What type of motor is suitable for a plotter type device?

[MRW]

Hello! It's been a while.

I got the idea of hacking an old inkjet color printer and turning it
into a flat bed. I can probably recycle the motors already in the
device, but let say that I just want to use the printer head and
completely rebuild the rest of the system.

What would be a suitable motor (e.g. stepper) to control the movement
of the printhead?

I was thinking of giving it an x,y,and z movement instead of just a 1-
dimensional movement.

Thanks!

 

[Tim Wescott]

MRW wrote:

Hello! It's been a while.

I got the idea of hacking an old inkjet color printer and turning it
into a flat bed. I can probably recycle the motors already in the
device, but let say that I just want to use the printer head and
completely rebuild the rest of the system.

What would be a suitable motor (e.g. stepper) to control the movement
of the printhead?

I was thinking of giving it an x,y,and z movement instead of just a 1-
dimensional movement.

Steppers are easy to use, and hard to optimize. If you keep them easy

they'll be big and power hungry.

DC motors are harder to use and easier to optimize (IMHO). You'll need
position feedback, and when you're done you'll know a bunch of
interesting control theory. They'll be smaller and less power hungry
than unoptimized steppers -- but getting them working initially will be
more difficult.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Wildepad]

On Mon, 29 Oct 2007 19:30:43 -0000, MRW <mr.whatever@gmail.com> wrote:

Hello! It's been a while.

I got the idea of hacking an old inkjet color printer and turning it
into a flat bed. I can probably recycle the motors already in the
device, but let say that I just want to use the printer head and
completely rebuild the rest of the system.

What would be a suitable motor (e.g. stepper) to control the movement
of the printhead?

I was thinking of giving it an x,y,and z movement instead of just a 1-
dimensional movement.

Thanks!

I doubt that you would be able to use the motor that drives the roller
-- it's probably too small to move the head and x assembly along the
y.

I guess you could use DC motors, but the construction and
troubleshooting would be much more difficult than using steppers.
Also, the learning curve might be very steep.

The best advice I can give is to start scrounging -- if you can find
some old dot matrix printers (especially ones by TI), you're all set.

The polished rods and the carrier are excellent for y travel, and
unlike modern (inkjet) printers, the steppers were usually quite
robust. Two of them (one on each side) will surely carry your x
assembly with little problem. A nice plus is that all the hardware
(belt, cable, or chain along with all pulleys and rollers) is also
right there, ready to use as is.

As for z, I'd suggest the stepper from a hard disk drive. Now you have
to find a real old one (anything above 25M probably uses a voice
coil), but they're invaluable.

Good luck!
--

 

[MRW]

On Oct 29, 5:31 pm, Tim Wescott <t...@seemywebsite.com> wrote:

MRW wrote:
Hello! It's been a while.

I got the idea of hacking an old inkjet color printer and turning it
into a flat bed. I can probably recycle the motors already in the
device, but let say that I just want to use the printer head and
completely rebuild the rest of the system.

What would be a suitable motor (e.g. stepper) to control the movement
of the printhead?

I was thinking of giving it an x,y,and z movement instead of just a 1-
dimensional movement.

Steppers are easy to use, and hard to optimize. If you keep them easy
they'll be big and power hungry.

That's the impression that I got from the motor tutorials that I've
been reading. I think having an open loop system is not so bad to
track the printerhead's position, but it seems like the motor accuracy
is about 7 to 15 degrees (verification please?) for the permanent
magnet versions. This will probably lead to alignment issues, no?

DC motors are harder to use and easier to optimize (IMHO). You'll need
position feedback, and when you're done you'll know a bunch of
interesting control theory. They'll be smaller and less power hungry
than unoptimized steppers -- but getting them working initially will be
more difficult.

Learning controls theory would be great. I only had one class of that
subject, and I already forgot. I need to find a good book on the
subject.

I also read that DC motors are load dependent, no? So, I might need a
bigger motor to drive the print head and holding rod.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html

Thanks, Tim!

 

[MRW]

On Oct 30, 12:55 am, Wildepad <noreplies> wrote:

On Mon, 29 Oct 2007 19:30:43 -0000, MRW <mr.whate...@gmail.com> wrote:
Hello! It's been a while.

I got the idea of hacking an old inkjet color printer and turning it
into a flat bed. I can probably recycle the motors already in the
device, but let say that I just want to use the printer head and
completely rebuild the rest of the system.

What would be a suitable motor (e.g. stepper) to control the movement
of the printhead?

I was thinking of giving it an x,y,and z movement instead of just a 1-
dimensional movement.

