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.

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/showt...highlight=g540
http://www.mechmate.com/forums/showt...highlight=g540

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

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.

Like DraftSight from Dassault

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

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

You guys are great as usual!

I found a way to use my drivers (gecko-251's) on this 34 motor. $100 34 stepper 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

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.

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/showt...6&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

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

Vern

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

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

(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)

(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

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".

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.

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

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

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 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

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

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?

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.

MetalHead,

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

Thanks,

Vern