Bug in temperature adjustments with hot bed

[dennisjm]

If I create a print that uses my left extruder it will work and use the left extruder.
If I then add a temperature to the hot bed so that after layer 5 the hot bed temperature decreases, that will work as expected.
However, at the same time the hot bed temperature adjusts, the print starts trying to print from the right extruder.

So... if I want to print on the left extruder I can't adjust the hot bed temperature mid print.

[dnewman]

What has happened is that the gcode sets a temp for the HBP *and* specifies T0 for the tool to which the HBP is associated. T0 is "tool 0" which is the right extruder. When it did that, that caused an implicit tool change over to the right extruder. There's two ways to deal with that,

1. Then switch back to T1 with a tool change command, or
2. If this is a Makerbot, then know that it's okay to use T1 or T0 when changing the HBP temp. The firmwares don't care which tool index is specified when you set a target temperature for the HBP. Mind you, the gcode to x3g translator may care -- it may not like seeing a HBP temp change on T1 if it thinks that the HBP is on T0. However, the firmware doesn't care. So, in theory it's possible to change the HBP temp without causing an implicit tool change.

Dan

[dennisjm]

This bit me again on a print today. I found a workaround. If you set the Temperature of the hotbed on layer N, then you need to also go and reset the temperature of T1 on the same layer N. Thus far it appears to be working. It doesn't seem very robust though because if the gcode generation just happened to set the T1 temperature 1st and then the hotbed, you'd still have the same bug. At least for now it worked on this print though to simply reset the T1 temperature on the same layer.

[dennisjm]

Ok, somebody needs to fix this...(using 2.1.2)

I have two processes because I'm printing multiple parts on a print bed. Both process use the left extruder so I have to use the workaround I mentioned before where I set the tool temperature on layer 2 to the same as layer 1 so that the tool won't switch to T0.

So.. I have no idea why, but I get the below code in layer 5. So it prints layers 1-4 ok and on layer 5 starts trying to print on the wrong tool... ruining the print and making me start over again !

What the heck is going on? Neither of my processes set the temperature on anything but layer 1 and 2.

The actual tool change temperature is being inserted on layer 3-5 though instead of 2.

; layer 3, Z = 0.36
; tool H0.2 W0.42
M140 S95 T0
M104 S242 T1
...
; layer 4, Z = 0.36
M140 S95 T0
M104 S242 T1
...
; layer 5, Z = 0.56
M140 S95 T0

It seems for multiple processes (I selected print continuous layer by layer) that the layer logic and temperature logic is screwed up.

Hm... I reported this tool switching issue a couple versions ago... makes me feel ignored.

[gelly]

Yes this needs to be fixed, this is a critical bug. How do we get attention from Simplify3D to fix this ?

[dennisjm]

Posting here is as good as you can do.

Did you find the workaround posts/threads on this?

[gelly]

yes i tried your workaround to add an additional temperature setpoint and reorder the temperature controllers. thanks

[dennisjm]

That works well enough until you start wanting to do multiple processes. With multiple processes the layer numbering gets all re-ordered. I gave up on multiple processes with the left extruder.

[dennisjm]

You'll still need your workarounds for 2.2. Maybe 2.2.1??

[gelly]

yeah, saw that. Hopefully it is fixed soon.