Thanks!

I doubt that you would be able to use the motor that drives the roller
-- it's probably too small to move the head and x assembly along the
y.

I guess you could use DC motors, but the construction and
troubleshooting would be much more difficult than using steppers.
Also, the learning curve might be very steep.

Do you know of any For Dummies book on DC motors?

The best advice I can give is to start scrounging -- if you can find
some old dot matrix printers (especially ones by TI), you're all set.

The polished rods and the carrier are excellent for y travel, and
unlike modern (inkjet) printers, the steppers were usually quite
robust. Two of them (one on each side) will surely carry your x
assembly with little problem. A nice plus is that all the hardware
(belt, cable, or chain along with all pulleys and rollers) is also
right there, ready to use as is.

Good idea. I usually see a bunch of old printers being given away on
Craigslist.

As for z, I'd suggest the stepper from a hard disk drive. Now you have
to find a real old one (anything above 25M probably uses a voice
coil), but they're invaluable.

Good luck!
--

Thanks!

 

[Tim Wescott]

On Tue, 30 Oct 2007 15:07:35 +0000, MRW wrote:

On Oct 29, 5:31 pm, Tim Wescott <t...@seemywebsite.com> wrote:
MRW wrote:
Hello! It's been a while.

I got the idea of hacking an old inkjet color printer and turning it
into a flat bed. I can probably recycle the motors already in the
device, but let say that I just want to use the printer head and
completely rebuild the rest of the system.

What would be a suitable motor (e.g. stepper) to control the movement
of the printhead?

I was thinking of giving it an x,y,and z movement instead of just a 1-
dimensional movement.

Steppers are easy to use, and hard to optimize. If you keep them easy
they'll be big and power hungry.


That's the impression that I got from the motor tutorials that I've
been reading. I think having an open loop system is not so bad to
track the printerhead's position, but it seems like the motor accuracy
is about 7 to 15 degrees (verification please?) for the permanent
magnet versions. This will probably lead to alignment issues, no?

You can get steppers with more steps/revolution than that -- I think 1.8
degrees/step is fairly common, but below that probably gets iffy. Look
around.

You can always gear them down, if you can accept the backlash in your gear
train.

DC motors are harder to use and easier to optimize (IMHO). You'll need
position feedback, and when you're done you'll know a bunch of
interesting control theory. They'll be smaller and less power hungry
than unoptimized steppers -- but getting them working initially will be
more difficult.



Learning controls theory would be great. I only had one class of that
subject, and I already forgot. I need to find a good book on the
subject.

Did you read my tag line? I have a book for you!

http://www.wescottdesign.com/actfes/actfes.html.

I also read that DC motors are load dependent, no? So, I might need a
bigger motor to drive the print head and holding rod.

If by "load dependent" you mean "need a bigger one for a heavier load" --

_all_ motors are like that, including steppers.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html

Thanks, Tim!

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

 

[Wildepad]

On Tue, 30 Oct 2007 15:10:42 -0000, MRW <mr.whatever@gmail.com> wrote:

On Oct 30, 12:55 am, Wildepad <noreplies> wrote:

The polished rods and the carrier are excellent for y travel, and
unlike modern (inkjet) printers, the steppers were usually quite
robust. Two of them (one on each side) will surely carry your x
assembly with little problem. A nice plus is that all the hardware
(belt, cable, or chain along with all pulleys and rollers) is also
right there, ready to use as is.

Good idea. I usually see a bunch of old printers being given away on
Craigslist.

There's one pitfall I should warn you about: for a long time, my hobby
was electronics, and I disassembled obsolete equipment for parts to
feed that hobby.

Then one day I suddenly realized that my hobby had actually become
tearing apart old stuff, and it had been years since I'd actually used
any of the parts for new electronics projects.

Weaning myself off of that and getting back into electronics was as
bad as trying to kick an addiction.
--

 

[Rich Grise]

On Mon, 29 Oct 2007 19:30:43 +0000, MRW wrote:

I got the idea of hacking an old inkjet color printer and turning it
into a flat bed. I can probably recycle the motors already in the
device, but let say that I just want to use the printer head and
completely rebuild the rest of the system.

What would be a suitable motor (e.g. stepper) to control the movement
of the printhead?

I was thinking of giving it an x,y,and z movement instead of just a 1-
dimensional movement.

For X, use the motor and carriage that the printer uses for X. Mount
it on a frame that you design, which you use ordinary OTS table-moving
stuff to move for Y.

Have Fun!
Rich