Plasma - direct drive - Gilbert Arizona

[Vern2]

My first post.

I don't know why, I always go down a different road then most.

I started down this road in 2009 and now have the itch again.

My investment in 2009.
4 - 2.4 amp, 200 step, nema 23 260 oz, 24v, 4 wire
4 - gecko drivers
4 axes usb controler board.
1 - 8.3 amp 24v power supply
1 - 3 amp 5v power supply

So with changes from steel to alumimum gantry and a 2' to 3' x 4' table my small motors may work.

Sorry. I've been reading the mm posts. Great stuff, thanks! I'm not directly finding my specific needs.

1) Ansi # for rack and pinion and teeth per inch on same?

Will go gear plates if you think direct drive is not a good idea.

2) If direct drive is okay, then I need the pinion teeth per inch. Or is there a kit I can buy?

3) If I need gear plates, what are the gears teeth per inch, pinion teeth per inch. Or is there a kit I can buy?

4) nema 23, spindle is .253". I know it's not the required .500".

I've got a small welding, machine shop in garage. It's too hot to work out there now, but I can make most anything.

The knowledge on CNC building here is amazing.

------------------
My Site (http://www.enichesoftware.com)
Vern

[Richards]

I've done a lot of experimenting with nema 23 motors (Oriental Motor PK268-02). Because of their small shaft size, you can use a 10-tooth or 12-tooth XL pulley. If you use a 72-tooth XL pulley on the drive shaft, you would have 7.2:1 or 6:1 reduction and 1,872 or 1,560 oz*in holding torque.

The biggest drawback is the distance between pulleys required by those small motors. You would need 6-inches or more separation between the XL pulleys to get enough belt wrapped around the small pulleys. Alternately, you could use idler pulleys to pinch the belt. That would add expense and complexity to a belt drive. I've used that method. It works.

[hans.arnell]

Hi Vern
I use nema 23 motors 305 oz on my Mechmate 2500mm x 1200mm size and Chinese spindle
i have reduction 3:1 and it works great
Hasse#14

[Vern2]

Richards,

Sorry, I'm trying to understand you reply.

I'm not on top of the mm build or lingo your using. I'm just trying to put what your saying in my words so I can understand your reply.

It looks like your telling me I need gear reduction plates. Don't use direct drive?

1) So there's no kit for 23 motors. yes, no?

2) The gear reductions plates take three gears, with pinion (spur gear).
Optional idler gear, four gears.
a) motor gear on gear plate will be 10 to 12 tooth.
b) drive reduction gear 72 teeth
c) pinion (spur gear) how many teeth?
d) what pitch is used on belt(0.2")?
e) belt width 1/4, 5/16, 3/8, 1/2?
f) Single-sided with Trapezoidal teeth?
g) Belt materal Urethane, Neoprene, silicone?

3) I still need to know what pitch used on rack and pinion (spur gear)?
4) Plus what face width of the rack?

5) Your saying the biggest drawback is the distance between pulleys. Where might I be going wrong, below?
If I'm building the gear plates, just mill the drive hole and motor mount slots further apart. Just use a little more 3/6" or 1/4" steel plate. Of course I'll buy timing belts first to measure distance and motor mounting slots to take up slack in timeing belt.

-----------------
My Site (http://www.enichesoftware.com)

Vern

[Vern2]

hans.arnell,

I just keeping missing it. Are you saying your using gear plates or direct drive?

I'm thinking with a pinion teeth being an unknown value to me, I'm not understanding where the 3:1 reduction is being made. Is the 3:1 reduction coming from the gear plates reduction or the pinion (spur gear) to rack reduction?

--------------
My Site (http://www.enichesoftware.com)

Vern

[hans.arnell]

I think you need some kind of reduction betveen the motor and the rack and pinion because of the small shaft size of nema 23 motor, i have a gearbox reduction and the shaft out from that is 12mm
Hasse.

[Vern2]

Hasse,

I guess I'm a little dense, sorry. 12mm is your output shaft for your spur gear(pinion), spur gear teeth could be more or less teeth for further reduction.

With 3:1 gear reduction, the motor shaft may have a 12-tooth, the drive shaft would need a 36 tooth gear. This would give me speed with less torque and less holding power.

With 6:1 gear reduction, the motor shaft may have a 12-tooth, the drive shaft would need a 72 tooth gear. This will give me less speed, more holding power, more torque.

