Custom Plastic Injection Molding for Electronic Housings

This gray ABS housing was developed for an electronic product with a production requirement of approximately 10,000 parts. Although the component is only about 150 × 60 mm, the inside contains deep perimeter walls, locating features, ribs, small clips and several assembly details that all need to be considered in the mold design.

The customer did not need very high monthly output, so there was little value in adding cavities simply to increase production capacity. After reviewing the part and expected volume, a single-cavity cold runner mold was selected—a straightforward tooling solution that could support the required batch while keeping the initial mold investment reasonable.

For projects like this, our custom plastic injection molding services cover the complete route from drawing and DFM review to injection mold manufacturing, mold trials and repeatable plastic parts production.

Project Overview

The Mold Design Starts from the Inside of the Housing

The outside of this component is relatively simple. Most of the tooling considerations are found on the inside.

The housing has deeper perimeter walls, several ribs and locating features, small retaining clips and detailed structures around both ends. Many of these features are there for assembly, so their geometry cannot be considered only from a cosmetic perspective.

Before cutting steel, the 3D model needs to be reviewed for draft, mold-opening direction, undercuts, wall thickness, gate location and ejection.

The clip-like features deserve particular attention. If one of them creates an undercut relative to the main opening direction, the mold may require a shut-off, lifter, side action or a modification to the feature itself.

This is why we prefer to review the customer's actual CAD data before confirming the final injection mold design and tooling cost.

Why One Cavity Was Enough

A 10,000-piece order justifies injection molding, but it does not automatically justify a multi-cavity tool.

The customer's ongoing demand for this part was moderate. A 1-cavity injection mold could provide the required output without increasing mold size and tooling complexity unnecessarily.

When deciding cavity count, the more useful calculation is not simply how many cavities can fit in the mold. We look at:

Order Quantity → Annual Forecast → Required Delivery → Cycle Time → Mold Investment → Part Cost

For a much larger annual requirement, two or four cavities could reduce the molding cost per part and shorten production time.

For this project, however, the additional tooling investment would have provided production capacity the customer did not currently need.

The mold was therefore designed around the actual production forecast rather than maximum possible output.

Why We Used a Cold Runner Mold

A cold runner followed the same cost logic.

Hot runner systems can reduce runner waste and offer advantages in continuous high-volume production, but they also increase tooling investment and maintenance complexity.

For approximately 10,000 ABS housings, a single-cavity cold runner mold provided a more appropriate balance.

The runner itself may be conventional, but its design still matters. Gate position influences how ABS fills the housing, where weld lines may occur, how the cavity packs and where the gate vestige remains on the finished component.

For an electronic housing, the gate should also be considered in relation to visible surfaces and assembly areas.

So the decision was not simply to use a lower-cost runner system. It was to use the level of tooling complexity that the production volume could justify.

Ribs, Clips and Wall Thickness Need DFM Attention

ABS is commonly used for injection molded electronic housings because it offers good moldability, rigidity, impact performance and surface quality.

The material does not eliminate the need for good part design.

On this housing, ribs and clips provide support and locating functions for later assembly. Where these structures connect to the main wall, local material thickness needs attention.

Excessive material accumulation can cool more slowly than the surrounding wall and contribute to sink marks on the opposite surface. Uneven sections can also influence shrinkage and warpage.

During DFM review, we therefore pay attention to the relationship between:

Main Wall → Ribs → Bosses → Clips → Assembly Features → Exterior Surface

The objective is to preserve the required function while identifying molding risks before the tool is manufactured.

Assembly Features Deserve More Attention Than Non-Critical Surfaces

Many of the small details inside this component exist for a reason.

They locate another component, retain an assembly or establish the position between mating parts.

For production control, those functional features deserve more attention than a non-critical internal surface.

A retaining clip, for example, does not only need to look correct. Its geometry needs to provide the intended engagement with the mating component.

The same applies to locating features and mounting areas.

