Dreaming of a Static Motor Arrangement and Less Vitamins I have been rolling around tons of ideas in my head on how to make all the steppers static and get rid of linear rails. I am positive that there is a simple solution out there that can drastically reduce the vitamin count. [url=http://reprap.org/wiki/Rostock]Rostock[/url], [url=http://reprap.harleystudio.co.za/]RepRap Morgan[/url], and [url=http://www.kickstarter.com/projects/wjsteele/ultra-bot-3d-printer/posts/362119]Ultra-Bot[/url] are pretty inspiring. I love stuff about each of them but they are still using rails. I came up with a [url=http://www.youtube.com/watch?v=uODPAHK6MmQ]horrible variation of a delta robot[/url]. It has an American football shaped work envelope. :( It also would have very limited speed. :( My point is not to promote this idea. My point is that this robot uses no rails and could have all the steppers in a static configuration under the build platform. It also could be fully printed barring the steppers, build platform, and extruder. I was hoping you guys/gals could bounce some ideas (or point me to existing ones) around with me to come up with a workable alternative to linear rails that hopefully don't require moving steppers. (Requiring static mounted steppers is just a byproduct of wanting to minimize the weight of the dynamic parts.) Ideas: *Floating extruder supported by several wires. (I love this idea but it isn't as easy as having the wires fix a point in 3D. You have to account for all 6 DOF. There is also the additional problem that wires have to be in tension. I rate this as possible but put it on the back burner.) *Mechanical linkage that produces straight-line motion. Hoeken's linkage would be an example. (This seems too complex to me. The main problem I have with this is that we don't need to produce straight lines to be able to accurately position something in 3D. I rate this as too complex.) *Actuated flexible mount. Imagine a 3D McDonald's symbol with an arch every 120 degrees. You could then actuate the point where they all join by appling tension to the top or bottom of the different arches. (This one could be really neat but the response would change as the material fatigues and temp changes and ... and. You would have to have some way to measure the position of the effector at all times. I am actually okay with that. It is about time that we make a breakthrough in closed loop 3D printing. Closed loop print would also lead to cheaper electronics. Mics and DC motors could be cheaper than a stepper. Find the effector's location could be achieved with an ultra sonic emitter on the effector and a few mics scattered around on the bot to measure the phase differences. I rate this as super cool but super hard.) *SCARA robot with a new take on the z-axis. (Looking at the lovely Morgan brings so many questions to mind. Can you make it shorter? Can you drive the arms directly without the concentric shaft? etc. I think the answer is yes for all of those. One thing that could really help is to forget about preserving the x and y location as your raise and lower the platform or raise the arms. Firmware is really good at doing math. I rate this as very promising.) *Delta robots can already do this. (Delta robots are inherently complex. My example along with many other successful attempts have proven that this can be done. My main complaint is that the part count is high and accuracy is harder to achieve. I rate this a okay but there has to be something better.) *etc. There are many other ideas waiting to be uncovered. Let me know what crazy ideas you have. https://reprap.org/forum/read.php?2,202918,202918#msg-202918 Thu, 14 May 2026 06:04:48 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?2,202918,686482#msg-686482 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,686482#msg-686482 Milton Developers Wed, 13 Jul 2016 16:50:42 -0400 https://reprap.org/forum/read.php?2,202918,685385#msg-685385 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,685385#msg-685385
This suggestion will surely anger the 'I know how this works' crowd:

Bucket of water hanging on ropes with gravity powering a clockwork mechanism that prints objects from reclaimed plastics in impoverished communities. Plastic is melted and poured into a vat that feeds an extruder that moves in a set pattern producing a limited range of geometries, but allows the production of several cylindrical objects such as tool handles that vastly improve the quality of life and productivity of the community. Making a useless visual trinket for the desk of some person living in the first world and using up far more of the earth's resources is not even cool, not even clever.]]> Milton Developers Sat, 09 Jul 2016 12:42:19 -0400 https://reprap.org/forum/read.php?2,202918,662068#msg-662068 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,662068#msg-662068
Quote
DRobs86
..do you really think that you are going to design a relay driven 3d printer...