My table will me tiny, 600 to 900mm x 1200mm. This is a plasma table. I know the mm is a router table, very heavy, very strong, makes large router cuts. I made a $600 mistake and bought nema 23 motors, drivers and power supply, long ago. So a combination plasma/router table is out for now. Maybe that's a new shop and two CNC tables.

Plasma cutting:
Cutting 1 mm mild steel at 10007 mm/min
Cutting 3 mm mild steel at 2210 mm/min

I'm a little more into speed, little torque. Maybe I've got the wrong table design and I'm wasting everyones time.

Vern

[MetalHead]

The MM can handle the speed no problem and use as a Plasma is covered here in the forum. Just need to make sure your electics are isolated from the table so the feedback from the plasma cutter will not cause issues.

[Vern2]

Two types of feed back, I can see. Using the table as ground for the plasma and the electronic ground hooked to same. The other is keeping the gun cable away from the metal electronic box. I'm I seeing it right?

I'm building this from 18 gage, the sides will be spot welded in, top hinged, with a simple turn handle. Using box as test bed and permanent closure after testing software and finishing box. Software is some simple Cad/Cam, written in Visual Basic. That's my usb controler.

Vern

http://www.enichesoftware.com/media/cnc_box.jpg


http://www.enichesoftware.com/media/usbcontroler.jpg

[Vern2]

I might be missing something. What is direct drive? I have my ideas, but of course I'm usually wrong.

1) motor connected to pinion, through swivel plate.

2) no belt between gear plates, just motor gear to drive gear.

Vern

[jehayes]

U got it!

[KenC]

Vern,
is that all the sheet metal you have?
Build the biggest box possible. Real estate is never enough once you started.

[Richards]

Vern,

Here are some part numbers from www.mcmaster.com for the pieces that I have used. When you look at the parts, you'll understand better.

12-tooth XL pulley, 6495K711
72-tooth XL pulley, 6495K733
200XL038 belt, 6484K23

30-tooth pinion, 5172T14
20-degree rack, 5174T21

Those parts are for reference only. They will give you an idea of what you could use.

Keep in mind that the biggest problem with using a 23 size motor is the number of teeth that will be in contact with the belt on the motor pulley. That pulley only has 10-teeth. Even if you have a large distance between pulleys, you will only have four teeth engaged. That means that there will be tremendous pressure on each tooth on the belt. You will have to use long ramp times, or you will have to use an idler pulley to force more pulley teeth into contact with the belt.

[Vern2]

jehayes,

Question on #2). Where do you get the messing gears? Looking at 3:1, with no belt.
1) Could I use pinion gears? One 20 tooth on motor and one 60 tooth on drive shaft. Then of course I'd use 20 tooth for pinion.

KenC,
I think the box will be fine. It actually turned out 12"x20". I'm using the box for testing. After I'm satisfied with tests, motors will be removed and screen will be installed at bottom of box. My 23 motors are double shaft, so I don't have that motor installed backward for testing. 24v fan will be in door at top. Got lots of sheet metal.

http://www.enichesoftware.com/media/breadsbox.jpg

Richards,

There is no belt. It's 20 tooth gear to 60 tooth or 72 tooth, if I can find one. My home built plates will be welded similar to the belt drive 34 plates, that are offered here. There's no plates available for the 23.

Just a thought, if you can buy geared motors, why not make your own gear box? The gears used by me will be twice as big and stronger. Gear box will be made from 1/4" steel and quality bearings. Once you get the first one made, just make 3 more. The first one takes all the time.

[Richards]

Vern,

Gearboxes have backlash. It is not a simple matter to remove backlash from a gearbox. A belt-drive can be tensioned to remove all backlash.

Please read and understand the posts that have been written about stepper-motors, gear reduction, and belt-drives. Others have spent thousands of dollars and countless hours testing the things that you are dismissing as irrelevant.

[Vern2]

Richards,

The plans for the mm build is perfect! I'm only trying to save on a $1000 mistake, I made 3 years ago, buying the wrong motors. I only wish I could just get a do over.

I'm not dismissing as irrelevant. There are disadvantages of using 23 motors with belt drive (number of teeth coming in contact with belt). Without the knowledge, I truly value your comments. Thank you! That's why I'm trying to spell out my thoughts. Nothing is carved in stone here.

