Retrofitting WEEKE BP05

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25 Jul 2018 12:43 #114796 by urkee
Replied by urkee on topic Retrofitting WEEKE BP05
Todd x axis drive is ball screw and nut, encoder is rack and pinion. Nut sounds like it's dirty inside (grease-saw dust deposits, clogs etc.) when i lubricate it sounds good but after week it sounds bad again. From today i am lubricating whith low viscosity oil, hope it will declog and rinse the tubes. But i don't see any brinelling in screw (it is STAR ball screw assembly, appears that balls are using only one track of two (balls are spreading grease only on one track), both looks same, also at the end part that ball is not reaching both tracks look same). I checked backlash, when i rotate ball by hand, machine(cantilever) moves promptly looks like no backlash. There is also screw on nut to adjust preload, and when i increase it machine doesn't move better. Y and Z sounds and moves very good all the time.

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25 Jul 2018 12:56 - 25 Jul 2018 12:59 #114797 by urkee
Replied by urkee on topic Retrofitting WEEKE BP05
Tommy we are furniture producers from Belgrade, Serbia.
I've made changes in my ini file and had some improvements.
First of all I've changed OUTPUT_MIN_LIMIT to -10
and OUTPUT_MAX_LIMIT to 10 for all my axes.
When I change Output_scale to 10, linuxCNC won't even start. So I left those values.
Biggest change that made huge difference was DEADBAND = 0.00042. Somehow machine was a lot calmer after that, and
I built my other values around it untill i had reasonably good ferror and overshoot.
I found that deadband should be somewhere about 3x encoder counts (it should be 3 x 0.00635 = 0.01905 for me), but
at that range loop becomes unstable and machine won't stand still. With this progress machine is 5 times calmer but I know it could be a bit better.
Other problem I have is that messa 7i77 is reacting on temperature change in enclosure. I found that over time as card became hotter
(from 20 to 40 celsius in electrical enclosure) overshoot started to emerge. After that I had to use other parameters for pid. I replaced that card, this one is a lot better but still i think there is some temperature dependency. Anyone had similar problem?
Below is new ini file.
Attachments:
Last edit: 25 Jul 2018 12:59 by urkee. Reason: editing

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25 Jul 2018 13:39 #114799 by urkee
Replied by urkee on topic Retrofitting WEEKE BP05
Andy i was thinking about option to decrease DRO precision in mm to reduce number of zeros from 3 to 2 like on woodworking cnc controls HOMAG, BIESSE, SCM see in attachment. But no only on screen also in LinuxCNC. Todd mentioned in this post that low axis resolution 0.00635mm like on our machine and other woodworking machine can make tunning tough. So i was thinking that reducing LinuxCNC precision on woodworking machines can make tunning easier.
Attachments:

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25 Jul 2018 13:48 #114800 by Todd Zuercher
A cantilever machine would not tolerate any slop/wear in the way bearings for the cantilever. Put a dial indicator on the end of it (furthest away from the bearings.) and check for slop by pushing on it, forward/backward/up/down.measuring the play in all of those directions, with the axis motor enabled so it won't move. Measure the slop in all directions. If you find significant play, you will need to replace all those way bearings (or adjust them if there is any form of adjustment). The weight of the cantilever will mask any play, so you will have to push hard enough to overcome that. If you can't eliminate play, you may have to reduce your accelerations for that axis to quiet the jerk induced vibrations. (A machine like this could benefit greatly from jerk limited acceleration, which Linuxcnc doesn't do.)

Not sure about your temp problem. I haven't noticed such on my machine using a 7i77, but it is in a separate enclosure from my drives, and isn't exposed to any heat sources.

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25 Jul 2018 14:49 #114803 by tommylight
Replied by tommylight on topic Retrofitting WEEKE BP05

When I change Output_scale to 10, linuxCNC won't even start.

That will not prevent Linuxcnc from starting. There is something else wrong there
from your ini file:
#####################
[TRAJ]
AXES = 3
COORDINATES = X Y Z
LINEAR_UNITS = mm
ANGULAR_UNITS = degree
CYCLE_TIME = 0.010
DEFAULT_VELOCITY = 1000.00 <==========that is 60 meters/minute, to much
MAX_LINEAR_VELOCITY = 65000.00 <======that is 3900 meters/minute !!!! Way to much
NO_FORCE_HOMING = 0
####################
Those settings are in units per second, or mm per second in your case.

