A few weeks ago, I learned of a new Kickstarter project named Ingocraft. At first glance I thought it was just another 3D printed construction kit – but then as I watched the video, I was impressed by the vision of the Ingocraft team. They are delivering a construction kit with injection molded parts, a 3D design app for building virtual items with the construction kit – and the added benefit of being able to 3D print parts if you want to add to your kit. They’ve also created a reward level that includes a monthly subscription to receive new parts as they are designed.
While watching the Ingocraft video, I noted that they are having their parts injection molded locally, which suprised me due to the number of projects I’ve encountered that utilize injection molding companies in China. I reached out to the Ingocraft team to learn more about how they designed and manufactured their injection molded parts.
Mike Benjamin from the Ingocraft team spent time sharing their design and manufacturing process as well as sharing some of the background on the Ingocraft team. The founders of Ingocraft are educators who found themselves frustrated by the lack of expandable construction sets that mimic real nut and bolt construction, so they set out to design something that they could use with their own children and then share with others. Mike’s background is in 3D modeling and prototyping props in the Los Angeles area, as well as some CNC manufacturing, so he joined the team to design the parts, lead the development of the application (it is based on the Unity engine), and work with the manufacturing partner.
How do you design for both 3D printing and injection molding?
We use mostly Sketchup for our modeling/prototyping, and have been in collaboration with our plastic molders from the beginning. We would make a concept piece, send a rough out 3D model, and they would put their touch on it, clean it up with solidworks, and then send us back an STL. We would test the STL on our 3D printers, and then restart the process over and over again.
These days now that we have the major dimensions figured out, we can do basically everything with sketchup, remixing new pieces, testing them on our printers, it’s quite a lot of fun.
You’ve got a number of different pieces – did you have a lot of revisions?
We have gone through a TON of iterations of the bar, cube, nuts and bolts concept. So many sizes, shapes, configurations.
Our biggest challenges were getting a consistent, easy, resilient attachment between pieces, the “snap”. Threading is pretty easy, but the tiny tolerances of the snap, which have to be both plastic molded AND 3d printed in 2 different materials and STILL have great action, has been one of our biggest challenges.
We also did not want to have to print with rafts or supports, so that has been a major design parameter.
Once you finalized a part design, what was the next step?
We have the plastic molders the go ahead to start creating a few tester molds. It was a nerve racking time, because they needed to be so perfect so that when we brought them back, printed a copy on the 3D printer, they would still work great together. We did our long and short bars first, and sure enough, a great fit!
It really did not take too long, a few weeks to get a mold made, depending on the complexity of the piece. The cube has been a very complex piece, took a bit more time than the others.
Once we knew it was possible we gave the green light to start moving on other molds, the cube, plate, nuts and bolts. At this point almost everything has a mold made for it and prototypes that work great.
How did you find your injection molding company?
We found our plastic molders because they are only a few miles from us, which means that we can frequently head over to their shop to see how things are going. We wanted to make sure that in creating a brand new product we had the team nearby so we could go talk to and hash things out in the middle of the day if there were problems that needed solving. You can’t do that when your injection molding company is in China!
Do you have any tips for someone looking to move from 3D printing to injection molding?
Start early and iterate often, and bring your concepts to the injection molder in order get some perspective. Going local helps quite a lot too, so you can witness the process, and collaborate on options. A good plastic injection/prototyping operation can be very helpful with product design, because the quality and character of a 3D printed part in PLA or ABS can be very different than a plastic injected part. There are also a wide range of options for making molds, and some are not as expensive as you might expect. It’s a lot of fun going from 3D printing to mold making, and seeing those molded prototypes is a great feeling.
Ingocraft still has a few days left in their Kickstarter campaign. They are on-track to reach their funding goal – and to deliver in time for the holidays! Our kids have moved onto real nuts & bolts so our Ingocraft kit will go to one of the schools we work with. I’m sure they will be excited to have another tool in their maker education toolbox.