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Messages - stirling

321
Show"N"Tell ( Your Machines) / Re: My first CNC (plasma) machine
« on: March 14, 2015, 01:09:39 PM »
Unusually for a kit, that looks to be not too badly matched so maybe you'll be fine - only one way to find out. Still think at the very least though they're massive overkill. I'll be interested to see when you're done, what accel and speeds you can get.

Ian


322
Mach3 and G-Rex / Re: ruining my new cnc from the beginning.
« on: March 14, 2015, 11:33:54 AM »
if it works sometimes and then doesn't and then does it's highly likely it's wiring/electronics issues, but as a start please post your xml file.

323
Show"N"Tell ( Your Machines) / Re: My first CNC (plasma) machine
« on: March 14, 2015, 06:38:06 AM »
Think that will be light enough for two 1232 oz. In. Steppers to move around?  Stirling, could you nudge me in the right direction with the 23 vs 34 topic? Ive searched but cant seem to find anything on this forum comparing the two.

GENERALLY 34's have higher inductance. Therefore to realize their potential in a CNC environment you need BIG voltage drivers and power supplies. GENERALLY 34's have higher mass rotors meaning more power is used just to accelerate the motor's own rotor mass. Post your motor, drive and power supply specs and we can take a quick stab at it if you like. Curiously, I thought this was pretty well known, certainly amongst the regulars here. I'm a tad surprised no-one's stepped up.

324
Show"N"Tell ( Your Machines) / Re: My first CNC (plasma) machine
« on: March 12, 2015, 06:43:04 AM »
Torque is a means to an end. What you NEED is the torque that gives you the speed to match your cut charts and the torque that gives you the acceleration to maintain that speed as much as is possible.

23's vs 34's: Have a search around there's a lot been said on this but briefly - bigger is not always better.

Gearing: I used direct 15 tooth mod1.

Ian

325
Show"N"Tell ( Your Machines) / Re: My first CNC (plasma) machine
« on: March 11, 2015, 02:07:08 PM »
Gear reduction only increases torque if you're prepared/able to accept the proportional loss of speed. Even then, with steppers, I'd argue you get better acceleration with direct drive. All the (stepper) plasma tables I've built have been direct drive - never had an issue and run 15m/min at 0.5+G no probs.

What I WOULD do is consider nema23's rather than 34's - you'll likely get better performance.

326
Brains Development / Re: Brains writing wrong values to DRO's
« on: March 10, 2015, 10:58:53 AM »
Completely understand Bob. So far you seem to be doing a good job.

Ian

327
General Mach Discussion / Re: Toggle output from button input?
« on: March 10, 2015, 10:56:30 AM »
Sorry Thomas - I just meant to say that the problem is that the macro runs late i.e. after any gcode buffer is emptied rather than when the trigger actually fires.

Ian

328
General Mach Discussion / Re: Toggle output from button input?
« on: March 10, 2015, 07:54:37 AM »
indeed (note that OEM triggers are fine - they fire immediately - it's just trigger MACROS that have the "turned up late for work" problem).

329
Brains Development / Re: Brains writing wrong values to DRO's
« on: March 10, 2015, 07:04:23 AM »
Just a thought but why don't you just send your 5 bits in ONE register rather than a separate register for each bit? (currently you're using 5 * 16 = 80 bits to send 5 bits of info)

If you did that your Brain would reduce to just one rung i.e.  Modbus reg -> formula (A*12.5) -> feed override.

Ian

330
General Mach Discussion / Re: Toggle output from button input?
« on: March 10, 2015, 06:51:54 AM »
i am not a friend of the macropump road.
can i get you into my OEMTRIGGER road as described in my small tutorial (PDF) ?

Hi Thomas

Unfortunately trigger macros have been "damaged" for many years. Your scheme as described (in your PDF) will work fine as long as Mach's not doing anything else but try triggering your macro whilst some gcode is running. I think you'll be disappointed. :'(

I tried for years to get this fixed but to no avail.

Ian