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  #1  
Old Sun 12 November 2006, 09:30
Gerald_D
Just call me:
 
The overall concept of the MM's Rack and Pinion design - springloading & antibacklash

These drawings show the assemblies:
M5 10 100 A
M5 10 200 A



The motor (or motor & gearbox)is screwed to the Motor Plate M5 10 012 D which is hinged to the car. The spring holds the pressure of the pinion gear against the rack. The stabiliser screw rides in a slot - it allows the motor plate to swing but not "flap" around. Teflon washers are fitted where the motor plate slides against the car.
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  #2  
Old Thu 24 July 2008, 16:18
plain ol Bill
Just call me: Bill
 
Olympia, WA
United States of America
Rack mounting dwg.

Well after having to go out of town to work for a long period and then my shop largely disappearing (kids "borrowing" tools) during the absence I am again looking at MechMate. I have been looking thru the drawings again and I KNOW there is a specific dwg. in there somewhere showing the mounting of the racks. After going thru them 3 times I'll just ask: Which dwg. number shows how the racks are mounted?
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  #3  
Old Thu 24 July 2008, 16:42
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Bill,

Look at 10 20 200 AA. I hope that helps you.

3M Tape 4955.
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  #4  
Old Thu 24 July 2008, 17:58
plain ol Bill
Just call me: Bill
 
Olympia, WA
United States of America
That's the one. I must have blown by that at least 10 times w/o seeing it. Oh well - I never claimed to be smart. Thanks for the reply.
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  #5  
Old Thu 24 July 2008, 18:47
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Bill,

Don't beat your self up. There are a lot of drawings and a lot of details. I think every one has had the problem of not being able to find a detail they need.
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  #6  
Old Mon 03 November 2008, 08:00
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Concept Rack and Pinion design

Ton started the thread before the posts above were copied into it . . . .

Dear All,
I am finding the concept of Rack and Pinion design. I am building plasma table at 4' x 8' ft. Who can advise me for the picture of rack and pinion design on X-axis and Y-axis.? I don't still understand of the method of design of each axis.
If who has the picture also,I would like to big thanks.


Best Regards,
Ton
mongkolnum@gmail.com
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  #7  
Old Mon 03 November 2008, 08:05
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Ton,
If you go to the download section, you will find links to download the Mechmate plans which detail the rack and pinion design that is the Mechmate.

See here.

http://www.mechmate.com/forums/showthread.php?t=376
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  #8  
Old Mon 03 November 2008, 11:28
Mongkol
Just call me: Ton
 
Bangkok
Thailand
concept rack and pinion design

Heath,
Thanks for your help. I downloaded Mechmate plan to find the concept of rack and pinion design. I am still puzzled with the connection and holding of motor with rack.( of each axis). It's difficult to imagine from the 2D drawing.
I don't know this drawing was written from solidwork or not. If yes, I want to download 3D it. Is it possible?

Ton
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  #9  
Old Mon 03 November 2008, 11:49
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
All 4 axes use a similar method. The motor swings against the rack and is held by spring force to eliminate backlash. See some build pictures:

http://www.mechmate.com/forums/showt...9&postcount=81

http://www.mechmate.com/forums/showt...&postcount=114

http://www.mechmate.com/forums/showt...2&postcount=86

It is simpler than what it looks!
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  #10  
Old Tue 04 November 2008, 08:24
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Rack and pinion concept

Gerald and All,
Big Thanks for information!!. It sound like the Y-axis use 2 stepping motors ( left and right)to control. Is this correct?

Ton
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  #11  
Old Tue 04 November 2008, 09:13
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Ton,
Usually the X axis is the longer of the two. This one has the two stepper motors and the Y axis (usually the shorter of the two and the one the Router Car runs on only has one Stepper motor and one passive hold down bearing assembly.
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  #12  
Old Tue 04 November 2008, 17:41
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Concept rack and pinion design

Big Thanks for detail
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  #13  
Old Sun 21 December 2008, 09:25
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Is it necessary to have the two stepper motors on X-axis?

Gerald and The Experter,
From your design,I am little puzzled with X-axis. Is it necessary to have the two stepper motors? It's possible or not if I only use the one stepper motor with double high torques.

Ton
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  #14  
Old Sun 21 December 2008, 09:51
Alan_c
Just call me: Alan (#11)
 
Cape Town (Western Cape)
South Africa
Send a message via Skype™ to Alan_c
Using only one stepper on one side will NOT work. I demonstrated that to myself while I was setting up my machine, one x-motor at a time, the other end (without the motor engaged in the rack) of the gantry swings quite dramatically when jogged, it lags behind on start up and overshoots on stopping. one is not able to flex the gantry like that by hand but the power of the motors is incredible - so in short its not possible.
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  #15  
Old Sun 21 December 2008, 21:19
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Hi Alan,
Thanks for your comment. I found Samson machine from this website http://www.samsoncnc.com/. It only use the one motor to drive of each axis.He use the rack-pinion method as same as Gerald design. I am confused why does it work smoothly.

Mongkol
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  #16  
Old Mon 22 December 2008, 00:07
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Ton, the samson machine has a very light gantry and is only use for plasma where there is zero cutting force. On the MechMate we have very high sideways cutting forces and therefore also a much heavier gantry.
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  #17  
Old Mon 22 December 2008, 05:52
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
Plasma vs. Routers

When I put in my Plasma system I wondered the same thing. I wanted to have a dual purpose system. But I learned it takes a lot more power to drive the router machines because the plasma never realy touches the work so the plasma does not need to be as rigid. My Dynatorch also has one driver for x, but the cool thing they do is use a driveshaft (red rod under the gantry) that transfers across the table to the other side to keep the system square. http://www.youtube.com/watch?v=VIwZUXPJwww

I was wondering about keeping things square with two motors, but after reading a post with 2-203V on one PMDX channel for the x I figured that was a good way to help keep the motors in sync as long as you zero the machine at startup.

