MechMate CNC Router Forum

Go Back   MechMate CNC Router Forum > Miscellaneous hardware and software > Miscellaneous / General / Whatever / Catchall
Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Reply
 
Thread Tools
  #1  
Old Fri 08 July 2011, 18:46
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
Plasma - direct drive - Gilbert Arizona

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
Vern

Last edited by Vern2; Fri 08 July 2011 at 19:03..
Reply With Quote
  #2  
Old Sat 09 July 2011, 08:43
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
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.
Reply With Quote
  #3  
Old Sat 09 July 2011, 08:52
hans.arnell
Just call me: Hasse #14
 
Soderhamn
Sweden
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
Reply With Quote
  #4  
Old Sat 09 July 2011, 10:27
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
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

Vern
Reply With Quote
  #5  
Old Sat 09 July 2011, 10:37
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
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

Vern
Reply With Quote
  #6  
Old Sat 09 July 2011, 13:28
hans.arnell
Just call me: Hasse #14
 
Soderhamn
Sweden
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.
Reply With Quote
  #7  
Old Sat 09 July 2011, 17:05
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
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
Reply With Quote
  #8  
Old Sun 10 July 2011, 04:40
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
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.
Reply With Quote
  #9  
Old Sun 10 July 2011, 08:48
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
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





Last edited by Vern2; Sun 10 July 2011 at 09:01..
Reply With Quote
  #10  
Old Sun 10 July 2011, 09:11
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
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
Reply With Quote
  #11  
Old Sun 10 July 2011, 21:18
jehayes
Just call me: Joe #53
 
Whidbey Island, Washington
United States of America
U got it!
Reply With Quote
  #12  
Old Sun 10 July 2011, 23:23
KenC
Just call me: Ken
 
Klang
Malaysia
Vern,
is that all the sheet metal you have?
Build the biggest box possible. Real estate is never enough once you started.
Reply With Quote
  #13  
Old Mon 11 July 2011, 07:07
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
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.
Reply With Quote
  #14  
Old Mon 11 July 2011, 10:48
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
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.



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.

Last edited by Vern2; Mon 11 July 2011 at 10:54..
Reply With Quote
  #15  
Old Mon 11 July 2011, 12:02
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
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.
Reply With Quote
  #16  
Old Mon 11 July 2011, 13:19
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
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
Reply With Quote
  #17  
Old Mon 11 July 2011, 13:49
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
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
Reply With Quote
  #18  
Old Mon 11 July 2011, 14:47
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
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.
Reply With Quote
  #19  
Old Mon 11 July 2011, 20:29
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
Richards,

Here is my 23 spindle shaft size, 0.252".


Reply With Quote
  #20  
Old Mon 11 July 2011, 21:00
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
Richards,

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



You can see the bore size (ID) 1/4"


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

Last edited by Vern2; Mon 11 July 2011 at 21:03..
Reply With Quote
  #21  
Old Tue 12 July 2011, 00:55
KenC
Just call me: Ken
 
Klang
Malaysia
If you must, you can always add an idler to increase the number of teeth contact.
Reply With Quote
  #22  
Old Tue 12 July 2011, 05:52
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
KenC,

I'm not pushing 600 in/lb, only 260 in/lb, 12 to 24v. If I could get a do over . 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. 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

Vern

Last edited by Vern2; Tue 12 July 2011 at 06:18..
Reply With Quote
  #23  
Old Tue 12 July 2011, 06:11
KenC
Just call me: Ken
 
Klang
Malaysia
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....
Reply With Quote
  #24  
Old Tue 12 July 2011, 08:23
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
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.
Reply With Quote
  #25  
Old Tue 12 July 2011, 09:03
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
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


Last edited by Vern2; Tue 12 July 2011 at 09:21..
Reply With Quote
  #26  
Old Tue 12 July 2011, 09:44
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
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. Enough room for a washer, done.

Last edited by Vern2; Tue 12 July 2011 at 09:56..
Reply With Quote
  #27  
Old Tue 12 July 2011, 09:49
Vern2
Just call me: Vern
 
Gilbert, Arizona
United States of America
KenC,
I bought one of those bracelets that give you super strength.

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

Vern

Last edited by Vern2; Tue 12 July 2011 at 09:55..
Reply With Quote
  #28  
Old Tue 12 July 2011, 18:27
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
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.
Reply With Quote
  #29  
Old Wed 13 July 2011, 04:15
KenC
Just call me: Ken
 
Klang
Malaysia
Vern, may the force be with you
Reply With Quote
  #30  
Old Wed 13 July 2011, 06:06
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
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.
Reply With Quote
Reply

Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Direct motors 4Nm and 6,8Nm tomasptacek Motors & their mountings 0 Wed 26 May 2010 02:25
Newbie needs help with figuring out drive configurations (slaved drive for x-axis) ikeike 701. Motor Drives 5 Mon 04 January 2010 21:06
Slaving a motor - put its drive in parallel to another drive on the same BOB output J.R. Hatcher 70. Control Systems 34 Mon 16 November 2009 09:13
Automation Direct power supply . . . or a Switch Mode MeanWell bfauska 702. Power Supplies 14 Tue 11 August 2009 10:16
MechMate in Arizona Kevin Construction started, but not cutting yet 7 Sat 22 December 2007 10:52


All times are GMT -6. The time now is 08:27.


Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.