New Mold, New Parts, Pretty Colors

A project log for Modular Continuous Track System

A inexpensive modular tank track system that can be used for robotic and radio controlled vehicles.

jupdykejupdyke 09/10/2015 at 07:250 Comments

Well it took me about 3 weeks to build the new mold from start to finish. I think I could do it all over again in one day if I had all the parts. That is the nice thing about this design. I have all the cnc gcode to run it again and the control unit is working. The mold worked great. The parts came out better than expected and the mold heated up and cured the parts much easier and faster. So all in all I would say it was a great success.

Getting the resin into the mold is a little bit tough still. I made the fill holes much smaller and am injecting using a syringe. It works but takes quite a bit of pressure to flow the resin through a small needle on the end. I make the fill holes a little larger and stopped using the luer lock needle. Now the syringe goes directly into the mold and the hole in the aluminum gets smaller just before the part. This worked better. But still is not ideal.

I ordered some parts to build a small pressured syringe. Rather than push the plunger by hand, I will use compressed air to do the hard work. That should be the final piece to the puzzle.

Below you can see the difference between the new molded parts on the right and the old molded part on the left. The surface finish is much better. You can see that the new parts are a little more rounded. This is because the smallest round endmill that I had was 1/16". So I can only make radius that are 1/32". The 3d printed part has sharper corners. I think the rounded on looks better actually.

The resin is a transparent yellow color when you first mix it. I add in dye to change the color. So far I have been mostly working with black. You don't have to worry about the ratio very much with black. A very little amount of dye goes a long way. 2-3 drops of black mixed in with 80 grams of resin will do the trick.

I decided to try out some other colors. The first results were not great. 3 drops of blue and the parts look almost black. The same goes for green. The red looked better but was still transparent. Maybe some people would think this is cool, and for another project I might agree. But for tracks I was hoping for solid colors. So I tried adding in white dye first. 5 drops of white gave me a creamy yellowish white resin. Then I added in a single drop of color. This worked much better and I was able to get the blue, red, green and purple treads you see below.

At this point I think I am almost ready to start selling this as a product. I started making the online store and working up how much it costs for me to produce these. Hopefully I can start selling them and see all the cool tracked vehicles people can design with them.