I don't know. Perhaps. It's an experiment.

Quote
DRobs86
...then send the 300 relays needed to drive it (or maybe just the nails and coils of wire for diy relays) with a bag of 3D printed parts to an uneducated impoverished man in the third world who will somehow know how to read your instructions (hey... No computers, better 3D print them too) and assemble and debug a huge series of logic gates?

No.

Quote
DRobs86
This obsession is more than anything, a waste of resources...

They are my resources to waste as I see fit! :) I find it an interesting problem, I think it's quite well formulated. The problem is about trying to make a constructing machine that can make useful objects, but which is as 'closed' as possible when it comes to the operations, information, material etc... needed to make itself. One of the difficulties is the control system: if it involves a microcontroller then the complexity and range of materials involved in making the control system is by far greater than that of any other part of the system. So it's interesting to see how much the complexity of the control system can be reduced.

Think of it as being like pure maths, but with physical stuff. In some areas of pure maths nobody worries about whether or not what they are doing is of practical importance or not. It's done just because it's interesting to do, and leads on to other interesting things. Sometimes some of these things end up having some practical, sometimes they don't (it's difficult to predict in advance).]]> WillStevens Developers Mon, 09 May 2016 18:41:14 -0400 https://reprap.org/forum/read.php?2,202918,662061#msg-662061 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,662061#msg-662061
Thanks for the links to the other escapement mechanisms. It uses a sliding escapement (not much point posting a diagram because I'm sure it could be improved). I haven't tried any other escapement mechanism yet.

Will]]> WillStevens Developers Mon, 09 May 2016 18:21:04 -0400 https://reprap.org/forum/read.php?2,202918,661379#msg-661379 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,661379#msg-661379
On the subject of retro sci-fi, I recent read Valis by Philip K Dick, and while previously I was an atheist, I am now becoming convinced by "Horselover Fat" that the Universe was indeed created by a deity, but an insane one. That actually explains the nature of the Universe much better. I also understand better the wisdom of Douglas Adams:

Quote
Douglas Adams

Slartibartfast: “Perhaps I'm old and tired, but I think that the chances of finding out what's actually going on are so absurdly remote that the only thing to do is to say, "Hang the sense of it," and keep yourself busy. I'd much rather be happy than right any day.”

Although the next lines are :
Quote

Arthur Dent: "And are you [happy]?
Slartibartfast:"Ah, no. Well, that's where it all falls down, of course.
]]> bobc Developers Sat, 07 May 2016 16:44:17 -0400 https://reprap.org/forum/read.php?2,202918,661340#msg-661340 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,661340#msg-661340
I honeslty commend you all on your genius and your effort, but do you really think that you are going to design a relay driven 3d printer, then send the 300 relays needed to drive it (or maybe just the nails and coils of wire for diy relays) with a bag of 3D printed parts to an uneducated impoverished man in the third world who will somehow know how to read your instructions (hey... No computers, better 3D print them too) and assemble and debug a huge series of logic gates?

This obsession is more than anything, a waste of resources. I want us to innovate, try new things, etc, but I dont want us to sit around having these sci fi... Or should i say retro sci fi fantasies that we are going to save the works or improve the lives of the destitute by some silly only plastic machine. Other materials exist for a reason.]]> DRobs86 Developers Sat, 07 May 2016 14:57:30 -0400 https://reprap.org/forum/read.php?2,202918,659882#msg-659882 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,659882#msg-659882
Quote
WillStevens
It needs more work to increase the available torque - the diameter of the toothed wheel could be increased.
I expect that the solenoid/electromagnet actuator can also be improved. It consumes about 7W when switched on.

I can't really see the details of the mechanism in the video, so it may already incorporate what I am about to suggest, but here goes anyway:

Would it help to use an escapement mechanism like that used in clocks? This might allow better amplification (i.e. a larger torque could be controlled with a smaller solenoid force).

There are several designs floating around:
Parametric Graham Escapement
Simple Graham Escapement

Alternate designs that might also work include the Verge Escapement, Single-pin Escapement, and Pin-wheel escapement.]]> MattMoses Developers Tue, 03 May 2016 15:58:30 -0400 https://reprap.org/forum/read.php?2,202918,659544#msg-659544 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,659544#msg-659544
The cardboard CNC is interesting - I like the hand-driven part of the video from about 4min 30s.

