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jbnh101
(@jbnh101)
New Member
Suddenly not working correctly

I have had the MK3S for several months now and have printed a handful of objects (including round ones) successfully.  I started noticing the Y axis belt was slipping so I tightened it and ran calibration wizard, (Tension of X axis: 260, Y axis: 266).  Now nothing seems to be printing correctly.  I've tried cleaning the plate with dish detergent and reflashing the firmware but still have the same issues.  I have also noticed it does not auto home correctly, even when I manually tell it to do so.  Anyone out there have any thoughts?  Tension of X axis: 260, Y axis: 266.

 

Posted : 08/11/2019 6:34 pm
bobstro
(@bobstro)
Illustrious Member
RE: Suddenly not working correctly
Posted by: @jbillingsley

[...]  I have also noticed it does not auto home correctly, even when I manually tell it to do so. 

Live-Z calibration goes hand-in-hand with bed cleanliness if you're experiencing "sudden" adhesion issues. If you're having homing issues though, that points at something more serious. Can you explain a bit more about what is happening during homing?

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 08/11/2019 7:06 pm
jbnh101
(@jbnh101)
New Member
Topic starter answered:
RE: Suddenly not working correctly

@bobstro

It's not automatically returning to home at the beginning of a print or calibration.  I started pushing 'home' in calibration menu to get it back to the correct starting point, (otherwise the y axis would try to move too far and cause an awful noise). This had been working for the most part, until today.  The extruder was in the middle left of the plate and when I pushed auto home, it stayed there.  So even that isn't working well now.

 

I'm new to 3D printing so I keep thinking it has to be something I'm doing wrong, but I've been working on this problem for a few weeks now and am at my wits end.

Posted : 08/11/2019 7:27 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Suddenly not working correctly

Have you checked that the Y axis moves smoothly

friction can cause the printer to find false home locations. 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 08/11/2019 7:52 pm
rmm200
(@rmm200)
Noble Member
RE: Suddenly not working correctly

Not only friction - but look for actually hitting something.

Look for zip ties sticking up or some cable catching.

Those will all mess up your Y axis move to the rear.

Posted : 08/11/2019 8:51 pm
toaf
 toaf
(@toaf)
Noble Member
RE: Suddenly not working correctly

how are your rods?  if you feel some wear, you can just play Chinese fire drill with the rods and move them around.

I had to do that while waiting for new rods.  I still haven't had to put them in yet.

This post was modified 5 years ago by toaf

I have a Prusa,therefore I research.

Posted : 08/11/2019 9:02 pm
jbnh101
(@jbnh101)
New Member
Topic starter answered:
RE: Suddenly not working correctly

Thanks for the input.  I have done a lot of fine tuning in the last week, including tightening the belts even though they were within range. Also turned up the nozzle temp 10 degrees.  I am now able to print a round object successfully.  Still having issues with homing, although I did notice the print fan wires were touching the x-axis belt some.  After I moved that out of the way, it's still not homing correctly.  It might be time to contact the good people at Prusa...

Posted : 14/11/2019 3:41 pm
--
 --
(@)
Illustrious Member
RE: Suddenly not working correctly

If you base belt tension off the LCD display, your belts are not properly tensioned.  

Belt Tension Calculations

Your drive gears are probably not installed properly.  Use this procedure to ensure they are properly attached to the motor shafts.

Flat First: Drive gears must be tightened flat-first.

1)   Start with both set screws fully loosened so the pulley is free to spin on the motor shaft.

2)   Align one set screw dead center with the flat on the motor shaft, slowly tighten the screw until it fully contacts the flat surface.

3)   Torque the flat set screw to spec.

4)   Now tighten the jam set screw, and torque it to spec.

Once tightened, never touch the flat set screw unless the jam screw is first fully loosened.

Why Flat First? Set screws have flat ends. If you tighten the jam screw first the set screw on the shaft flat doesn't fully contact the shaft, only one small edge of the screw surface is biting. Reversing torques can easily shift the shaft to a position the flat screw no longer contacts the shaft. This lets the jam screw wriggle loose. And after a while, vibration loosens the screws until the gear is free to rotate.

Posted : 14/11/2019 7:53 pm
jbnh101
(@jbnh101)
New Member
Topic starter answered:
RE: Suddenly not working correctly

@tim-m30

Good to know!  I actually figured out part of the problem has been my trying to get the Y axis between 240 and 300, (like beating my head against a wall).  When I just tightened the Y belt to what "felt good" it started printing better than ever.  Go figure.

Posted : 19/11/2019 7:41 pm
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