Shenzhen Alu Rapid Prototype Precision Co., Ltd.

Making a silicone prototype typically involves creating a mold (often from a master pattern) and then casting room-temperature vulcanizing (RTV) silicone into it to produce flexible, rubber-like parts. This is a popular low-volume prototyping method because it's cost-effective, allows for complex shapes, and produces parts with good detail and flexibility.

Common Methods Overview

1.DIY/Home Approach — Best for hobbyists or small-scale testing: Use 3D printing or sculpting for a master pattern, make a silicone mold, then cast RTV silicone.

2.Professional Approach — For more accurate/functional prototypes: Compression molding, liquid silicone rubber (LSR) injection, or casting with machined molds.

3.Emerging: Direct 3D printing in silicone (limited availability and material similarity to production silicone).

The most accessible DIY method is casting RTV silicone using a 3D-printed or hand-made master and mold.

Step-by-Step Guide (DIY RTV Silicone Casting)

1.Design and Create the Master Pattern

Design your part in CAD software. Avoid sharp corners (use fillets to prevent tearing) and ensure uniform wall thickness.

Produce the master: 3D print (SLA resin for smooth finish is ideal), CNC machine, or sculpt with clay/plasticine.

Apply a release agent (e.g., petroleum jelly or specialized spray) to the master so the mold doesn't stick.

2.Build a Mold Box and Make the Silicone Mold

Secure the master in a containment box (e.g., made from LEGO, cardboard, or 3D-printed walls). Add sprues/vents for pouring and air escape.

Mix platinum-cure RTV silicone rubber (e.g., Smooth-On Mold Star or similar—preferred for durability and no inhibition issues).

Pour the silicone over the master slowly to minimize bubbles (degas in a vacuum chamber if possible).

Cure at room temperature (follow product instructions, usually 6-24 hours).

3.Demold and Prepare for Casting the Prototype

Remove the master from the cured silicone mold (flex the mold gently). For complex shapes, make a two-part mold by embedding half the master in clay first.

Apply mold release if needed (platinum silicones often don't require it for silicone casting).

4.Cast the Silicone Prototype

Mix your prototyping silicone (RTV platinum-cure for best results; match hardness/durometer to needs, e.g., Shore 30A for soft parts).

Pour into the mold (degas or use pressure/vacuum for bubble-free results).

Cure fully, then demold. Trim flash (excess material) with scissors or cryogenic deflashing for clean edges.

5.Test and Iterate

Evaluate fit, flexibility, and function. Make design tweaks and repeat.

Materials Recommendations

Mold-Making Silicone → Platinum-cure RTV (e.g., Smooth-On, high tear strength).

Prototyping Silicone → RTV for visuals; HCR or LSR for functional testing (closer to production).

Safety: Work in a ventilated area, wear gloves, and follow MSDS.