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Recommendations needed for inexpensive linear motion

Recommendations needed for inexpensive linear motion

(OP)


Hi Folks,

I'm pretty rusty when it comes to engineering and design having not worked directly in the area for awhile. I'm hoping someone may have some good suggestions for me. I'm trying to design a 20 x 20 matrix of columns which can be individually raised and lowered (only about 5" max) in any pattern desired. I'm at a loss to come up with an economical way to build something that allows individual movements of 400 columns. I've certainly considered linear actuators, but they are very expensive (especially x400). Would anyone have any suggestions? Thanks so much!

Scott

RE: Recommendations needed for inexpensive linear motion

You haven't stated if they're UP or DOWN or some intermediate. And how much force they have on them or what they weigh.

Pneumatic is pretty cheap.

I could see turning the blocks into the pistons in square bores too, depending on the forces/time etc.

Need a lot more details as they will/will-not allow various techniques.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Recommendations needed for inexpensive linear motion

This looks to be the cheapest possible solution:
http://www.ebay.com/itm/5PCS-DC-3-5V-2-Phase-4-Wir...

that's ~$0.70 each for the actuator, and probably roughly the same for a 2-phase driver circuit

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Recommendations needed for inexpensive linear motion

Nice IR that would probably work pretty well. Be a fun one to control. :)

Keith Cress
kcress - http://www.flaminsystems.com

RE: Recommendations needed for inexpensive linear motion

(OP)
Thank you IRSTUFF! I have not seen these before but they look very promising.....I'm going to check them out

RE: Recommendations needed for inexpensive linear motion

(OP)
Itssmoked - Sorry there wasn't enough details. In regards to up and down, I would actually need it to be be able to stop at different intervals, maybe every half inch or every inch from 0" to 5" max. I'm not sure if pneumatic could do that or if it could only do "up or down?" If it could allow incremental positions, it might be a great way to go. In regards to weight, I haven't determined that as these might be made of wood or plastic. Either way they should be very light. I'd certainly appreciate any other thoughts you may have or examples on how pneumatics may work. Thank you! Scott

RE: Recommendations needed for inexpensive linear motion

You haven't mentioned how you intend to control these 400 actuators. Do you intend to control them from a single common point? If not, you could buy 400 hand crank trailer jacks and manually adjust each one. How will you know where each one is? Do you intend to have individual position feedback on each one, or are you just going to adjust each one visually? Or is it your intent to feed in some XYZ data defining a 3D surface to the control system and have them move to that theoretical surface? I designed a similar system once as a machining fixture to hold the composite wing skin of a large airliner in place (and in the correct three dimensional shape) for a waterjet trimming operation. Each of the 400 actuators actuator probably cost $1500.

RE: Recommendations needed for inexpensive linear motion

I recently was chasing an idea and surfed through eBay for some inexpensive CNC router spindles from China. I stumbled on stuff from "RATTM Motor" if I recall correctly (and certainly there are other sellers). They had an inexpensive kit with all the bits needed for a simple 3-axis positioner, presumably for a home-made 3D printer.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering
www.bluetechnik.com

RE: Recommendations needed for inexpensive linear motion

What is the target price point you're shooting for? Kinda looks like some type of nifty toy. Based on your statement of 5" extension, and assuming that the tallest blocks in your picture are at 5", it looks like your blocks are about 2" square. If you manage to get IRstuff's suggested product at half the price he mentioned, that's $280 just for your actuators. If you could get all the rest of the stuff for $20 (drastically low estimate) that puts retail at $599.95.

-handleman, CSWP (The new, easy test)

RE: Recommendations needed for inexpensive linear motion

How fast does it need to work? Set up some sort of threaded/drive screw arrangement to raise/lower each block, then have a single motor run around and turn each screw one at a time.

RE: Recommendations needed for inexpensive linear motion

(OP)
Handleman - That's pretty close on the rough dimensions - if I could build it for $500 I'd actually be pretty happy but there will be a lot beyond the actuators to add to the cost. On the one hand it feels like it should be very straightforward, but when you try to fit 400 in such a small space and keep the costs reasonable, it suddenly seems like quite a challenge.

RE: Recommendations needed for inexpensive linear motion

(OP)
hi 1Gibson and Tyger - Ideally the blocks would all move at once instead of having say a CNC type system move under each one at a time and position them.

RE: Recommendations needed for inexpensive linear motion

400 linear actuators with 5" stroke and internal guidance each of which will fit inside a 2" square and be end-mounted for around $500 total? Not asking for much are you?

RE: Recommendations needed for inexpensive linear motion

(OP)
Jboggs - well, that's why I was originally asking about other ideas (like pneumatics). If the solution was easy I might have figured it out by now...

RE: Recommendations needed for inexpensive linear motion

How often will it change? Position a grid of set screws below the surface, then raise the grid to contact the blocks. Fit the blocks tight enough that they hold position, pull a vacuum to lower/reset them all before raising the screw grid to set new configuration.

RE: Recommendations needed for inexpensive linear motion

Do you require position feedback, or are you going to adjust each one visually?

RE: Recommendations needed for inexpensive linear motion

A two-axis XY stage with a single lead screw motor and clutch could potentially drive an array of lead screws, one at a time. Getting rid of 399 motors and drivers might be a good compromise.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Recommendations needed for inexpensive linear motion

I like where MintJulep's head is at, and it falls right in line with my initial thought: Arduino.

