Jerk Control M566

Phaedrux

Out of curiosity, could my M360 micro stepping interpolation of 1/16 have any adverse effects causing the machine to lose track of position?

Not really, no.

Can you speculate on the weight of the print head carriage?

If 1.5A is still no signs of overheating I would try to raise it some more. The Duet 2 is good to 2A with cooling on the drivers.

kroybal

@Phaedrux

Id say >4kg
Approximately 2kg of motors, 1.5-2kg of wire chains, 300g of metal components, 300g of printed components, and however much a 20mm aluminum extrusion bar of 1m length would weigh. Neglecting fasteners, switches and belts.

A more detailed description for those that are curious:
I got an aluminum extrusion bar approximately a meter long.

With two cloned print heads each with:
two motors (by inspection 40x40x40mm), a large wire chain, four water cooling tubes, all resting on a flat aluminum plate (by inspection 60x120x5 mm) and a variety of idlers, hob gears, 3D printed housing and strapping components.

The gantry itself has two more (smaller) wire chains that gotta add up to be at least a 500g, and two hot end brushes. The gantry is closed loop belt driven by two mirrored motors (40x40x60 mm) but does not bare their weight.

kroybal

At this point, too much jerk produced bad results and too little jerk also did the same. Layer shifting has found its way through many diagnostics and proposed solutions. Could we be dealing with a faulty motor encoder? The problem is I got 4 motors driving the gantry, so which If any could be bad? The shifting is exclusively along the x axis either + or - direction so I reduced it down to x motors. I have tried isolating the motor issue by swapping roles of left and right tools from primary and support but the failures were consistent as before.

Someone else in the shop asked, could it be the file upload via the ethernet?

Personally I don't think so.

I am just so hung up over jerk settings because any time I adjust it I can observe changes in print quality. In some past cases I could print a quality part with one model, but layer shift with another holding my settings constant.

Phaedrux

Yes that is a lot of weight. So I'm not surprised there is some skips with higher jerks. It makes the super low motor currents all the more suspicious. I would have imagined some rather beefy NEMA17s or even NEMA23s with that much heft to move around. It really seems like your motors just don't have the torque.

To get decent quality we simply have to get it up to a minimum jerk level otherwise the facets will be exaggerated. I would try lowering your acceleration a bit, maybe to M201 X300 Y300 and bump the jerk up a bit to M566 X100 Y100 and try for 2A of current. That's as high as you can easily go with the Duet anyway.

@kroybal said in Jerk Control M566:

Could we be dealing with a faulty motor encoder?

You mentioned closed loop belt, but are the motors closed loop as well? It's really too bad we're so in the dark about what the motors actually are.

@kroybal said in Jerk Control M566:

Someone else in the shop asked, could it be the file upload via the ethernet?

As in, could the file be corrupted? Highly unlikely. If it was you'd likely get bad command errors. Anyway, the CRC check on upload should catch it. But you can download the file again and run a compare on it against the original file from your PC as a check.

MikeS

@kroybal for this weight i also exprected at least nema23 motors, also the frame should be really rigid to get decent print speed/time. Seeing that it is a professional commercial printer i won't say that requirements are not met and also you should really come in contact with the manufacturer to, at least, get the basic configuration they use for this machine. Anyway i wouldn't be surprise if the motors are really bigger than nema17 and current is too low. Let us know when the manufacturer answer you and if they help you fix the problem

Last thing i would check is that all the slicer speed/acceleration override are turned off...some slicer can modify the speed/acceleration based on feature type so it could overwrite your settings in config.g

kroybal

@MikeS said in Jerk Control M566:

Seeing that it is a professional commercial printer i won't say that requirements are not met and also you should really come in contact with the manufacturer to, at least, get the basic configuration they use for this machine.

Well I got a hold of Aon finally, apparently they're updating their calling system. Anyways, the support team said that the M1 model is mostly a prototype for proof of concept. There are issues with the model, and there are success stories with it as well. They lined me up to talk to the machine's designer so I can get some answers on its anatomy. The support agent does not know a whole lot about their legacy machine, but she does know that the set screws used to tension the toolhead to the belt wiggle loose over time and that was one of the design updates they did going into the M2 model. That said I'm going to tighten screws where I can and see if they help control it from shifting. But based on the nature of the shifts it doesn't stand out as being mechanical slipping as much as it could be configuration.

We'll see. I am just happy to have talked to an Aon team member.

MikeS

@kroybal Nice! let us know if you get it printing and show us some results

dc42

@bot said in Jerk Control M566:

I've noticed that with very low "jerk" rates, the facets of the model are much more visible. This is likely due to the extrudate "bulging" as the print head slows down to the jerk rate. In the case of OP, this is 0.1 mm/sec.

At low jerk rates the slow down and speed up will cause over- followed by under-extrusion at those points if not compensated by pressure advance, hence bulging at the intersections of the facets. Thinking about it, this could be a good way to tune pressure advance.

kroybal

UPDATE:

Still playing phone tag with AON to no avail... they will cave soon and return my call.

Something that slipped through the cracks for many of us and especially me is my driver assignments on my config.g (listed above). The problem is that my x-axis steppers are on my toolboard LC the key term here is LC.

When I began the process of doing what could be the first ever duet powered M1 I did several iterations in wiring and driver assignments.

I have a PT100 daughterboard which is bound to the MB6HC, which also binds my extruders (1.3A rated motors) too.

