stepper motor and drivers

[sirknight]

First of all I am new so if I am doing this wrong let me know. I have spent the last 2 weeks designing my router on AutoCAD and am down to the motors and drivers. I have a 25 by 20 working surface with a 5.5 in z all with diy rails and acme rods. I hope to do wood carving and engraving projects. I have read a lot and have been focusing on the 2 kits from

probotix and build your own cnc

Mostly due to I have a low budget but don’t wont to get stuck replacing parts a month after I build it. Is this the best way to go about this or dose anyone have recommendations. I have noticed a big difference in price for drivers from 20 to 150$. Thank you for your time

I will post link soon It will not let me post one yet

[ger21]

For best performance, motors and drives need to be matched to the machine, and choice is based on performance goals.

What kind of acme screws are you using? 1 start, 2 start, 5 start?
What's the machine made of? How much do the moving components weigh?

One big mistake people make is buying motors that are too big for the drives, or have too high inductance, resulting in low performance.

Without knowing exactly what you have, If you don't mind soldering, HobbyCNC probably offers the best bang for the buck.

[sirknight]

The acme rods I found but not purchased yet are 7.07 $ a foot which is why I was looking at them.
Major Diameter: 1/2" (in.)
Threads Per Inch: 10 (Threads/in.)
Number of Starts: 1
Lead: .100 (in./rev.)
Effective Threads Per Inch: 10 (Effective TPI)
Hand: Right Hand

I am planning on building the machine out of 3/4in oak plywood I have a tone in the garage and it is stronger than MDF. Weight not sure right now I would have to weigh a square foot and calculate it out for you but not hard to do.
Ultimate goal was wood carving detail work, signs and some engraving projects on metal or glass etching. Speed in not my top concern right now it can do its thing when I am not in the room.
Thankyou

[Torchhead]

...Speed in not my top concern right now it can do its thing when I am not in the room.

Probably a good thing since with drives running on 24VDC and a 10 TPI screw you MIGHT be able to hit 35IPM top speed. Detailed multi-pass carvings will take overnight to run!

There are two ways to get more speed from the table with steppers: More voltage and courser leadscrews. You can get two start leadscrews and some two start anti-backlash nuts (see dumpsterCNC.com) and get more than double the IPM. Then a venture into something like the Gecko G540 and a 48V power supply will double it again. it can get pretty boring even doing simple jobs and jogging something that takes a full minute to go from one end to the other!

Rotary or scratch engraving on glass is pretty hard to do with a conventional CNC setup. It's MUCH easier to cut a stencil and sandblast the design. It's called sandcarving and there are groups and websites (and vendors) setup just for that Even simple flat engraving becomes a challenge with a rigid mounted engraving tool. Then there is the RPM of the cutter to deal with.

TOM caudle
www.Candcnc.com

[sirknight]

I am trying to learn as I go I was not aware that the starts would affect the speed of the machine. I new the amount of strats changed the angle of the thread so that is very good to know and look in to. As far as the voltage I have been reading a lot and seeing that most people are pushing the 32 volt systems.
I would love to have a geckodrive system but when the G540 is 300$ with no motors it is not a option.
I have been putting a lot of thought into the hobbyCNC kit's with 300 or 400oz steppers
or the kits that (kelinginc) sells with the same size steppers

the whole glass etching thing was just a neat idea I presently do it with cutting out the design and using etching acid. But saw it on a cnc shark video and figured it would be neat. Ultimately I would be using my machine for wood work.
Thankyou