Hi,
I need some form of mechanism that will provide 20mm of linear motion. The force required will be minimal, 10g, slightly more. Ideally it must be waterproof and about 30mm square size wise. I was thinking a small solenoid but wanted to consider other options first.
I have a cnc and metal working lathe and a milling machine available to me.
And, it can be operated either from:
22psi water, 100psi air or 12vdc.Let me know if you think of anything,
Thanks
Michael
motion. The
Medical syringe off either the water or the air
AWEM
Not with normal syringe seals, you will have too much trouble with friction. How about a balloon / bellows operated with water e.g. from a U tube arrangement. London Rubber Company products might be possible
With 22psi water or 100psi air he has No problem !
AWEM
But that does need bidirectional control of the motor (and perhaps on/off control as well, if it's not acceptable to leave the motor running). Can the control system provide that ?
Similarly, air or water actuators may need an electric control valve to enable them - this device will have a similar mechanism to a solenoid or motor actuator, so you need two actuators instead of one. That's if the original control system is electrical - if it can be arranged to use a mechanical valve to switch the air/water supply then those are good possiblities.
So what's the source of the control signal, and can you choose it ?
-adrian
Small 12 V motor driving a short length of studding with a nut to get the linear movement. Motion can be limited by turning off the thread past the limit of travel and lightly springing the nut back towards the centre of the threaded section.
I will be using a microcontroller to control it.
I've bought a pack of 2ml syringes, should come wednesday, and will let you know how it comes along.
Thanks
Michael
There are two basic designs of syringe plunger: the rubber bung and the thin plastic (polypropylene?) disc. Given good lubrication, the rubber piston type is easier to move smoothly than the plastic disc. I've used the rubber type to provide motion in a vacuum chamber. One difficulty is finding an effective lubricant that neither rots the rubber nor dries out quickly.
The Screwfix FloPlast silicone spray (for plumbing fittings) is pretty good. Or plumbers silicone oil / grease. But I still think you will have trouble getting a controllable 10 g force. If it doesn't matter that you get 1000 g, OK. I'd assumed from the original posting that you wanted 10 g but not a great deal more
Castor oil?
Jim
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.