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1
3D Printing / removable magnetic print surface
« Last post by jinx on October 12, 2018, 03:13:37 AM »
 
                      
           
                           Description on ali as Magnetic Print Bed Tape square Print Sticker Flex Plate, in short its a removable magnetic print surface,and perhaps the best development in build plates since the introduction of thermal polymer sheets for a print surface, PLA sticks so well to this material its possible to ruin a Z axis of a hypercube  removing a print. from what I can find its seems to be an unbranded copy of easy-peelzy. 

               
      arrives 2 weeks after ordering sandwiched between a makeshift cardboard envelope and a plastic bag.
     

               

          Installation is really easy you be done in 5 minutes, I ordered the 214*214 which completely covers the heat bed so with scissor cut of the corners for the spring/bolt head,I use M3 dome heads which never extrude above the new print surface. (no risk of catching a bolt with the nozzle!)  Next pull off the 3M backing tape of part B and gently roll the magnetic tape across the HB. (it take some effort to put a kink in it!) Then trim of the excess and you done, I used a scalpel for a clean cut. Now take the top print surface place that on the bed  "line it up with the rear and trim the sides the front should have a small overlap leave this as is, it helps removing prints later on.

             

overall: Price wise just can't grumble little over £13 including postage, its about the best thermal sheet option out there (you can spend that on a static build surface and fight with the little shit getting the print off!).
       Its great so far after four months of testing, never had a print fail with lifting or curling..  printing with PLA with a bed temperature of 50C been as low 40C with short prints (under an hour). you get the bed level you can achieve a near smooth metallic finish look for the first layer, and once the print finish just lift the plate off and slowly bend the surface the print just rolls of. 
 
           

          Though the surface want stay a matt black for long each print leaves it's ghostly impression on the surface.

something to keep in mind though they are producing higher temp surfaces for ABS theses days.
        Warning: Do not expose Easy-Peelzy to heat over 80 °C or 176 °F, or your Easy-Peelzy risk demagnetizing! Due to the magnetic nature of Easy-Peelzy, magnetic printer bed leveling sensors might not work with it.

links:
https://www.3d-easy.xyz/

buy one!: where I got one from
https://www.aliexpress.com/item/2018-New-Magnetic-Print-Bed-Tape-square-150-200-214-220-250mm-Print-Sticker-Build-Plate/32871643572.html?spm=a2g0s.9042311.0.0.48e54c4dyNmL2z
2
@MEgg, your last link was helpful as it confirmed that silicone rubber was the polymer used in the original discovery of QTC.

David Lussey's composite, loaded above the percolation threshold with Ni powder, should have been conductive but was insulating until deformed. It became conductive when not only when compressed but also when stretched or bent. Our studies revealed that the silicone elastomer matrix intimately coated the Ni particles, which retained sharp surface features with nanometre dimensions1.
3
G'day MEgg,

Thanks for the links, I'll check them out. As far as hurdles go I can see a few.

1. The mixture will need to be very consistent otherwise I will get patches that short out or remain insulating.
2. The ratio of polymer to metal powder probably needs to be very precise.
3. The size of the metal particles will need to be very uniform.

4
General Discussion / Re: QTC - quantum tunneling composite. Can we make our own sensors?
« Last post by MEgg on October 08, 2018, 03:53:25 PM »
Interesting stuff.
Do I see that correct, that the layers have to be very thin?

Also read this one:
https://www.electronicdesign.com/embedded-revolution/11-myths-about-qtc-touch-sensors
and this:
https://www.peratech.com/qtc-single-point-sensors/
https://www.peratech.com/touch-development-kit.html

I am trying to get their development kit (hopefully for free).
:-)

You probably already found these:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5621037/
https://www.dur.ac.uk/cmp/themes/opto-semi/psm/research/
5
Yes it is hard to get consistent results with pressure sensors although I read that NASA used QTC for their robonaught.
https://news.thomasnet.com/companystory/peratech-presented-with-award-by-nasa-for-its-qtc-touch-technology-623451

I believe QTC gives more consistent results than something like conductive foam or thin film pressure sensors. I had some once but never got around to testing it for repeatable results.
6
General Discussion / Re: QTC - quantum tunneling composite. Can we make our own sensors?
« Last post by Bajdi on October 07, 2018, 04:10:20 AM »
Interesting stuff. Some time ago I fitted a gripper (on the service droid) with a pressure sensor. Was difficult to get good consistent results.
7
General Discussion / QTC - quantum tunneling composite. Can we make our own sensors?
« Last post by OddBot on October 07, 2018, 12:53:49 AM »
If you are unfamiliar with QTC then read this first: https://en.wikipedia.org/wiki/Quantum_tunnelling_composite

I am working on a robot hand and want to add force sensors to measure how tight the hand is gripping an object. Originally I bought some strain gauges and HX711 breakout boards. The HX711 chip is a 24 bit ADC with additional circuitry designed specifically for measuring strain gauges.

Unfortunately it is all too big to fit in a robot hand. Especially when you want at least 1 sensor for each finger and at least 2 for the thumb.
QTC pills were the obvious solution however they are expensive and very hard to find these days. Also their shape was not what I wanted.
I want to make a washer that will fit on a thrust bearing to measure the force on the bearing.



