Nicole Friederichs – 12. Machine Design

Design

Claw Machine

A type of arcade vending game where players use a joystick to control a mechanical claw, attempting to grab prizes.

Design Process

To begin designing the machine, I first created a moodboard to define the visual direction I wanted for the project. At the same time, I established the main design requirements for the machine:

- Modularity

- Avoiding the use of glue

- Organic aesthetic

After that, I started sketching different ideas for the claw machine.

Sketches — Initial sketches exploring different enclosure configurations.

Material Selection

The most challenging part was finding a complete solution that met all my requirements, especially because I did not want the screws to be visible. At first, I considered three possible materials for the enclosure:

- 3D printing

- Wood

- Metal

After analysing the different options, I decided to build it out of wood. This choice allowed me to complete the 3D model in SolidWorks. Once I had figured out how to make almost all the parts, I started assembling the box.

3D Model — SolidWorks

SolidWorks

I normally use SolidWorks to plan and test how I want to build a product. It provides me with the measurements and parts that I need.

SOFTWARE & TOOLS

SolidWorks — 3D parametric modelling
Measure — dimension extraction from the team assembly
Extrude Boss / Cut — building and hollowing solids
Fillet — adding organic rounded edges
Assembly — checking fit between all pieces

DESIGN WORKFLOW

01 Open team assembly → extract dimensions with Measure tool.
02 Model each structural piece individually based on sketches.
03 Build a sub-assembly to check that pieces fit together.
04 Iterate — adjust measurements until joints are correct.

Here you can find the general process of how I made the 3D model. I used the same tools I learned in the 3D modeling week, check the page if you want a more detailed explanation of how to build in SolidWorks.

1. Opening the Assembly File

I opened the assembly file that my team made.

2. Using the Measure Tool

I used the Measure tool to get the dimensions that I needed for the parts.

3. Reading Face Dimensions

To get the dimensions, just click on the faces you need and the dimension will appear.

4. Designing Individual Pieces

Then I designed each piece of the model, basing it on the sketch I had previously made of the machine. It was an iterative process of measuring and assembling to verify the pieces were correct.

5. Building the Assembly

I made an assembly and added all the pieces that I modelled. Here you can see all of them together.

6. Identifying & Fixing Mistakes

While joining the parts I could see the mistakes I had made and adjusted the measurements accordingly.

7. Model Ready for Fabrication

After I had a solid understanding of the measurements and parts, I moved on to the fabrication stage, starting with the structure.

Download SolidWorks Files

Problem

At first I designed a machine that was supposed to have a disposing structure under the metal structure, but then my team sent me the 3D model of the machine and I had to change some things.

Structure Fabrication

Safety Measures

If you work with machines it is important to wear the correct equipment: overalls, safety boots, safety glasses and preferably a face mask (otherwise you could end up with a sore throat like I did). Also make sure to pay full attention when using the machines to prevent accidents.

MACHINES USED

Miter Saw — crosscut pine boards to length
Router Table — mill grooves for panel insertion
Laser Cutter — cut 4 mm plywood front panels
Band Saw — cut brackets and extension pieces
Dremel — trim metal corner brackets to size

MATERIALS

Pine wood boards — 1.22 m × 2 (main frame)
4 mm plywood (triplay) — front panels
Metal corner brackets — structural joints
Flat-head wood screws
Wooden dowels (first joint attempt)
Clear acetate sheet — front window panel

Below are the detailed steps I followed to fabricate the structure. The process combined miter cutting, router milling, laser cutting, and wood joinery into one integrated workflow.

0 — Sourcing Materials

First, I went to Home Depot, where I bought two 1.22 m pine wood boards for building the main frame of the machine.

1 — Cutting Pine Boards to Length

I cut six wooden pieces of 63 cm using the miter saw. I based these dimensions directly on the measurements of my 3D model so that all the structural components would match the planned design.

2 — Planning the Grooves

The next step was making the grooves where the front plywood panels would later be inserted. I decided to include these grooves so the entire box would look more integrated and compact, while also reducing the need for external attachments.

