Developing a custom silicone product usually begins with an idea, a sketch, an existing sample or a practical problem that needs to be solved. However, turning that initial concept into a reliable molded product requires more than choosing a shape and color.
The product developer must define how the part will be used, select an appropriate silicone material, create a manufacturable 3D design, determine the molding process and test prototypes before beginning mass production.
This guide explains the main steps involved in custom silicone product development and the information a manufacturer needs to evaluate your project.
1. Define the Product’s Application
Before creating a mold, clearly describe what the silicone product must do.
The intended application affects nearly every later decision, including material hardness, product thickness, surface texture, molding method and testing requirements.
Start by answering these questions:
- Will the product be used indoors or outdoors?
- Will it come into contact with skin, food, water, oil or chemicals?
- Does it need to stretch, bend, seal, grip or absorb impact?
- Will it be exposed to high or low temperatures?
- Does the surface need to be smooth, polished, matte or anti-slip?
- Is the product disposable or intended for repeated use?
- What is the expected service life?
- What quantity will be required after prototype approval?
For example, a wearable silicone component used in a wet environment may require a comfortable hardness, tear-resistant connection points and a textured contact surface. An industrial gasket, by comparison, may be selected primarily according to sealing pressure, temperature and chemical exposure.
A clear application description helps the manufacturer evaluate whether silicone rubber is the right material or whether another elastomer should be considered.
2. Decide Whether Silicone Is the Right Material
Silicone rubber is used for flexible molded parts, seals, gaskets, protective components, electrical insulation and products that require stable performance across different environmental conditions.
However, “silicone” is not a single universal material. Different silicone formulations can have different levels of:
- Hardness
- Tensile strength
- Elongation
- Tear resistance
- Compression set
- Temperature resistance
- Transparency
- Colorability
- Electrical properties
- Regulatory suitability
WACKER’s silicone processing guide explains that material and process selection should be based on the required physical and chemical properties, part geometry, production volume and available manufacturing method. It also identifies compression molding, transfer molding, injection molding and extrusion as common silicone processing methods. WACKER silicone material and processing guidelines.
Do not select a material only because it is described as “soft silicone” or “high-quality silicone.” The specification must be connected to the actual product function.
3. Establish the Required Silicone Hardness
Silicone hardness is commonly expressed using the Shore A scale. A lower Shore A value generally indicates a softer material, while a higher value indicates a firmer material.
The correct hardness depends on the function of the finished part:
- Softer silicone may be appropriate for flexible, wearable or cushioning components.
- Medium-hardness silicone is often considered for general molded products, seals and protective parts.
- Firmer silicone may be required where the product must maintain its shape or resist deformation.
Hardness should not be evaluated alone. A thin component made from a firmer material may still feel flexible, while a thick component made from a softer material may feel relatively stiff.
Tear strength is particularly important when a design includes thin straps, holes, tabs or narrow connecting sections. These areas can experience concentrated stress during stretching and repeated use.
For this reason, the manufacturer may recommend testing more than one hardness during the prototype stage.
4. Convert the Idea or Sketch Into a 3D Drawing
A hand sketch, reference image or written description can be sufficient for an initial discussion, but a production mold normally requires an accurate 3D CAD model.
The 3D drawing should define:
- Overall length, width and height
- Wall thickness
- Holes, slots and openings
- Ribs, straps, tabs and connecting features
- Inside and outside radii
- Surface texture
- Logo position
- Assembly areas
- Critical tolerances
- Left-hand and right-hand versions
- Areas that must remain free from mold lines or flash
If the product requires an anti-slip surface, the pattern should be included in the 3D design before the mold is manufactured. Adding texture after tooling has started can require mold modification and additional cost.
Whenever possible, identify which dimensions affect function and which dimensions are only cosmetic. This allows the engineering team to focus tolerance control on the most important areas.
5. Review the Design for Silicone Molding
Design for manufacturability, commonly called DFM, should be completed before mold production.
A silicone part may look correct in a rendering but still be difficult to mold, demold or use. Important DFM considerations include:
Wall thickness
Sudden changes between thick and thin sections can affect curing, material flow and product consistency. The design should use practical transitions wherever possible.
Sharp corners
Sharp internal corners can create stress concentration and increase the risk of tearing. Suitable radii or fillets are often added to make the part stronger and easier to demold.
Thin straps and connection points
An integral strap may reduce assembly work, but the area where the strap connects to the main body must withstand repeated stretching. This transition may require additional thickness or a larger radius.
Undercuts
Silicone’s flexibility allows some undercuts to be demolded, but the feasibility depends on the geometry, material hardness and depth of the undercut.
Parting lines
The mold parting line can affect appearance, sealing and comfort. It should not be placed on a critical sealing or contact surface when this can be avoided.
Flash control
Liquid silicone rubber can flow into extremely small mold gaps, making flash control an important part of mold design. Protolabs also recommends minimizing sharp edges and carefully planning parting lines to reduce tearing and cosmetic defects in LSR parts. Designing for liquid silicone rubber
6. Choose the Manufacturing Process
The best molding process depends on the material, product geometry, quality requirements and expected production quantity.
| Process | Suitable applications | Important considerations |
|---|---|---|
| Compression molding | Custom molded parts, gaskets, pads and low-to-medium production volumes | Tooling may be more economical, but cycle time and manual processing can be higher |
| Liquid silicone rubber injection molding | Complex, consistent parts and medium-to-high production volumes | Higher tooling and equipment requirements |
| Transfer molding | Parts requiring controlled material transfer or inserts | Mold structure and material flow require engineering review |
| Extrusion | Continuous tubing, cords, strips and custom profiles | Best for continuous cross-sectional shapes rather than individual 3D parts |
| Die cutting | Flat gaskets, washers and sheet-based components | Suitable when the product can be cut from silicone sheet |
WACKER notes that injection molding is efficient for producing larger quantities with consistent dimensional quality, while solid silicone processing can offer flexibility for small-to-medium production series. The final choice should be made after reviewing geometry, quantity and performance requirements.
