Welcome! Log In Create A New Profile

Calculating steps per mm

jnsbanman

Calculating steps per mm
January 22, 2016 11:37AM

Registered: 8 years ago
Posts: 49

I am building my own printer...

I know the generic steps per mm calculation but my situation is a little different. It is a core XY style.

The stepper will have a 16 tooth GT2 pulley and the shaft will have a 40 tooth gt2 pulley. 40 tooth because they are 12mm linear shafts.

How do I calculate the steps per mm when 2 pulleys of different sizes are involved?

Thanks

Reply Quote

jnsbanman

Re: Calculating steps per mm
January 22, 2016 12:03PM

Registered: 8 years ago
Posts: 49

Well I found a calculation... what I came up with is this

steps/mm = 200 (motor steps per rev) x 40 (teeth on shaft) * 32 (microsteps) / 16 (teeth on motor) x (3.14x12) = 424.62 steps per mm... does that make sense? or should i use 16x microstepping for 212.31 steps per mm?

Is this even in the realm of close?

Reply Quote

Floyd

Re: Calculating steps per mm
January 22, 2016 03:10PM

Registered: 10 years ago
Posts: 770

It should get you close enough for a test print. From there you would need to see what the difference is in size and adjust to make it match the model.

Reply Quote

VDX

Re: Calculating steps per mm
January 22, 2016 03:52PM

Admin
Registered: 16 years ago
Posts: 13,884

... I'm mostly doing a rough estimation for the steps_per_mm and after finishing the machine, then print or laserengrave a square of let's say 200x200mm, measure the exact size and adjust the steps_per_mm accordingly (same in Z and rotating axes, if included)

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Reply Quote

DjDemonD

Re: Calculating steps per mm
January 24, 2016 05:11AM

Registered: 8 years ago
Posts: 3,525

If in doubt estimate low and try it then adjust. If you estimate high you might run a carriage into its limits. Use a move 10mm command first just in case. Use m92 command to adjust steps per mm, via your host, then when you've got 100mm actual movement after you command 100mm movement use m500 to save (you need to enable eeprom in firmware) or reflash your firmware with the new value.

Reply Quote

jnsbanman

Re: Calculating steps per mm
January 25, 2016 12:33PM

Registered: 8 years ago
Posts: 49

Ok great thanks guys. I might be back when I get to that point lol smiling smiley

Reply Quote

DaGameFace

Re: Calculating steps per mm
January 25, 2016 01:28PM

Registered: 8 years ago
Posts: 318

The steps per mm calculation only cares about the drive pulley, if the other is just an idler(think yours is?) then ignore it in the calculations

Reply Quote

jnsbanman

Re: Calculating steps per mm
January 29, 2016 12:49PM

Registered: 8 years ago
Posts: 49

The other (40 tooth) would be attached to the axis that is rotating. I think the design would be similar to the ultimaker where the support rods on the x axis to move the gantry on the Y and vice versa.