nanoDLP

eB3rlin

Member

Registered: 2020-04-17

Posts: 7

TOS project - motor problems

Hey,

iam working on the "FDM printed SLA printer" project from thingiverse/TOS.
when iam starting the printer the motor didnt really move correctly. its to slow and to load.
my first thought was the "wrong power supply". but now i have ordered a 12V 5A power supply and the issue remains..

here is a quick video:
https://youtu.be/koLFJBBjYLE

any ideas ?

best regards
erik

bigfilsing

Member

Registered: 2016-11-20

Posts: 306

Re: TOS project - motor problems

doesnt look so slow to me ???  What control board have you used ?  The firmware usually determines the travel , print and home speeds.
As for the noise thats probably down to the stepper driver you have used

eB3rlin

Member

Registered: 2020-04-17

Posts: 7

Re: TOS project - motor problems

iam using a raspberry pi and the nano dlp shield 2.2

bigfilsing

Member

Registered: 2016-11-20

Posts: 306

Re: TOS project - motor problems

Im afraid i don't own or have any experience with the 2.2 motor shield

Depending on which stepper driver you have i would check the dip switches are correctly configured  ( microstepping)

Then double check your settings in NanoDLP

Once that's done make sure when you give the UP Z 10 command it actually moves 10mm

Good luck

Last edited by bigfilsing (2020-04-23 01:40:29)

eB3rlin

Member

Registered: 2020-04-17

Posts: 7

Re: TOS project - motor problems

Thanks for your reply,

i changed the dip switches and now its moving much better.
... a bit to fast, but i will play with the config on the nanoDLP webinterface , to change that.

i got two endstops. on printer start, the z axes moves to the upper one, turns around and then randomly stops at the middle of the axes.
normally its has to hit the second endstop also, right ?

bigfilsing

Member

Registered: 2016-11-20

Posts: 306

Re: TOS project - motor problems

Back to the previous response ....When you click up Z10 does it go up by 10 mm ??

When you say changed the DIP switches ...what did you change

What stepper driver do you have ??

Last edited by bigfilsing (2020-04-23 07:00:38)

bigfilsing

Member

Registered: 2016-11-20

Posts: 306

Re: TOS project - motor problems

Thanks for your reply,

i changed the dip switches and now its moving much better.
... a bit to fast, but i will play with the config on the nanoDLP webinterface , to change that.

i got two endstops. on printer start, the z axes moves to the upper one, turns around and then randomly stops at the middle of the axes.
normally its has to hit the second endstop also, right ?

Typically at the start the z axis should lower the build plate to the screen and hit the endstop there
( while youre are experimenting i recommend you take the build plate off the machine , that way there's no danger of hitting the screen
Not sure with the 2.2 shield but the top endstop is normally to stop the axis exceeding its travel limit and wouldnt normally be used during a print sequence.
A lot of printers don't even have a top endstop!

eB3rlin

Member

Registered: 2020-04-17

Posts: 7

Re: TOS project - motor problems

1. Back to the previous response ....When you click up Z10 does it go up by 10 mm ??

2. When you say changed the DIP switches ...what did you change

3. What stepper driver do you have ??

1. no xD, i tested it and its completly wrong; 10mm are nearly 40mm
2. all three down
3.  DRV8825 Board(and i use a nema 17)

... think the dipswitches dont match the configured resolution in the webinterface, right ? (16)

i changed the switches to LOW LOW HIGH, and my leadscrew pitch value was at 8. didnt recognize that this was also wrong. i changed it to 2.
now the printer moves 10mm . but it is no fluent movement . he stops every few mm and starts again until he reached the 10mm

iam also hearing like a little noise from the motor when it didnt moves... in the same 'rythm'
here is a little demovideo: https://youtu.be/TIuhuHalynk

UPDATE:
i changed the position of the stepper driver poti and it got better

Last edited by eB3rlin (2020-04-25 09:35:54)

bigfilsing

Member

Registered: 2016-11-20

Posts: 306

Re: TOS project - motor problems

Ok ill try and explain
the dip switches set the micro stepping for the driver
5 states on a standard 4988 stepper
full step ( no micro stepping ) all dips off / all jumpers off ( on a 3D printer board there are usally jumpers no dip switches SO Off Off Off
1/2 step On Off Off
1/4 step Off On Off
1/8 step On On Off
1/16 step On On On
In your case you have a DRV8825 ( which is good .. better torque & more micro steps)
So set all the dip switches to On which should give 1/32nd step
Then you know your stepper driver is operating in its highest resolution mode
then you need to adjust the setting in NanoDLP to the lead screw pitch you have

You also need to set the current for your stepper . This is done by using a multimeter and measuring a reference voltage at the poti ( the poti itself can be measured!!)
( are you German ??  I think Germans are the only ones to call a potentiometer a poti :-)
As a starting point set it to 1 VoltDC     ( i remember that normal DRV8255  that two times Volt vref is  equal to amperage So 1 voltDC should be 2 amp drive current
If the stepper gets hot quickly then reduce to 0.75 VDC and try again.
Watch this >>
https://www.youtube.com/watch?v=YJSmrbeZUp4

Last edited by bigfilsing (2020-04-25 10:05:12)

bigfilsing

Member

Registered: 2016-11-20

Posts: 306

Re: TOS project - motor problems

I just took a look at the demo page for reference ( i dont have an actual shield)

If you scroll down you see Actuator / Motor
Chances are 99% sure you have a 1.8 deg stepper ( 1 rotation = 200 steps ) so leave that a 1.8
if you have all dip switches on your DRV8225 will give 32 microsteps
your lead screw pitch is whatever it is . Basically how far the nut travels during 1 rotation of the lead screw
and as for the Z axis height you need quite a large number here .  This acts a s a travel limit Start with
Example  with 4mm pitch lead screw .   100 mm travel / 4 = 25 rotations .  1 rotation is 200 steps times 32 micro steps = 6400 steps per rotation So then X 25 would be  160000  steps /pulses for a 100mm travel.

eB3rlin

Member

Registered: 2020-04-17

Posts: 7

Re: TOS project - motor problems

thanks for the great answer. ! this helped me a lot
the z axis movement now seems to be good

the final assembling is now finished and iam ready for the first test print..,
but i broke my display and have order a new one

do i need a seperate slicing software or is there any functionalty in the nanodlp webinterface for slicing stl files ?
i would like to print a benchy . without the lcd display, just to see if the movement works right and maybe to configure the print start gcodes or homing commands

PS.:
( are you German ??  I think Germans are the only ones to call a potentiometer a poti :-)
Yes, you are right, iam living in berlin

bigfilsing

Member

Registered: 2016-11-20

Posts: 306

Re: TOS project - motor problems

Glad the Z in now working

There is a slicer in NanoDLP and its definitely worth getting to know.
In fact i think there is a test plate in NanoDLP already
Run NanoDLP and go to "plates" and see what you have
You will also need to set up a resin profile for the resin you intend to use.

Alternatively many people use ChiTuBox slicer which has very good support generation
https://www.chitubox.com/download.html
There's plenty of tutorials on how to use Chitu slice on YT

Good luck

PS when you run your test print check the stepper motor isn't getting to hot.  Remember stepper motors consume current even when not moving !!!

Last edited by bigfilsing (2020-04-27 09:49:46)