RE: Recommendations needed for inexpensive linear motion

And, if we're going to play that game, winky smile the same motors appear to be available directly from China for $0.12 each:
https://www.aliexpress.com/item/50pcs-2-phase-4-wi...

That means the entire 400 motors could be had for $47.60! But, the drivers aren't going to be in the same boat, although you could use switching matrix to multiplex a single driver across the array.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Recommendations needed for inexpensive linear motion

(OP)
damn - you guys are great - every time I get a chance to come back here and check you've provided more options and good ideas - thank you!

RE: Recommendations needed for inexpensive linear motion

Hi NDVermin.
Pneumatics is not the solution for you. That's why I asked just UP? DOWN? or in between? You can, of course use pneumatics for in-between but it more than triples the cost since you need special valves and scales and etc., etc.

The Bag-O-Steppers Mint showed you is probably the best type solution. Yes, the controls are a bit involved and will cost considerably more than those cheap steppers. Your wish for them all to move at once considerably increases the cost of the electronics, I'd say by about a factor of... a hundred (100).

The height resolution desired will also greatly affect the cost of the solution.

Can you describe what this will be used for? It would help us, help you, determine the best solution.

We still have no idea what:
1) Forces will be involved.
2) What environment this will be in. Under water? Outdoors? Clean room?
3) What speed the blocks need to move at.
4) What ambient temperature.
5) Speed of motion.
6) Desired control input. List? Dynamic? Surface profile?
7) What power is available.
8) Position resolution
9) Actual block dimensions.
10) Block material
11)
12)
13)


20) Special considerations; sterilizable?, hazardous atmosphere? Portability?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Recommendations needed for inexpensive linear motion

Sheesh, 12 cents a piece... wish I had access to places like AliExpress/AliBaba back in the day.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Recommendations needed for inexpensive linear motion

Those motors have about 4mm travel. If the lead nut is cut out there's still only about 7mm of thread to work with. There are others that have longer reaches. I wonder what the original use is.

Thankfully the credit card is out of easy reach or I would be tempted to order up a ton of junk that is such a good deal for which I have no use.

RE: Recommendations needed for inexpensive linear motion

Quote:

I would be tempted to order up a ton of junk that is such a good deal for which I have no use
I was thinking the same thing Dave!

Keith Cress
kcress - http://www.flaminsystems.com

RE: Recommendations needed for inexpensive linear motion

IR; we're going to need to hold your credit card now..

Keith Cress
kcress - http://www.flaminsystems.com

RE: Recommendations needed for inexpensive linear motion

Even worse, I bought the ones from Amazon at $0.16/ea, since they should get here faster than the usual slow boat method.

Nevertheless, the sheer audacity of a motor + lead screw + assembly + handling + postage at $0.16/ea is mind boggling. Even assuming that everything is automated, that implies massive manufacturing. Makes you wonder what the actual intended use is.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Recommendations needed for inexpensive linear motion

Oh, wow, those things are TEEEENY, which I knew, intellectually...

They look like they might be used as an actuator in a microUAV. The mounting holes look too big for 2/56 screws, which are the smallest that I know the nomenclature for. Coincidently, one of my hardcopy-only journals was lying around. winky smile

However, if the OP can get them to work, they'd look ideal for a reasonable size for his project.



TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Recommendations needed for inexpensive linear motion

Wow. How do you make something that small, much less for pennies! That is SO tiny! OP did mention 5" stroke, although no mention of why. Looks like these would work for a 1/25 scale model... About 5mm stroke, right?

-handleman, CSWP (The new, easy test)

RE: Recommendations needed for inexpensive linear motion

Let's make a cyborg sea cucumber!! They motivate via hundreds of little 5mm tentacles.


Keith Cress
kcress - http://www.flaminsystems.com

RE: Recommendations needed for inexpensive linear motion

IRstuff - you need to hang around the model train section of the hobby shop. 2-56 is giant compared to what's common there.

RE: Recommendations needed for inexpensive linear motion

Think 0000.

RE: Recommendations needed for inexpensive linear motion

I skipped right to the bottom, so please excuse me if this has been suggested. Can you use inductance coils and magnets to electronically actuate each block? I'm thinking to pound a nail in each one, wrap it inside a coil of wire and then use a kwyboard to actuate each. A fine 7th grade science project!

RE: Recommendations needed for inexpensive linear motion

Just some thoughts.

An X-Y array of "Solinoid Coils. All Rows connected to a"Sinking" transistor and all Columns connected to "Sourcing Transistors." One column and one row "On" addresses one coil. The rows and columns can be "Raster Scanned."

RE: Recommendations needed for inexpensive linear motion

Solenoid guys.. He needs intermediate positions! Solenoids are OUT!

Keith Cress
kcress - http://www.flaminsystems.com

RE: Recommendations needed for inexpensive linear motion

Meh... I could see a spring-loaded linear actuator working with a solenoid-like mechanism. PWM control of the solenoid pulls against the spring to set the position. No idea what level of positioning control one could get out of such a setup, at least on the cheap... but if no feedback is used (i.e., you get whatever position you get), I bet it could be pretty cheap. You could also use some form of locking mechanism to keep each plunger in the same position when not being actively driven.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Recommendations needed for inexpensive linear motion

I wonder would it would sound like?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Recommendations needed for inexpensive linear motion

I would love to see what this contraption looks like with moving "images" playing on it.

je suis charlie

RE: Recommendations needed for inexpensive linear motion

I was being very general when I said "Solenoid." Assume the solenoid core was on a spring. and that its speed of motion depended on air leakage around the core. And you controlled the drive voltage with a duty cycle.

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