Brother TC-225 / TC-229 adventure!

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07 Aug 2017 17:06 #97113 by ihavenofish
I think the non stop chip to tool change can be done by swapping to W axis right from the last z position. w and z will share coordinates, so we don't need to hit home z again and could use g64. so:

--- last line of code before tool change
M3 S0.1 (fast spindle stop from 6000 in 200ms)
M5 (spindle cut)
issue tool change command
// swap z to w - and swap spindle to c (instead of the normal orient for now cause I can wrap my head around it)
// spindle encoder needs to be looping a count to know where the index is at all times when running in normal mode
--
G64 (so the moves are continuous)
G01 W17 (home of z/w) C0 (home of spindle) F590
G01 X? Y? (pre stage next positions in program) W20 (home of atc) F590
// rotate carousel (should we make this an axis?)
G01 W17 (home of z/w) F590
G01 W? (next Z position in program)
G61
// swap W back to Z, and C back to spindle
M3 S6000
--
---- back to code

were still likely a few days from getting to the atc finer points, but I'm thinking ahead :)

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07 Aug 2017 17:09 #97115 by ihavenofish

andypugh wrote: It probably isn't. The problem is that the controller only knows which direction the axis is moving, not which direction the cutting force is acting, or if that cutting force is enough to move the table.
.


I noticed I have seemingly less backlash under the brother control. peculiar. about 0.0003". either I measured wrong first time, or, the "backlash" is in fact spongy servo response. I think bad measuring :)

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08 Aug 2017 04:23 #97158 by ihavenofish
well, the servo error issue on the brother control was directly related to my linuxcnc pc being wired into the machines 100v.

with the machine attached, error. without, no error. so the 100v line must be finicky. the drives for xyz are 100v single phase for some reason. spindle is 200v 3 phase.

under the Linux control, the z still errors. no matter how the power is run to the pc. y and z are fine, work simultaneously. z errors when its enabled. I'm not sure if its even the same error now, its just a red led and I have no descriptions.

I have to recheck again now on the brother control if theres any extra signals coming from the brother board to the drive. the only thing I can imagine at this point is an extra "brake off" signal.

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08 Aug 2017 16:57 #97189 by andypugh

ihavenofish wrote: G64 (so the moves are continuous)
G01 W17 (home of z/w) C0 (home of spindle) F590

were still likely a few days from getting to the atc finer points, but I'm thinking ahead :)


You probably want to be using G53 to move to absolute axis positions.

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08 Aug 2017 17:17 #97193 by ihavenofish
oh, right, to bypass any offsets. thanks.

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09 Aug 2017 02:17 #97227 by ihavenofish
Well. All I've learned is the z drive has 6 error let's and the x and y have 5.

The drive cable though does not seem to have anything special going on.

It has to be looking for a brake signal... but where?

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09 Aug 2017 03:18 - 09 Aug 2017 04:55 #97228 by ihavenofish
Fixed. Was just timing. I set power up t e stop. Enable to Machine on.

Tuning is giving me grief. Up is fine. Down likes to oscilate. Any thoughts on a better start point?
Last edit: 09 Aug 2017 04:55 by ihavenofish.

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09 Aug 2017 09:52 #97235 by andypugh
You might need to set up the PID with a bias t to compensate for the weight of the head.

Jog the head up and stop, note the PID output. Jog down and stop, look at the PID output again. Then set the pid.2.bias to the average of the two values.

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09 Aug 2017 15:41 #97241 by ihavenofish
ok ill look at that tonight.

its not offset from 0 - at least not very visibly in the scope. its just resonating on the down motion.

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09 Aug 2017 18:46 - 09 Aug 2017 18:47 #97252 by Todd Zuercher
That makes sense to me. There is more resistance going up than, down, so more P is needed going up, but it causes overshoot going down. Using the scope try to compare the following error for an up and down moves. (Do a short incremental jog in both directions, to try to get both moves showing on the scope at one time.) Try to adjust the bias to get the following error as close to the same on both moves as you can.
Last edit: 09 Aug 2017 18:47 by Todd Zuercher.

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