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Posted by GregS on June 25, 2008, 10:56 am
Please log in for more thread options >GregS wrote:
> mike_l_rossREMOVE@EMOVEcomcast.net wrote:
>>> GregS wrote:
>>>
>>>> All I need is about a 1 inch stroke for an application. A solenoid might
>>>> work but it might not. I'm considering a small linear actuator or motor.
>>>> Are there any good choices or companies that have a small devices. I have
>>>> to get the speed down to 100 ms.
>>>>
>>>> greg
>>>
>>> If you don't have to control to intermediate positions, I think a solenoid
>>> is going to be your cheapest solution. Any motor that can do that speed
>>> will probably be expensive and require a controller. All you need for a
>>> solenoid is current. The solenoids are faster because they don't have to
>>> drive as much mass.
>>>
>>> Surplus 12V solenoids with roughly 1" travel are $5 to $10US around here.
>>>
>>>
>>> Mike Ross
>>
>>
>> OK I have seen some good answers here. My load is a small sliding lens, and
>> I can't say exactly how massive it is.
>
> Suggest investigating concept of "scale".
>
We will construct it after the type of drive is selected.
>> The 100 ms is what someone suggested
>> but I think we can use a slower speed, maybe 250 ms. Still contemplating,
> solenoids
>> are what we will probably use, with a pivot to get more travel. I would like
> to use
>> two for push pull, so we don't have to use a spring. I just didn't know of
> good
>> companies to explore linear actuators.
>
> Ah, another vague actuator requirement. Try Google.
Unfortunately Google does not always give what you want.
> There are many different short-distance linear actuator devices available.
>If you're going to build stuff, you need to be aware of available parts.
>This isn't hard, because most vendors have on-line catalogs.
>
> Questions to think about?
>
> - How often is movement required? If you can allow cool-down time,
> you can use a much smaller solenoid at a low duty cycle.
>
> - Does power consumption matter? If this thing has 120VAC available,
> power probably isn't going to be an issue. If it has to run on an
> AA battery, efficiency will have to be higher.
>
> - How precise does the stopping point have to be? 5mm? 1mm? 0.01mm?
> Is a mechanical stop with a rubber bumper good enough, or is more
> precise positioning required?
>
> - Is there a noise issue? If you slam a solenoid into a hard stop,
> there's going to be a click or a a bang.
>
> - What about size and cost? This is easier to do if you don't have
> to cram the actuator into a tight spot. And how many do you need?
>
> - What's the life cycle? 100 operations? 100,000,000 operations?
>
>A Festo SLTE actuator will probably do the job for you. They're not
>cheap, but they're a turn-key solution for linear motion.
>
>http://www.festo.com/INetDomino/us/en/cc7bba1d0b919dfbc125709200547d6a.htm
>
> John Nagle
Thanks for the link. Most all of the actuators I have run into have way too much
power for what we want. I am considerig a 300 rpm gear motor with a arm or
circular
drive feeding an arm. I can set direction and how long of a pulse I need to let
the
motor rest after its traveled.
The servo link was great. I might use a servo but its seems more complicated
using
pulses for control.
I am used to the old analog DC servos.
What I am doing is replacing a Nikon device doing the same thing, but much
faster.
greg
greg
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