Which stepper for TR10x2 leadscrew

Hello,

I've got some high precision TR10x2 leadscrews for the Z-axes of my 3d printer. To drive the X and Y axes of my printer I use the cheap 0.9° high torque Wantai NEMA17 stepper motors.

My question here is: Should I use the same stepper motors for these leadscrews as well, or would it be that with 0.9° the screws would rotate much to slow?

Hi,

Any motor is labeled "high torque", that means nothing. Torque is a value.
0.9° means your motor have 400 steps per turn (increments) : 1 step = 0.9° ; 360/ 0.9=400 steps.
There's not a lot of difference with 1.8° motors which have 200 steps per turn.
Just the 0.9° motor have twice the resolution of the 1.8° motor.

In operation, no matter the number of steps per turn of your motor.
You just need to set up your firmware to make that axis move of the expected value.
In Marlin it's the "#define DEFAULT_AXIS_STEPS_PER_UNIT" you should setup using the formula below :

steps_per_mm = (motor_steps_per_rev * driver_microstep) / thread_pitch

motor_steps_per_rev = 200 for 1.8° motor ; 400 for 0.9° motor
driver_microstep = is 1 to 128 depending of your driver and its settings
thread pitch = is the pitch of your screw : the distance crossed by the nut in one turn of the screw.

It wont be drasticaly slower form one motor to another. But the biger the pitch of the screw, the faster.

Lead screws multiply the output torque of the motor, so you should not need very powerfull motors to move it.
Because the nut rolls around the perimeter of the screw, resolution is increased bu leadscrews.
So you will probably not need 0.9° motors too, because a 1.8° motor on a Z axis allows theoricaly at full step layers of 10µm !
And thats at last 5 times what we need for printing !

++JM

Thanks a lot for your reply.
Please correct me if I'm wrong but I have to insert 2 for the "thread pitch" setting in firmware?

no you input the steps

I have same leadscrew, if you run it with 16 micro stepping, your input is 1600 steps

I have same motor also, which I too plan to use them on x y carriage, I will be experimenting between 16, 8, 4 micro stepping with them and see whats better, but it be a while, I need to print all the parts out first

I meant the last line in J-Max's code box. I guess TR10x2 stands for 10mm diameter and 2mm pitch. In my case, with 0.9° stepper, and 32 microsteps driver, it would be (400 x 32) / 2 = 6400 steps_per_mm, isn't it?

thats correct

At 6400 steps per mm, if you're running marlin on an ATMega2560, you be limited to a maximum speed of 40,000/6400=6.25 mm/sec. Probably OK for a Z axis, but something to think about if you're going to try to drive X or Y axis with a screw.

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

How many starts does your leadscrew have?

A TR8 has 4...

TR8 Leadscrew
2mm pitch
4 starts

steps per mm = (motor_steps_per_rev * driver_microstep) / thread_pitch*starts

If the TR10 also has 4 then...

.09 Stepper + 32 microsteps driver
steps per mm = (400*32) / 2*4
steps per mm = 12800 / 8
steps per mm = 1600

Mike, could you please point out what you mean by "starts"? I've never heard that before in the context of leadscrews.

"starts" is the number of grooves cut into the screw. If you look at the screw from the end, you can count the number of starts. A normal threaded rod has 1 start so the pitch=lead. In a lead screw with 2mm pitch and 4 starts, the lead will be 2 x 4 = 8 mm.
The lead is what determines the distance per per revolution.

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

Thank you guys. You helped me a lot.