I have recently "upgraded" my BigBox Z-Axis to 8mm (2mm pitch) 4 start lead screws. Since I completed it I have been having this strange clicking issue (it actually seems like it is sticking) and I can not figure out what the issue is.

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I have tried upping and lowering the voltage. I have checked and re-checked the bed is both level and square. It slides nice and freely on the bearings.
I have checked the steps 1.8° motor ( (200*16)/8 ) so 400 steps set in firmware.

The other weird thing is that the BLTouch reports that there is almost a 2mm difference from left to right. I have physically measured this and it is level. The Axis are all level as well so I can only think this must be linked?

At this rate I might just return to my old lead screws!

With the coarse pitch, is it possible the weight of the bed is miss steps or move downwards
What torque motors are they?

just an idea .
i may be talking rubbish tho

If you changed from a two start screw to a 4 start screw, you doubled the lead (the distance traveled per rotation) which increases the load on the motor. The noise you're hearing may be the motor skipping steps, just like the noise the extruder motor makes when the hot-end is jammed. Your motors may not have sufficient torque for the increased load.

...or...

Leveling isn't about being level to the earth- it's about being parallel to the XY plane defined by the printer's X and Y axis guide rails. If the bed support (not the bed) is not in that plane it may be because one of the Z motors has missed some steps and has tilted the bed support. If the bed support is tilted, the Z axis bearings may bind, increasing the load on the motor(s), and causing the motors to skip steps which will make the clicking noises. The bed can usually be leveled independently of its support. TLDR: the bed support must be in the XY plane to keep the Z axis bearings moving smoothly and the bed must be in the XY plane to keep the first layer of the print stuck to the bed.

The BL Touch measures the distance between the XY plane that the extruder carriage travels in (defined by the X and Y axis guide rails) and bed surface. If it says its tilted by 2mm, it probably is.

Edited 2 time(s). Last edit at 01/12/2017 07:04AM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Thanks for the suggestions. I have measured the bed support to the frame and that is definitely within the error the BLTouch picks up. I have checked the X and Y and they are parallel with the frame. It can only be the bed itself.

Just to clarify if the BLTouch reads a larger number then it is further away from the Bed correct?

I have the same problem with the same pitch 4 start lead screw. Prints are coming out fine, but that clicking sound drives me nuts. I have
conucon M 1717 stepper motors and drv 8825 drivers set @ 0,6V which equals to 1,2A so 70% of the 1.7A.
@Symatic, have you found a solution for that problem?

Kind Regards
Herb

Quote
doublehelix
I have conucon M 1717 stepper motors and drv 8825 drivers set @ 0,6V which equals to 1,2A so 70% of the 1.7A.

Hi Herb, you used plural for both motors and drivers, is that accurate? i.e. you are using two stepper drivers and two motors? I ask because the more common approach is one driver running two motors, and then the question arises as to how the motors are connected to the driver. Ramps connects the Z motors in parallel by default, so the set current is divided between the motors and you need to double up the ref voltage in order to get sensible drive currents (assuming the drivers don't overheat). It's also possible to connect two motors in series, in which case you don't double the ref voltage, but you may need a higher supply voltage to drive the motors effectively.

'Clicking' is usually an indication of the motors stalling due to insufficient torque, and with 8mm lead the most common cause to is too high acceleration and velocity settings, or too low a reference voltage on the drivers. If the motors don't get warm then they are not being driven anywhere near their current rating (since the current rating is effectively a thermal management limit).

Edit: reasonable acceleration to try: 100 mm/s^2, and velocity 10 mm/s

Edited 1 time(s). Last edit at 02/09/2017 03:14PM by JamesK.

Hi James, thank you very much for your reply!
Yes you are right, I'm using 2 motors, but just on one driver, so the 2 motors are parallel
to one driver on a rumba board. So I should double the voltage as you suggested, e.g. 1.2V?

Edited 2 time(s). Last edit at 02/09/2017 05:10PM by doublehelix.

Quote
doublehelix
Yes you are right, I'm using 2 motors, but just on one driver, so the 2 motors are parallel
to one driver on a rumba board. So I should double the voltage as you suggested, e.g. 1.2V?

