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Author Topic: Oscillating bit in Z axis to equalize tool wear  (Read 10306 times)

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Re: Oscillating bit in Z axis to equalize tool wear
« Reply #20 on: September 21, 2011, 06:23:23 AM »
Okay, will do.  I am wondering about one thing though.  Earlier you wrote that, while you thought Z oscillation was likely to be impossible, Mach has some tricks up its sleeve.  Then we got onto this discussion about brains, and you gave me your ideas related to that.  Were these the tricks you were referring to, or did you have something else in mind that you haven't even mentioned yet?
Re: Oscillating bit in Z axis to equalize tool wear
« Reply #21 on: September 22, 2011, 12:32:35 PM »
Just thinking outloud;
Set-up a second computer running Mach3, driving just the Z axis. Wire up a multi-pin plug for the Z motor power/encoder/tack feedback to make a quick changeover. The Z progam could be incremental steps rising and falling, with shorter steps at beginning and end of each end of travel to mimic a s-curve for smoother performance.  Use a pot for feedoverride to regulate the speed of osscilation. Lots of cheap used computers out there, maybe even an old laptop would work. A second breakout board needed also.  :)
Re: Oscillating bit in Z axis to equalize tool wear
« Reply #22 on: October 21, 2012, 06:30:08 PM »
> Let us know IF you get stuck, (;-) TP

Well, here I am over a year later finally trying to implement this (don't ask)... AND... I am stuck.

I set myself the simpler task of, upon an M7 Mist On code, moving the Z axis by any amount.  I ran into two problems:

1) I first set up a brain that works exactly like the sample brain in the intro to brains tutorial video.  That brain sets output 2 if the X feed rate is greater than zero.  All I did was change the input from X Feed Rate to Mist On.  The brain broke.  When I watch it in the viewer I can see that the input block shows Mist Coolant On is 1 when I enter an M7 code, however the Compare Immediate lobe fails to light up. 

2) I then decided to try modifying the output side, so that on X Feed Rate > 0 the Z axis would start moving.  I cannot figure out what sort of termination block to create to do that.  I tried for example to issue a Jog Z Right button press, which resulted in no movement when I started the X axis moving.  Perhaps this is because the jog buttons are ignored when G code is running?  In any event, I am not sure how I should be getting the Z axis to move in tandem with ongoing X/Y movements coming from my G code.

I appreciate any help anyone can provide...

Thanks.

Offline BR549

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Re: Oscillating bit in Z axis to equalize tool wear
« Reply #23 on: October 21, 2012, 08:52:26 PM »
In all honesty this is something BEST handled from your CAM. It can add the code in to do the up/down and amount moved based on amount of travel  of the cutter.

The THC function on MACH3 is a SLAP and go feature.  You cannot really control how much it moves it just does until you release control.

(;-) TP

Re: Oscillating bit in Z axis to equalize tool wear
« Reply #24 on: October 21, 2012, 10:06:33 PM »
Thanks, I know I can do this by pre-processing my G code, but there are various reasons why I still want to be able to just turn the Z oscillation on and off with an M code.  Earlier in this thread you pointed me in the direction of using the M7 code to trigger a brain that does the oscillating.  i am stuck in the two ways I mentioned: can't seem to trigger the brain from the Mist On LED, and can't seem to find a way to trigger a Z move from within the brain.  If anyone has a clue about either issue I would greatly appreciate hearing it.

Offline BR549

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Re: Oscillating bit in Z axis to equalize tool wear
« Reply #25 on: October 22, 2012, 02:02:58 AM »
OK IS it possible yes I just did it . IS it reliable and safe NO.  MACH3 does not have 100% control over the sync of the CB thread and it can run away.

SO being it is a safety issue I am not going to talk about it further.

It would have to been done internally to be safe and that would be up to Brian to create.

IT IS a good idea though, (;-) TP
Re: Oscillating bit in Z axis to equalize tool wear
« Reply #26 on: October 22, 2012, 09:10:58 AM »
Thanks for trying.  You mentioned that you did it with a CB thread - would that be a macro pump, or a brain?

Offline BR549

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Re: Oscillating bit in Z axis to equalize tool wear
« Reply #27 on: October 22, 2012, 10:21:31 AM »
Macro PUmp  That way you CAN compare the Z height to drive the function up and DOWN (;-)  IF I can find a way to make it safe I will get back to you.

That's all , (;-) TP
Re: Oscillating bit in Z axis to equalize tool wear
« Reply #28 on: October 22, 2012, 11:56:54 AM »
Is there a way to get a brain to issue a Z move command, or to generate pulse and direction outputs directly to the Z axis?  That had been our original thought.

Thanks. 

Offline BR549

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Re: Oscillating bit in Z axis to equalize tool wear
« Reply #29 on: October 22, 2012, 01:17:06 PM »
No there is not a "direct" way from the brain. (;-)


(;-) TP