I got a gravity powered unidirectional stepper motor working this morning:

Gravity powered stepper motor

It needs more work to increase the available torque - the diameter of the toothed wheel could be increased.

I expect that the solenoid/electromagnet actuator can also be improved. It consumes about 7W when switched on.

I recently came across a mechanical Turing machine that uses gravity driven unidirectional motors (with a differential to get bidirectional motion).

Artificial muscle computer]]> WillStevens Developers Mon, 02 May 2016 18:06:59 -0400 https://reprap.org/forum/read.php?2,202918,659074#msg-659074 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,659074#msg-659074 Overall plan for a 2D plotter. I can't wait to see this in action! :)

In related news, there was a recent post on Hackaday that readers of this thread might be interested in:

Cardboard and paperclip CNC plotter destined for self-replication

The cardboard and paperclip CNC is driven by an arduino and RC servos, but it is not hard to imagine driving that machine with a relay-reprap controller.]]> MattMoses Developers Sun, 01 May 2016 12:44:58 -0400 https://reprap.org/forum/read.php?2,202918,639163#msg-639163 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,639163#msg-639163
I've started a blog about exploring the possibility of making a Reprappable control system for a Reprap:

RelayRepRap blog]]> WillStevens Developers Sun, 13 Mar 2016 15:04:44 -0400 https://reprap.org/forum/read.php?2,202918,637659#msg-637659 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,637659#msg-637659 Snappy RepRap printer has gotten rid of most of the standard vitamins, to the point that it snaps together without screws, and uses no pulleys, belts or metal rails, and the frame is completely printed.]]> RevarBat Developers Thu, 10 Mar 2016 01:34:01 -0500 https://reprap.org/forum/read.php?2,202918,626456#msg-626456 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,626456#msg-626456
http://www.srm.org.uk/transfer/stepper_speed_control2.jpg

The other parts of the circuit are the clock and the stepper driver from previous posts (Clock, Stepper Driver).

The simplification that I had hoped to make (mentioned in my last post) did not work - not yet at least.

I've also been working on a punched card reader and 3D printed relay:

Punched card reader

Relay]]> WillStevens Developers Sun, 14 Feb 2016 18:38:58 -0500 https://reprap.org/forum/read.php?2,202918,624104#msg-624104 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,624104#msg-624104
http://www.srm.org.uk/transfer/relay_clock.jpg

It doesn't produce an entirely clean output - there is bouncing for a few milliseconds on the transitions, more so on the closed-to-open transition than on the open-to-closed transition. That doesn't seem to matter. However, if I take the clock signal from the normally open contact of the relay on the right (rather than from the NC contact of the relay on the left as in the diagram) the bouncing does seem to matter and the clock is not able to properly drive the rest of the circuit - I'd like to understand why.

If the capacitors are removed the clock oscillates very irregularly with a frequency of about 300Hz, so the capacitors are necessary.

The sodium-bicarbonate "capacitors" give the same clock frequency (about 15 Hz) as 40 microfarad capacitors. I briefly tried to characterize them this evening, but without success - I thought perhaps they might behave like a resistor and capacitor in parallel, with another resistor in series, but it seems to be more complex than that.

The circuit seems to run okay without missing steps at 26Hz, but at 30Hz it begins to miss steps every so often - the part of the circuit that seems to fail is the divide-by-N stage. It's possible that a cleaner clock signal would give a higher maximum operating frequency.

I'll draw a diagram for the rest of the circuit at the weekend - since making it I've thought of some improvements that might reduce the relay count and increase the maximum operating frequency, but I haven't tried them out yet.]]> WillStevens Developers Tue, 09 Feb 2016 18:37:01 -0500 https://reprap.org/forum/read.php?2,202918,623478#msg-623478 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,623478#msg-623478
Quote
WillStevens
It uses 14 relays for the stepper motor driver, 15 for the 2-bit divider stage and 2 for the clock. The clock timing is determined by two capacitors made from sodium-bicarbonate solution and aluminium foil (in the glass beakers).

