Custom Silicone Rubber Parts for Electronic Product Assembly

For small silicone components used inside an electronic product, the difficult part is often not making the first sample. It is keeping the same fit and molded condition when production reaches thousands of sets.

This project involved 10,000 sets of custom black silicone rubber parts for an electronic product manufactured for a customer in Italy. The specified hardness was 50 Shore A.

The components include small button-related parts and rectangular mounting pieces with holes and raised functional areas. Their dimensions and flexibility are closely related to the surrounding assembly, making consistency particularly important during volume production.

Project Overview

Small Silicone Parts with Tight Assembly Relationships

These are custom molded components rather than standard rubber parts.

Looking closely at the design, the parts contain several features that relate directly to assembly: defined outer edges, mounting holes, local raised areas and small button-related structures.

None of these features works independently.

The silicone part has to sit in the intended position relative to the surrounding housing, frame or button. If its position shifts or the molded geometry varies too much, the available clearance around neighboring components can change.

This is why we do not evaluate silicone components for electronics only by looking at the rubber part itself. Where fit is important, the relationship with mating components also needs to be considered.

For compact electronic assemblies, a seemingly small difference can become noticeable once all the parts are put together.

50 Shore A: Hardness Is Part of the Design

The customer specified 50 Shore A silicone rubber for this project.

Shore hardness influences how a molded silicone component feels, deforms and returns to its original shape. For button-related parts, it can also contribute to the way the component behaves when pressed or retained inside the assembly.

We therefore treat hardness as a functional specification rather than simply another line on the material list.

A customer requesting custom silicone rubber parts can define the required hardness together with color, dimensions and other product requirements. If a specific silicone grade is required, that should also be identified before production.

The goal is to manufacture the part according to its actual application—not to assume that one silicone hardness works for every electronic product.

10,000 Sets Changes the Manufacturing Focus

A few approved samples tell us whether the basic tooling and part design are working.

A 10,000-set production order asks a different question:

Can that result be maintained consistently?

For this type of project, repeatability matters across the entire batch. Hole positions, molded edges, button areas and overall shape should not gradually become less controlled as production continues.

Our attention therefore shifts from simply “making the part” to maintaining the approved condition during production.

Checks may focus on areas such as:

• overall molded dimensions;
• mounting and locating features;
• button-related geometry;
• edge and parting-line condition;
• excessive flash;
• visible deformation;
• surface appearance;
• specified material and Shore hardness.

The exact inspection requirements depend on the drawing and which features are critical to the customer's assembly.

Flash Can Become an Assembly Problem

Flash is a particularly relevant issue on small molded silicone parts.

Because silicone can flow into very small gaps, unwanted material may appear around parting lines, holes or other local features if tooling and molding conditions are not properly controlled.

Not every trace of a molding line affects function. Location matters.

A small amount of excess material on a non-critical external edge may be very different from flash around a button interface or mounting hole. In a closely fitted electronic assembly, material in the wrong place can reduce clearance or make installation less consistent.

For that reason, functional areas deserve specific attention during silicone rubber molding, rather than applying the same visual standard to every surface.

From Sample Approval to Volume Production

For custom silicone parts, moving into production should come after the important requirements have been established.

We normally work from the customer's 3D CAD data and 2D drawings, together with information such as silicone specification, Shore hardness, color and quantity.

When a component has a close relationship with neighboring parts, assembly information can also be useful.

A typical project may move through:

Drawing Review → Tooling → Sample Molding → Fit / Appearance Check → Customer Approval → Volume Production → Final Inspection

The exact sequence can vary depending on the project.

What matters is that the 10,000-set order is based on an agreed part condition rather than discovering assembly problems only after volume production has begun.

Why Molding Makes Sense for 10,000 Sets

3D printing and other prototype processes are useful when a design is still changing or only a handful of parts are required.

This project had moved beyond that stage.

With 10,000 repeated sets, custom tooling and silicone molding provide a more appropriate route for producing the same geometry efficiently across the batch.

Once the design and mold are confirmed, small holes, raised structures, flexible areas and locating features can be formed as part of the molded component.

This is particularly useful for non-standard electronic products where a catalog rubber part cannot match the required shape.

Custom Silicone Molding for Electronic Products

YS Precision provides custom silicone rubber molding services for electronic and industrial applications based on customer drawings.

Projects may include button components, flexible interfaces, covers, seals, cushions, protective parts and other non-standard molded silicone components. Depending on the application, requirements can include material grade, hardness, color, dimensional features, surface condition and assembly fit.

For this Italian project, the requirement was 10,000 sets of black 50 Shore A silicone rubber components. The manufacturing focus was not simply quantity, but maintaining the small functional features and assembly consistency needed throughout the batch.

If you are sourcing custom silicone rubber parts for an electronic product, send us your 2D/3D drawings, silicone requirements, Shore hardness, color, quantity and critical assembly information. We can review the parts before tooling and volume production.