Miami Heat Logo | ENGI 210: Prototyping and Fabrication

Miami Heat Logo

For my cut out, I went with the Miami Heat’s basketball team logo shown below.

I converted the image to the proper file type then uploaded it to carbide create.

I made a cutout on the perimeter and on the inside of the ring. The rest I made 1/8″ deep pockets. For the exterior cutout, I did the least amount of offset possible to preserve the overall shape, but this created some issues later on.

CNC

My first piece was cut during the TA tutorial. The piece was clamped with the strips at the end. This impeded the calibration device which had to sit in the corner. So, the CNC was calibrated than the wood was clamped. This interfered with the cutting process as the wood was pressed down after calibration. The result was that the first pass was above the piece. As a result, my piece did not fully cut out. Also, the piece of wood was warped.

The layer left uncut was very thin making it fairly easy to remove my part. Then some sanding on the bottom helped to clean it up.

For my next cut, I used the planar as suggested to make my wood level. I also changed how I did the clamps. I used three corner clamps leaving the last corner exposed for calibration. This set up works very well and fixed the previous calibration error. One caveat is that the star pattern for tightening should be used. If one clamp is fully tightened before the others it forces the opposite corner up.

My second cut the calibration was off resulting in the part of my piece on the left side not being on the wood. I was trying to make the cut as large as possible which worked the first time but leaves no margin for error in the calibration. My third cut I shrunk the piece to give room for error. Unfortunately, I forgot to reinsert tabs which get deleted when going from carbide V7 to V6. I stopped the print a little too late resulting in my part popping up and getting damaged. After cutting I vacuumed all the dust.

Since I made the outside cut so close, my edge walls are thin making them prone to breaking. Some sections broke during cutting; others broke while sanding the part when I was not careful. I was able to glue the ones I broke back into place though.

Post Processing

I wanted to match the coloring of the logo. As I am not a skilled painter, I planned to spray paint the entire part black then fill the pockets with resin. During the post processing, I did not take advantage of my second cut to use as a test piece resulting in me learning as I went on my final pieces.

When I poured the resin in the first section I quickly ran into my first mistake. The red resin on black spray paint was just black. To correct this, I used the acrylic paint to match my desired coloring. As I am not a good painter, I left a lot of brush strokes, and I got paint on the raised edges. Difficult to paint the small nooks and crannies that my part has.

This worked very well with the white resin. I also made sure that the resin was opaque by adding multiple drops of white.

I then moved on to the yellow and red. I didn’t get the exact coloring I wanted for the yellow resin. It came out more orange as I couldn’t find the white to mix in. For both the red and yellow, I may not have put enough drops to make it opaque. Unlike the white, I could see the painting underneath.

Pouring the resin proved to be difficult with the shape of my pockets. I kept overfilling causing it to get on the edges. Also, the popsicle stick is too big for effectively guiding and moving the resin around on my part. A toothpick would been great.

Lessons Learned

I definitely rushed a little bit on this project, slowing down would improve the quality. Most importantly though would to have used my failed print as a test piece to practice and learn.

A better method for making this part would have been to spray paint first, cut, then do the resin. This way, when the pockets are cut out, it removes the spray paint leaving behind wood. The wood could be stained with tung oil or left as it for the resin. The one downside of spray painting first is that the paint can get damaged during cutting. This also avoids the need to paint and leave behind brush strokes. Lastly, I would use a toothpick for pouring the resin and pour slower to not overfill.

Cost Breakdown

Tools:

CNC – free with OEDK access

Materials

1/2″ x 4″ x 5″ wood x3 – $2
Spray Paint – $1
Resin Paint – $4

Labor: Required some specialized skill

$22/hr *5hr

Total cost: $117 for the two pieces.