Delta -- Layer Shift Upward and Towards the Y tower

[wepollock]

I just seemed to have developed a problem on the Artemis delta whereby I am getting a layer shift towards the Y tower. The shifting is upward towards the tower. My thinking is that delta arms Z and X are where they should be with the y-axis moving up randomly.

I did a M122 and everything looks fine. There were no changes in the configurations. Any ideas on where to start?

[Veti]

disconnect the belts and see if the carriages can move freely without much resistance.

[wepollock]

Thanks for the reply
--the MGN sliders move freely.

The Y slider might be moving too far up. The arm is moving upwards too much.
The layer shifting is towards the tower.
The shift is like an upward arrow pointing right at the tower.

I have some mass on the effector as I have an extruder mounted on it.

-I was thinking perhaps the connection between the stepper and the board is bad
-perhaps I am not holding against the momentum of the effector.
-stepper driver?
-too much speed (I run slow)
-I have no idea, but it feels like electrical.

Up to this issue, my prints have been consistently very good. I print some really big things 275mm high such as lamps https://www.thingiverse.com/thing:3328807 and in this case, I am printing delta parts for a 500mm D build. I have had several (2 prototype - 2 actual arms, 4 centers) perfect parts using the same config.

*At first, and perhaps, it is/was a layer adhesion problem, but that is not the case.
A layer shift would not explain how the Y arm is actually going higher progressively.

To preclude layer adhesion I raised the temperature, changed filaments, and adjusted layer hight.

I print some really big things 275mm high*

[Veti]

do post the m122 output

[wepollock]

@veti
M122
=== Diagnostics ===
RepRapFirmware for Duet 2 WiFi/Ethernet version 2.0(RTOS)RC2 running on Duet WiFi 1.02 or later
Board ID: 08DGM-95BNL-MGPSJ-6J1F4-3SN6N-KJWRY
Used output buffers: 4 of 20 (10 max)
=== RTOS ===
Static ram: 28564
Dynamic ram: 96104 of which 16 recycled
Exception stack ram used: 288
Never used ram: 6100
Task NETWORK ready, free stack 476
Task HEAT blocked, free stack 1256
Task MAIN running, free stack 3796
=== Platform ===
Last reset 00:00:19 ago, cause: power up
Last software reset at 2019-02-03 09:05, reason: User, spinning module GCodes, available RAM 5536 bytes (slot 1)
Software reset code 0x0003 HFSR 0x00000000, CFSR 0x00000000, ICSR 0x0041f000, BFAR 0xe000ed38, SP 0xffffffff
Error status: 0
Free file entries: 10
SD card 0 detected, interface speed: 20.0MBytes/sec
SD card longest block write time: 0.0ms
MCU temperature: min 18.4, current 22.4, max 22.5
Supply voltage: min 12.2, current 12.3, max 12.4, under voltage events: 0, over voltage events: 0
Driver 0: standstill, SG min/max not available
Driver 1: standstill, SG min/max not available
Driver 2: standstill, SG min/max not available
Driver 3: standstill, SG min/max not available
Driver 4: standstill, SG min/max not available
Date/time: 2019-02-04 09:18:52
Slowest main loop (seconds): 0.007159; fastest: 0.000065
=== Move ===
Hiccups: 0, StepErrors: 0, LaErrors: 0, FreeDm: 240, MinFreeDm 240, MaxWait: 0ms, Underruns: 0, 0
Scheduled moves: 0, completed moves: 0
Bed compensation in use: none
Bed probe heights: 0.000 0.000 0.000 0.000 0.000
=== Heat ===
Bed heaters = 0 -1 -1 -1, chamberHeaters = -1 -1
Heater 1 is on, I-accum = 0.0
=== GCodes ===
Segments left: 0
Stack records: 2 allocated, 0 in use
Movement lock held by null
http is idle in state(s) 0
telnet is idle in state(s) 0
file is idle in state(s) 0
serial is idle in state(s) 0
aux is idle in state(s) 0
daemon is idle in state(s) 0
queue is idle in state(s) 0
autopause is idle in state(s) 0
Code queue is empty.
=== Network ===
Responder states: HTTP(0) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0) Telnet(0)
HTTP sessions: 1 of 8

