JgAurora A5 Magic number

itisnot_me

So i have been reading about magic layer height number and would like to see if i can work this into my settings. But in order to try and figure this out i would need to know lead screw thread pitch for the A5. Also need to know stepper motor step angle

I tried looking for this but i either dont know what to search for or how to find it. 

Can i please get help on this? some info on what i am talking about is below. its going to be in layer height section
https://io3dprint.com/tips-for-3d-printing-miniatures/

Samuel Pinches

• The lead screws are 8mm outer diameter, 2mm pitch, and 4mm lead.

Hope this helps

itisnot_me

Nice thanks. Where and how did you figure this out? I like to make sure that i understand it for the future and how to explain it to others. 

Also how would i figure out the stepper motor angle? There is a lot of info on the web but its all trying to be confusing

Samuel Pinches

The lead screw measurements are better explained elsewhere sorry, we worked it out a while back and I would have to relearn it to try to explain it.

I don't know the stepper motor angle, usually if you look up the motor model number or check the label, it might be printed there. But we can try to work it out too:

Stepper motor angle = 360º ÷ number of steps per revolution

= 360 ÷ ( [A] circumference length mm * [B] steps per mm)

[A] = 2 * pi * 11mm

[B] = steps per mm in firmware / microstepping rate

= 100 steps per mm from firmware configuration.h DEFAULT_AXIS_STEPS_PER_UNIT ÷ 16x microstepping

Stepper motor angle = 360 ÷ (2 * pi * 11 * 100 ÷ 16 ) = 0.83º per step approx

Since steppers are either 1.8º or 0.9º, then it looks like the steppers must be 0.9º per step.

itisnot_me

Damn dropping knowledge. lol

I know that i upgraded to the new stepper driver and had to change some values. And i cut a pin that i did not need to so we had to bring my firmware to 1/8 step until i can put the pin back. would this change the math slightly?

chilman408

Hello,

So what is the magic number for the A5?

I just want to be spoon fed...

itisnot_me

@chilman408 never knew you replied. My printer has also been down for the last month or so and i forgot all of the items. 

But .3 and .2 falls right in line really the only other ones that i have changed was .1 to .12

you can test things out by using this link https://www.prusaprinters.org/calculator/#optimallayer stick with .9 or 1.8 degree. I believe that my research stated those are the difference between 1/8th or 1/16th steps. Use the pitch above for lead screw. But i do not remember what the pitch preset i used was.

Either way i want to believe that the 1.2 looks a little better than .1 but until my printer is up and running again i wont be able to do correct tests.

cmarabate

Isn't the magic number supposed to have more decimal places? Something like 0.04375mm but that number is for a different 3D printer.

The following link explains how to do the calculation but it is incredibly confusing to me and I can't find all the correct specs to plug in to the calculation to figure out the magic layer height...
https://io3dprint.com/tips-for-3d-printing-miniatures/

Can anybody help?

I am trying to print little D&D miniatures but they keep coming out too fragile. I'm guessing that setting the magic layer height for the JGMaker Magic is what might resolve this issue but please let me know if anybody knows of other settings I could tweak to make my mini's print out thicker(Less fragile).

Thanks,

Chris

cmarabate

(Removed duplicate post)

Laser8302

I think what you are thinking of is the "golden layer height" that delta printers like. That's 0.1618mm.
Our printers are of cartesian design.
The lead screw is of 4mm pitch, the stepper is 1.8º and therefore 800 micro steps = 1mm.
However that's MICRO STEPS, we want FULL STEPS to make sure we aren't trying to hold the motor at some strange level.
800/16 = 50 full steps per mm
1mm/50 steps = 0.02mm per FULL step

So that you've got +/- a couple steps, go with a 0.06 or 0.08mm layer height. 0.10mm works well too. You could try 0.04 but then you might need a 0.3mm or 0.2mm nozzle and those might be prone to clogging.

For crazy detail, you'd need a SLA printer.

cmarabate

Cool, thanks for the clarification!