[jlnading]

I found Stock Drive Products with a little use of the search button. Do I want MXL or XL pulleys? I understand they have teeth differences....but does it matter? I cant find a 72 tooth pulley with a 1/2" bore.

As long as the teeth are the same on both disc pulleys and belt, it should not make a difference, just know what the gear ratio is.

[mikemaat]

The table I have is JUST the table, no electronics but does have vrails and a gear rack. I have figured out the pitch, etc on the rack so it should be a no brainer to build a gantry for this table.

Back to the belt reduction. I am planning on using the KL23H2100-35-4B from Keling which is 381 oz-in, 1/4 dual shaft and no gear reduction.

I found these two parts on SDP/SI:

A 6A16-020DF3708 - 1/4" Hub, 3/8" Belt, 20 Teeth
A 6A16-060DF3708 - 1/4" Hub, 3/8" Belt, 60 Teeth

So I cadded up the keling motor and both bushings into a reduction component. Picture is included. Do you see any issues with this? (Besides the obvious lack of standoffs between the plates and no collars on the 1/4" shaft).

These pulleys should give me a 3:1 ratio, correct? They are quite a bit smaller than what you have on your machine in terms of overall diameter, as well as hub size (1/4" compared to 1/2"). Is this going to be okay? I dont think it should make a difference should it? I dont think im overpowering that 1/4" shaft?

* Note: In my mockup drawing the plates are 1/2" thick aluminum which is going to be too thick - not enought shaft on the motor for the pulley I selected. Ill have to go down to 3/8" or 1/4" aluminum (which i think will still be plenty strong enough, no?

[lumberjack_jeff]

Those motors are too small. You need at least Nema 34.

Selecting motors

[mikemaat]

Those motors are too small. You need at least Nema 34.

Selecting motors

Really? Why do I keep seeing Nema 23 in posts....is that only for small MDF machines and mills?

[jlnading]

The table I have is JUST the table, no electronics but does have vrails and a gear rack. I have figured out the pitch, etc on the rack so it should be a no brainer to build a gantry for this table.

Back to the belt reduction. I am planning on using the KL23H2100-35-4B from Keling which is 381 oz-in, 1/4 dual shaft and no gear reduction.

I found these two parts on SDP/SI:

A 6A16-020DF3708 - 1/4" Hub, 3/8" Belt, 20 Teeth
A 6A16-060DF3708 - 1/4" Hub, 3/8" Belt, 60 Teeth

So I cadded up the keling motor and both bushings into a reduction component. Picture is included. Do you see any issues with this? (Besides the obvious lack of standoffs between the plates and no collars on the 1/4" shaft).

These pulleys should give me a 3:1 ratio, correct? They are quite a bit smaller than what you have on your machine in terms of overall diameter, as well as hub size (1/4" compared to 1/2"). Is this going to be okay? I dont think it should make a difference should it? I dont think im overpowering that 1/4" shaft?

* Note: In my mockup drawing the plates are 1/2" thick aluminum which is going to be too thick - not enought shaft on the motor for the pulley I selected. Ill have to go down to 3/8" or 1/4" aluminum (which i think will still be plenty strong enough, no?

Looks like you have a plan, 1/4" aluminum plate is fine for the belt reduction box frame, the only thing I see that you will need is bearings on both sides of the large pulley for the shaft to turn on, bore the aluminum plates to fit bearings that have a shoulder on them or C clips, to keep them from pushing through the aluminum plates all the way, weld the pinion on the shaft so it does not slip on the shaft, which would give you problems, I cut a flat on the shafts where the cap or allen screws would tighten against the shaft. Make a locking collar 1" dia. 1/2" bore with an allen screw to lock the shaft in place, with the pinion on the opposite side, this will keep the belt in alinement, try to make your gantry as lite as possible, this will only help the motors to last longer. Jeff.:wave:

[mikemaat]

Jeff, you seem quite knowledgable, and I am confused.

If I intend to plasma cut and mill aluminum what size motors do I need (oz-in and Nema size).

