-- SamsonPhan - 15 Apr 2008 I successfully filled and planed the conductive epoxy filled groove. After pulling the part out of the mold, I manipulated the flexible urethane, which resulted int eh cracking of the conductive epoxy. The bond between the two materials was rather weak. as well.

-- SamsonPhan - 02 Apr 2008 I got interested in etching conductive paths on the soft urethane. If possible, we would be able forego the joints and replace them with flexures with conductive paths. The flexures would ease the difficulties involving passing electrical conduits through the joint. Planing of Vytaflex 60 can be done, albeit very carefully at low speed (feed rate 10%). To ensure that the machining path is clear, it is necessary to pass through the area twice, in opposite directions. Note that the resultant path is much larger than the tool bit itself.

• Attempt to mill soft urethane after planing. The mill was placed in the middle, then proceeded south before returning north. The path that was milled twice can be clearly differentiated from the tool path that was milled only once:
  

-- SamsonPhan - 20 Mar 2008 Somewhat difficult to attach leads onto the samples. The conductive epoxy doesn't get hot enough for a good bond between the solder and itself; the polymer part starts melting. Best practice so far: tape lead joint side down (to create a small pocket). Dab a drop of solder in the pocket. Next time, leave a wire in the mold andpour conductive epoxy around it. Theorectically, all those that showed some conductivity would be able to be electroplated. However, the incorporation of the lead led to a lot of losses. Only two were successful, conductive epoxy and silver print.

Results: Both were electroplated for 300 sec. "Silver print" showed a non uniform layer of copper deposited on the bottom and very little, if any, deposition on the side. "Conductive Epoxy" showed deposition on areas that were milled or not submerged. Resistance values listed below.

Conclusion: Certain conductive epoxies can act as electrodeposition substrates. The long sulfuric acid bath showed that the Task 9 and various conductive polymers could survive the submersion in electrodeposit solution, however, the acid stripped away the conductive material. In areas that were not milled, there was no deposition because the surface was essentially an insulator with no electrical field lines.

Future work: 1. How to incorporate into SDM (process planning). Very interesting would be the multiplex grid. 2. How to interface with transducers. 3. Find optimal strategy for creating conductive paths, both surface and buried. This includes comparison to sputter based methods, conventional wiring.

• Succesful samples:
  
• Joint closeup:
  
• Before electrodeposition:
  
• Silver Print Sidewall:
  

-- SamsonPhan - 19 Mar 2008 Met with Dave Beach to discuss ideas. While he doesn't know, he doesn't think that laser CAMM after sputtering is a good idea as the electroplate may be highly reflective. Laser etching the sputter before electroplating may be better as it requires less energy. He feels though that urethane + Laser CAMM may give off lots of vapors that may fog the optics. Silicone may be better, but is still unknown. Prof. Beach suggests having a urethane core, followed by a silicone layer to be supptered and consequently etched. Contact Craig Milroy to explore the idea further. Edward Flaherty (eflaherty@sanjosedelta.com) may give insight. Get in touch with people at PRN. They may help.

Urethane and conductive polymer acid test: Task 9 survived intact. Nickel epoxies from Epoxies etc. suffered some discoloration. Silver print: noticed the submerged part of the paint dissolved away such that one could see through it. All planed and were milled very well. Not much evidence of voids, except for Nickel Print. Best way to attach leads to conductive polymers: Put a drop of solder on the polymer, tape lead to part. Melt solder between.

-- SamsonPhan - 18 Mar 2008

Met with Munkazu Motoyama in Fritz's lab. Discussed with him the possibility of using their electroplating setup. Note: they extensively use it, so getting time on the machine will involve late nights or early mornings. They are currently setup to electroplate nickel and copper, either of which is very cheap. Currently testing urethane and conductive polymer compatibility with sulfuric acid based electroplating solution.

-- SamsonPhan - 17 Mar 2008

We created 1 x 2 inch urethane blanks, then created a 2 x 2 mm groove on top, to be filled with various types of conductive polymers. We want to use them either as conductive paths to replace wiring or as a "seed" in which to electrodeposit.

Name	Resistance 3/17/08	Resistance 3/19/08	Resistance 3/20/08 (post electroplate)
Conductive Epoxy (from Physics Store)	0.8	0.6	0.3
Nickel print (from Physics Store)	4	5.2
Nickel Epoxy (from Epoxies etc)	No reading	No reading
Nickel Epoxy Sample 2 (from Epoxies etc)	No reading	No reading
Silver Epoxy (from Epoxies etc)	4.5	8.5
Silver Epoxy Sample 2(from Epoxies etc)	Variable	Variable
Silver Print (from Physics Store)	0.5	0.5	0.3
Silver Print Sample 2(from Physics Store)	1.9	2.0