Sorry for the wait on updates, I've been quite busy lately with school starting up again and working full time while going to school. I haven't had a whole lot of time to work on the pads.
First off, I've given up on circular designs. they are just too hard to cut out of the contact paper with a clean edge. From my research online, circular designs are found to have a stronger normal force while ladder designs have a stronger shear force, but the difference in normal force isn't huge.
Now I got Tired of it taking a week of drying time to make a single pad, so I went exploring for ways to accelerate the drying process. So I found Oogoo. Silicone I caulk, cures by absorbing the moisture in the air, Oogoo accelerates the drying process by mixing Corn Starch into the silicone. the corn starch releases moisture into the silicone and dries the silicone from the inside out. This looked like a promising solution, so I tried it.
I made many pads with different ratios of silicone to Corn Starch, with little success and much frustration. It did greatly decrease drying time to only a couple hours But the pads kept failing. The problem was that when I mixed the silicone with corn starch, I introduced air into the silicone. This caused tiny little air bubbles (and sometimes large ones) to remain when the pad was formed. These air bubbles made a week spot in the silicone where sparks would eventually break through. The pad might work for a hundred cycles or so, but would eventually start to intermittently spark and soon after, completely short and burn through the silicone. So this solution obviously will not be ideal unless I had some way to mix the corn starch in a vacuum.
This led me to believe that my previous problems with electrode gap size may not be because the silicone caulk can not withstand it, (In fact I have proven that it can withstand at least 12kv per 600um as that is the thickness of the adhesive layer.) but that I may have had a tiny air bubble stuck in there which caused it to spark. My current test pads are using a 4mm electrode width and gap.
So I decided to go back to pure silicone caulk. I modified my process so that I could remove the shelf liner off the top of the silicone before it was completely dry. This increases the contact with the air so that the silicone is able to dry faster.
It may be possible to accelerate the drying process by using a humidifier, but I have not tried this.
I also found that the silicone sometimes has trouble pealing off the contact paper without ripping a hole in the silicone pad. So I am just making the pad on shelf liner which the silicone peals off with no trouble at all once dry. I have updated the instructions to reflect these changes.
I am also working on a control box for the electroadhesives. It will be using a flyback transformer, supplied with a 12v power supply to generate up to about 15kv. It will have a switch to turn it on and off. It will use high voltage resistors in parallel with the electroadhesive to provide automatic release (normally I need to short the ends to remove stored charge in the pad for release). I also hope to make it flexible for use with any electroadhesive pad.
I hope to post a demonstration video soon of the pad lifting different materials, I just need to find the time to do so.
In January I figured that, since I would be working with these products which produce fumes, I should make an exhaust chamber for my work space. So I built an exhaust chamber out of my closet with two sheets of Plexiglass which is held on with sticky velcro. It has some ducting for exhaust through a window fan. The bottom plexiglass sheet can be swung open to allow me to work inside the chamber. It works pretty well, I can hardly smell anything when it is closed and running.
Even though it's winter, it doesn't cool off the room too much as the window is below the ducting to the chamber, this keeps hot air in the top part of the ducting to restrict cold air from leaking into the room....
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