3D Printed Injection Tube Mold

3D Printed Injection Tube Mold

February 28, 2020

3D Printed Soft Plastic Injection Tube Mold

STL’s for this lure mold are available for purchase from Cults3d.com.

This page shows some of the 3D printed injection molds I have been working of for making tube baits. This was my first attempt at making injection molds for soft plastics.

Here is the full design and build Video.

This project actually started back in November of 2019 as a hand poured tube mold. (it’s just taken me this long to post it) I saw videos on YouTube were people dipped metal rods by hand to form the tubes but figured it might be quicker with a mold.

The basic idea was an aluminum rod was inserted into the mold that created the outer portion of the bait and the rod was held in place by the top guide piece. Plastisol was then poured into the window to form the tube. An alternative method was to pour the plastisol in first then insert the rod/guide setup.

After the tube cured enough the entire rod and tube where then stuck into another guide tube….

… where I then could use a razor blade to cut the skirt legs.

While this method of making tubes did work (as you can see from this picture) it was way to labor intensive so I decided to just try designing an injection mold next.

This is the injection mold setup I came up with next.

This is the insert that is used to create the inside wall of the tube as well as the skirt legs.

The insert is just inserted into the mold block and sandwiched in between the two mold halves. Plastisol is then injected into the mold to form the tubes.

Here are some of the finished tube baits.

Once I had the single cavity mold working I went back and designed a 6 cavity mold to increase production.

I added a 1/8″ metal rod to the inserts this time to help keep it from warping.

Here is the printed mold with the inserts in place before clamping the two mold halves together. I had a few issues with this mold but over all it worked very well.

Injecting into 3D printed molds does leave a dull finish (compared to aluminum molds) and also can leave a unique texture on the finished bait because of the printed layer lines. Overall these came out great and should work just like any other store bought tube bait.

Mini Tubes

I also designed another mold to make mini tube baits. This mold produces 2 3/8″ tubes.

Here are some of those finished baits…

…and here they are compared to the larger ones that I made.

I ran a 1/8″ stainless steel rod through the entire mini mold too. I’m hoping this might keep it from warping. (time will tell if it works)

Another batch of hot pink minis fresh out of the curing bath.

All Information, Pictures, and Material is copyright © 2020 by Stephen Thone and may not be used for any personal or commercial purposes without the consent of the author. All rights reserved. The Author makes no guarantees or warranties as to the accuracy or completeness of, or results to be obtained from accessing and using the Information herein.