Silicone Prototypes & Silicone Parts
Cost and Lead Times
We are capable of delivering 1-1000 quality silicone prototypes within 3 business days and 1000-25,000 silicone parts within 15 business days. Our tool prices start at $1295. Costing and lead time depends on part complexity and material selection.
Part Design for Silicone Prototypes
It is recommended that basic part design principles from thermoplastic injection molding, are followed for design of silicone parts. Uniform wall thicknesses are preferred in silicone injection molding although silicone material does not sink and warp like thermoplastics. It is still suggested for silicone parts, as it allows for uniform silicone material flow in the mold during the liquid injection molding process.Silicone parts allow the designer an added advantage of designing with heavy undercuts as the material has the ability to deform easily and will expand and relieve itself from tooling geometry such as cores and severe undercuts.Silicone parts wall thicknesses begin from 0.015" and go up to inches. It is advised to avoid sharp corners and edges, as this could propagate a tear during the silicone prototype or silicone part demolding process.
Konark's machining capabilities include CNC and EDM machining. Through a consultation with a product development engineer, the silicone part and resulting mold complexity will be used to identify the most suitable process for machining. Based on factors such as project budget, timeline and confidence of the part designer, we will also recommend appropriate mold materials. While it is standard practice to use aluminum for prototyping and steel for production tooling, we also take into consideration how quickly you would like to transition from silicone prototyping stage to production. It is possible to build a production grade, 'steel safe' tool where the critical dimensions are adjustable after molding samples and testing for your application.
Silicone Part Tolerances
We follow the Rubber Manufacturer Association tolerance standards for production tooling which are A1 (High Precision), A2 (Precision), A3 (Commercial) and A4 (Basic).
Tool surface finish
We are capable of achieving highly polished surface finishes if required for the application. In general, glossy mold surfaces cause the silicone parts to stick to the mold and result in increased demolding times. We suggest a D2 surface as it is best for releasing the molded silicone prototypes.
Silicone over molding
Silicone can be over molded onto several thermoplastic materials such as Polycarbonate, PEEK and Nylon or Polyamides. The insert and the silicone part can be designed to have a mechanical bond. If that is not feasible, a primer could be applied to the surface of the insert which would help the adhesion when over molded with silicone. There are also self-adhesive silicone materials available which adhere to certain plastics without the use of a primer. Our engineers can advise in the selection of a primer.
Our silicone prototyping process allows silicone encapsulation to be achieved in multiple ways. The criteria for successful encapsulation is for insert or substrate to be fixed in place without movement, deflection or being damaged due to injection pressure. There are few different approaches to keeping the insert in place in the mold cavity. We will suggest the appropriate encapsulation technique based on the insert and the silicone part design.