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Z Axis Height Calibration
#51
(12-02-2019, 08:40 AM)usergoo Wrote: Either I am over simplifying things, or this thread is being way over complicated. I will test this afternoon to find out.
This thread details the solution as unlocking the set z=o parameter and then manually adjusting the variance each time you level the bed and resetting the z(home position). Why would you want to do this each time when you can just set this statically in steps in the configuration?



I'll test another cube today, but if i am understanding these parameters correctly, you machine is now calibrated and all you have to do is level like normal each time and print. Am I missing something?
No! No! No!

Do not mess with the steps! They are correct.
This problem has been solved lang ago...
What I described before was a workaround to manually set zero which by the way works pretty well.

The problem is only regarding the 1st few layers. Messing with the steps will mess up your overall height.
Elegoo provides different z-motors without spring washer on request ond conveniently provide 500ml resin as well for the efforts.

Use either the workaround or the new motor. (or both)
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#52
(12-02-2019, 10:51 AM)Blackbird2016 Wrote:
(12-02-2019, 08:40 AM)usergoo Wrote: Either I am over simplifying things, or this thread is being way over complicated. I will test this afternoon to find out.
This thread details the solution as unlocking the set z=o parameter and then manually adjusting the variance each time you level the bed and resetting the z(home position). Why would you want to do this each time when you can just set this statically in steps in the configuration?



I'll test another cube today, but if i am understanding these parameters correctly, you machine is now calibrated and all you have to do is level like normal each time and print. Am I missing something?
No! No! No!

Do not mess with the steps! They are correct.
This problem has been solved lang ago...
What I described before was a workaround to manually set zero which by the way works pretty well.

The problem is only regarding the 1st few layers. Messing with the steps will mess up your overall height.
Elegoo provides different z-motors without spring washer on request ond conveniently provide 500ml resin as well for the efforts.

Use either the workaround or the new motor. (or both)
Please learn to read before going into tirades.No one is changing the step height..M8084 is z offset. Z offset is in steps and calculated from the steps/mm defined in M8010. The difference between sensor read 0 and software z=0. It is exactly what you are temporarily setting when you press the z=0 button. Setting it in Gcode makes the setting static . You are absolutely correct that changing 8010 would be a nightmare, but this is not what was stated. I don't want a stepper without a spring because it is there to protect the screen. This is just basic printer calibration. Thank you and goodbye.
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#53
(12-02-2019, 11:48 AM)usergoo Wrote: Please learn to read before going into tirades.No one is changing the step height..M8084 is z offset. Z offset is in steps and calculated from the steps/mm defined in M8010. The difference between sensor read 0 and software z=0. It is exactly what you are temporarily setting when you press the z=0 button. Setting it in Gcode makes the setting static . You are absolutely correct that changing 8010 would be a nightmare, but this is not what was stated. I don't want a stepper without a spring because it is there to protect the screen. This is just basic printer calibration. Thank you and goodbye.

You are certainly right, I didn´t read attentive enough. (although I certainly did learn how to, already)

Skimming such big a text on an already solved problem I overlooked that you basically described how to unlock the "set-zero" function as is already known.
It´s up to you, to use the button or a fixed offset,. There are people out there who use a 3D-printed PETG taper bushing
instead of the insane rigid metal one and hence prefer the button.
There are also good reasons to level and determine "zero" below the sensor-zero. No pressure on the display while leveling in any case e.g.
Whereas the spring washer is not much protection with it´s 1-1,5mm when it really comes that a part falls of the built-plate.

But whatsoever, there´s a workaround, no matter with or without fixed offset.
Elegoo also provides a motor the same style as the newer printers are equipped and people have been happy with both ever since...
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#54
(12-03-2019, 12:21 AM)Blackbird2016 Wrote:
(12-02-2019, 11:48 AM)usergoo Wrote: Please learn to read before going into tirades.No one is changing the step height..M8084 is z offset. Z offset is in steps and calculated from the steps/mm defined in M8010. The difference between sensor read 0 and software z=0. It is exactly what you are temporarily setting when you press the z=0 button. Setting it in Gcode makes the setting static . You are absolutely correct that changing 8010 would be a nightmare, but this is not what was stated. I don't want a stepper without a spring because it is there to protect the screen. This is just basic printer calibration. Thank you and goodbye.

You are certainly right, I didn´t read attentive enough. (although I certainly did learn how to, already)

Skimming such big a text on an already solved problem I overlooked that you basically described how to unlock the "set-zero" function as is already known.
It´s up to you, to use the button or a fixed offset,. There are people out there who use a 3D-printed PETG taper bushing
instead of the insane rigid metal one and hence prefer the button.
There are also good reasons to level and determine "zero" below the sensor-zero. No pressure on the display while leveling in any case e.g.
Whereas the spring washer is not much protection with it´s 1-1,5mm when it really comes that a part falls of the built-plate.