7. Select the Right Prototype Method
Not every prototype serves the same purpose. Before ordering samples, define what the prototype must prove.
Appearance prototype
An appearance prototype is used to evaluate size, shape, color and general ergonomics. It may not use the final production material.
Functional prototype
A functional prototype should reproduce the important flexibility, hardness, fit, grip or sealing performance of the proposed product.
Prototype mold sample
A prototype or low-volume mold can produce parts closer to the intended silicone material and molding process. This is useful when the design must be physically tested before investing in full production tooling.
Production-mold sample
After the production mold is completed, initial samples are checked for dimensions, appearance, flash, performance and consistency before mass production begins.
A 3D-printed soft prototype can be useful for checking shape, but it should not automatically be treated as proof that the same geometry can be mass-produced in silicone. Prototype design and production-mold design should be reviewed together.
8. Test the Prototype Before Mass Production
Prototype approval should be based on measurable requirements rather than appearance alone.
Depending on the product, testing may include:
- Overall dimensional inspection
- Fit and assembly testing
- Hardness verification
- Stretch and recovery testing
- Tear testing around holes or straps
- Surface grip or anti-slip evaluation
- Compression testing
- Water-exposure testing
- Temperature testing
- Repeated-use or fatigue testing
- Color and surface inspection
- Packaging and transportation testing
For a new consumer or wearable product, feedback from real users can reveal pressure points, movement, discomfort or fit problems that are difficult to identify from a 3D model.
Any required material compliance or third-party testing should be confirmed before the production material is finalized. A supplier’s general material statement should not be treated as proof that every finished custom product satisfies a specific regulation.
Information to Send to a Custom Silicone Manufacturer
Providing complete RFQ information can make the engineering review and quotation more accurate.
Prepare the following information when possible:
- Product description and intended application
- 2D drawing or 3D CAD file
- Overall dimensions and critical tolerances
- Preferred material or required performance
- Silicone hardness requirement
- Color or Pantone reference
- Surface finish or anti-slip texture
- Logo, printing or marking requirements
- Required prototype quantity
- Estimated production quantity
- Testing or compliance requirements
- Target delivery schedule
- Reference sample or photographs
If a completed 3D file is not available, send a clear sketch with dimensions and explain how the product should function. The manufacturer can then identify the missing details that must be resolved before tooling.
Common Mistakes in Custom Silicone Product Development
Starting the mold before confirming the design
Changing dimensions, texture or connection points after mold production can create additional tooling cost.
Choosing hardness without testing thickness
The perceived flexibility of a silicone product depends on both material hardness and part geometry.
Making straps or tabs too thin
Flexible features can fail at their connection points if repeated stretching and tear resistance are not considered.
Ignoring the production quantity
A process that is economical for 50 samples may not be efficient for 50,000 production parts. Expected volume should be discussed early.
Treating a visual prototype as a functional sample
A prototype may look correct while using a material that behaves differently from molded silicone.
Leaving surface texture until the end
Functional textures, grip patterns and cosmetic finishes should be included in the design and mold review before tooling begins.
Frequently Asked Questions
Can a custom silicone product be developed from a sketch?
Yes. A sketch, product description or reference sample can start the discussion. However, a manufacturable 3D CAD model is normally required before the production mold is made.
Do I need to specify the silicone hardness?
It is helpful, but not always necessary at the initial inquiry stage. If the hardness is unknown, describe how soft, firm, flexible or stretchable the product needs to be. The manufacturer can then recommend materials for prototype testing.
Can straps and flexible loops be molded together with the main product?
In many cases, integral features are possible. Their feasibility depends on thickness, geometry, required stretch, tear strength, mold structure and demolding method. The connection areas should receive a DFM review.
Can an anti-slip pattern be added to a silicone product?
Yes. A texture or raised pattern can often be incorporated into the mold. It should be defined in the 3D drawing before the mold is manufactured.
Which is better: compression molding or LSR injection molding?
Neither process is automatically better. Compression molding may suit certain custom parts and lower production volumes, while LSR injection molding may be appropriate for complex shapes, automation and larger quantities. Product geometry, material and order volume determine the suitable process.
How much does a custom silicone prototype cost?
The cost depends on product size, complexity, material, prototype method, mold structure and sample quantity. A drawing and estimated production quantity are normally required for an accurate quotation.
What files should I send for a silicone molding quotation?
STEP, STP, X_T and other editable 3D formats are generally more useful for engineering review than image-only files. A dimensioned PDF drawing, material requirements, quantity and application description should also be provided.
Start Your Custom Silicone Product Development Project
A successful custom silicone product begins with a clear application definition and a manufacturable design. Material hardness, wall thickness, surface texture, connection points, molding process and testing requirements should all be reviewed before production tooling begins.
LSAN works with customers who require custom silicone rubber parts based on drawings, samples and application requirements.
To begin an engineering review, contact LSAN and provide your sketch, 3D drawing, required material, prototype quantity and estimated production volume.
