CNC Router from scratch

[Punk_Boy]

Hello my friends.
I am an hobby lover that has come to a point that needs a CNC router to fill some of the gaps that my limits impose on me.
As such, i would like to build a CNC router with a working area of 2000x15000mm.
I´ve already been searching and tossing some concepts and ideas, but for now (since the router structure won’t be a major problem because i have a business that consists in metal work) the electronic part has got me thinking.
I would like the CNC to able to work plastic, as well as aluminium. I was thinking on NEMA 34 stepper motors with 13 Nm but this is just about as far as I’ve gotten.
I would like to ask your advice on what should i buy and what components i will need in order to achieve my goal (spindle, limit sensors, Breakout board or something else) ...
I know i have to start someplace, and I’m counting on you to help me and even guide me through the right path if I’m going down a wrong one.

Thank you for you help.

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[louieatienza]

Hello my friends.
I am an hobby lover that has come to a point that needs a CNC router to fill some of the gaps that my limits impose on me.
As such, i would like to build a CNC router with a working area of 2000x15000mm.
I´ve already been searching and tossing some concepts and ideas, but for now (since the router structure won’t be a major problem because i have a business that consists in metal work) the electronic part has got me thinking.
I would like the CNC to able to work plastic, as well as aluminium. I was thinking on NEMA 34 stepper motors with 13 Nm but this is just about as far as I’ve gotten.
I would like to ask your advice on what should i buy and what components i will need in order to achieve my goal (spindle, limit sensors, Breakout board or something else) ...
I know i have to start someplace, and I’m counting on you to help me and even guide me through the right path if I’m going down a wrong one.

Thank you for you help.

If you look around you'll see nobody uses steppers like those, not even the Bridgeport retrofits. You'd be better off with servos and gear reduction of some sort

[Punk_Boy]

If you look around you'll see nobody uses steppers like those, not even the Bridgeport retrofits. You'd be better off with servos and gear reduction of some sort

Thank you. But what type of servos and gear reduction would you advise?

[louieatienza]

Thank you. But what type of servos and gear reduction would you advise?

Depends, if you're using ballscrews or rack and pinion? Expected gantry weight, including all components? A few online calculators that can help..

[Punk_Boy]

I´m going to use linear guide.



The gantry will be made with aluminium profile but i dont know how to calculate all of the components weight. Can you please tell me where to find that online calculator?
Sorry for the questions. I´ve been reading about this for 48 h +- but still have many questions

[louieatienza]

I´m going to use linear guide.



The gantry will be made with aluminium profile but i dont know how to calculate all of the components weight. Can you please tell me where to find that online calculator?
Sorry for the questions. I´ve been reading about this for 48 h +- but still have many questions

Just Google "motor sizing calculator" or "servo sizing calculator." All suppliers will have specs as to weight per foot for extrusions, rotor inertia for motors, ballscrews, even coupling weight, and Google for densities of metals.

[ger21]

Design the machine first, and pick the motors and electronics last.

[Jim Dawson]

Hello my friends.

As such, i would like to build a CNC router with a working area of 2000x15000mm.

Thank you for you help.

''working area of 2000x15000mm.''

If the above size is what you want to build then I agree with louieatienza. On a machine that size you will want to use AC servos, maybe in the 1 to 1.5 KW range for the X/Y axis, maybe 0.75 KW for the Z axis. Too much mass for stepper motors to operate at reasonable speeds and acceleration. The torque of a 13 Nm, NEMA 34 stepper drops of very fast as the RPM increases. For a machine the size that you propose, I would also concider a moving table machine, rather than a moving gantry. Much more stable.

If you meant to type 2000x1500mm then that is a different machine and NEMA 34 steppers in the 9 Nm range would work if you are using high quality steppers and drives, and supply them with maximum voltage that the drive is rated for. Calculate the gearing to keep the stepper motor speeds to < 12 RPS for best performance. This should give you the capability of rapid moves at about 250 mm/sec, and cutting speeds up to 125 mm/sec at reasonable acceleration.

If you buy steppers from reputable manufactures, they will have published, and reasonably accurate torque charts that will show the expected performance under various operating conditions. Also look at closed loop steppers and servos.

[MajorTendonitis]

OP , I want to do the same and will be watching this thread with great interest. This is where I found some linear guides for the most affordable price . They have different sizes available.
https://www.aliexpress.com/store/pro...612.0.0.MvrWrA
I've never had any succes getting anything sent from Aliexpress, but maybe others can verify ?



As mentioned, I suspect your 15000 mm was a typo , and you really meant 1500mm ?

[ger21]

I know a lot of people that have purchased from BST.

[MajorTendonitis]

I know a lot of people that have purchased from BST.