Maybe a 20 tooth gear on the 23 motor and a 60 tooth on the 1/2" pinion drive shaft will fix the number of teeth that comes in contact with the belt. What are your thoughts on that? Like I said, I'm not changing the mm plans. I saving $1000.

My only reason for changing the mm planes are to salvage a bad purchase of the 23 motors 3 years ago. Making it right, is buying new motors $400, new drivers $400, new power supply $200. So I'm trying to save $1000.

Vern

[Vern2]

Richards,

McMaster-Carr does have:
20 tooth XL Drive pulleys 6495K718 $7.99
60 tooth XL Drive pulleys 6495K732 $33.33 3:1
72 tooth XL Drive pulleys 6495K733 $41.17 3.6:1

Thanks for the nudge,

Vern

[Richards]

Vern,

You may have to fabricate special bushings for those XL pulleys. The shaft size on some pulleys is too large for 23 size motors.

$1,000 is a lot of money, but doing the wrong thing can cost a lot more than $1,000.

[Vern2]

Richards,

Here is my 23 spindle shaft size, 0.252".
http://www.enichesoftware.com/media/20pulley.jpg

http://www.enichesoftware.com/media/20pulleyspec.jpg

[Vern2]

Richards,

This is my 23 spindle shaft size, mic 0.252".

http://www.enichesoftware.com/media/20pulley.jpg

You can see the bore size (ID) 1/4"
http://www.enichesoftware.com/media/20pulleyspec.jpg

Looks like I can take .002" off of shaft if needed. My 23's look like a fit.

Was suggested to use a 10 tooth to a 30 tooth, 3:1. Without adding anymore torque on two set screws. I'm thinking 20 tooth and 60 tooth, 3:1, will not place any more stress on the gear reduction, bearings, spindle, belt or gears. But that combination will give me more teeth contact with belt. Also might think about building an, out side adjustment with lock nut, to take up belt slack. That way the motor shaft to drive shaft can be adjusted after assembly.

Would there be a suggestion for making flat spots where set screws hit motor spindle? Don't know if this is needed.

Vern

[KenC]

If you must, you can always add an idler to increase the number of teeth contact.

[Vern2]

KenC,

I'm not pushing 600 in/lb, only 260 in/lb, 12 to 24v. If I could get a do over :D. I'd build a double mounting on the z axes or double z, for a router/plasma table. But now it looks like two small tables and a new shop.

I've got a 30'x37' platform for solar ramada at back of house. A new ready to use 60 amp sub panel installed. Just add floor, walls, central air, bath room and a nap sofa:D. What I have wired, under ground 75' of 1 1/2" conduit, 4 - #6 gage copper, 1-RG6(cable) and 1-cat5(network). Of course solar has it's own 1 1/2" conduit. I'm pushing two 600vdc 30 amp arrays to two 5k watt inverters. It's like building your house under a power company.

shop location (http://www.enichesoftware.com/solar/102909.wmv)

Vern

[KenC]

60A does come in handy, at the end of outfitting MM, you will eventually need more power to run the Dust collector, the Vacuum hold down, ventilation fan.
IMHO, fire & wood don't go along very well. In the I-Ching's 5 element, (metal, wood, water, fire, earth) these 2 are contradicts each other's chi... you will loose ying-yang balance as the outcome.... :p

[Richards]

Vern,

I've always bored out the pulleys instead of turning down the shafts.

I'm a little worried about the forces your motors will have to bear. Remember the bearings are designed for a specific load. By the time you have tightened up the belts enough to eliminate backlash, you may have overloaded the bearings. That's the main reason the almost everyone uses the size 34 motors. Their larger 1/2-inch shafts can handle heavier loads.

[Vern2]

Here a solution:

Have access to these bearing, 5/8" x 1/4" bore, 0.196" width, sealed bearings. They allow room for the 20 tooth pulley and the bearing onto 23 motor spindle, plus does it makes a diference if the motors have double shafts (bearings at both ends of spindle). Of course bearing can be cut into belt drive plate. This makes 3 bearing on the 23 motor spindle.

I measured it again, the pulley takes up all the room on the shaft. Looks like spindle is to short.

