Messages

5381

General Mach Discussion / Re: Laser Focal lens selection method

« on: July 05, 2012, 06:58:53 AM »

Hi Andre,

The lens focal length is measured from the centre of the lens to the work.

Line up you machine with your Perspex gauge then measure from the work surface to the position that the old lens was fitted and then, if possible, obtain a new lens with a similar focal length to the distance that you just measured.

There are two common types of lens material used with CO2 lasers. The yellow colour lenses (seen on ebay) are made from Zinc Selenide (ZnSe) and are the cheapest – the grey colour lenses are made from Galium Arsenide (GaAs), are usually quite expensive but are considered to be more hard wearing.

I have lenses of both types but the ZnSe is the one I use all the time.

Remember to fit your new lens with the convex side towards the laser tube and the flat side towards the work.

Tweakie.

5382

Show"N"Tell ( What you have made with your CNC machine.) / Re: Constructing a Low Profile Tool Height Setter.

« on: July 05, 2012, 05:54:52 AM »

The tool path for the re-designed case has now been verified, new case made and anodized.

Tweakie.

5383

Show"N"Tell ( What you have made with your CNC machine.) / Re: Constructing a Low Profile Tool Height Setter.

« on: July 05, 2012, 02:53:35 AM »

Hi Terry,

With my Acceleration of 100 & Feed 200 for the Z axis our good friend Ian has calculated the over travel distance from the activation point to be 0.0555mm 


Tweakie.

5384

General Mach Discussion / Re: Cut parts are wonrg size

« on: July 04, 2012, 02:40:31 AM »

Hi Dave,

Use your existing system to create the GCode for a square part.
When you load it into Mach check the Program Limits DRO's in the tool path window - do they indicate the correct size of the part ??
When you make the part does it come out to the correct dimensions ??

This will tell you if your problem is with your software or your Mach configuration (steps per unit).

Tweakie.

5385

Show"N"Tell ( What you have made with your CNC machine.) / Re: Constructing a Low Profile Tool Height Setter.

« on: July 04, 2012, 01:20:57 AM »

Hi Astroguy,

Sorry for the delay.

By including the over-travel switch, the wiring between this and the main panel makes it difficult to dis-assemble / re-assemble so the case has been re-designed to include a pocket to accommodate a wiring loop and I have just not been able to get the time to test the tool path for the new case yet.
The control board PCB has yet to be laid out and I am still awaiting delivery of some low current opto isolators from China - it is all work in progress. 

Tweakie.

5386

FAQs / Re: Can Mach3 Do PCB Drilling using an NC file

« on: July 03, 2012, 08:05:48 AM »

Hi Nick,

As you have, quite correctly, pointed out Mach3 is able open / load an ‘.nc’ file.

Unfortunately, nothing is ever truly simple and the (Excellon format) .nc drill files contain many commands that Mach3 does not recognize also the absence of the Z axis commands further complicates the issue.
Just for reference http://www.excellon.com/manuals/program.htm

There are, however, a number of ‘free to use’ converter programs (some work better than others) to create GCode files from .nc files and one such program can be found here http://hans-w.com/download.htm

The similar Gerber files (.gbr) can, in many instances, be handled by LazyCam which will create the necessary GCode for Mach3 use but I have never tried LazyCam with an .nc drill file - maybe it could be persuaded ??

Hope this helps.

Tweakie.

5387

General Mach Discussion / Re: Noise - Aluminium foil screen? - Faraday Cage?

« on: July 02, 2012, 01:41:57 AM »

Hi Nigel,

Re-wiring your limit switches (separate to your motor cables) using shielded cable (with the shield grounded at the controller end only) is the best way forward in curing your problem of the random stops.

Tweakie.

5388

General Mach Discussion / Re: Communication failure with mach 3

« on: July 01, 2012, 02:10:05 AM »

Hi Darren,

If you are running XP or 2000 then this little application will show the state of your parallel port http://www.geekhideout.com/parmon.shtml

Tweakie.

5389

General Mach Discussion / Re: Rank newbie question

« on: July 01, 2012, 02:06:46 AM »

Hi Terry,

I started out with GSimple http://www.gsimple.eu/

It is pretty basic, easy to learn and again it is free.

Tweakie.

5390

Show"N"Tell ( Your Machines) / Re: Eventually getting started on a 4th axis

« on: July 01, 2012, 01:18:09 AM »

Hi Hood,

That certainly is a lump and a grand project indeed. I am looking forward to seeing the pics of your progress.

( looks like you could use my De-Mag for that spanner  )

Tweakie.