This is why the customer's 2D drawing and assembly requirements remain important even when a complete 3D model is supplied. They help identify which dimensions need closer inspection during plastic injection molding production.

Selecting the Injection Molding Machine

Based on the approximate 150 × 60 mm size and single-cavity mold, this project could initially be evaluated around an 80–120 ton injection molding machine range.

The actual machine, however, should be selected after the mold design is established.

Clamping force depends on projected area and cavity pressure, while machine suitability also depends on shot weight, mold dimensions, platen size and tie-bar spacing.

For that reason, we would not define the machine simply by looking at the 150 × 60 mm outside dimensions.

The practical sequence is:

Estimate during quotation → Calculate from the mold → Confirm before production.

This gives the production team a more reliable basis for machine selection.

Mold Trial Before the 10,000-Part Run

Once the injection mold is completed, the first step is trial molding—not immediately running the complete order.

Initial molded parts provide an opportunity to check how the ABS fills and releases from the tool and whether the housing meets the agreed requirements.

Depending on the customer's drawings, checks can include:

critical dimensions, clip features, locating points, deformation, surface condition and mating relationships.

Process-related issues can often be addressed through molding parameters. If the problem comes from tooling or part geometry, it can be evaluated before thousands of parts are produced.

The production route therefore follows:

DFM Review → Mold Manufacturing → Mold Trial → Sample Evaluation → Process Confirmation → 10,000-Part Production → Inspection → Packing

This separates mold development from stable batch production.

Gray ABS Parts for Repeatable Production

The customer specified gray ABS for the finished parts.

If a specific shade is required, the color can be defined using a Pantone or RAL reference, or an approved physical sample where appropriate.

Producing the housing directly in the required molded color avoids a separate painting operation.

Once the mold samples and molding conditions are confirmed, the focus shifts to maintaining consistent parts throughout the production run—particularly the clips, locating features and mating areas that influence assembly.

For a 10,000-piece order, repeatability across the batch is more meaningful than producing one perfect sample.

From Injection Mold Tooling to Plastic Parts Production

Our role in a custom plastic injection molding project can cover both tooling development and subsequent production.

For a new customer-designed component, the typical route can include:

Drawing & DFM Review
↓
Injection Mold Design & Manufacturing
↓
Mold Trial and Sample Evaluation
↓
Plastic Injection Molding
↓
Batch Parts Production
↓
Inspection and Packing

This means customers do not need to source the mold and molded parts as two unrelated projects.

The tooling strategy can be developed around the same quantity, material, assembly and production requirements that will later apply to the molded components.

The Right Mold Is Not Always the Bigger Mold

This project is a good example.

The customer needed approximately 10,000 ABS housings—not the production capacity for millions of parts per year.

The selected solution was therefore:

ABS + 10,000 Parts + 1 Cavity + Cold Runner

It provided the required production route without adding cavities or a hot runner system simply because those options were technically possible.

If future demand increases substantially, the economics can be reviewed again.

For the current project, the more important question was:

What tooling investment makes sense for the number of parts the customer actually expects to buy?

That is often a more useful starting point for production managers than comparing mold prices or cavity counts alone.

Custom Plastic Injection Molding Services

We provide custom plastic injection molding services for electronic housings, equipment enclosures and other customer-designed plastic components.

Our production support can include DFM review, injection mold manufacturing, mold trials, ABS injection molding, engineering plastic molding, batch production, inspection and packing.

For each new project, the mold structure and production approach are reviewed according to the part geometry, material, expected quantity and assembly requirements.

Request a Plastic Injection Molding Quote

For a new plastic injection molding project, please send:

3D CAD + 2D Drawings + Material Specification + Color Requirement + Initial Order Quantity + Estimated Annual Volume + Critical Tolerances + Assembly Requirements + Cosmetic Requirements

If you have not yet decided between a single-cavity or multi-cavity mold, or between cold runner and hot runner tooling, the expected annual volume is especially useful.

It gives us a better basis for evaluating the tooling configuration before quotation.