Vern

http://www.enichesoftware.com/media/23motorbearing.jpg

[Vern2]

Can't edit last post. But I can change spec. pictures. The spec. The spindle is 0.772" long. If you add the new pulley width to the 1/4" bore, 5/8" bearing of 0.195 it works. I have 0.015 clearance.:D Enough room for a washer, done.

[Vern2]

KenC,
I bought one of those bracelets that give you super strength.:D

Still got ying-yang balance. I'm building it into the mm table, (bracelet).

Vern

[Richards]

Vern,

A bearing on the shaft will not work. The shaft has to drive the load. A bearing will just let it spin.

Sometimes trying to save money on things that you've already purchased will cost much more than if you accept the loss and then buy the parts that you really need.

A size 23 motor can do a lot, but it was not designed to move the load that a size 34 motor can move. That does not mean that a size 23 motor is "underpowered", but it does mean that you'll have to verify that it can do the job required by thoroughly testing that motor.

I've got two test benches totally set up where I test various motors, power supplies, and stepper drivers. Each test bench cost more than $2,500 to build, but having those test benches has made it possible to thoroughly test different motors, different power supplies and different stepper drivers. You'll have to build a test bench and then test your motors, your stepper drivers and your power supply. If I were you, I would do that before committing on any particular design. Finding a flaw before you build the machine will save you a lot of time and money further down the road.

As a side note, I've used a lot of size 23 motors geared 5:1 and 6:1 that drove a paper advance system in Kodak S-printers. They were totally reliable. Not one of the motors failed and only one of the stepper drivers ever had to be replaced. That's not bad when more than 100 motors and drivers were in use for more than 10 years. BUT, the load on those motors was less than the load on a CNC machine, even if you use aluminum. Those motors were driven with a 24VDC power supply even though Geckodrive recommends a 50VDC power supply. The ramp times were slow because a paper-back printer required relatively slow paper movement. In other words, the actual use of those motors did not strain the capabilities of those motors. I'm just a little afraid that you are expecting more than your motors will be able to deliver.

Test them thoroughly and then you'll know for yourself whether they can handle the job.

[KenC]

Vern, may the force be with you :D

[MetalHead]

Vern - PM me if your interested I can make you a set of bushings that will step up your shaft diameter to .5 if you have already purchased your pulleys. What is the part number of your motors. I bet the .25 bore size pulleys will fit that no problem. You should be able to setup a belt reduction no problem by ordering the correct flange pulley for that motor. That is probably the best way to go.

[Vern2]

Richards,
Your way beyond be in knowledge on cnc building. I don't want to be in anyway disrespectable of your comments. I hope you don't take it that way.

I found some 23 motors that are 400 oz/in. for $69. Mine are 260 oz/in. That's about $300 for 4. Motor dealer (http://www.probotix.com/stepper_motors) No plans to enlarge table to 4'x4' or 4'x8'. A 2'x4' is a nice size plasma table for a home shop. The gantry will be across the 2' width, very low weight. If I find the 260 oz/in is too small, it will be easy to change to the 400 oz/in motors. Expenses continue to pile up in the black hole, I call my shop. DRO for the Mill $700, height control on plasma table $500, A $4000 power tube roller underway, building on the cheap $600.

MetalHead,
For the last year I've been building leadscrews and bushing blocks. How do I know that lead screws are not the way to go on a cnc table...
http://www.enichesoftware.com/media/11x27lathe.jpg

[Vern2]

MetalHead,
For the last year I've been building leadscrews and bushing blocks. How do I know that lead screws are not the way to go on a cnc tables... I need one part made, just one, on another project. So I'm starting the plasma table build again. I don't want to spend $12 to $20k for a plasma table. It's really more fun building one yourself. My projects come with no completion dates. I know the plasma table will come in handy, for many projects. It's fun to meet people that build things, that's all I've every wanted to do.
http://www.enichesoftware.com/media/11x27liftseat.jpg

[KenC]

260oz-in? I use those for my bench top CNC toy. :D
Bite the bullet & write off the bad purchase, you will get better price if the motors are NIB condition on Ebay. you can also get Nema34 at less then US$69... if you scrounge hard enough...

[Vern2]

KenC,

Ebay:
About getting 4 motors exactly the same. I don't want to try and cut a circle and get an oval. That may not make sense, but that's what I envision.:eek:

You guys are going to cause me to buy 34's!;)

I need some DXF software, bought CorelDraw last night. Will be looking for a free program to convert DXF to m-code then tweak it a little for simple 2D parts.