@kroybal said in Hotend heater fault status:

This issue was resolved for those who experience a similar issue... I had my hotend heater mapped to a toolboard using pt100 sensors on the mainboard. Some rewiring and swapping pins around was in play.

This caused me to assign two of my axis steppers to the Toolboards kicking off my originally assigned extruders and hotends. I thought this was a solution but I was overlooking LC. The idea was it would allow me to continue using my PT100's since this M1 machine prides itself on how hot it can get. But in turn it could be the basis of all my issues. All of my layer shifting has been solely in the x-axial directions.

I got assigned this board swap task after all the boards had been purchased. I was initially bummed that boss man didn't buy a 3HC Expansion board and now its coming to realization that my initial scoff at the toolboards might be valid.

I am still waiting on the motor specs for the machine... thoughts?

Phaedrux

So you're driving the X axis off of tool boards? And the tool boards are in the heated enclosure? How hot does the enclosure get? The tool boards can handle quite a bit, but still, probably should be running the X axis off the mainboard. I'm not sure I follow the reasoning though, the PT100 could still be wired back to the mainboard with the extruders on the tool boards.

; ======={ Drives }========================================	
; 0.x corresponds to main board /// 20.x corresponds to tooloard-1 /// 21.x corresponds to toolboard-2
; X
M569 P20.0 S0                                   ; physical drive 0.0 goes forwards
M569 P21.0 S0									; physical drive 0.1 goes forwards
; Y
M569 P0.2 S0                                    ; physical drive 0.2 goes forwards
M569 P0.3 S1									; physical drive 0.3 goes backwards 
; Z
M569 P0.4 S0                                    ; physical drive 0.4 goes backwards
M569 P0.5 S0									; physical drive 0.5 goes backwards
 
; ======={ Extruders }=====================================
M569 P0.0 S1                                    ; physical drive 1.0 goes forwards
M569 P0.1 S1                                    ; physical drive 2.0 goes forwards
M584 X20.0 Y0.2:0.3 Z0.4:0.5 U21.0 E0.0:0.1     ; set drive mapping

kroybal

@Phaedrux said in Jerk Control M566:

So you're driving the X axis off of tool boards? And the tool boards are in the heated enclosure? How hot does the enclosure get?

The toolboards are located in a separate enclosure with a radiation shield between. None of the boards are exposed to extreme temperatures.

@Phaedrux said in Jerk Control M566:

The tool boards can handle quite a bit, but still, probably should be running the X axis off the mainboard. I'm not sure I follow the reasoning though, the PT100 could still be wired back to the mainboard with the extruders on the tool boards.

The x and u-axes are driven by the toolboards because the extruder drives had to move from toolboard to the main board per the bullet point criteria from this section. I responded to that criteria by moving the drives around ending up with the IDEX motors on toolboards.

dc42

@kroybal said in Jerk Control M566:

The x and u-axes are driven by the toolboards because the extruder drives had to move from toolboard to the main board per the bullet point criteria from this section. I responded to that criteria by moving the drives around ending up with the IDEX motors on toolboards.

Which particular constraint prevented you from using the tool boards to drive the extruders?

kroybal

@dc42 said in Jerk Control M566:

Which particular constraint prevented you from using the tool boards to drive the extruders?

Below, I bolded part of a quote from a previous thread. At the time my firmware was not up to date which would have allowed me to connect my IR Filament monitoring to a toolboard per this criteria.

@kroybal said in Hotend heater fault status:

@Veti
from the link:

A heater on an expansion or tool board can only be controlled by a temperature sensor on the same expansion board

I am measuring my hot ends with pt100 sensors on a temperature daughterboard. I feel as though as I will have to swap around my arrangement, perhaps swap my extruder driver to the main board and run my two hot-end carriages (they move independently along the x-axis). I also have IR filament monitors I need to setup.

Currently:
Driver 0 -- X (left carriage/X axis)
Driver 1 -- X (right carriage/U axis)
Driver 2 -- Y1 motor
Driver 3 -- Y2 motor
Driver 4 -- Z1 motor
Driver 5 -- Z2 motor
Toolboard 20 Driver 0 -- E0
Toolboard 21 Driver 0 -- E1
out1 -- signal to bed idec relay
out2 -- signal to chamber idec relay
temp0 -- Bed thermistor
temp1 -- Chamber thermistor

Revisions implemented:
Driver 0 -- E0
Driver 1 -- E1
out1 -- left hot end
out2 -- right hot end
Driver 20.0 -- X (left carriage)
Driver 21.0 -- X (right carriage)
20.out0 -- signal to bed idec relay
21.out0 -- signal to chamber idec relay
20.temp0 -- bed thermistor
21.temp0 -- chamber thermistor

this way my extruder motors are monitored by filament monitors and pt100 on the same board. And my heaters are all being monitored by sensors on the same address.

kroybal

I have updated the firmware for the MB and TB's to the recent release about a week ago, that said I can rewire somethings and see what results it'll produce. I am still waiting to hear back from the machine's designer to ID the motors so that I can specify current ratings in the config.

kroybal

The support team over at AON have been really delaying getting back to me. However, my boss went ahead and ordered a duet EX3HC. The results were excellent right out of the gate. All of the layer shifted existed on the x-axis which at the time was powered by low current channels . At any rate, I have new issues to uncover and fix but for now I will call this a victory. I will start a new thread in regards to complications I face with the expansion board.

Thanks for everyones help and suggestions, ultimately it led to discovering a trivial mistake.