I like the capacitors. :)

Do you have an estimate for what value they are? What is the maximum clock speed? Are the capacitors necessary or does it just run at full speed when they are removed? Can you share a circuit diagram for this version too?]]> MattMoses Developers Mon, 08 Feb 2016 14:36:02 -0500 https://reprap.org/forum/read.php?2,202918,623066#msg-623066 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,623066#msg-623066 Yamaha Scara Robot]]> simspeed Developers Mon, 08 Feb 2016 02:26:24 -0500 https://reprap.org/forum/read.php?2,202918,623059#msg-623059 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,623059#msg-623059
[attachment 72089 ScaraHex1.JPG][attachment 72088 ScaraHex2.JPG][attachment 72087 ScaraHex3.JPG][attachment 72086 ScaraHex7.JPG][attachment 72085 ScaraHex11.JPG][attachment 72084 ScaraHex12.JPG][attachment 72083 ScaraHex13.JPG][attachment 72082 ScaraHex16.JPG][attachment 72081 ScaraHex17.JPG][attachment 72080 ScaraHexXYAssemblyCrossSection.JPG]]]> simspeed Developers Mon, 08 Feb 2016 02:01:38 -0500 https://reprap.org/forum/read.php?2,202918,622435#msg-622435 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,622435#msg-622435
https://www.youtube.com/watch?v=Vq8iM2-N2kw

It uses 14 relays for the stepper motor driver, 15 for the 2-bit divider stage and 2 for the clock. The clock timing is determined by two capacitors made from sodium-bicarbonate solution and aluminium foil (in the glass beakers).]]> WillStevens Developers Sat, 06 Feb 2016 13:56:47 -0500 https://reprap.org/forum/read.php?2,202918,618345#msg-618345 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,618345#msg-618345
https://www.youtube.com/watch?v=ebBBnpma_iQ

This is the circuit diagram for the improved version:

http://www.srm.org.uk/transfer/stepper_driver_circuit.jpg

And here is an idea about how to make a 3D printed relay from nails and copper wire (at the time of writing it is only SPST, I hope to make it SPDT soon):

https://www.youtube.com/watch?v=kyCSweoaub4

I'd be interested to know whether anybody else has come across other 3D printed relays.]]> WillStevens Developers Sat, 30 Jan 2016 16:45:10 -0500 https://reprap.org/forum/read.php?2,202918,618326#msg-618326 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,618326#msg-618326
Quote
the_digital_dentist
in what sense is using a handful of $5 relays ... any improvement over using a $5 single-chip?

Will said it best earlier in this same thread:

Quote
WillStevens
There is the practical goal of making a cheap, autonomous, and versatile personal manufacturing system. If that is the objective then the number of vitamin parts and the complexity of the machine and its control system are irrelevant unless they affect the price and performance of the machine, and the range of people who have access to it.

The self-replicating or closed-cycle manufacturing system goal is a separate one (but with some overlaps in the realisation), which may or may not turn out to be feasible or useful, but I find it interesting from a pure science perspective regardless of whether it is useful or not. For this goal, the number of vitamin parts, and the complexity of construction of both the mechanical part of the machine and the control system are fundamental considerations. There are reprappers who are interested in one or the other or both of these goals (I'm interested in both).
]]> MattMoses Developers Sat, 30 Jan 2016 16:11:34 -0500 https://reprap.org/forum/read.php?2,202918,618257#msg-618257 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,618257#msg-618257 the_digital_dentist Developers Sat, 30 Jan 2016 14:08:15 -0500 https://reprap.org/forum/read.php?2,202918,618206#msg-618206 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,618206#msg-618206
Quote
WillStevens
Here's a video of a stepper motor controller made from relays:

[www.youtube.com]

I'll post the circuit diagram later.
]]> MattMoses Developers Sat, 30 Jan 2016 12:55:42 -0500 https://reprap.org/forum/read.php?2,202918,617875#msg-617875 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,617875#msg-617875
https://www.youtube.com/watch?v=1C2gLwbhtlY