I actually have the "z" working through USB and CAD software.:D

Don't laugh it works.
http://www.enichesoftware.com/media/firstlife.jpg

Vern

[Vern2]

Looks like their is 400 oz/in 23 motors. This way I can move up to larger motors if I need to. That way I can keep my drivers with the 23's. New drivers for 34's are $147 each, new 34's are $99.95, total $1000.

Vern

[danilom]

contact Deitech for drives, last time I checked they had drives for half of that price.
www.driver-motor.com/Products.aspx

[Richards]

In this type of forum, we all share our experiences. When one poster says that something works for him, and he includes enough data so we can see what he is using and why that motor/driver/power supply worked for him, we can draw conclusions about whether it might work for us.

On the other hand, when a poster writes that a particular motor/driver/power supply might NOT work and if he gives sufficient data so that we can see why he thinks that the user should try something else, we can draw conclusions about whether it might work for us.

Under the right circumstances, a 23 size motor MIGHT work in a CNC application, whether that application is traditional or whether it is something like plasma cutting. We all know that a size 34 motor, IF used with the correct gearing, power supply and driver, WILL work. So the question is whether we want to take a chance on something that MIGHT work, or whether we want to use something that others have proven DOES work.

I've spent many thousands of dollars finding out what MIGHT work. When I've proved that it DOES work, I've used it. Now, I play it safe and save my money. I use things that others have tested, things that others have tried, things that others have wasted their money on proving that they actually do work.

Motors are expensive. Drivers are expensive. Power supplies are expensive. It's best to let others pay the price of innovation and use only what they have found to be reliable solutions.

False economy is using the wrong part and then having to replace it because it was too small.

[Vern2]

Richards,

I think there is a slow progression of cost in the three steps.

Plan (A): Build table with the motors, drivers I have. Cost $0.00

Plan (B): Change from 260 oz to 400 oz. I can reuse everything. It's just a motor change. Cost $278.60

Plan (C): Buy everything. 4 - 34 motors, 4 - drivers, rebuild new motor plates, 4 new 1/2" bore pulleys and belts. $1000 +, major cost.

Is there major parts I'm missing?

Vern

[danilom]

I had a comment but Richards said it all.

Why do you need new drives in Plan(C) ? What gecko's do you have? They all pretty much can drive nema34 given the right specs (current and voltage(inductance))

[Vern2]

Thank you for responding and checking my list.

danilom,

I bought 251 geco drivers http://www.geckodrive.com/g251x-p-38.html, they are limited to 3.5 amps. I have to get the 203 geco drivers $. When you get above 400 oz/in the amps seem to go above 3.5 amps for 34's. The 400 oz/in motors are not available or very hard to find. I have to go to 650 oz/in motors that need more then 3.5 amps. I really hope you can find that the geco 251 drivers will work for 34 motors, I'll get 34's. With drivers and 34's it's $1000.

Vern

[Vern2]

I've got a 6" roter table, for the mill, haven't found a use for it yet, maybe now. The small table should make bearing pockets for me in 3/8" aluminum for motor plates. A while ago I went to a CNC builder and bought 2 each of all his bearings, So when I need a bearing I can grab one thats close and measure it. This one measures .496" bore, .312" width, will work good on 3/8" aluminum plate. If the bearing fits my needs, I place an order. The aluminum motor plates might be easy to build. Build some stand-offs for the pulley gap and recess tapered head bolts, to keep the back-side smooth 20# spring for pivot for rack and pinion matting, done. Have to buy some 3/8" aluminum plate.

[danilom]

Well they are being used a lot, but in form of Geckodrive G540 which has 4 of them integrated.
Look here for information
http://www.mechmate.com/forums/showthread.php?t=628&highlight=g540
http://www.mechmate.com/forums/showthread.php?t=3066&highlight=g540

also search the forum for G540 to find other threads of users which are using them.

[KenC]

There are a lot free open source software out there which can produce .dxf. you could had saved that for your 34s.
Personally, I will spend time looking for other saving rather then hoarding over the 24s. This is my preference, everyone has their own.

[danilom]

Like DraftSight from Dassault

http://www.3ds.com/products/draftsight/free-cad-software/

[KenC]

Coraldraw Equivalent free open source such as Inkscape, GIMP2 just to name two...

