Cost of linear actuators

Posted by eganders on November 2, 2007, 11:59 pm

I have an application where I have to move a 3 lb object in a 3 ft
cubic space. I am not looking at high performance or high accuracy.
It can take as much as 30 seconds to traverse the 3 ft distance and
the accuracy could be no better than 0.020 or 0.050 inch (possibly the
spec could be even looser).

Linear actuators would appear to be the best solution, but I am
finding that they are hundreds or even thousands of dollars. The
product I want to build will have to cost no more than $2,000 for a 3
axis device with controller, overhead and profit.

What is it in a linear actuator that costs so much that you could not
build a low cost version using a threaded rod, servo or stepper motor
and an extruded frame for a lot less?

Does anyone know of a linear actuator that can provide the kind of
performance I am looking for for a couple hundred dollars?

Posted by on November 3, 2007, 10:46 am

Yes, people commonly (even normally) build linear actuators from
things like threaded rod. Here is one source for the components.
www.mcmaster.com Search for the phrase "Acme Threaded Rods". They
have an extraordinarily well done web site. There is a link on the
right to show the actual catalog page, which is easier to view when
you are looking to find the cheapest product. Also if you search for
"linear actuator" you can get to a catalog page with a list of various
types of linear actuators.

However, if you are not used to specifiying the components for
something like this, it might be better to find a complete package.

Also, here is a link to a web site www.cnczone.com that has a forum on
a do-it-yourself cnc router (mostly gantry types).
http://www.cnczone.com/forums/forumdisplay.php?fH

Joe Dunfee

Posted by eganders on November 4, 2007, 4:11 pm

On Nov 3, 9:46 am, cadco...@yahoo.com wrote:

> Yes, people commonly (even normally) build linear actuators from
> things like threaded rod. Here is one source for the

components.www.mcmaster.com Search for the phrase "Acme Threaded Rods". They

> have an extraordinarily well done web site. There is a link on the
> right to show the actual catalog page, which is easier to view when
> you are looking to find the cheapest product. Also if you search for
> "linear actuator" you can get to a catalog page with a list of various
> types of linear actuators.
> However, if you are not used to specifiying the components for
> something like this, it might be better to find a complete package.
> Also, here is a link to a web sitewww.cnczone.comthat has a forum on
> a do-it-yourself cnc router (mostly gantry

types).http://www.cnczone.com/forums/forumdisplay.php?fH

> Joe Dunfee

Joe,

Thanks for reminding me of McMaster-Carr. I am looking at some
possibilities there. They are my heros anyway. Best website and
service on the planet for buying parts of all kinds!!

I would like to be a little more specific about what I am trying to
do. I understand that I could design the components myself.
Ultimately I expect to be building low production quantities of these
and was hoping that a linear actuator/controller combination might
exist in the marketplace so I don't have to redesign the wheel. I
have designed high-speed line printers and automotive sensors in my
career, so I could build one of these. However, I don't want to find
(as I have in the past) that a simple, low cost solution exists that I
could use out-of-the-box and that is already being built in production
quantities. Ideally, I would like to have 3 linear actuators, 2 of
which would be on an X-Y base and the 3rd that would travel vertically
from this X-Y base (call this the Z axis). I would need to control
the three with a controller that would be programmed from a computer
program I would write for the specific application I have in mind. (I
can't divulge the purpose of this device at this time in case there
are patent issues). I need to be able to represent the position on a
computer screen and be able to return to that position (by storing the
X-Y-Z coordinates).

Posted by on November 4, 2007, 5:29 pm

> a simple, low cost solution exists that Icould use out-of-the-box
>and that is already being built in production quantities.

I don't think you are going to do it in your price range. Here is a
commercial unit which I think represents the closest you are going to
get to your goals. It set a new price point when it was introduced.

www.shopbottools.com

Joe Dunfee

Posted by Gordon McComb on November 4, 2007, 11:59 pm

eganders wrote:

> Ideally, I would like to have 3 linear actuators, 2 of
> which would be on an X-Y base and the 3rd that would travel vertically
> from this X-Y base (call this the Z axis). I would need to control
> the three with a controller that would be programmed from a computer
> program I would write for the specific application I have in mind. (I
> can't divulge the purpose of this device at this time in case there
> are patent issues). I need to be able to represent the position on a
> computer screen and be able to return to that position (by storing the
> X-Y-Z coordinates).

You have precisely described a common three-axis CNC mill or router. Do
a Google search and you should find a lot of commercial and homebrew
examples you can learn from.

-- Gordon

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