I'll post the circuit diagram later.]]> WillStevens Developers Fri, 29 Jan 2016 19:30:43 -0500 https://reprap.org/forum/read.php?2,202918,231787#msg-231787 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,231787#msg-231787
http://reprap.org/wiki/Uconduit
http://www.thingiverse.com/thing:102972

The vitamin count is still similar to most repraps though.]]> iquizzle Developers Thu, 01 Aug 2013 11:43:14 -0400 https://reprap.org/forum/read.php?2,202918,230110#msg-230110 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,230110#msg-230110 woo Developers Fri, 26 Jul 2013 09:42:54 -0400 https://reprap.org/forum/read.php?2,202918,224789#msg-224789 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,224789#msg-224789
RepRap Morgan
This one is very refined and won the Gada Prize. It uses only two rails.

RepRap Simpson
The one uses more parts than the Morgan but has no rails. It will be the future of large format printing but not desktop printing.

RepRap Wally
This one is not done yet but it has no rails and leads itself to having an ATC (Automatic Tool Changer). We are planning on using strong magnets for the ATC. There will be no need for and locking mechanism.]]> nicholas.seward Developers Sun, 07 Jul 2013 10:37:34 -0400 https://reprap.org/forum/read.php?2,202918,224778#msg-224778 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,224778#msg-224778 david depuy Developers Sun, 07 Jul 2013 09:23:38 -0400 https://reprap.org/forum/read.php?2,202918,222032#msg-222032 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,222032#msg-222032 RepRap Simpson. I made it after I started this post.

Note: the setup I use isn't trickier than a rostock.]]> nicholas.seward Developers Thu, 27 Jun 2013 10:10:07 -0400 https://reprap.org/forum/read.php?2,202918,221891#msg-221891 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,221891#msg-221891 pick and place

I was think that you could build it up the other way so that there was no need to build a support frame.
Getting the controller right to convert the G-code might be a little trickier than the Rostock style.

[www.enemygadgets.com]]]> MikeWazowski Developers Wed, 26 Jun 2013 22:41:50 -0400 https://reprap.org/forum/read.php?2,202918,219094#msg-219094 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,219094#msg-219094
That's going to be quite a bit of contacts to replace though. Changing step rate is not going to change the number of steps it takes until failure. We might be able to do something like the soundcard and use the relays to control oscillators and use some feedback to figure out where we are roughly. This way we can cycle relays less.

Perhaps we could even use even more exotic non-linear circuit elements, after all it only takes a point contact to make a memristor. And it seems someone has devised a means of making logic gates from memristors alone.

How easy is it to make a memristor? Here's a memristor made from garbage.]]> Gene Hacker Developers Mon, 17 Jun 2013 13:24:11 -0400 https://reprap.org/forum/read.php?2,202918,217545#msg-217545 Re: Dreaming of a Static Motor Arrangement and Less Vitamins https://reprap.org/forum/read.php?2,202918,217545#msg-217545
On the relays:

A typical low power signal relay (like the TE Connectivity IM03GR) is rated for 100,000,000 mechanical operations. The maximum electrical operations depend on the load, but they range from 100,000 to 2,500,000 operations (for this relay). Just a rough calculation - if the stepper motors are running on average 100 steps per second, then a relay driver would last at most 25,000 seconds (about 7 hours).

But you may not need 100 steps per second. You could probably get by with much less.

If you're printing your own relays, you might come up with an easy way to clean the contacts off after every print. With regular service they could perhaps last longer than 2.5 million operations.

If one didn't mind replacing or servicing the core of the "relay stepper driver" every few prints, then the lifetime issue might not be a problem.

This is vaguely related, but if anyone hasn't seen it yet, you guys will probably like the Turbo Entabulator, a 3D printed mechanical computer.

This quote from the designer's page is particularly interesting:

Quote
Chris Fenton
It (the 1895 book "The Mechanism of Weaving") also made me think Charles Babbage must have been a huge jerk to not be able to get his machine working, since power-loom engineers were definitely building things nearly as complicated just for making rugs quickly...
]]> MattMoses Developers Tue, 11 Jun 2013 18:31:20 -0400