My intentions are not to do single pass wood routering with lots of torque. I THINK that Nema 23 should be fine for plasma (although my cnc knowledge is limited). Would Nema 23 with ~380 oz-in motors be okay for aluminum milling as well, as long as the passes were not overly deep?

I mainly just want to do plasma brackets and small aluminum block of plates etc with this machine for now. In the future maybe ill upgrade to huge motors that can do 1/2" MDF in one pass, but for now im trying to keep it *somewhat* economical.

Also, my gantry is going to be fairly light. The main beam is going to be 3x6 aluminum 8020 extrusion. I dont expect the gantry to be crazy heavy.

Any help is GREATLY appreciated.

[jlnading]

Jeff, you seem quite knowledgable, and I am confused.

If I intend to plasma cut and mill aluminum what size motors do I need (oz-in and Nema size).

My intentions are not to do single pass wood routering with lots of torque. I THINK that Nema 23 should be fine for plasma (although my cnc knowledge is limited). Would Nema 23 with ~380 oz-in motors be okay for aluminum milling as well, as long as the passes were not overly deep?

I mainly just want to do plasma brackets and small aluminum block of plates etc with this machine for now. In the future maybe ill upgrade to huge motors that can do 1/2" MDF in one pass, but for now im trying to keep it *somewhat* economical.
The main beam is going to be 3x6 aluminum 8020 extrusion. I dont expect the gantry to be crazy heavy.

Any help is GREATLY appreciated.

I think you will be fine using those motors [steppers] they will have more low end torque, making multiple passes is also the way to go. Next thing to think about are the electronics and software.Jeff.
.

[lumberjack_jeff]

Really? Why do I keep seeing Nema 23 in posts....is that only for small MDF machines and mills?

A shop bot (presumably at least 4' wide) able to mill aluminum, is going to be equipped with a heavy, robust gantry. The gantry on my MechMate weighs at least 200#. To accelerate that kind of mass, you need torque.

For plasma cutting, that might be barely enough, but you need at least 640 oz-in to accelerate the gantry while routing wood or aluminum.

My MechMate will rout plywood well (like buttah!), but it has a very hard time with aluminum.

I have nema 34 640 oz-in steppers with 7.5:1 gear reduction. I am in the process of replacing them with 640 oz-in steppers with a 4:1 timing belt reduction.

[mikemaat]

It is 4' x 4' and the gantry will be similiar looking and functioning to the current PRSAlpha gantry they make.

So....You may have me convinced to go Nema 34. Keling has 400 oz-in steppers for 80 bucks (30 more than the Nema 23's I was gonna get). So not a huge additional investment. Im thinking ill start with them and if I find I need even more torque ill upgrade later. Ill do a 3:1 reduction.

Here is the part number from keling:
KL34H260-35-4B

It says its designed for the G540 from gecko, which I want to use.

If I run 4 of these Keling Nema 34's, will a 48v 12.5A power supply be enough? Or what is the proper size, keeping in mind I want to use the G540.

[lumberjack_jeff]

Really? Why do I keep seeing Nema 23 in posts....is that only for small MDF machines and mills?

It is 4' x 4' and the gantry will be similiar looking and functioning to the current PRSAlpha gantry they make.

So....You may have me convinced to go Nema 34. Keling has 400 oz-in steppers for 80 bucks (30 more than the Nema 23's I was gonna get). So not a huge additional investment. Im thinking ill start with them and if I find I need even more torque ill upgrade later. Ill do a 3:1 reduction.

Here is the part number from keling:
KL34H260-35-4B

It says its designed for the G540 from gecko, which I want to use.

If I run 4 of these Keling Nema 34's, will a 48v 12.5A power supply be enough? Or what is the proper size, keeping in mind I want to use the G540.

I bought KL34H280 45 4A. $89. I can't give any performance review yet, but I anticipate rapids of about 500ipm. I have a question about how well they'll work with my 57v power supply.

I also don't know anyone who uses the second shaft on a stepper - except to hook your jacket as you walk past.

The optimum power supply for that stepper motor is found by using the "Mariss Formula" 32 X SQRT(Impedance) or 32*sqrt(4.2) or 65.5v. I *think* that 48v should be fine.