[Vern2]

You guys are great as usual!

I found a way to use my drivers (gecko-251's) on this 34 motor. $100 34 stepper (http://www.probotix.com/index.php?view=product&path=14&product_id=127) There was a couple of requirements. 1) it had to find 8 wire motors. 2) a configuration at 3.5 amps or less. I can wire it as a Series connect, taking the 8 wires to 4, for the 251drivers.

I've been using draw programs for many years. There basically the same, nothing to learn for me. I just need to get on the CAM program manual. You guys have to realize that plasma tables are all 2D.

Will this motor work?

http://www.enichesoftware.com/media/8wire34motor.jpg

Vern

[bradm]

In series, the inductance is pretty high, and Geckos don't like that. I think you want to use bipolar half-coil (which you can do with either 6 or 8 wire motors). That should have the same numbers as the unipolar column. Driving at 3.5A, you will not get the full torque, (guesstimate: about 350 OzIn, projecting from the table above).

A common G540 configuration, and the one I use, is with the OM motors with 7.2 gear reduction. Although the motor in this configuration is rated for higher amperage alone, the gear box torque ratings make the maximum safe amperage lower.

You will be in a similar situation. Since your plasma won't be seeing cutting forces, you may not need a transmission to multiply your torque.

So with the small boost in torque, why go with the larger motors? Because, as mentioned above, the 1/2" vs 1/4" shaft and corresponding bearings will be much more robust. I agree with the crowd; you'll save more $$ and hassle with the 34s.

[chopper]

Vern,
you can run the nema 23 motors and the 4 to on belt drives with out issue...
you do not need to worry about the belt wrap on the pulleys yeah I know it is less than what is recommended but there are no issues, I designed the drives that metal head is selling, and I am currently building a plasma cutter based on the MM using nema 23 motors, all you have to do is drill the smaller pattern for the 23's instead of the 34's you can see them here http://www.mechmate.com/forums/showthread.php?p=28006&postcount=93
and a few posts down there are drawings on how to build them...the only thing I have done different is I changed from a 20 tooth gear to a 30 tooth gear, because I wore out the smaller dia pinions this changes the ratio but I actually got better cuts with the 30's than the 20's... you also have to take into consideration that the MM's are pushing against material when they cut which takes more torque and power the plasma just moves the torch above the material and has no real load against it unless you crash..
but the wost thing that happens is the pinions walk out of the racks, if you have any questions you can pm me, if you like I will give you my phone number or regular email address, I don't spend much time here any more. if you are going to use reductions I would go with belt ( little or no back lash) vrs gear. I have been blasted in the past for these thoughts, but it seems that most are coming around to my line of thinking...I think you could also direct drive without the reductions see if that works then you can always use the plasma cutter to build your transmissions..
good luck .
//chopper

[Vern2]

chopper, (sent PM)

Maybe there is light at the end of the plasma tunnel.

Thanks for the link. Great stuff.

Here may be a problem. This is a video of z axes motor spinning. It just seems to slow. I may be building a gear box that speeds up the motor. I try to speed it up in software and the stepper starts to chatter. I can take a video of that, if needed.

Do I have a speed problem?

stepper trouble (http://www.enichesoftware.com/media/zmotion.wmv)

Vern

[danilom]

If you are using 24V for power supply that is the problem.

Are these your motors? at inductance of 3.5mH , voltage at which you could spin them fast as you would like is about 50V

[Vern2]

The motor in question may not be used. It's an odd ball motor I have. The other motors are not connected yet, only Z.

Here are the spec on the right motors not connected yet. The odd ball motor is being used because the other motors are on backorder. I just thought it was 24v like the others, I've got no spec on the odd ball motor, the wrong motor was shipped to me. I went to order 34's, there on backorder also. Spec. on both below.

260 Oz In. Hybrid
1.8° /200 Steps Per Rev.
2.5 Amps Current Per Phase
12-24 Volts
4-wire Bi-polar
NEMA 23 Frame

600 Oz In. Hybrid
1.8° /200 Steps Per Rev.
6 Amps Current Per Phase (Bi-polar)
8-wire Uni-polar or Bi-polar
NEMA 34 Frame
Single Shaft

[KenC]

(MetalHead has made a few edits to this post)

Vern, numbers on the specs. sheet are almost useless to the actual motor selection process. The most useful numbers on the data sheet is the Inductance per phase, current rating & number of wire. other numbers which actually contribute a tiny bit is the torque number.