I decided against a combo machine becuase I have since learned fire and wood are not good partners .... . (Joking of course) If you have never seen plasma in action just think about where all the saw dust gets to while the router is cutting. Now imagine that is fire (kind of like a sparkler on steriods). Best to have two seprate machines. http://www.youtube.com/watch?v=QzeEoNCUsVM
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  #18  
Old Mon 22 December 2008, 07:20
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by MetalHead View Post
. . . . keep the motors in sync as long as you zero the machine at startup. . . .
The motors' detent torque keeps them in sync while the motors are shut down. We don't normally zero the machine at startup, unless we suspect that someone has bumped it out of square.
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  #19  
Old Mon 22 December 2008, 09:09
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Hi Gerald,
Thanks for your reply. I feel clear. I agree with you the router machine have to touch on material but the plasma machine don't need to touch. Then,It's necessary to have the two motors of X-axis for router machine.
I have one question.
How many torque of motor do you use for each axis?
The 400 Oz-in stepper motor for each axis is enough ? Pls advise.

Mongkol
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  #20  
Old Mon 22 December 2008, 09:30
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Selecting motors for the MechMate
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  #21  
Old Mon 22 December 2008, 21:17
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Gerald,
I will choose at third choice.

Big Thanks
Mongkol
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  #22  
Old Sun 28 December 2008, 09:06
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Puzzled with plate-supportmotor.

Hi Gerald and All,
I am designing table by using mechmate method and I can not find the plate-supportmotor drawing on the downloaded file.I am little puzzled with Mechmate design and have some questions.
1) I found two holes on the plate-supportmotor in the drawing.I would like to know what is the function of two holes.
2) I know points 1,2,3 and 4 screwed to hold the motor on the plate but I don't sure the design of Fixed-A and Slotted-B.
Fixed-A, This point is fixed with screw to be rotation point or not. Is it correct?
Slotted-B,This point is slotted hole for plate-motor to move flexible or not. Is it correct?
I have not ever designed with rack-pinion method. Pls advise.

Hope your help
Ton
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  #23  
Old Sun 28 December 2008, 10:05
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Point A is the rotation center.

The slot at B is an arc with the center at A

At A and B, the screws are tightened against plastic washers - the motor plate is inside the sandwich of plastic washers. The motor plate can move inside the plastic washers.

The spring rotates the motor plate counter-clockwise until the pinion gear is against the rack.

The function of the extra holes is for mounting the gear-type Oriental Motor's gearbox.
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  #24  
Old Sun 28 December 2008, 10:30
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Hi Gerald,
1)I am puzzled why do you use plastic washer. Is it possible to use metal washer? Pls advise.
2)Two holes from picture,Do you mean that they are extra holes for Oriental Motor's gearbox. it's right or wrong.
Assume,If I use stepper motor from 34HS9801.I can not directly connect with pinion on motor. I should have the timing pulley to reduce the revolution of motor. Is it correct?

Ton
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  #25  
Old Sun 28 December 2008, 10:48
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
1.) The rack is not perfectly parallel to the rail. As the car moves along the rail & rack the pinion must move up and down a little bit. The motor slides inside the plastic for this small movement. The plastic can be tightened for a controlled friction grip. Steel will also work, but then the tightening, lubrication and corrosion are critical.

2.) Have you seen drawing M5 10 312 P? The holes are explained there. (bottom left)
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  #26  
Old Mon 29 December 2008, 06:06
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Quote:
Originally Posted by Gerald D View Post
1.) The rack is not perfectly parallel to the rail. As the car moves along the rail & rack the pinion must move up and down a little bit. The motor slides inside the plastic for this small movement. The plastic can be tightened for a controlled friction grip. Steel will also work, but then the tightening, lubrication and corrosion are critical.


2.) Have you seen drawing M5 10 312 P? The holes are explained there. (bottom left)
Gerald, I clear for item1 and item2 for your help.
I have some questions in drawing M5 10 312 and picture as below.
1)I saw the drawing M5 10 312 and found no.8 description show M10 fender washer. I would like to know the material of fender washer is teflon ( plastic) or not.
2) From the picture, I unclear the drawing of plate-supportmotor
2.1) What is the angle between y' axis and c'axis ( spring axis) ? 45 degree or not? Is it necessary to concentrate 45 degree ?
2.2) What milimeters is the distance from point A to B about ?
2.3) Fixed spring,this is an arc with the center at A or not. What milimeters is the distance from point A to fixed spring about ?

Sorry if I disturb you
Ton
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  #27  
Old Mon 29 December 2008, 07:12
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
1) It is steel. You can put plastic under it if you want.

2.1) y' axis has no meaning.
2.2) & 2.3) Use your CAD program to open the .dxf files - there you can measure all exactly.

Enough of those questions now.
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  #28  
Old Mon 29 December 2008, 07:35
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Gerald,
Big Thank for the detail
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  #29  
Old Thu 15 January 2009, 10:30
jvfc
Just call me: Vladimir
 
Curitiba
Brazil
Send a message via MSN to jvfc
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  #30  
Old Thu 10 September 2009, 23:17
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Vladimir,
Big Thanks. It's easy to imagine.

Mongkol
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