[jlnading]

The stepper motors I have are, three 740 oz. nema 34, and one 510 oz. nema 23. The pdf files I am sending will help in figuring torque and oz. needed to build a table, and show specs on two other motors.

[jlnading]

Motors Here is a link to some stronger stepper motors, close to the same price, single shaft.:wave:

[mikemaat]

I think ive decided to go with the Gecko G540 and 3 Keling KL34H295-43-8A (2 on X-axis, 1 on Y). I will then get a NEMA 23 for the Z.

According to this very helpful website : Page 101
I should get 522 oz-in of torque and very quick speed when they are detuned. Plus this gives me the option later (when funds permit, and if needed) to upgrade to G203V Drives and get up to 900 oz-in of torque (before belt reduction).

Im going to go with a 3:1 belt reduction. Anyone see any issues with all this? Also, what size power supply will I need? Will a 48V 15A supply be good since the motors will be detuned in both voltage and amperage?

[jlnading]

I think ive decided to go with the Gecko G540 and 3 Keling KL34H295-43-8A (2 on X-axis, 1 on Y). I will then get a NEMA 23 for the Z.

According to this very helpful website : Page 101
I should get 522 oz-in of torque and very quick speed when they are detuned. Plus this gives me the option later (when funds permit, and if needed) to upgrade to G203V Drives and get up to 900 oz-in of torque (before belt reduction).

Im going to go with a 3:1 belt reduction. Anyone see any issues with all this? Also, what size power supply will I need? Will a 48V 15A supply be good since the motors will be detuned in both voltage and amperage?

On the power supply, I would go higher voltage and amperage than you need to, so you can upgrade motors latter on, spend a little more now and not worry about it latter on.:cheers:

[mikemaat]

Im learning so much haha!

So, upgradability aside, is it a fair statement to say that no matter what motors you run on the G540, the biggest power supply that it is capable of USING is 48V 7.5A and anything bigger is just excess and unused? (This is also assuming that motors over the 3.5A and 50V restriction are tuned down)

[jlnading]

Im learning so much haha!

So, upgradability aside, is it a fair statement to say that no matter what motors you run on the G540, the biggest power supply that it is capable of USING is 48V 7.5A and anything bigger is just excess and unused? (This is also assuming that motors over the 3.5A and 50V restriction are tuned down)

Yes Mike, after reading the specs for the G540 on page 101, looks like it will work, and is a nice unit :banana:, I use four G203V Gecko drives, that way if one blows I don't have to replace them all, I keep a spare just in case. I do need to say though that Gecko drives are very reliable and work well. Question though, what are you going to use for torch hight control? :wave:

[mikemaat]

I know I need one, and I will get there, but I havent researched that yet. Im going to get the table running and make some fixed heights cuts just to please myself first

Once I see some cutting, ill be upgrading it with a torch height control, and one day a machine torch end. Then itll be on to a spindle attachment! So much excitement!!!

[lumberjack_jeff]

I bought KL34H280 45 4A. $89. I can't give any performance review yet, but I anticipate rapids of about 500ipm. I have a question about how well they'll work with my 57v power supply.

Now I can!

Just installed them, they work great. 500ipm is more than twice as fast as my previous setup, and the only apparent backlash comes from insufficient belt tension.

:banana:

[ahren]

The G540 is a great drive (which is why we sell it with our electronics kits), but is limited to 3.5A/phase of current. You will not see a lot of benefit from moving to a larger motor but then running it at less than its rated current.

That being said, The G540 and Nema 23's work well for a lot of people with our Rack and Pinion drive kits:

CNCRouterParts

Also, a bit of advice if you are building your belt reduction from scratch. Make sure you do some math to get at least the minimum number of teeth engaged -- people often miss this when trying to go to a large reduction in a single stage. You also don't want your motor pulley too small -- this puts an extraordinary amount of tension on the belt.

Hope this helps!

Ahren
CNCRouterParts

[mrosupply]

https://mrosupply.com/category/197-G...%20Gear%20Rack