(edit - removed text)

[chopper]

(MetalHead has made a few edits to this post)

Vern,
I would like to clarify I in no way am saying that the exact motors you have will work, what I am saying is nema 23's will work...I did not look at your spec's I was responding to the " the belt do not have enough wrap" and the nema 23's are to small statements, I am using the nema 23's currently on a plasma cutter, ( with my 4 to 1 drives) and I am telling you as for a fact that they do work, a company called candcnc use's nema 23's plasma cam uses them, torchmate uses them etc.. etc... EDIT Text Ken you do not need large motors for plasma in fact you want the smaller motors with less rotor inertia to maintain a more even velocity when making corners, if the machine has to ramp up and down a lot when making a corner it will result in poor quality cuts most plasma cutters use nema 23's..... if you have the right electrical spec's on your stuff, and you are using 260 ozin motors and a 4 to 1 reduction the would put you at 1040 ozin of torque (Edit Text), I use 450 ozin nema 34's on my machine and they work perfectly...Edit TextThis does go out side the norm or at least the MM norm, Edit Text

(Edit Text) Most are going to the belt drives. The geared motors have to much back lash. The norm was the geared Oriental motors and now the norm seems to be belt drives. I did see this coming.

(Edit Text) I must have done something right metalhead is using my drives, I can cut stainless, steel, aluminum, and get get great cuts...

I have (Edit Text) proved this, and that the 4 to 1 drives work. (Edit Text),

Vern, this is why I wanted to go the pm route,
//chopper

[smreish]

Ok, before the whole forum goes into "he said, she said" let's all call a truce.
It's clear (to me at least) that Vern is trying to find a way, either by reason, experience, cost or rationale that the motor's he has will work for his application.

The only true way to calculate what you need is by calculating the basics of your machine requirements. The root of all that starts with KNOWING what your force requirement needs to be with adequate headroom.

This is called drawbar - the force needed to move and object along a path with regards to its resistance which takes into account a lot of forces like (rolling, skidding, breakover friction, inertia, friction due to materials, and many more)

For instance, the drawbar for a MM gantry (my #5 machine) was roughly .6 to 1.8# unloaded and not cutting, upto 20# fully loaded and cutting)
A plasma (non contact cutter) will have similar values on the unloaded value if not using a "contact and skidding tip).



Summary should show that you need to know all the requirements of the motor / driver / mechanical transmission you choose.

Some tid bits of those things you NEED to know to make a proper choice:

- overhung load the torque induces on the shaft which will dictate the shaft diameter required to transmit the torque from the motor to the transmission (thus why Nema 23 are often not suggested due to shaft diameter and grub screws not rated for the load even though the motor can produce the amount of force required)
- rack and pinion and ball screws have different friction a requirements
- motors are selected by knowing what torque you need at what speed. Thus a direct coorelation of HP which is HP=550#/ft/sec. Which in our world comes down to ozin and inches per minute.
- duty cycle or service duty (it might work for 30% of the time, but not continous duty due to heat, wire windings, etc.)


Fortunately for the MM community, the machine was designed and engineered by one person with the knowledge and background that accounts for all these variables and came up with a design that works. The forum here supports THAT design and it's varients that meet the original requirements. If you choose to go off the reservation with a machine design that doesn't meet this forum needs, then it's all on you to make sound choices. It's up to us in the forum to keep it clean and responses clear and not full of "spirited jibbing".

[MetalHead]

I have made a few edits in a few of these posts because I think the content is one that is worth leaving in the post. Like Sean said, lets keep to the topics and not poke at each other. Please PM me if you have questions.

I think that it has been proven with the MM design that you can proceed with your build as your budget has allowed. Your mileage in the support area will vary and if you go off the norm.

MechMate systems are installed all over the globe and we can support them here as long as they are built to what is known to work and as you can see we encourage everyone to "Stick to the Plan".

I will say some are going belt drive and some are staying with the geared systems. Some even have NEMA 23 drives working. I did use chopper's design when we all worked on the thread to come up with other possibilities for the larger belt drive configuration plates. I have been shipping 3.3:1 pullies for these plates, but they do support up to 4:1 pullies like chopper designed.

