Wood Pencil Case & Keychains

For my passion project, I decided to have two different outputs. The first is a pencil case and the second are keychains I can give to my friends. The passion project had a requirement where at least 2 different machines had to be used for the output. To comply with this, I decided to use the CNC machine to make the pencil case and the Laser Cutter to make the keychains.

To accomplish this task I used

1. CNC Machine
2. Laser Cutter
3. 30 cm x 30 cm Wood Piece
4. Acrylic Pieces
5. Small Hinges (Bought Online)

Before designing the pencil case, I first decided what stationery items I wanted in a pencil case. After careful deliberation I decided that it should hold:

1. 2 Mechanical Pencil Leads
2. Eraser
3. 5 Pen/Pencils

(I initially wanted to include my correction tape, but I found out it was too thick for my wood piece so i scrapped it.)

With these in mind, I measured the dimensions of my stationery using an electronic caliper to create the slots where they would go in the pencil case. After a few configurations I ended up with a design I was happy with and a form factor that wasn't that different from the pencil cases I used to own (refer to V1)

The dimensions I used for the slots in the picture above are slightly larger than the actual stationery I used to allow for more flexibility with what can fit in the pencil case. The pen slots were the result of me taking the measurements of few of my pens and getting the largest measurement in each dimension. An updated version of this design was made that allowed for easier removal of the contents of the pencil case (refer to Final)

Some things to take note of:

1. The whole cut fits in a 300 mm x 300 mm x 10 mm wood board
2. The drill bit used was 5 mm wide
3. Due to how engraving works, I reduced 2.5 mm from all sides (-5 mm in total length, -5 mm in total width) to make sure the slots are <>

Tool Settings:

1. Diameter: 5 mm
2. Pass Depth: 2.5 mm
3. Stepover 4.25 mm (85%)
4. Spindle Speed: 12000 rpm
5. Feed Rate: 500 mm/min
6. Plunge Rate: 200 mm/min

Pencil Case Body (1):

1. Dimensions: 249.735 mm (W), 129.735 mm (H)
2. Start Depth: 0 mm, Cut Depth: 11 mm
3. Machine Vector: Outside
4. Tabs: 5 mm (L), 7 mm (T)

General Pen (2):

1. Dimensions: 146 mm (W), 13.5 mm (H)
2. Engrave Depth: 6 mm
3. Fill
4. Stepover: 4.25 mm
5. Offset

Pilot Gspec (3):

1. Dimensions: 140 mm (W), 15 mm (H)
2. Engrave Depth: 8 mm
3. Fill
4. Stepover: 4.25 mm
5. Offset

Eraser (4):

1. Dimensions: 23 mm (W), 63 mm (H)
2. Engrave Depth: 7 mm
3. Fill
4. Stepover: 4.25 mm
5. Offset

Pencil Lead (5):

1. Dimensions: 7 mm (W), 170.5 mm (H)
2. Engrave Depth: 4 mm
3. Fill
4. Stepover: 4.25 mm
5. Offset

Plaque (6):

1. Dimensions: 59.713 mm (W), 24 mm (H)
2. Engrave Depth: 3 mm
3. Fill
4. Stepover: 4.25 mm
5. Offset

Latch (7):

1. Dimensions: 20 mm (W), 3 mm (H)
2. Engrave Depth: 2 mm
3. Fill
4. Stepover: 4.25 mm
5. Offset

Gap 1 (8):

1. Dimensions: 32 mm (W), 10 mm (H)
2. Engrave Depth: 2 mm
3. Fill
4. Stepover: 4.25 mm
5. Offset

Gap 2 (9):

1. Dimensions: 51.462 mm (W), 7 mm (H)
2. Engrave Depth: 2 mm
3. Fill
4. Stepover: 4.25 mm
5. Offset

Gap 3 (10):

1. Dimensions: 10 mm (W), 75.481 mm (H)
2. Engrave Depth: 2 mm
3. Fill
4. Stepover: 4.25 mm
5. Offset

This is what the piece looks like after cutting it and sanding it.

Some notes that could help in assembly:

1. With tiny screws it will greatly help if you pierce the screw through multiple layers of paper before trying to hammer it in as the paper helps keep the screw in place
2. The sander helps a lot with the overall finish but for the individual slots, manual sanding is required

I'll be using an example to show my general procedure when creating a keychain. Using the image above that I found off the internet, we can import it into Inkscape.

From here we can select on the image and select Path > Trace Bitmap.

Depending on the image or what we want we can either select Multicolor or Single Scan:

Single scan has 2 settings that I use, which are

1. Edge detection (useful if you only want edges)
2. Brightness cutoff (which I use to get a fully black silhouette).

Multicolor

1. Brightness Steps (what you use to get a black and white version of the image)

In this case we want to get a black and white version, so we use multicolor and mess around with the settings a bit until we get something we like

The settings I used are:

1. Smooth, Stack, Remove Background
2. Speckles: 2
3. Smooth Corners 1.00
4. Optimise: 0.2

We want the shape of the key chain to closely reassemble that of the sword, so what we do is we select Path > Trace Bitmap again on the original image, and use brightness cutoff. In here we go to the highest possible threshold where only the sword is fully blacked out.

With the shape, we can then go into Path > Dynamic Offset to enlarge the image. We stop at our desired size and clean up messed up nodes by deleting them/altering them. After this we set the fill to none, and the stroke to red with a thickness of 0.025 mm

We can then combine the two outputs from the previous 2 steps into one by using the align feature to have our finished design. The design can then be exported into a pdf and is now ready to be used by the lasercutter