Hello Guest it is February 25, 2021, 06:27:01 AM

Author Topic: Machine wont zero after Homing  (Read 19596 times)

0 Members and 1 Guest are viewing this topic.

Re: Machine wont zero after Homing
« Reply #30 on: April 20, 2014, 04:55:14 PM »
what happens if you disconnect the belt and just turn the motor, does it still blip? also what voltage does your power supply kick out?
Re: Machine wont zero after Homing
« Reply #31 on: April 20, 2014, 05:02:37 PM »
Also check the pitch and quantity of teeth  on your pulleys, it would seem that the steps / mm are very critical, i changed mine by -.5 and -.6mm on the other, and i got really weird results when drawing out a block of 4x4 25mm circles
Re: Machine wont zero after Homing
« Reply #32 on: April 20, 2014, 05:07:08 PM »
yeah - still get the blipping with the belt off. Tried that...

However I have just ran a 1500 line gcode (In mid air) over 7min 30secs and it did return fairly accurately to zero afterwards.
Maybe i should ignore the blips.
I am wondering if I had my multipass depth to high. I was trying to cut 6mm mdf in passes of 1.5mm with a 1/8 cutter.

Maybe i was asking to much and it just coulden't cope with it. Somewhere in the program the cutter definitely moved from where it was supposed to be.
I have since cut down my Z axis length and made the gantry more rigid by adjusting the wheels...
Will run some more tests this week.

PS. What do you use yours for?

Cheers
Martin
Re: Machine wont zero after Homing
« Reply #33 on: April 20, 2014, 05:09:17 PM »
Also check the pitch and quantity of teeth  on your pulleys, it would seem that the steps / mm are very critical, i changed mine by -.5 and -.6mm

Where, how did you change that ?
In mach 3 or got different belts pulleys etc
Re: Machine wont zero after Homing
« Reply #34 on: April 20, 2014, 06:20:10 PM »
motor tuning
Re: Machine wont zero after Homing
« Reply #35 on: April 21, 2014, 05:25:55 AM »
Hello martin,  2 things i have found this morning that makes a difference to the smooth running

Turn off watchdog on relay 1, its done by going to  Config > config plugins > hycnc_4l, this made a huge difference

Set the voltage correctly on the motor driver to match the current required for the nema motors, have you looked at this yet?
Re: Machine wont zero after Homing
« Reply #36 on: April 21, 2014, 04:40:38 PM »
Hey Piccyman....

So my Watchdog checkbox is off already...
Do you mean set the Amps to match the ampage of the motors on the driver board - Mine are about right I think.
My Motors say 3Amps per phase.. I assume that means 3A on the pots on the boards.

So ran some code tonight to cut out letters of kids names as a test.

Machine running much more smoothly tonight when running Gcode, (but seemed only to skip when jogging.)
However the machine kept stopping half way through the code, as it was in the middle of cutting out a letter. It did it 3 times.

I have just run the same code at least 3 times without the cutter running and it did not stop once. That surely must be down to the router causing interference of some kind.
So i have just ordered shielded cable. I have heard it and been told it, so I thought i would get it and do it, then that is ruled out.

I think i have also decided to forget the Machine co-ordinates being zero. I can't see that it matters to much as i think you said.
I will use the switches on the X & Y as limit switches rather than homing switches, and forget homing. I will just set work zero at the corner of my job.

Hopefully that will get around the A Axis problem of homing not working when you have a slaved axis.

My Z axis shortening seems to of made the machine more solid anyway.

Cheers
Martin

Re: Machine wont zero after Homing
« Reply #37 on: April 21, 2014, 05:22:41 PM »
I think its down to a process hogging interrupts or processor time on your pc, like anti virus, it doesn't matter how powerful your machine a lot of software is written so poorly and with no regards for other software running


As for the machine homing, just home it after you have run the job and have finished

My A axis homes well now
 

Offline stirling

*
  • *
  •  2,188 2,188
  • UK
    • View Profile
    • www.razordance.co.uk
Re: Machine wont zero after Homing
« Reply #38 on: April 22, 2014, 07:32:05 AM »
You shouldn't need to be guessing things.

your (Nema23) motors rated currents are 3A so that is what you should set your drives to. From what I can see on the pictures you linked to you should do this by monitoring Vref as you turn the pot - is this what your documentation says?. The formula appears to be I=(vref*1/3)/0.151 from what I can see so for 3A you should be looking for a vref of 1.359V if my maths is correct.

You haven't given info about your Nema17 so I can't comment.

From the info you posted about your N23 motors, they ideally need 43V however your drivers have a max of 36V so that is what your power supply should be - is it?

Your power supply should be able to source at least 2/3 of all your motor requirements added together. i.e. your two N23s will need 6A*2/3 + 2/3 of whatever your N17 needs - can it?

From your pics it looks like you are only driving your gantry from one side - is that correct?. If so then you're going to suffer from racking so you can't expect much in terms of accurate cuts.

As has been said earlier (and I agree) your homing issues are more than likely down to your external motion controler/plugin.

When you're using an external controller, what's running on Windows is not particularly of any concern as it would be if you were using the parallel port.
Re: Machine wont zero after Homing
« Reply #39 on: April 23, 2014, 10:36:06 AM »
Thanks Stirling.

Power supply is 24V / 20A.
Gantry is waiting A Axis driver. Only have 3 at the moment. 4th in transit.
Will Check the voltage using the forumla you supplied and see if its somewhere near. Where do i put my meter to measure the Vref ?

Thanks for your help
Martin