Final Project: Tom & Jerry | ENGI 210: Prototyping and Fabrication

Nahom Dagnachew and Michael Woldeab

For our final project, we went with the simple model design based on David’s Machine Design with slight altercations. Thus, our model was designed around Mechanical Movement #158. The design was based around the show Tom and Jerry centered around Tom’s expected harassment of Jerry. Essentially, we wanted to use the curvilinear motion output by the circular motion of the crank as the motion of Tom’s arm crashing down on Jerry (attached to a spring) with a hammer (per usual).

Step 1: Creating 2D files

To start off the project we had to begin with adobe illustrator to create 2D files. This is how we will draw up our parts to be cut with the laser cutter and water jet. We used David’s adobe file shapes to begin making our own as a starting point. From there we added our touch such as creating Tom’s arm with the hammer to be implemented. This required we take a google image of Tom’s arm and a hammer from the noun project and created an outline and image traced their shape.

Step 2: Low-Fidelity Project

For a proof of concept, we used the 2D files to create a low-fidelity prototype. We laser cut some cardboard and put the assembly together using hot glue. We cut out some wooden pegs by marking where to cut when inserted into the model then using the band saw to cut them out. As shown in the video below, the prototype was a success but we wanted to increase the range of motion of Tom’s arm. Furthermore, we noticed the size of the holes in the connecting arm was too large causing it to fall out a lot.

Low-Fidelity Prototype Video: IMG-2307

Step 3: 2D Drawing pt. 2

To create more range of motion we decided to test 3 different lengths of the connecting arm (5in, 6in, and 7in) as well as move the hole on the rotating disk further from its center.

Using the low-fidelity prototype, we found the 6in the arm to be the best length for just enough range where there is noticeable movement and leaves enough room for Jerry which we will add later. Furthermore, we tested three different diameters for the connecting armhole with the medium-fidelity prototype (0.2425in, 0.2325in, and 2225in).

We concluded the 0.2325in diameter hole was tight but not too tight where it inhibited the movement of Tom’s arm. At this stage, we also began drawing up Jerry. We took a google image of him running and ran it through Adobe’s black and white logo image trace at a threshold where we had a good balance of detail and complexity (so the waterjet cutter would be able to cut it out).

We also added the tom and jerry heads from the logo to the base of the assembly for a little flair and in case people were confused about what the metal piece was supposed to be. The final adobe file is attached below below (excluding jerry, since he was cut out with the waterjet and not the laser cutter).

Total Adobe File

Step 4: Medium-Fidelity prototype

With the medium-fidelity prototype, we wanted to test the recent modifications we made using wood instead of cardboard for a closer-to-concept model. This was a rougher model without any post-processing and Jerry.

Step 5. Jerry and the Box (with some post-processing)

Since jerry is made out of 0.19in thick steel it needed support in order to stand upright when attached to the spring. To keep in the theme, we decided to use a box as a representation of a countertop jerry would usually be running on. We created the adobe file using makercase.io with dimensions of 4inx2.25inx2in. We also added a slit that was 4in long and 0.25in thick for jerry to pop out of. Using a spring from the Machine Shop, we cut it down to a length where Jerry would pop out of the box for Tom’s hammer to hit him. Below, one can see Jerry’s Adobe file in the Protomax MAKE software where we send the waterjet instructions to cut out this piece.

Before, the file was prepared in Protomax Layout (shown below) where the file was cleaned and prepared for water jet cutting.

After the cut, we immediately post-processed using 180 grit sandpaper to remove heavy debris and finishing with 400 grit for a smooth finish.

Step 6: High Fidelity prototype

After we concluded that the model was functional when using higher fidelity materials such as wood, we moved onto making a high fidelity prototype that was both functional and aesthetically pleasing. In the previous Illustrator files, it was found that some of the holes for the wooden dowels to go through were ellipses instead of circles so this was the first thing fixed before printing the final pieces along with being more accurate in the dowel lengths cut.

Additionally, the kerf for the box was a bit high and it made assembling it a hassle so it was lowered for a better fit. After the said edits to the files, the pieces were ready to be cut using the same process used before for the medium fidelity prototype. Additionally, for a better look, the wood used for the final pieces was covered in tape after the etching process was completed as it’s a good way to avoid burn marks on the wood surface.

Step 7: Post Processing/Finishing

After careful consideration, we came to the conclusion that the model would look the best if we were to stain and clear coat the wooden pieces and spray paint the metal cut out of jerry. Using the oils on top of the simply white penetrating stain, all of the wooden components were stained on both sides. After staining, a clear coat was applied to said pieces as can be seen below.

For the Jerry cutout, to match the color of the cartoon, a bronze/chrome spray paint was applied on both sides of the piece.

The last step in finishing was to create a sticker/emblem using the vinyl cutter. To again match the theme of Tom and Jerry, a cut out of cheese was cut using a dark yellow vinyl sheet and it was attached to the box which Jerry resides in to complete the post processing.

The initial file was prepared in adobe illustrator and transferred to the Summa Winplot interface to be sent to the vinyl cutter.

Step 8: Final Assembly

After all components of the model were post processed/ finished, it was time to assemble the model. Dowells were attached in the same locations as the previous medium fidelity model and were sanded down so they don’t protrude in the model. The mechanical model was super glued onto the base with our name plate and all that was left was where to place Jerry and the box. Through trial and error, we found the location where the hammer would hit Jerry and the vibrations of the spring would be heard, fitting with the cartoon aesthetic a bit more. Then we super glued the box and found the super glue gel to be better suited for the spring. The final piece can be seen below accompanied with a video.

Final Assembly Video: IMG-2386