Question Mark Keycap Injection Molding Instructions

FDM Slicing Settings

• Material: PETG/PC
• Nozzle Diameter: 0.4 mm
• Wall Thickness: 8 layers (≈3.2 mm, high compressive strength, resistant to multiple injections)
• Top Layer Thickness: 3 mm
• Bottom Layer Thickness: 2 mm
• Infill Density: 25% (balance between strength and material saving)
• Infill Pattern: Recommended Grid
• Layer Height: 0.2 mm

Preparation Materials

1. PVC stock solution
2. PVC special color paste (yellow, milky white)
3. Release agent (recommended: PTFE-based release agent; edible oil can also be used, but the release effect is not as good)
4. Fast-drying PVC soft glue adhesive
5. 3D printed mold
6. SALTGATOR injection molding machine

Injection Molding Steps

1. Evenly spray release agent (release oil) on the mold surface.
2. Assemble the mold according to the exploded view. <img src="https://vzyklpazwxemgkrpkblc.supabase.co/storage/v1/object/public/mold-images/1756636520067-5romid.png" alt="Question Mark Keycap" width="400" />

<font color=#DCDCDC>"Exploded View For Assembly Reference"</font>

<img src="https://vzyklpazwxemgkrpkblc.supabase.co/storage/v1/object/public/mold-images/1756636565534-99bnqp.png" alt="Question Mark Keycap" width="400" /> <font color=#DCDCDC>"Align the keycap’s bottom hole with the mold hole."</font> <img src="https://vzyklpazwxemgkrpkblc.supabase.co/storage/v1/object/public/mold-images/1756636267949-jhurr.png" alt="Question Mark Keycap" width="400" /> <font color=#DCDCDC>"Align the “?” position in the mold vertically."</font>

3. Add an appropriate amount of PVC stock solution and PVC special color paste into the injection machine, set to 170℃, and start heating.
4. After heating is completed, use the injection machine to inject material into the mold's injection port (push the plunger until it cannot be pushed further and hold for 3-5 seconds to remove larger bubbles).
5. After injection, wait 6-8 minutes to allow the PVC soft gel to cool.
6. Once cooled, first pull out each core pin and open the mold, then demold. During demolding, slowly separate the soft gel from the mold to avoid damaging the model by excessive force.
7. Remove flash and excess soft gel formed at the vent and injection port.