Help with 3 axis CNC motor and drives

[domagoj55]

Hello,

can you please help me to choose electronics for my CNC. I was looking all over the internet about that and the more i read the less i know. Everything looked so easy at the beginning, but now looks like nightmare. I already spent half of my savings so i can't return now or quit.

I already bought mechanics for my CNC. Table size would be around 1200 x 800 x 300 mm.

I was thinking to buy nema 34 motors. Motor specifications are: 5.6 A/phase, 4.1 mH/phase, 7.7 Nm or 1090 oz-in, rotor inertia 1700g-cm2, 4 wire.

Drivers for that are DQ860MA, and power supply 350W, 60 VDC for each motor.

Can you tell me is that ok? Is the motor strenght enough for table with dimensions from above? I would like to mill in wood, aluminum and other soft materials. Can you also help me with driver settings. All those microswitches... i don't know where to begin. What current, how many microsteps...

Sorry for grammatical errors, i am writing from Croatia.

Regards, Domagoj

[martin54]

Welcome to the forum, lots of useful posts about this subject so spend some time reading through them might be the best place to start.
This is one of them:

http://www.mycncuk.com/forums/faqs-p...do-i-need.html

[domagoj55]

thanks for reply . In meantime i saw that link. I can find there usefull informations. When i come with some new questions, i will ask, but untill than does anyone have experience with drivers or motor that i am planing to use? I can't find users reviews or judgements for that tipe of drives. I found only reviews for 2M542 drives, but that is insufficient for nema 34 stepper motor.

[martin54]

If you have a look at the build logs on the forum you will see that most people use nema 23 motors. These would be quite suitable for the machine you are building. Why do you want such large motors? You could save yourself some money by using nema 23 3.1Nm motors which would be up to the job, 7.7Nm is over the top for what you want to cut.

[domagoj55]

I looked build logs, and will look more. First i also planed to use nema 23 425 oz (3 Nm) motors. The first time when i doubted about nema23 was when i took my linear rails. They were very heavy because they are also diy, and made from stainless steel. Second doubt was when i spoke with older guy from work. He also has cnc. He uses 9 Nm motors!!!! I said to myself then... WTF are you doing with 3 Nm motors? I think that gantry will in the end be around 20 to 30 kg. Is that heavy for 3 Nm nema motors? I have SFU 1605 ball screw. I would be happy if nema23 could do wood and some small aluminum things. My budget is weak and there is still a lot of work to do.

[domagoj55]

What do you think about replacing my first choice (Nema34) with this components:

3 x Stepper motors Nema 23

voltage 3.78 V
current 4.2 A/phase
resistance 0,9 Ohm/phase
inductance 3.8 mH/phase
holding torque 3 Nm
rotor inertia 810 g-cm2
detent torque 1.2 kg-cm

3 x Stepper motor driver M542H
voltage 20 – 100 VDC
current 1 – 4.5 A

3 x Regulated power supply 48V 5A