2 — Installing the Router Bit

To make the grooves, I first installed the router bit. I used a 1/8" straight cutting bit for material removal. To secure the bit correctly, fixed hexagonal wrenches are required.

3 — Mounting the Router Table

Then, I mounted the router onto the router table available in the EdIT lab. For this, I turned the table upside down, positioned the router underneath, and fixed it in place using the safety locks tightened with wing nuts. Recommendation: make sure the bit is centered in the table hole to avoid vibration or uneven cuts.

4 — Unlocking the Router

In order to adjust the cutting depth, the first step is to unlock the router by opening its safety lock.

5 — Adjusting Bit Height

Once unlocked, the bit height can be modified by turning the black adjustment thread.

Adjusting bit height with adjustment thread

6 — Verifying Groove Dimensions

I verified the final height with a vernier caliper so that all the grooves would have the correct dimensions. Each groove was made with approximately 4 mm depth and 2 cm width, matching the plywood insertion requirements.

Measuring groove depth with vernier caliper

7 — Brief Interruption

At this point, we had a short pause because someone burned plastic in the IDIT, so the work had to stop temporarily.

8 — Setting the Guide Fence

After resuming, I placed a guide fence for the wooden pieces. I improvised this guide using a scrap wood piece fixed to the table with two C-clamps.

Improvised guide fence clamped to router table

9 — Adding a Stopper

With another clamp, I placed a stopper to ensure that all the grooves would be cut at exactly the same position and height.

Clamp stopper ensuring consistent groove position

10 — Marking the Pieces

Recommendation: before machining, it is very useful to mark with a pencil or pen which wooden pieces go together and where each groove should be located. This avoids confusion later during assembly.

Marking groove positions on pine boards with pencil

11 — Routing the Grooves

Then I turned on the router and carefully passed each wooden piece through the bit to cut all the grooves. The upper grooves were made with a length of 12 cm, while the lower grooves were made with 15.5 cm, according to the front panel design.

Passing wood pieces through router bit to cut grooves

12 — Moving to Laser Cutting

Once all the pine structure pieces had their grooves finished, I moved on to the laser cutting process.

Finished grooved pine pieces ready for laser cutting

13 — Laser Cutting Front Panels

I laser cut the front plywood panels using 4 mm triplay. The detailed settings and process for laser cutting can be seen in Week 3: Computer Controlled Cutting.

14 — Checking Panel Fit

After cutting, I checked that all the front panels fit correctly into the grooves and verified that the insertion was tight enough to hold them in place.

Testing plywood panel fit into routed grooves

15 — Rounding the Corners

The next step was rounding the outer corners of the wooden structure to obtain a softer and more organic aesthetic. For this, I changed the router bit again using a fixed wrench, following the same tool changing process as before.

16 — Rounding All Corners

I placed the guide fence once again and carefully rounded each corner. Before machining the final pieces, I first tested the setup using one of the previous scrap pieces to ensure the cut was working correctly.

17 — First Joint Attempt: Wooden Dowels

After finishing all the cuts, I started joining the wooden parts together. For the first assembly attempt, I used wooden dowels. I drilled the corresponding holes, inserted the dowels, and then used a rubber hammer to press them into place. Problem: several dowels broke during insertion and the final alignment was not completely straight.

Wooden dowel joint attempt with rubber hammer

18 — Second Joint: Metal Corner Brackets

To avoid the previous problem, I assembled the second part using metal corner brackets, which I highly recommend because they are much simpler, faster, and provide a more reliable joint. The brackets were too long on one side, so I cut them with a Dremel. I first measured the exact positions, marked them with a pen, then drilled and screwed them in place.

Metal corner brackets screwed in place for stronger joint

General Recommendation

Try testing your project on scrap pieces first to avoid wasting material.

Problem

Since we had limited time to build the machine, I based the box design on the measurements my team sent me. However, when I finished and compared it to the machine's frame, I realized the frame was slightly taller, which meant my box didn't fit.

Box height mismatch with machine frame — Box height didn't match the machine frame.

Solution

I used a spare board, cutting two pieces to the width and length of the machine. I cut these in half with a band saw and screwed them to the underside of the machine. In the end, the problem had a silver lining: it gave the structure more stability.