach Discussion / Re: Still can not get part to cut same from mill and router

« on: April 20, 2009, 09:25:42 AM »

Hi Paul,

Are you using the same PC for both the Mill and Router operation ?.

Tweakie.

8639

Show"N"Tell ( Your Machines) / Re: Taig CNC Lathe: First Run...

« on: April 19, 2009, 06:11:42 AM »

Excellent Dave.   

Tweakie.

8640

Show"N"Tell ( Your Machines) / Re: BladeRunner

« on: April 14, 2009, 09:43:36 AM »

Nice machine H - I expect to see pictures of some airplane parts posted in the near future.

Tweakie.