Threaded rod, Leadscrew, or belt drive ?

Guys,
I am planning to build my first 4 axis hot wire cutting CNC. Have seen several DIY videos, and threads for the builds. My machine size would be approx 4ft 2 ft.
Confused as to whether I should use threaded rod, lead screw or belt for the drive assembly.
Many people have said that threaded rod wobbles and has back lash . The lead screw nut and screws themselves cost a bit, perhaps as much as belt drives.

The downside on belt drive seems to be the added complexity, thats all

Would be really helpful if experienced users can 'guide' me here !

Thanks !

Why not to run with rope or fish wire ;) as modern 3D printer are using this method.

My machine uses #25 roller chain on the x and y and lead screw on the z. Cheaper than rack and pinion, less backlash than belt, much cheaper than lead screw. There are several ways to convert rotary motion to linear motion. The key is precision and available torque.

A lot comes down to speed. At the speed you will be able to cut with hot wire, threaded rod should be quite sufficient . As for backlash, google the "evanut", as it should be more than accurate for this app. You can always swap out for ball screws later.
Dave

Thanks All

I got some M8 threaded rod. Would it be better to go with higher thickness, say M12 ? Also the rod isnt straight, so would wobble around. I guess need to do flexible coupling to save the motor ?
Concerned about the backlash ... Does the software compensation in Mach3 work ?

Thanks !

The backlash compensation in Mach 3 is a compromise at best. You can either use 2 drive nuts working against each other or a precision acme threaded lead screw with a wear compensating nut to eliminate most of the backlash. You will always have some backlash or the system would be so tight that it couldn't move. Threaded rod is the slowest method of converting rotation to linear motion. Acme threaded rod is available with multiple starts. A single start 1/2-10 lead screw requires 10 turns to the inch whereas a 5-start 1/2-10 lead screw requires 2 turns to the inch. I have seen systems using screws that spin the nut instead of the rod which would eliminate the problem of the rod's whipping. No matter the system the coupling needs to be somewhat flexible to save motor wear but can be tight enough to prevent some backlash. Mcmaster.com is a good source for components.

make yourself a delrin nut and never worry about backlash, it'll be so small that you'll not notice it when cutting foam with a hot wire. Also use stainless steel threaded rod as it tends to be better quality than the mildsteel stuff

Hello.

I am also new on CNC but I was willing to make myself a 4-axis CNC. Nevertheless, I was willing to use a drive belt as I would to have a more quiet equipment. Am I correct thinking that a belt drive will solve my problem?

BTW do you guys have the plans you are using to build your own CNCs. I would appreciate if any of you could share them.

Cheers,

Gustavo

Hello. Did you ever build your hot wire cutter? I'm looking at building a small one also, and I would like to know how yours turned out.

Thanks