Recently I printed a component tray for my friend Parker (Longhorn Engineer) which he documented on his website (http://longhornengineer.com/2014/06/11/3d-printed-part-tray-for-a-pick-and-place/) and which received a write-up on Hack-a-day (http://hackaday.com/2014/06/12/3d-printed-trays-for-your-pick-and-place-machine/). The purpose of the tray is to hold special sized components for a pick-and-place machine. The tray turned out pretty well and fit the machine as desired.
After receiving the tray Parker used an ESD spray to make the tray safe to use with actual components.
The one question that remained in the back of our minds is if it would work to use conductive filament instead of the PLA I used for the original tray.
I purchased a spool of conductive filament from Makergeeks.com (http://makergeeks.com/co3dfi.html).
After some trial and error I managed to get a print. It uses ABS plastic as the base with what appears to be a fair amount of graphite material added. I had some issues with bed adhesion but eventually the print got going.
In the end it turned out pretty well.
Conductivity testing showed that the material is well within the range required for ESD safety. I unfortunately do not have the specific results available. I delivered the tray to Parker without capturing the information myself.
At first it seemed like it did not have the right properties because we tested the conductivity of the bottom of the tray. I realized that the reason the bottom did not test well is because I used some “ABS Juice” on the build platform and that affected the bottom layer of the print. The top of the print itself was fine. In the future if I print something that needs to use the bottom as a conductive surface I will have to make a special batch of ABS juice that is made from the conductive filament or find another way to insure bed adhesion.
The material itself feels somewhat dry after extruding. I assume this is caused by the material mixed in to give it conductive properties. It does not have the normal smoothness of ABS and it was more challenging to get to stick on the first layer. It also has a unique smell which also must come from the conductive filler. The smell is hard to describe but to me it seemed like it is probably graphite.
Another issue I had was when it came time to unload the filament. It took a significant amount of time to get the black material to extrude out when I replaced the filament with a new color. The filler that gives it the conductive properties, which I suspect is graphite, is very difficult to purge from the nozzle. In the future I plan to remove the nozzle from the printer and manually clean out the conductive filament when I am done.
It is an interesting material to work with and it seems to work well for producing ESD safe objects. I did not have any significant issues printing with the material and just had to take time with getting the layer adhesion down. The quality of the print is affected by the foreign material in there but not in a way that made the print unusable.