How can I slow the Z movement before the purge?

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helifrek
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How can I slow the Z movement before the purge?

Post by helifrek » Fri Oct 16, 2015 5:04 pm

Hello all,
I have an issue where sometimes the Z motor will skip when it tries to move the bed up really fast right before it purges the nozzle. How can I slow this movement down? I have been just sitting by my M2 before it starts a print and helping the bed up with my hand to prevent the motor from skipping. I have had this issue before but it seems to be back, I have cleaned the Z-rod and the brass nut to spin it up and down by hand to see if there is any excessive resistance but there isn't any. Thanks in advance guys!

Brandon
Last edited by helifrek on Sat Oct 17, 2015 1:51 am, edited 1 time in total.

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Matt_Sharkey
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Re: How can I slow the X movement before the purge?

Post by Matt_Sharkey » Fri Oct 16, 2015 11:26 pm

you cleaned the rod, but did you lubricate it too?

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PcS
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Re: How can I slow the X movement before the purge?

Post by PcS » Sat Oct 17, 2015 1:10 am

You can change it in s3d under other tab for fff profile.

jsc
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Re: How can I slow the X movement before the purge?

Post by jsc » Sat Oct 17, 2015 1:23 am

There is some confusion going on here. Are you referring to the Z (not X) move after the extruder moves off the right side of the bed? Just add an "F" parameter to the end of the relevant G1 command in the startup script. Argument is in mm/min, and if there isn't one it will use whatever speed was set the last time it saw an F parameter.

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helifrek
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Re: How can I slow the X movement before the purge?

Post by helifrek » Sat Oct 17, 2015 1:51 am

I am an idiot.... yes I meant Z! Thanks for the help guys, I will adjust it and let you know what happens!

Last time I lubricated it with the included grease is when it really started skipping. Should I use a lighter machine oil or something?

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helifrek
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Re: How can I slow the Z movement before the purge?

Post by helifrek » Sat Oct 17, 2015 5:32 pm

Here is my startup G-code

M204 T10000 ; increase default retraction acceleration
M201 X1200 Y800 Z500 ; reduce maximum acceleration to reduce ringing
G28 ; home all axes
G1 Y50 Z0.3 F9600 ; move forward to avoid binder clips
G1 X205 Z10 ; move off platform
G1 Z0.4 ; position nozzle <------ Is this where I would add the F command? What would be a good speed to start at?
G92 E0 ; zero extruder
G1 E25 F225 ; purge nozzle
G92 E0 ; zero extruder
G1 X190 Z0.1 E1.0 F1200 ; slow wipe
G1 X180 Z0.25 ; lift

Thanks!
Brandon

jsc
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Re: How can I slow the Z movement before the purge?

Post by jsc » Sat Oct 17, 2015 5:36 pm

Yes. The default max z feedrate is 1500, so it is weird that your M2 can't handle that. Try half that. But it really should be able to handle the max.

When you lubricated it, did you apply the grease to the threaded rod only? The smooth rods should take 3-in-one or similar light oil.

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helifrek
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Re: How can I slow the Z movement before the purge?

Post by helifrek » Sat Oct 17, 2015 6:05 pm

It worked fine for the first 6 months or so and then that started happening. It doesn't do it everytime. Last time I lubricated the printer I used the grease included with the kit and I don't remember if I did the smooth rods but I do remember cleaning them with isopropyl alcohol. I have some tri-flow I could probably use on the smooth rods. I have a feeling I will probably teardown the M2 and rebuild it here soon just so everything gets cleaned up and lubed properly. Thanks for the help.

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innkeeper
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Re: How can I slow the Z movement before the purge?

Post by innkeeper » Sat Oct 17, 2015 7:32 pm

i don't disagree with the above recommendations...
however another additional option you might consider .. upgrade the z stepper.

I upgraded it because i was running an older m2 that had a z stepper which was not appropriately spec'ed and was eventually makergear changed production to a different model.
there are a few that think even the current z stepper is a bit under spec'ed

see viewtopic.php?f=10&t=2622&hilit=+z+stepper

also see an excellent write up by ednisley he used a bit stronger stepper then i did.
http://softsolder.com/2013/06/28/makerg ... ransplant/
M2 - Smoothieboard Electronics - Upg Z stepper - IR auto bed leveling - Astrosyn dampers X/Y/Z - MIC 6, Zebra and PEI .25 Build Plates - Pico, E3D, V3B Hotends - Plastic and metal Extruder blocks, 24v Upg, - GLCD Smart Controller - other 3d printers

wmgeorge
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Re: How can I slow the Z movement before the purge?

Post by wmgeorge » Sat Oct 17, 2015 10:10 pm

helifrek wrote:It worked fine for the first 6 months or so and then that started happening. It doesn't do it everytime. Last time I lubricated the printer I used the grease included with the kit and I don't remember if I did the smooth rods but I do remember cleaning them with isopropyl alcohol. I have some tri-flow I could probably use on the smooth rods. I have a feeling I will probably teardown the M2 and rebuild it here soon just so everything gets cleaned up and lubed properly. Thanks for the help.
My first guess is clean the grease off and use light oil, NOT WD-40 on the rails. Its also possible the grease on the screw is full of dirt and gunk and if its like my shop that is a very good possibility. Its due for a cleaning and re-greasing also. I bet what you have planned will make it work like new.
Retired Master Electrician, Commercial HVAC/R,CNC Router, MakerGear M2...and more.

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