But whatsoever, there´s a workaround, no matter with or without fixed offset.
Elegoo also provides a motor the same style as the newer printers are equipped and people have been happy with both ever since...
Pretty sure I already have the newer motor. My springs  are strong, which is also why this probably doesn't make as much sense to me. People talking about the viscosity of the fluid causing inaccuracy really was making me wonder how because you really have to push on mine to get any play. Mine is almost brand new. Its an "M10xxxxx" model.
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#55
This thread is so confusing to me. I haven't noticed any problems with my prints...how do i know if i have a z- height problem? I don't know mechanical stuff well so if I do have a problem I don't understand what all these washers are and their serial numbers or where to even find such things. Then even after I would find them how I am to install. I know alot of this probably seems simple to you all but that isn't the case forme. I have read a few of the "step by step" tutorials on what to do to fix but they skip alot that they just assume the person watching shoulld know.
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#56
Hello everyone,
just wanted to report that one of the solutions found by a user and described on his blog (using a pair of F8-19G axial bearings) does not work. I tried to exchange the bearings but even, if they fit, the rotor will not turn because of friction. Even if you try to use just one F8-19G at the bottom the rotor still will not turn. However I would like to confirm that the problem is mechanical because the spring washer allows for some axial play. Since the plate goes up and down each cycle the spring will relieved and compressed continuously yielding (slightly) different result at each re-positioning. The error may be attenuated by using a stronger spring but this will increase load on the radial bearings.
The only way to resolve this completely (and achieve accuracy around +/- 0.02) is to redesign the Z axis linear actuator using separate bearings for the lead screw, an elastic coupling for the stepper AND a linear encoder. This way the axis will not rely on motor bearings (there is an increasing trend nowadays on using motor bearings as load bearings... Rolleyes ), the elastic coupling will accommodate for any motor misalignment (so the motor bearing will not suffer) and the linear encoder will ensure accurate positioning.
I realize this would be a completely different printer with a much higher price tag and it would still be uncertainty about the behavior of the FEP film (an elastic build surface on a rigid machine...).
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#57
I was 1mm of on my 20mm calibration cube, and after I followed this tutorial nothing sticks to my build plate any more Undecided
I first did a 1mm adjustment and then after a failed print, I redid z=0 with 0.5mm adjustment, and still nothing sticks...
Now going to clean the vat again and remove the stuck resin from the fep and then I am going to try just 0.02mm and see what happens. Cross your fingers for me.
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#58
(01-19-2020, 02:04 AM)SnyggJohan Wrote: I was 1mm of on my 20mm calibration cube, and after I followed this tutorial nothing sticks to my build plate any more Undecided
I first did a 1mm adjustment and then after a failed print, I redid z=0 with 0.5mm adjustment, and still nothing sticks...
Now going to clean the vat again and remove the stuck resin from the fep and then I am going to try just 0.02mm and see what happens. Cross your fingers for me.

i havent had a chance to update the instructions, but if you have more then 0.4mm - 0.5mm of offset, more then likely, the stepper only has a single spring washer installed and needs to be modded with the washer, or have another spring washer installed.
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#59
But your method is just to raise the build platform 0.4mm so the first layer has to cure a 0.05 + 0.4 mm gap. Thats why nothing sticks anymore to the build platform.
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#60
After searching through this Elegoo's forum, FB forum, and Google, I have not been able to find one person saying that their standard size Elegoo Mars printer came preinstalled with firmware V4.3.0_LCDF/1440x2560/F2.12.
 I am able to print objects accurately if I add supports to the object, but am having issues with the z height accuracy when I try to print a flat object directly on the bed with no supports. I followed instructions carefully including "printing" the Mars_Config_Modified_English_Z_MOD.gcode file, but my objects are consistently off by 0.4mm (19.6mm instead of 20mm) before and after following his step by step guide. It seems to me like the gcode file is not having any effect on the machine.
My Elegoo Mars (M09) came with firmware V4.3.0_LCDF/1440x2560/F2.12 installed on the machine. I downloaded the latest firmware from Elegoo's website, but it's for V4.2.20.3. Logically, that sounds like a downgrade from V4.3.0 to V4.2.20.3. I am nervous about changing the firmware, as the machine did not come with a backup file of the firmware that came preinstalled.
I am wondering if I change (downgrade?) the firmware if the gcode file to modify the Z height will take effect and let me do the offset like his instructions state?
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