Yes, but be aware that the driver will be working hard and might over-heat unless you have a fan cooling it. You may need to find a compromise setting

I think it would be also possible to use one free extruder port to power a second motor
for the z axis, in that way I could run the two motors with 0,6V each right? Is there any disadvantage
e.g. unsynchronous movement between these motors?

Quote
doublehelix
I think it would be also possible to use one free extruder port to power a second motor
for the z axis, in that way I could run the two motors with 0,6V each right? Is there any disadvantage
e.g. unsynchronous movement between these motors?

Yes, that should also be possible, although I haven't tried it. I'm pretty sure I've seen the support in repetier-firmware and I suspect it's there in the other firmwares too. I don't think there is any more chance of losing synch than with the default config. Most of the problems with dual motor setups will come from one motor missing a step due to binding, and/or slippage when the motors are not powered. (0.6V ref is a bit on the low side in my experience, and missed steps on Z are difficult to spot and diagnose, so I'd boost it up a bit until you at least feel some warmth in the motors. I think I even use more than that on my nema14 extruders, but they do run near the ragged edge.)

Edited 1 time(s). Last edit at 02/09/2017 05:28PM by JamesK.

The Anet printers all happily drive two Z motors in parallel off the same LR7843 stepper driver. The main thing to ensure is that both Z leadscrews turn freely and that there are no tight spots between the Z axis guides.

What's a "LR7843 stepper driver" ? I can find a mosfet with that number, good for 100+ amps at 30V, so if it's a driver which uses those as external mosfets then I can see that not having too much trouble with a couple of nema17s There are lots of printers that drive a pair of nema17s with a single pololu style driver, but it is quite possible to run into the current/heat limits in that config.

The brain slipped out of gear in my last post, seems to be happening a bit lately (must be getting old).

I should have said that the Anets happily drive two Nema17 type motors with 8mm lead-screws in parallel off the same A4988 stepper driver .

Quote
Supermec
The brain slipped out of gear in my last post, seems to be happening a bit lately (must be getting old).

I know that feeling oh so well.

Quote

I should have said that the Anets happily drive two Nema17 type motors with 8mm lead-screws in parallel off the same A4988 stepper driver .

I have a slightly different config with two 8mm lead screws driven from a single motor via a belt from a drv8825. I recently discovered it was right on it's limits and missing steps, probably as a result of a rather heavy X axis which I made even heavier with a dual direct drive extruder setup. I ended up fixing the problem by replacing the pulleys on the lead screws with 40 tooth versions, giving a 2:1 gearing reduction from the 20 tooth pulley on the motor. It can be surprising how Z axis problems creep up on you without being terribly obvious.

Ok, clicking is gone now thy very much James!!!
But now I have another problem. The motor which is connected to the default z
stepper runs just fine, but the second motor which is now connected to the E2 stepper
starts skipping movement or refuses to move at all. But only during print time. I've also enabled
autobedleveling. Do I've to tell marlin that I'm using 2 different stepper drivers now except from the basic configuration
like:

#define Z_DUAL_STEPPER_DRIVERS

and

// Steppers
//
#define X_STEP_PIN         17
#define X_DIR_PIN          16
#define X_ENABLE_PIN       48

#define Y_STEP_PIN         54
#define Y_DIR_PIN          47
#define Y_ENABLE_PIN       55

#define Z_STEP_PIN         57
#define Z_DIR_PIN          56
#define Z_ENABLE_PIN       62

//DUAL Z

#define Z2_STEP_PIN        29
#define Z2_DIR_PIN         28
#define Z2_ENABLE_PIN      39

#define E0_STEP_PIN        23
#define E0_DIR_PIN         22
#define E0_ENABLE_PIN      24

#define E1_STEP_PIN        26
#define E1_DIR_PIN         25
#define E1_ENABLE_PIN      27

#define E2_STEP_PIN        29
#define E2_DIR_PIN         28
#define E2_ENABLE_PIN      39

EDIT: Ok I've nailed it. The problem was, that I had set the number of extruders to 3, so marlin wasn't able to choose between
the different feedrates for the extruder and the z axis and just gave up

Edited 1 time(s). Last edit at 02/11/2017 05:40AM by doublehelix.

Ah, great, glad you got it sorted. I haven't used marlin for a while, so I was going to struggle to help