Vern - you can see a lot of options on how to build your MechMate here on this forum. We try to keep the forum focused so new people can research and learn how the MechMate works withing a few slight design "updates" that do not effect the overall quality of the design.

You will make your decision on how to procedd based on your particular situation. But if your design is to far out of the norm, folks here may not be willing or able to answer your questions.

[Vern2]

Thanks guys.

I have on order 4 - 400 oz/in 34's and 48v, 8.3 amp power supply. I bought the small motors for plasma table 3' x 5'. Just a home shop table. That way my drivers do not have to be replaced. The cost was less then $400.

One big thing I want to cutout on the plasma table is security, glass and screen door art. They will be large insert drawings of cowboy art, mountains and cactus. I have 5 of then to build for my house. That alone will pay for the table.

Got the controller, drivers and stand-in nema 23's, working. Took a drawing of the mm motor plate, cleaned it up, converted to DXF, loaded to CAM software, everything turned on, USB plugged in. The drawing came up in CAM window. Black cut lines, blue move lines. Clicked cycle button. The z motor made sounds, the drawing moved the tool location from home to the first cut line. The z motor sounded off again . The lines turned from black and blue to red as the CAM program was running.:eek: Looks like CorelDRAW is going to work for 2D and DXF files.

Now I have to continue reading threads.

http://www.enichesoftware.com/media/firstlife.jpg

Thank's

Vern

[Vern2]

You can see I've dumped the 23's. Got 4 - 34's 400 in/oz steppers and a 8.3 amp 48v power. I found I've got to dump my control board.:( I called the developer and he basically said "Plasma!":eek: Going with CandCNC control with THC, MACH3 , SheetCAM, CorelDraw, Hypertherm, keep my gecko's.:D

The BIG thing now! Move things around in shop, to make room for 4' x 4' plasma table location and build area.

Vern

[Vern2]

Was wondering when I'm going to get kicked off the forum?

If I'm still around, This thread is fine to be moved to the build section, but not cutting.

Everything is going to be normal until I get going on the x axes build and the x car. Don't want the heavy Machmate car, sorry. Will have the two y motors and total rack and pinion build. The x car won't be so high, I want a much lower profile. Instead of a car, it will be a balanced side car to it's axes. Want to build an engraver on the same car. engraver video (http://youtu.be/FexVafKl5JU) Call it a MachPlasma build if you let me stay. The computer and plasma will be up in the air above table, maybe a swing out. Will find a way to build a control table and seat that will swing out from above and below the plasma table. So If I'm going to use the table I'll swing out computer screen, key board, mouse with seat.

A slowdown coming up. I'm in a two car garage now, on the right, shared by my truck. I'm moving into the green outlined area. Single garage with 3 walls and a garage door. Really much more room because I can line equipment up on both sides of the new shop area.


This is actually a drawing of a central air, not install. You can see Their's a clean room next to the new area. 11' x 20' space for the plasma table and the moved equipment.
http://www.enichesoftware.com/media/heat pump.jpg

Vern

[Vern2]

Have to make some basic table size decisions.

I want a 4' x 4' table. I don't really need the full 48" working width. I do need to place a fill width 48" sheet on the cutting table. Plus I need to be able to push past the end of the cutting surface some. I'm putting together a drawing, that shows the concept of what I planning. I added 2" to 'x' width and 8" on the 'y' axes. That's for 'y' roller box width and gear box mounting. This will be adjusted for 'y' rack and pinion to rack.

A plasma only problem:

It's a good idea to isolate the cutting surface from the table. Now that brings up, a balance of materal waste and table size.

X axes car balance. The 'x' motor and rack will be installed on opposite side of 'z' car. No aluminum, two flimsy, only way to use it is, clamp it, bolt it. No welding.

http://www.enichesoftware.com/media/plasmatable1.jpg

[bradm]

Make sure you factor in the gantry width and the y car length; your drawings show an actual work area of about 24" x 26". Is that satisfactory?

[MetalHead]

I have placed this tread out of the general build area as it appears this device will not be following the standard. I will be keeping an eye on the thread to see how it may benifit the MechMate group going forward.

Have fun with your build and if you do decide on the MechMate design, I will place your thread back over in the build area.

[Vern2]

MetalHead,

It all comes down to the money, I'm basically removed.

Thanks,

Vern