Cura & Firmware debugging help

Hello -

I have noticed a couple of curiosities (characteristics, IMO bugs, opportunities, etc.) in both the Cura (3.6.24) and TAZ 5 firmware (v1.1.9.34) as related to use of the Lulzbot Dual V3.1 toolhead.

My ultimate goal would be to ferret out and fix these issues myself. But to climb that mountain there are too many steps to take right off the bat.

What I like (FIRST) is an explanation of where to look in the sources for each of these issues. So, I will describe what I’ve noticed below. If one or more experts on the software can identify the specific code modules for me, that would be helpful.

Cura issue:

With the dual-extruder, I am using the brim (single layer) to judge both my TAZ 5 table leveling and table waviness. In principle, if I have a brim from each extruder, say 5 lines wide and spaced apart, I will have an item whose thickness I can measure.

What’s happening is that the Cura algorithm that calculates placement of the dual brims will never print move that a single brim for whatever extruder is defined as the second one. So, the most I can obtain is 5-lines of the first extruder with a single line of the 2nd one. Further, I cannot get the two brims spaced apart from each other. So, my conclusion is an algorithm math error.

With some guidance, I like to know where in the code that algorithm is?

Lulzbot TAZ 5 firmware:

There’s at least one forum topic thread reporting V3x toolhead errors, specifically referring to “E1 Heating failed PRINTER HALTED Please reset”. The Dual V3.1 I have was purchased at the end of November & installed on my TAZ 5 for the first time this week (last week of Feb, 2021)

I’ve read those posts. The common thread is that there is :“poor crimping” in the thermister wiring. I have dismantled and examined both the thermister & heating wiring for both extruders. There was nothing amiss with thermister wiring. The only possible weakness was the heater pigtail to wire crimp. I soldered those, just to be sure.

The issue was that the E1 failure would always occur at the same point in a print set up to evaluate TAZ 5 table level-ness. Specfically, E1 was set up with ABS while E2 had PLA. As there were several minutes between the patterns done by E1 and E2, each extruder cooled to its idle temperature before being needed again.

What I believe triggered the E1 (ABS) failure was the fact that the E1 extruder was not heating up fast enough (timeout???).

To check this, I set the ABS idle temp from 200-C to 240-C; thus, eliminating the “re-heating” delay. In this second case, the test print completed.

So, once again, I am asking for assistance to locate that portion of source code where a decision to trigger an E1 Heating failed condition.

Thanks for any help!!!

Here is our source repository, LulzBot 3D / Cura-LE / CuraLE · GitLab , as for the location of the algorithm you are interested in, I don’t know off of the top of my head. As for firmware you can find it here , LulzBot 3D / Marlin · GitLab . My suggestion would start with looking for things specifically related to brims.