Custom Aluminum Die Cast Mechanical Housing with CNC Machining

A complex mechanical housing is not simply a shape to be reproduced in aluminum. Before tooling begins, the design needs to work with the die casting process, critical interfaces need to be identified for secondary machining, and the finishing requirements need to be considered alongside the part geometry.

For this custom aluminum die cast mechanical housing, we started with DFM and drawing review.

The component measures approximately 200 × 120 × 100 mm and combines a multi-sided body, curved reinforcing ribs, a large central opening, mounting holes and several functional interfaces. We reviewed the customer's 2D drawings and 3D CAD data, discussed manufacturability concerns with their engineering team, and agreed on the required design details before tooling.

A dedicated single-cavity high-pressure die casting die was then developed. After casting, the housing goes through secondary CNC machining, grinding, sandblasting and spray painting before shipment to Italy.

Project Overview

Start with DFM, Not with Tooling

For custom aluminum die casting, the best time to solve a manufacturability issue is before the die is built.

This housing contains ribs, bosses, openings, mounting features and transitions between different wall sections. Each of these features can influence tooling, metal flow, part release or the machining operations that follow.

During DFM, we review details such as:

• parting-line location and die opening direction;
• draft angles;
• wall and rib thickness;
• fillets and transitions between sections;
• bosses and mounting features;
• gate, overflow and venting considerations;
• ejection requirements;
• machining allowance on critical interfaces;
• coating and masking requirements.

If we identify a feature that could create difficulty in tooling, casting or subsequent machining, we discuss it with the customer before the design is released for die manufacturing.

The objective is to preserve the intended function while making the part practical to manufacture.

Curved Reinforcing Ribs Add More Than Shape

The curved ribs across the upper body are one of the defining features of this die cast aluminum housing.

They reinforce the structure without requiring the entire upper section to become a thick, heavy wall. Because the ribs follow the profile of the housing, they can be formed together with the main body during high-pressure die casting.

Their design still matters to the casting process.

Rib thickness, draft, fillet radii and transitions into adjacent walls can influence filling, solidification and die release. Abrupt changes in section thickness can also make the casting more difficult to control.

For this reason, the ribs are reviewed as part of the overall casting structure during DFM rather than treated as isolated external features.

Die Cast the Geometry, CNC Machine the Interfaces

Most of the housing geometry—including the body, ribs, bosses and general mounting structure—is created during high-pressure aluminum die casting.

Selected features then receive secondary CNC machining where the drawing requires additional dimensional control.

Depending on the final design, these operations can include:

• machining the large central opening;
• finishing mounting and mating surfaces;
• drilling, boring or reaming holes;
• drilling and tapping threaded features;
• machining locating features;
• finishing assembly interfaces.

Machining allowance is planned before the die is manufactured. This ensures that surfaces requiring CNC finishing retain appropriate stock after casting.

The principle is straightforward: use die casting for complex near-net-shape geometry and CNC machining where precision affects fit or function.

This avoids unnecessary machining while providing tighter control over the features that matter to assembly.

Why a Single-Cavity Die for This Housing?

Cavity count should be determined by the component and production requirements rather than maximized by default.

For this approximately 200 × 120 × 100 mm multi-sided housing, a single-cavity die was selected to suit the part geometry and tooling layout.

The die needs to accommodate the curved ribs, central opening, mounting structures and multiple exterior faces while providing suitable filling, venting, ejection and process stability.

Once the tool is completed, trial castings are used to evaluate the actual part before regular production proceeds.

This stage provides an opportunity to check the casting condition and drawing-defined features on a real component rather than relying only on the CAD model.

From Raw Casting to a Painted Mechanical Housing

The component is supplied as a finished housing rather than a raw die casting.

After casting, trimming and CNC machining, local grinding is performed where required to remove unwanted marks and prepare the surface. Sandblasting follows to produce a more uniform texture before spray painting.

The manufacturing route is:

DFM & Drawing Review → Die Casting Tooling → Trial Casting → High-Pressure Die Casting → Trimming & Deburring → CNC Machining → Grinding → Sandblasting → Spray Painting → Inspection

The multi-sided structure creates ribs, recesses and intersecting surfaces that all need to be considered during finishing.

Threaded holes, precision interfaces or other areas that must remain paint-free can be masked according to the drawing requirements.

Inspect Before and After Surface Finishing

A good painted surface cannot compensate for a dimensional problem underneath it.

Inspection therefore follows the component through the manufacturing process.

The casting is checked for relevant defects, deformation and general condition before secondary processing. After CNC machining, drawing-controlled holes, locating features and mating surfaces are verified before painting.

Final inspection then covers paint appearance, coverage, masking boundaries and protected functional areas.

Checking the part at these stages makes it easier to identify an issue before additional processing has added unnecessary time and cost.

One Manufacturing Route from Drawing to Finished Housing

For an overseas buyer sourcing custom die cast aluminum parts, coordinating tooling, casting, machining and finishing through separate suppliers can add complexity to a project.

For this mechanical housing, these processes are considered around the same drawing from the beginning.

DFM determines what should be addressed before tooling. Die casting creates the complex body efficiently. CNC machining controls the critical interfaces. Grinding, sandblasting and painting complete the specified exterior.

This approach is suitable for custom mechanical housings, equipment enclosures and other non-standard aluminum die cast components that require more than a raw casting.

Need a Custom Aluminum Die Cast Housing?

If you are developing a custom aluminum die cast mechanical housing, send us your 2D drawings and 3D CAD files for review.

We can evaluate the casting geometry, draft, wall and rib design, tooling feasibility, machining allowance, critical interfaces and surface finish requirements before die manufacturing begins.

By resolving these details early, tooling, die casting, CNC machining and finishing can be planned around the final component requirements rather than treated as separate manufacturing problems.