Thank you Gerry , good to know . I also seen a place called overstocked ,and it's in North America . Not sure which route would be best . Maybe I shouldn't be mentioning this site , as they will be out of stock lol

overstock & surplus automation products: Motion Control, Linear Bearings/Rail

[louieatienza]

Thank you Gerry , good to know . I also seen a place called overstocked ,and it's in North America . Not sure which route would be best . Maybe I shouldn't be mentioning this site , as they will be out of stock lol

overstock & surplus automation products: Motion Control, Linear Bearings/Rail

Motion Constrained is now an online dealer for HiWin rails and blocks, out of Colorado...

I purchased sone H.S.A.C blocks and rails a while back, and they're of very goid quality...

[ger21]

I bought my rails fro Automation Overstock, before they sold out of all the good Hiwin Stuff.
But these look like a very good deal, and are cheaper than I paid for my Hiwins.
discounted automation products: BLH Linear Guideway, BLH 20mm Linear Guideways

Just be aware that anything over 8ft long will be very expensive to ship. My 10ft rails cost about $170 in shipping.

[MajorTendonitis]

Motion Constrained is now an online dealer for HiWin rails and blocks, out of Colorado...

I purchased sone H.S.A.C blocks and rails a while back, and they're of very goid quality...

Thank you for the link . The prices seem very competitive from what I've seen so far.
1100 bucks for two sets . I think it's the quality stuff?

[louieatienza]

Thank you for the link . The prices seem very competitive from what I've seen so far.
1100 bucks for two sets . I think it's the quality stuff?

Yes, this is their heavy load capacity rail and block...

[MajorTendonitis]

Yes, this is their heavy load capacity rail and block...

Good to know , thanks again . I think if you see green and red plastic on them , that there the high accuracy style .
OP , I apologize if I seem to be highjacking your thread .

[MajorTendonitis]

Guys , I noticed the price difference is not that much to go from 25mm to 30mm . Dumb question I suspect, but is there any reason I shouldn't upgrade to 30mm rail and blocks if that's the case ?
I'm wanting to build a machine with approx 4'x5' cutting area , and with good repeatability.

[louieatienza]

Guys , I noticed the price difference is not that much to go from 25mm to 30mm . Dumb question I suspect, but is there any reason I shouldn't upgrade to 30mm rail and blocks if that's the case ?
I'm wanting to build a machine with approx 4'x5' cutting area , and with good repeatability.

Unless you're building your machine out of cast iron, and getting the mounting surfaces ground, I doubt you'll get any benefit. Repeatability will come more from your motors and drive system... That said, HiWin rails also come as matched sets, and in three or four precision grades. And as you'd expect, the higher up you go, the more they'll cost.

[Punk_Boy]

''working area of 2000x15000mm.''

If the above size is what you want to build then I agree with louieatienza. On a machine that size you will want to use AC servos, maybe in the 1 to 1.5 KW range for the X/Y axis, maybe 0.75 KW for the Z axis. Too much mass for stepper motors to operate at reasonable speeds and acceleration. The torque of a 13 Nm, NEMA 34 stepper drops of very fast as the RPM increases. For a machine the size that you propose, I would also concider a moving table machine, rather than a moving gantry. Much more stable.

If you meant to type 2000x1500mm then that is a different machine and NEMA 34 steppers in the 9 Nm range would work if you are using high quality steppers and drives, and supply them with maximum voltage that the drive is rated for. Calculate the gearing to keep the stepper motor speeds to < 12 RPS for best performance. This should give you the capability of rapid moves at about 250 mm/sec, and cutting speeds up to 125 mm/sec at reasonable acceleration.

If you buy steppers from reputable manufactures, they will have published, and reasonably accurate torque charts that will show the expected performance under various operating conditions. Also look at closed loop steppers and servos.

Yes. 2000x1500mm! It was a typo! Sorry ��

Ok that was for the motors. What about the BOB and Drivers. What do you advise?

[Jim Dawson]

The BOB is going to be partly dictated by the CNC software you are using, and others here would have better advice than myself. I only really work with industrial hardware and have very little experience hobby class equipment. My prefered controllers are Galil Motion Control products Motion Controllers | Galil Compatible with Mach3/4 and other CNC software.

You want to match motors and drives from the same vendor. My prefered stepper drive is the STP-DRV-80100 from Automation Direct and their motors.
https://www.automationdirect.com/adc.../STP-DRV-80100

Also take a look at the ClearPath SD servos https://www.teknic.com/products/clea...-servo-motors/
I have used the ClearPath products and was happy with the result. They save a lot of wiring because the drive is built into the motor, and closes the loop internally, no lost steps.

And the DMM-Tech products DMM | AC SERVO DRIVE | AC SERVO MOTOR | ROTARY ENCODER