Let's Make Robots!

PolyMorph Workshop 1 - How to make " Trivots © "

PolyMorph - how to make a pivot joint out of PolyMorph

PolyMorph Workshop 1

Here is the first in a series of PolyMorph workshops that will unfold when time permits.

The first one shows a number of techniques that can be used to form PolyMorph.

PolyMorph is a low melt plastic , it softens in boiling water.

When hot it can be formed to any shape your heart desires.

When it cools down again your shape is ....as hard as nails.

PolyMorph is like Nylon and has similar feel - its good as a sliding surface - which is why it works well for my application.

 The Video shows how i made these "Trivots ©" for my latest Robot Experiment "Moooooo"

The Hole in the washer is an interference fit and helps in assembling and holding the joint tight untill its welded.

Motheo_020.jpgMotheo_017.jpg

None Streaming Video Here PolyMorph Workshop 1 (circa 70Meg)

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is that the

SolderPro 50 Butane Soldering Iron Kit       (edit :- link removed)

I had the "Heat Shrink Thingy" from Maplins it is an Iroda SolderPro50 ..... which has way too much power (they even do a 70 and 120 version) .... the 50 is more than enough for light robotic work - it comes with a solder-tip/heat-knife/heat-gun/blow-torch attachments (maga useful).......and portable (ie cordless) and fast to heat up - ideal for quick solder job.

Thank you Gareth -- this workshop was a big help for me.  For the last year I have had a broken inline skate boot joint (image below), which is similar to the joints you are joining here with the Trivots (c).  I used some of the techniques taught here to attempt a Polymorph fix.  At left there is a metal joint/rivet to attach the ankle support to the rest of the skate boot.  At right there is a Polymorph joint. 

jcd_inline_skate_boot_joint.JPG

Since I made the repair there have been 4 days of heavy rain (causing flooding, evacuations and property damage in some parts of Los Angeles, USA), but as soon as there is some sunny weather I'll be testing the joint to see whether it holds (if it breaks every 20 miles, I'll drop it in a cup of tea and mold a new one.  If it breaks every mile I'll probably replace it with something else).  Thanks!  -John

Nice work there - looks like you put extra bulge in the middle to help with spreading the load.

I would love to hear how long they last - so far i have had no failures with mine (and they are pretty light weight)

Its very difficult to "sheer" polymorph (in a confined hole) ie the tighter the fit within the through hole the better...... 

 

The skate fix is still working with no maintenance required -- it lasted through the Spring 2010 semester at my university and are still holding.  Great stuff!  -John

 

I think you choose the right material for the job.....

...Thanks for the feedback.

The PolyMorph is quite a slippery material - simular to PTFE , maybe this property of sliding has helped with your set up.

Great work!!

Thank you for the inspiration!! I know I will try this one of these days  :-)

Can't wait to see more of your poly workshops :-)

Nice job on that design, but I though of something preventing you from having to make the rings. You take a rod longer than it needs to be. Place it in the holes. heat up the ends and sorta smush them creating a ring without having to create a separate ring

 

 

I think this would work - however i am not sure if the polymorph rod will buckle out inside the hole, which is not such a bad idea as it will give a tighter fit in the hole.

The reason i used the washer :- it holds everything together and makes it easier to handle and adjust.

....  i am game to try it out and i will post the results here.

Thanks for making your video China friendly :D

One suggestion I have for those who do not have a hole punch is to use a hot soldering iron to poke the hole in your washer. Like a hot knife through butter! This has the added advantage of melting the inner section without burning your fingers :P