I did try to contact the company that makes them (Peratech) but I got no reply.

While trying to find the QTC pills I came across this article: http://practicalphysics.org/qtc-%e2%80%93-discovery-novel-material.html

"QTC was discovered by David Lussey, working in Darlington (UK). At the time, he was trying to make a conductive adhesive for use in a security system. Computers would be attached by a wire to an alarm; the glue joining the wire to the computer would be conducting, so that if the wire was detached, the alarm would sound.
 
David Lussey describes himself and what he was trying to achieve:
 
I’m not a scientist but I am a practical person with a technical background from the military. When I needed a conductive adhesive and found there wasn’t one available, I decided to make one.
 
To make a conducting adhesive, David mixed metal powders with adhesives in different combinations. One turned out to be very special. When two metal plates were glued together, they did not conduct – the glue between them acted as an insulator. However, when he tried to pull the plates apart, they started to conduct.
 
This was very strange and not what I was looking for. So I put that on one side (in fact I threw it on one side!) and it wasn’t until some little while later that I thought, ‘Well, that was a strange reaction.’ I went back and measured it with a meter and found I got something very unusual.
 
It was not obvious at this stage that the material had commercial possibilities; nor did David understand how the material worked to produce this strange behaviour."


After reading this I decided it might be worth trying to make my own QTC sensors. The article states that:

"QTC is a material made from particles of a metal (nickel) embedded in a polymer. Its resistance changes dramatically when it is compressed. Uncompressed, it is an almost perfect electrical insulator. When a force is applied, it conducts as well as a metal."

I have bought 3 different types of nickel powder - pulverized, ultra fine and electrolytic.
For the polymer I bought some silicone gasket sealant. From what I have read I don't think it matters too much what you use as the "polymer" too much. It is simply an insulator that separates the nickel particles.



I chose silicone gasket sealant because it is rubbery and compresses easily. I suspect that David Lussey may have also uses a silicone rubber glue because it sticks to glass as well as most other materials and does not crack with age. Remember he was trying to make a conductive glue for security systems.

I will need to experiment with different percentages of nickel powder and silicone so I bought some small electronic scales with a resolution of 0.01g to measure the amounts I use. I am just waiting for some small disposable plastic cups to arrive which I will use to mix different batches in.



I will update this post once my first test results are it.









8
Firmware / Re: [ Firmware ] Klipper - the cool firmware for 3d Printers
« Last post by tinhead on October 03, 2018, 12:29:14 PM »
In the meantime it works pretty well it has a lot of features.
Enjoy  :)
9
Firmware / Re: [ Firmware ] Klipper - the cool firmware for 3d Printers
« Last post by Elloel on October 03, 2018, 12:15:36 PM »
Just found this site while looking for some information on the mksbase gen l v1 board. while i do like Marlin for 3d printers, I feel it can sometimes be a little confusing when configuring a new printer. I think i'll give klipper a try. thank you!
10
Links / Re: Raspberry Pi / Python eBook - free for the next 11 hours!
« Last post by jinx on September 27, 2018, 03:18:15 AM »
damn Megg you becoming our registered librarian, keep up the good work bud , sure i be requesting a  copy or two in the winter season and those coming dark hours .
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* Recent Posts

removable magnetic print surface by jinx
[October 12, 2018, 03:13:37 AM]


Re: QTC - quantum tunneling composite. Can we make our own sensors? by OddBot
[October 10, 2018, 12:47:01 PM]


Re: QTC - quantum tunneling composite. Can we make our own sensors? by OddBot
[October 10, 2018, 12:32:20 PM]


Re: QTC - quantum tunneling composite. Can we make our own sensors? by MEgg
[October 08, 2018, 03:53:25 PM]


Re: QTC - quantum tunneling composite. Can we make our own sensors? by OddBot
[October 07, 2018, 04:28:33 AM]


Re: QTC - quantum tunneling composite. Can we make our own sensors? by Bajdi
[October 07, 2018, 04:10:20 AM]


QTC - quantum tunneling composite. Can we make our own sensors? by OddBot
[October 07, 2018, 12:53:49 AM]


Re: [ Firmware ] Klipper - the cool firmware for 3d Printers by tinhead
[October 03, 2018, 12:29:14 PM]


Re: [ Firmware ] Klipper - the cool firmware for 3d Printers by Elloel
[October 03, 2018, 12:15:36 PM]


Re: Raspberry Pi / Python eBook - free for the next 11 hours! by jinx
[September 27, 2018, 03:18:15 AM]


Re: Raspberry Pi / Python eBook - free for the next 11 hours! by MEgg
[September 26, 2018, 04:00:49 PM]


Re: Gordon McComb Passes by jinx
[September 18, 2018, 02:12:53 AM]


Gordon McComb Passes by erco
[September 17, 2018, 10:00:37 PM]


Re: sdsds by jinx
[September 16, 2018, 04:11:16 AM]


sdsds by sdsds
[September 15, 2018, 03:55:20 PM]