Servo Driven X-Y Stage

Hello Everyone,

I'm new to the RepRap / Makerbot community.

I recently came in possession of a machine with a high precision X-Y Stage with 300mm of travel in both axes. The stage has linear ball bearing slides, 24V DC servos, ball bearing leadscrews, and rotary encoders for positional feedback. This machine is a perfect platform for creating a RepRap/MakerBot. I would like to know if anyone has created a RepRap that uses servo control with positional feedback for the X-Y & Z?



One of the mechanical engineers I work with suggested using a Geckodrive [www.geckodrive.com] which allows you to control a servo with encoder using stepper control signals which I understand would interface perfectly with a reprap motherboard.

What do you guys think?

Just an FYI I am a Mechanical Designer and have no programming experience and basic electronics skills.

Thanks,
Matthew LaBerge

Yes your best bet is the Geckodrive, my stages had servo motors and encoders but since the servo motors had bushs I elected to replace them with the standard stepper motors since it was also a NEMA 23 mount.

Though it might be cheaper and less of a learning curve to swap out with steppers, looks like your stage has standard motor mounts.

My blog.

[exmrclean.blogspot.com]

Nice score. I have been searching ebay every day for a high precision x/y stage that's cheap enough to justify me buying it.

very nice =)

Labmat,

That, my friend, is a real find! Are there any more available?!?
FYI, reprap core member Nophead based his machine, [hydraraptor.blogspot.com] on a somewhat similar XY stage. I heartily suggest you read his blog, especially (in your case) the early posts, where he documents his Cartesian mechanism.

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Larry Pfeffer,

My blog about building repstrap Cerberus:
[repstrap-cerberus.blogspot.com]

Thanks for all of the links guys; lots of good info out there.

I think I'm going to give the Geckodrives a shot. I would like to keep the servo motors and cabling intact as I still have the original servo amps and PC based MEI motion controller. It would be rather simple for me to swap the cabling between the geckodrives and original servo amps so I can use other CNC software that supports an MEI motion controller.

It was a lucky find; I happen to work for the company that manufactured this piece of equipment... it was just sitting and gathering dust in our basement. In a former life it used to be a piece of automated semiconductor inspection equipment, but I think it will make a fine RepRap.





Edited 1 time(s). Last edit at 05/31/2009 01:48AM by labmat.

Since the it was orginally a inspection machine, does it run G-Code and have controllable inputs and output that you can sync via the G-Code?

I am working with some high school students and we taking that approach with a pro light 100 mill. The plan is to have Skeinforge output the appropiate G-code files to load into the mill and then drive a extruder control via the I/O ports.

Great looking hardware!

The card I have is an MEI PCX/DSP programmable 8 axis motion controller. You program it in C/C++ but since I'm a mechanical designer I know nothing of programming. One could design a program to convert the G-Code to something the MEI could understand.

You can look over the datasheet if you like.

[support.motioneng.com]

I think I may see if I can pull one of my software comrades into this project.

labmat,

I took a quick look at that datasheet, and I have two questions you probably want to think about:

Do you have the *software* for programing this board?

Also, it's an ISA card (several generations back in PC add-on slot interfaces.)
So, do you have a (working) PC with an ISA slot to put the MEI board into?

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Larry Pfeffer,

My blog about building repstrap Cerberus:
[repstrap-cerberus.blogspot.com]

Hey Larry,

I have both the software and the original computer that shipped with the machine. I do however need to do some work to reconnect the motion controller to the servo amps as the last person to touch the machine hacked into the cabling with a pair of side cutters.

labmat,

Good to hear you have the hardware and software needed to use the original motion controller. Having extra channels gives you the possibility to build servo-driven extruders! BTW, I keep one of my older PCs around because it has a few ISA slots, and I have a couple ISA cards useful for motion control. Keep us posted on your progress. It looks like you have the foudation for an excellent repstrap!

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Larry Pfeffer,

My blog about building repstrap Cerberus:
[repstrap-cerberus.blogspot.com]