Best posts made by SteveYYC

Update: Shrink-tubing around the bearing worked for a short while, but since the tubing is soft it quickly developed a groove and began to slip again.

Still much better than using the bare shiny metal, but I did wind up getting a negative movement on a section of complex infill. Since negative values for R do not seem to work, even setting minimum to 0 I will still get pausing without actual jams/issues on a job.

Next attempt will be to use salt water and electricity to etch the outer rim of the bearing. I have done this with other SS items and the result is usually an even, "frosted" surface. I don't know if this will be enough "texture" to grab the filament or not.

@steveyyc Update: Salt Water Etching didn't touch the stainless so I resorted to an emery board and the garnet abrasive took the shine of the bearing very quickly.

It's definitely going to be hard to get negative values now - the range has shifted to min 555% and max 588%

Provided this result lasts through a few more jobs I think sanding the bearing may be the solution to the slippage.

I have a "purge.g" in my macros subdirectory.

I call it with an M98 command.

M98 P"/macros/printing/purge.g";

; purge.g
; macro to purge leave a print in process and purge some filament in a safe location before returning to the print
; currently configured for use with a fixed (x,y,z) purge bucket
; NOTE: When using G1"R" to restore a position, axis args are offset and any axis not mentioned will not restore
; (So use X0 Y0 Z0 with restore moves or else the tool will just sit there)

G60 S2 		; Store Current Tool Coordinates in slot 2 (same as would occur at tool change)
G1 X0 Y0 Z5 R2 F6000	; move up 5 mm @ 100mm/s

G1 X0 Y80 F12000	; move to a spot above the bucket location (in front of Z tower) @ 200mm/s
G60 S1			; store position slot 1
G1 X0 Y80 Z0.1 F6000	; move to purge coordinates @ 100mm/s
G1 E20 F900		; purge 20mm filament @ 15mm/s
G4 S2			; Wait for 2 second &
G10			; retract to minimize ooze
G1 X0 Y0 Z0 R1 F6000	; return to stored position 0 (above purge) @ 100mm/s
G1 X0 Y0 Z5 R2 F12000	; return to stored position 2 (Z offset 5mm above print) @ 200mm/s
G1 X0 Y0 Z0 R2 F3000	; return to stored position 2 (contact print) @ 50mm/s
G11			; unretract

; print will resume at this point

@cosmowave I have a stock 220mm build plate with a 200mm ultrabase plate on it. The bed is a little loose at room temperature with a fraction of a mm play in X/Y but when it's hotter than 50 degrees it does not move in x/y. If I want it to be rigid at room temperature I can loosen the M3 nearest the towers and rotate the mounts inward a bit and take the slack out of the system (That's why I have the adjustment slots in the mounts).

I have considered adding some springs under the bed to pull the three mounts inward at any temperature which would get rid of the tiny bit of slop when the bed is cold but I rarely print on a cold bed so I haven't gotten around to it.

@brunofporto I was considering something like this stuff from Rustoleum

https://www.rustoleum.ca/product-catalog/consumer-brands/epoxyshield/concrete-accessories-and-additives/anti-slip/

If you don't want to use conditional processing (or upgrade to RRF3):

You could set your firmware retract for the tool in the tool change macro (ie tpostn.g for tool n):

M207 S-10  F3600 ; retract 10 mm

then use G10/G11 firmware retracts in the pause command

G10 ; retract the filament by a tool-specific amount

Wouldn't you effectively get separate jerk settings for printing and moving if you set the jerk for E to the print jerk and X,Y,Z to the move jerk?

The firmware would be smart enough to never jerk the move axes faster than the extruder can keep up, so during printing wouldn't this effectively limit the jerk on the move axes to the E axis value?

@spllg

1. If you put an M80 command in your config.g does the ATX control show up? On my machine it will only appear in the interface after the power supply has been turned on once by manually entering M80.

2. Do you have a move command at the end of your print to move to a fixed position that coincides with layer 249? If you put a comment starting with the letter "E" after that move like this:

G1 Z50   ;E

The Duet will not add that Z value to the height of the object and you should see the height of the last printing layer instead.

Got mine printed and assembled, but I'm getting an extremely large range of values for min & maximum. Does this mean my bearings are slipping?

M591 D0
produces the following:

Duet3D laser filament monitor on input 4, disabled, allow 25% to 440%, check every 3.0mm, current pos 5.7, brightness 110, shutter 35, measured min 4% avg 181% max 492% over 994.7mm

@Ntrack
When you initate a tool change the Duet stores the current tool coordinates as if you'd issued the following G60 command:

G60 S2

You can also store coordinates in S0 and S1

Using this stored location (S2) you can move up 15 mm by issuing a G1 command with the "Restore" argument R

G1 R2 Z15

This will move to the location stored in slot 2, with an offset of 15 in the Z axis.

I find this much easier to reverse than switching to and from relative coordinates. For example, you can perform whatever purge maneuvers you need to do and then just issue the command:

G1 R2 X0 Y0 Z15

to return to 15mm above the last printed point on your model.

G1 R2 X0 Y0 Z0

will put the tool back in contact with the model and should probably be the last instruction in tpost.g

@brunofporto I've put a ring of electrical shrink-wrap tubing around the upper bearing - it's now dark grey but it's not exhibiting any slipping when I push filament through manually. Will let you know once I do some testing with it how it calibrates.

@dc42 My foolish mistake - I was still running f/w 2.02
I have updated to 2.03-RC2 and can now see that my sensor is version 2 (and appears to be producing more reasonable values).

@adrian52 That graph does an excellent job of showing the sweet spot of 17-22mm distance between the sensor and the bearing. I didn't expect it to be that sharply defined.