#********************
# Axis X
#********************
[AXIS_0]
TYPE = LINEAR
HOME = 0.0
FERROR = 10.0
MIN_FERROR = 8.0 <=========should be 1, not 8
MAX_VELOCITY = 45000 <======= again , way to much
MAX_ACCELERATION = 1800 <==== try 500 max, after you get everything working properly, try 700.
P = 4
I = 1.5
D = 0.000002
FF0 = 0
FF1 = 0.0007379
FF2 = 0.000005
BIAS = 0
DEADBAND = 0.00042
MAX_OUTPUT = 10
ENCODER_SCALE = -160
OUTPUT_SCALE = 1 <======should be 10 in your case
OUTPUT_MIN_LIMIT = -10
OUTPUT_MAX_LIMIT = 10
MIN_LIMIT = -2500.0 <====== Why negative ? Should be on the Max_limit, positive
MAX_LIMIT = 50.0
HOME_OFFSET = -44.11 ;(-37.63 minus 6.48)
HOME_SEARCH_VEL = 50.000000
HOME_LATCH_VEL = -10.00000
HOME_FINAL_VEL = 10.000000
HOME_USE_INDEX = YES
HOME_SEQUENCE = 1
################################
This is on all axis.

Urose ja sam sa Kosova.
Translation:
Uros, i am from Kosovo.

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30 Jul 2018 11:49 #115117 by urkee
Replied by urkee on topic Retrofitting WEEKE BP05
Tommy we have set the speeds, motion behaviour is best so far, only x axis is slightly worse than y,z . I want to replace x axis encoder. I have found 10000PPR used one for reasonable price, it will enhance encoder scale from 160 to 800(Y=533 Z=1745) is there any chance that this could help improving x axis behaviour?

Tomi nikad nisam bio na Kosovu, jesi još uvek tamo? Bio sam pre nekoliko godina u Dermiju na moru u Albaniji, mnogo je lepo mesto.
pozdrav Uroš

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30 Jul 2018 12:08 #115122 by urkee
Replied by urkee on topic Retrofitting WEEKE BP05
Todd i have checked X axis play by your instructions it is about (0,05-0,07)mm. It is in manufacturers tolerance. I think that maybe some part of jerky motion is caused by x axis mechanics i saw screw oscilating sometimes in high speed motion. X axis nut has preload setting. I tried to tighten it down to min diameter but haven't noticed any difference in halscope or visual.

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30 Jul 2018 13:08 #115135 by tommylight
Replied by tommylight on topic Retrofitting WEEKE BP05

Tomi nikad nisam bio na Kosovu, jesi još uvek tamo? Bio sam pre nekoliko godina u Dermiju na moru u Albaniji, mnogo je lepo mesto.
pozdrav Uroš


Da jos sam ovde i ako imam americko drzavljanstvo. Ja sa odrastao neko doba na banovom brdu u beogradu.
Translation,
Urke : tom i was never in Kosovo, are you still livingthere ? I was in Albania in dhermi by the sea some years ago, it is beautiful.
Me: yes i still live here although i have american citizenship. I have grown in Belgrade for some time in my childhood, in Banovo Brdo.

Sorry to get off topic.

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30 Jul 2018 19:04 - 30 Jul 2018 19:05 #115162 by PCW
Replied by PCW on topic Retrofitting WEEKE BP05
If this is RMA 21313, I have tested this 7I77 card and it passes all tests.
In addition, since you had reported temperature issues I tested at +70C and -51 (freeze mist) I found no issues other than an about 42 PPM/C temperature drift which is expected with the reference used (-0.5% change from -51C to +70C

I could have missed something, but I think Its more likely that you have an issue with connectors or drives
Last edit: 30 Jul 2018 19:05 by PCW.

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03 Aug 2018 06:50 #115488 by urkee
Replied by urkee on topic Retrofitting WEEKE BP05
PCW yes it is i've sent you an email .

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