Introduction

Since this project marked the beginning of the end of this class, we (Damian Gonzalez and Jonah Wagner) decided that we needed to go out with a bang. We wanted to create a set of Batmen chess pieces. In doing this, we were going to 3D print one side and CNC the other side. The batman piece was found from thingiverse.

Preparing the Files

We ran into problems early on because our part contained some design features that had a lot of detail to them, specifically the face, but in order to see them, we needed to size up our chess piece. Eventually, it got to the point where the piece was becoming too big, so we had to make shift the proportions in Solidworks and made sure that it was appropriately sized to maximize both the details in the face but without making the piece unfeasibly large—we had size constraints of the wood to keep in mind as well as length of time to create the molds.

3D Printing

The 3D printing portion was the easiest part. Once the file had been prepared in SolidWorks, we sent it to one of the 3D printers in the OEDK with the default settings and the part came out perfectly. To prepare it to be filled with mold, we surrounded each side with cardboard and use hot glue to create a seal.

CNC Milling

The CNC milling portion was the most challenging part of this project because our piece was very large and the larger CNC machine was not fit for use at the time of this project, something we discovered after hours of failed cuts and other issues. This meant we had to use the smaller, yet more reliable, CNC machine to create our part, and the maximum size end mill that is meant to be used on that machine is ⅛”. Due to the inefficiency of this method, we had to spend a lot of time messing with the settings in VCarve. Many of the choices we were forced to make to get the time down from 8+ hours (the time required if the recommended settings were used) to 3 hours, which when combined with troubleshooting, caused the cut to take more like four hours total. Since the smaller machine also does not have clamps, we had to get incredibly creative with using tape to secure the piece. Ultimately, it worked almost perfectly; we had one small error that resulted in a scratch on the back of the Batman piece.

Molding and Casting

Now that the 3D printed and CNC pieces were completed, it was time to create the molds. We closely followed the instructions provided to us to create the molds; at this point we could begin casting.

For the casting process, we also added some dyes to give the various pieces different colors. Since the molds were not holding as tightly as we wanted them to, we used rubber bands and blocks of wood to help keep them securely fastened together. After 30 seconds of stirring and 9.5 minutes of curing. The pieces could be removed and briefly post processed by removing any material around the edges of the molds.

Final Assessment

Over the course of this process, we got to use all of the 3D fabrication methods learned over the second portion of the semester, combined into one project. The CNC portion grossly outweighed the others both in difficulty and quantity of time, but the outcome was effective and repeatable.

Cost

Materials: Negligible compared to labor

Equipment: $0 (Shared resource)

Labor ($15/hr for ~20 combined hours): $300

Cost for mold: $300

 

Materials (4 cubic inches ~0.017 gal at $120/gal): $2.08

Labor ($15/hr for ~10 active minutes): $2.5

Cost for piece: $4.58