Messages

4011

Show"N"Tell ( Your Machines) / Re: DC-K40 Laser conversion issue

« on: January 17, 2013, 10:01:52 AM »

Thats great, I am really pleased that you have got it working 

For the long-term, there are a couple of other points you may wish to consider…

It would be prudent to use and opto-isolator (or similar buffer) in the TTL connection to your laser PSU. This would offer a reasonable degree of protection to your controller / computer should the PSU suffer a catastrophic failure. This may also prevent the TTL logic conflict if your ‘Test’ button is used.

If using the Z axis Direction pin (rather than an output#) it may be beneficial to include your spindle relay (normally open contact) in series with the PSU protection circuit. This will prevent the laser being turned on (accidentally at start-up) unless a GCode M3 command has been issued – it will also allow (depending on the Mach3 configuration) the laser to always be turned off at program end or if the e-stop or limit switches are invoked.

Personally, I now much prefer using the M10P1 / M11P1 command set with an Output# as this is a much neater and safer way of operation.

Tweakie.

4012

General Mach Discussion / Re: Cambam to Mach3

« on: January 17, 2013, 09:58:23 AM »

Hope this is of some help...

The Mach3 Toolpath window shows the actual Toolpath rather than the design.
The Z axis can be jogged with the Page Up / Page Down keys.
The depth of cut is set within CamBam.

Tweakie.

4013

Show"N"Tell ( Your Machines) / Re: DC-K40 Laser conversion issue

« on: January 17, 2013, 08:27:56 AM »

Connect the GND directly to GND and not through the spindle relay connection.
 
For the TTL - either choose an LPT Output pin that is not used by your stepper motors (for M10P1 / M11P1 control of the laser) or the Z axis Direction pin if you are taking that route.
If your pin 4 is Z axis Direction then Mach3 will set this pin high or low depending on your GCode Z axis +/- moves. In turn the laser beam will be switched on or off.

Tweakie.

4014

Show"N"Tell ( Your Machines) / Re: DC-K40 Laser conversion issue

« on: January 17, 2013, 06:51:54 AM »

With regard to interfacing with Mach3 my notes here may be of interest http://www.cooperman.talktalk.net/files/27_files/Page652.htm

Tweakie.

4015

Show"N"Tell ( Your Machines) / Re: DC-K40 Laser conversion issue

« on: January 17, 2013, 06:33:52 AM »

There is no absolute guarantee that the markings on your PSU board are correct as there is no international standard but this is way I would connect it.

Tweakie.

4016

General Mach Discussion / Re: delay in PWM pulse (LaserMode)

« on: January 16, 2013, 12:30:27 PM »

Hi bdn,

It would be helpful if you could zip and attach a simple GCode program which demonstrates the problem.

Tweakie.

4017

General Mach Discussion / Re: unwanted creep in jog mode?

« on: January 16, 2013, 12:06:22 PM »

Can you try a ps/2 keyboard?

Hi Hal,

Unfortunately I don't have PS/2 available on my PC so I can't try that option here - perhaps Tony will have some more information.

Would be interesting to hear if others have seen this weird behaviour also.

Tweakie.

4018

General Mach Discussion / Re: delay in PWM pulse (LaserMode)

« on: January 16, 2013, 11:39:23 AM »

what about the minimum DC in mach config, it has no effect on the outgoing pulse of com, i've set it to 50% and the worse resualt, it doesn't pulse untill to reach 50% of feed rate and at that point starts with 50% DC, so more uncutted path of the shape!

Hi bdn,

Sorry, I can't be of much help with that one as I don't use Mach3 to control my laser output power via the PWM pulse train.

Tweakie.

 

4019

General Mach Discussion / Re: unwanted creep in jog mode?

« on: January 16, 2013, 03:18:29 AM »

Interesting problem this and I wonder what the solution will be.

This creep, very occasionally, happens to me but I have made a few observations…

When opening Mach3 the Reset is flashing – if it can be cancelled using the keyboard  ‘  character then the creep never happens. If the Reset can only be cancelled by clicking on the Reset button then creep can occur. My solution is to close and re-open Mach3 and only run it when the Reset can be cancelled by the keyboard  ‘  character.
I know it is just a work-around but it works for me.
My suspicion is that it is related to the way in which my PC handles USB keyboard etc. communications but I would love to know the definitive answer.

Tweakie.

4020

General Mach Discussion / Re: delay in PWM pulse (LaserMode)

« on: January 16, 2013, 02:20:38 AM »

Hi bdn,

Please ignore what I said about the Spin-Up / Down delays, it will make no difference – My head was still full of another post I had made regarding over-burn with the use of the M3 / M5 command set. 

I think you have identified the cause. My tube requires a minimum of 4mA to fire instantly at it’s first trigger (this would translate to 20% PWM). Thereafter it will fire at 2mA if the next pulse is within approx 100mS of the previous pulse.
The RF tubes have a slightly larger threshold so they overcome this problem by providing the 5kHz ‘tickle pulse’ before and in-between triggers.

I don’t fully understand the physics behind this but it appears that the various gasses within the tube need to be mixed / agitated in order to keep the tube in a state or readiness so you could perhaps try modifying your GCode to include an initial pulse or two (outside the work area) in order to prepare the tube before starting the cut.

Tweakie.