Week 10: Machine Design

As described on the group page, we worked on various topics within the group. Naturally, we delved into and supported all topics as much as we could. Personally, I focused mainly on two topics: Gearbox and Housing Construction.

Gears

Gears are mechanical components with teeth that mesh together to transmit rotational motion and force between different parts of a machine or device. They are used to change or adjust the rotational speed, direction of rotation, and torque.

One member of our group quickly developed a prototype of the gearbox. It worked well but was not aesthetically pleasing and did not operate smoothly. Additionally, we wanted to use a different material. However, we already had the drawings, so we didn't have to start from scratch. Nonetheless, there was still a lot to do. We decided to cut with Laysercut Acrylic. Initially, we opted for a thin acrylic plate. However, during the process, we switched to a thicker acrylic plate.

The pictures show the file we used and how we adjusted it. In the first step, we left the sizes of the gears as they were. However, we adjusted the centers of the gears because we wanted to connect them via different elements that had different sizes. I recreated the file.

With the finished file, we went to the laser cut machine. We performed the first cut. Unfortunately, the gears were much too small, so we couldn't use them. We found that we hadn't set the size properly in the program on the machine. It wasn't set to 100% print size.

It took us a while to find the right parameters to cut the vinyl. We only cut out a test square each time. But it wasn't cut properly. In the end, we decided to use a different machine. There, the laser cut worked better.

We then removed the gears from the Acryl and assembled the gears for the first time. It worked, but the gears were very delicate, so they didn't grip perfectly. The plan was therefore to change the size of the gears again.

Housing Box

Since we hadn't found anyone to build the wooden box, I took over this process and handed over the gearbox to another group member.

For the resonance box, we decided to build a wooden box. The wooden box should fulfill the following tasks:

  1. Form a resonant chamber that amplifies sound
  2. Hold the motor and the gearbox
  3. Serve as an attachment for the string
  4. Hold the bridge to allow the guitar string to pass over it

I started designing the box in Fusion. To cut it with the CNC machine, I need to edit it later in Rhino CAM.

I worked on an initial sketch with Fusion. I used sketch mode and the parameter option to easily change individual parameters later if necessary.I prepared the hole sketch and also some pieces to do a joinery test.

The following steps must be carried out to prepare for the CNC cut:

  • Save the Fusion file as a DXF file
  • Open the DXF file in Rhino
  • Prepare the cutting plan - important: connect all individual parts using the "join" command
  • Save the Rhino file as a Rhino 5 file
  • Open the Rhino file on a computer with Rhino CAM and prepare it for cutting
  • First, set points for the screws
  • Then adjust all parameters for pocketing and cutting
  • First, save the screw file as a post
  • Then save all other files as posts

I initially tested the joineries. Some of the parts fit very well, while others needed adjustments.

After that, I adjusted the cutting plan and cut out the complete box.

Group assignment

On this page, you will find all the information regarding to our group assignment.