Hi all. I am at the planning stage for my cnc router and was planning on having 2 x axis steppers. Do I drive these in paralell or do I need a seperate driver for each motor. Sorry if it's obvious but I've looked and can't find the answer yet. Thanks

You need a driver for each stepper

Thanks for the response monte55. Looking over the site it's all a bit confusing at the moment and I can see a lot more planning before I actually do something, never realised there was so many ways to achieve the same thing. Was planning a small'ish one about 1000 x 600mm. If I need any more help I'll post knowing I'll get a response. Great forum.

You need a driver for each stepper

What about lost steps, and what would you do, it seems to be a common occurance?

What about lost steps, and what would you do, it seems to be a common occurance?

Don't try to run your machine faster than it's capable of. That's what causes lost steps. If you want to cut at 100ipm, build a machine that will cut at 150ipm and have more power than you need.

Don't try to run your machine faster than it's capable of. That's what causes lost steps. If you want to cut at 100ipm, build a machine that will cut at 150ipm and have more power than you need.

For us newbies:
What are the things that enable a machine to be built to the 150ipm lever? And please don't just say bigger.

For cutting MDF:
PS Volts?
PS Amps?
Example of Min driver board (Manuf/Model)?
Stepper size?
Screw type?
Screw size?

For Aluminum:
PS Volts?
PS Amps?
Example of Min driver board (Manuf/Model)?
Stepper size?
Screw type?
Screw size?

Material doesn't really matter, but different materials may need different spindle HP.

Size and weight of machine makes a huge difference, so what works for one may not work for another. Volts and amps are dictated by the motors you use, so there is no general rule.

What you need to do, is decide how much force you want to have at a given speed. Then using the leadscrew you plan to use, calculate how much torque the motor needs to have at the rpm it's running at your target velocity. Then choose a motor that will provide that torque at that rpm. You'll need to see a motors torque curve to figure this out.

Material doesn't really matter, but different materials may need different spindle HP.

Size and weight of machine makes a huge difference, so what works for one may not work for another. Volts and amps are dictated by the motors you use, so there is no general rule.

What you need to do, is decide how much force you want to have at a given speed. Then using the leadscrew you plan to use, calculate how much torque the motor needs to have at the rpm it's running at your target velocity. Then choose a motor that will provide that torque at that rpm. You'll need to see a motors torque curve to figure this out.

"For us newbies:
What are the things that enable a machine to be built to the 150ipm lever? And please don't just say bigger."

Well you didn't say bigger.

Let me ask it this way.

What IPM would you say this machine would calculate out to?

116 OzIn Steppers. (From Xylotex) configured as Unipolar.
Drive board set to full step.
1/2" 1 start acme thread.
1 3/4 HP single speed Porter Cable router.
1/4" 2 flute HS bit.

Is that enough information?

"For us newbies:
What are the things that enable a machine to be built to the 150ipm lever? And please don't just say bigger."

Well you didn't say bigger.

Let me ask it this way.

What IPM would you say this machine would calculate out to?

116 OzIn Steppers. (From Xylotex) configured as Unipolar.
Drive board set to full step.
1/2" 1 start acme thread.
1 3/4 HP single speed Porter Cable router.
1/4" 2 flute HS bit.

Is that enough information?

Sorry, I didn't have much time to elaborate earlier.

That's really not enough info to go buy. As I said, You need to have a torque curve chart for your motor to know how much torque it has at any given rpm. A stepper motors torque falls off as rpm's increase, and without a chart, you really don't know how much torque it will have at any given rpm. Taking a shot in the dark, I'd guess you're looking at 30- 50ipm out of that, but it depends on a lot of things.


Assuming a machine similar in size to Joes 2006, You can get 100ipm with 300 oz motors and 1/2-8 2 start acme running at 36V with a HobbyCNC board. Want to go faster? Get some 5-6amp motors and Gecko Drives, and run them at 15-20x their rated voltage. Faster still? Move up to 400 oz-in 6 amp motors, get some 1/2-10 5 start screws, and a 36V-48V power supply. You can probably get 300ipm from that.

I did say I was a newbie didn't I. I see there's a lot more to it than I first thought, I was planning a smallish fairly basic machine to do a bit of cnc work for fun and interest. I feel a bit inferior now hearing about 400oz/in motors and 300in/min. Does this mean I have to set my sights higher, or can I stay, dare I say it, Small-ish. Thanks

I did say I was a newbie didn't I. I see there's a lot more to it than I first thought, I was planning a smallish fairly basic machine to do a bit of cnc work for fun and interest. I feel a bit inferior now hearing about 400oz/in motors and 300in/min. Does this mean I have to set my sights higher, or can I stay, dare I say it, Small-ish. Thanks

Sorry MrFreon,
I didn't mean to Hyjack your thread.
Mr.Chips:cheers:

Move up to 400 oz-in 6 amp motors, get some 1/2-10 5 start screws, and a 36V-48V power supply. You can probably get 300ipm from that.

Gerry,

Did I read that correctly? 1/2-10 5 start ?

That would be, um, 1/2 in. per revolution?

Smokin!

Might be hard to find leadnuts, though.

Might be hard to find leadnuts, though.
Nope.
http://www.dumpstercnc.com/leadnuts_acme.html

<snip>

Assuming a machine similar in size to Joes 2006, You can get 100ipm with 300 oz motors and 1/2-8 2 start acme running at 36V with a HobbyCNC board. Want to go faster? Get some 5-6amp motors and Gecko Drives, and run them at 15-20x their rated voltage. Faster still? Move up to 400 oz-in 6 amp motors, get some 1/2-10 5 start screws, and a 36V-48V power supply. You can probably get 300ipm from that.

I have a Joes 2006 running the HobbyCNC kit with 305 motors, and 1/2-8 2 start screws. I regularly run the machine at 100 ipm cutting speed. Rapids have been as high as 250 ipm, but now are usually set at 200 ipm. I once typoed the feed rate at 500 ipm instead of 50 ipm into a Vcarve file. The machine ran at max (250 ipm at the time) until I realized it and hit feed hold in Mach. No problem, and I was using a 1/4" bit at 0.25" cut depth at the time.
I would say Ger21 is correct, at least on a Joes machine and the HobbyCNC kit. I could probably run a little faster if I wanted (125 - 150 ipm), but 100 is comfortable and I have no issues at that speed.
The HCNC motors are rated 305 ounce inch unipolar (which is what the HCNC board will do). If you run them bipolar with geckos you can get 425 ounce inch. Geckos can also deal with a higher voltage supply than the HCNC board. You might get 200 ipm out of the same motors with Geckos, if you up the screw to 1/2-10 5 start.