Linear actuator

But check your math.

What maximum mass could you accellerate to around 6 meters per second mid velocity and zero meters per second final velocity with how many Newtons?

Um, 990 times three is $2970. There were THREE sliders, not just two. One slider lacked the stepper motor.

These flew on outta here. We do still have bunches of the SUV cargo nets they were used to produce. At $19 per case of FIFTY.

We only have eight of the Adept sliders left, five medium duty 950 mm and three heavy duty 1000 mm. Repositionable to ONE TENTH OF A MIL!!!!!!

... [about linear actuator]

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Glancing at that, I see your 2 Parker Hauser robotic sliders listed at $990 each or $1990 for the lot -- why that extra $10 ?

-jiw

Also, unless partial position repeatability is important, hydraulic or pneumatic solutions would be ridiculously cheaper and simpler.

Looking for a LA with a stroke of around 30cm, force around 1000N and capable of full stroke in less than 200mS.

Anyone any idea where I can find that, or how much I can expect to pay?

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Probably several million times. Accuracy is not too critical, and repeatability within a mm is acceptable.

Why would you "avoid all that stuff", when pneumatics or hydraulics is by far the simplest and most cost effective solution where it is applicable?

If repeatability is not particularly relevant, pneumatics should do it for under ten dollars.

Probably more like 8 kg or less if a reasonable velocity profile is used. Ideally your initial and final velocity should be zero.

Otherwise the neighbors a block or two down the road may complain.

Again, your 1500 watts will be more like 5000 watts with an acceptable velocity profile.

Except that the point being made is that what is 'possible', depends on the mass of the attached object. If this is more than about 33Kg, the force available, will not be enough to meet your 0.2sec specification. You need to be including these limits in your thinking _now_, or you will have major problems latter...

Best Wishes

I'm trying to avoid all of that stuff. I might eventually go for a DIY version using a high speed motor and optical encoder with some custom electronics. As I said, repeatability is not especially relevant, but brute force is. The kind of price I'm looking for is around the $150 mark for production runs of

The arithmetic I can take care of when I get down to the detailed design. Right now I'm just doing a quick survey of what's possible.

In most any industrial situation, pneumatics or hydraulics beats linear actuators hands down.

It is not even remotely close.

Except when extreme precision is requred.

Another advantage of pneumatics or hydaulics: Energy storage is trivial and the peak power can ridiculously exceed average.

of

Depends - how much is 1000N in "real" units? ;-P

Thanks, Rich

The physics tells you that :

force(N=kgm/s^2) = mass(kg) * acceleration(m/s^2)

using the max force to acclelerate and the max negative force for braking gives 15cm in 100ms = 1/2* a*t^2

Solve for "a" gives 30m/s^2 . Since the force is 1000N, the mass is 33kg or lower.

Rene

Well, I don't know much about plumbing. Plus electric seems more reliable, given that it will all start to leak after a while.

I did a slightly different bit of maths.

Still, correct to within a factor of two or three for my pursposes. I'm still looking for the most cost effective solution given the constraints, one of which is that the machine should be able to handle a million cycles.

A factor of 2 or 3 probably won't translate into a cost differential of 2 or 3. Right now I'm just in the hand waving phase of a possible project.

As sidenote : the work is force times pathlength, and power is work per time.

so : 1000N times 0.3m in 200ms is 300Nm/0.2s =1500Watt

Rene