3d printing a Touch-proof connector

I’m currently working at the Electronics and 3D Prototyping Laboratory at the Facultad de Ingeniería, Universidad Nacional de Entre Ríos.  We are working on a biopotential amplifier based on a ADS1299.  The amplifier uses 1.5mm touch proof connectors like this one. Unfortunately Plastics1 is the only manufacturer (and seller) of these particular connectors. The purchase have not been done yet, and it will take a while to have them in the lab. That was a problem as we needed to make some tests ASAP. We have a couple of 3d printers so we decided to make the connectors ourselves with the stuff we have in the Lab.

I had already made the connectors’ 3D model in Solidworks in order to generate the step an wrl files for KiCad.

pcb

I modified the housing to fit standard 2.54mm pin headers. The main fear we had was that the printed plastic wouldn’t tolerate the heat while being soldered to the PCB. For that reason we didn’t use just the metal pins but also the plastic part of them. That material is designed to withstand the heat while being solder and was used to minimize direct metal-to-housing contact. The pins at the front of the connector were soldered first to the PCB and then the housing was press fit into them.

ensamblaje

We printed the connector in a Objet Eden 260 from Stratasys. The material used is VeroWhite.

ambos3

We found out about a connector with pins in a similar size to the one we needed. Circular Plastic Connectors (CPC) use 1.58mm pins, close enough.  We had a couple in the lab from another project but we needed more. Luckily my cousin (who is studying there as well) is working in a similar project for his thesis and bought a bunch of these pins to be used in a similar way. The pins were disassembled as seen in the picture and only the front part was used.

ambos

A single 17 mm long pin header was slided inside the contact and soldered in place. The pin was then bended…

ambos2

.. and gluded in the printed housing.

ambos4

As I said before, the pins in the front were soldered first:

cam00571the connector was press fit into them and the central contact soldered.

cam00602

We made several connectors, they are not pretty but they work great.