• WiFi -
  Network state is running
  WiFi module is connected to access point
  Failed messages: pending 0, notready 0, noresp 0
  WiFi firmware version 1.21
  WiFi MAC address 2c:3a:e8:0b:25:67
  WiFi Vcc 3.36, reset reason Turned on by main processor
  WiFi flash size 4194304, free heap 16200
  WiFi IP address 192.168.0.150
  WiFi signal strength -48dBm, reconnections 0, sleep mode modem
  Socket states: 0 0 0 0 0 0 0 0
  === Expansion ===

[Veti]

@wepollock said in Delta -- Layer Shift Upward and Towards the Y tower:

Last reset 00:00:19 ago, cause: power up

this does not look like a log after a print has happend.

[wepollock]

My mistake.. I should have saved the log (my mistake in not doing so) but I did not see any exceptions.

To do list?
(today or tomorrow)
-I will open up the case and look for mechanical issues on that axis.
-I am also going to re-crimp the Y stepper.

As a third step;
-Can you swap around the Y stepper driver to the spare extruder driver?

[dc42]

Have you checked that the pulley grub screw is tight on the motor shaft, and the belt tension is correct?

[wepollock]

@dc42

Thanks Dave..

I am going to open up the printer and check the mechanical stuff out first.

[wepollock]

FOUND THE PROBLEM..

The whole motor mount has unseated itself from the extrusion.
Four screws are loose, two hidden behind the power supply.

Dave do you know where I could source a 500mm diameter delta bed? I have a laser cut wood mockup presently.
I am going to use the Duet Smart Effector.

[dc42]

If I was building a delta now, I would probably try to source a piece of cast aluminium tooling plate and have it cut to a hexagonal shape. I've just asked Aluminium Warehouse if they can do that.

[wepollock]

@dc42

Dave.

That would be great if you could hook me up. I think I am going to have a rigid printer using 3d printed parts. I have one arm built and I am going to anchor it down to 3/4 inch 600mm plywood circle I am having cut.

What got me going was the price tag on "The Boss" $4000-$5000 not happening. *I had to take the Artemis apart today, it was very hard to service. Some of the Seemecnc design points are brilliant, my choices would be different here or there. The Rostock max is more serviceable. *

I was thinking of having wood laser cut to accommodate the extrusion but I decided to print strong but huge parts. I am clamping into the plastic using a 40x40mm aluminum clamp with 4 bolts connected to the 4040 extrusions. The arms are 60x120mm I-beams that print without support. Then the motor mounts also tie into the extrusion. I will anchor arms into the plywood base.

My thinking was that everything would still be of use if I wanted to replace the 3d printed parts with aluminum. In my testing there is near zero deflection.

Here is one arm
590mm carbon fiber arms, with ball cups
Effector base for Duet Leveling
Extrusions are clamped on four points

[Wyvern]

@wepollock
If you live in the states, Midwest metals has ATP-5 that they can cut circular- possibly other shapes too.

Wasn't bad for a 1/4 13X13, like $50 shipped.

[wepollock]

@wyvern Thanks for the tip.

I am going to give the 3d print and plywood a try.

Here is a cross section of an arm. The shell is 3 layers at .70 mm each
I paid attention as to how I would place my infill on each part.

It's almost uncrushable.

[wepollock]

Looking at the Seemecnc machine it's actually a small plate that is holding the extrusions in place.
So I don't know how the movement is telegraphed through the structure.

[wepollock]

For two aluminum 1/4 inch plates, I am getting a $450 price quote.
The tolerances quoted are not great.
As you can see I have staggered holes to accommodate different geometries.

The real kicker is that if you go up to 25 parts the price goes down from $200 each to $80-$100 each.
It would be great if this could be cost-shared in some way.