Product Specification

CNC Machined Aluminum Housing for Home Appliances

This project involved 300 sets of custom aluminum housings for a home appliance customer in the United States. Each housing measured approximately 450 × 300 mm and featured a large internal cavity, rounded side walls, stepped perimeter edges and multiple openings machined on different faces.
After CNC machining, the components were ground and prepared for 150-grit sandblasting, followed by clear anodizing.
The main production challenge was not one isolated precision feature. It was maintaining the overall geometry of a large enclosure after extensive material removal while achieving consistent surface quality across all 300 sets.

Project Overview

Large-Cavity Aluminum CNC Machining

The broad internal cavity is the defining feature of this housing. Producing it requires removing a substantial volume of aluminum while retaining the cavity floor, rounded walls, perimeter structure and internal mounting details.
At the beginning of machining, the aluminum blank has sufficient rigidity. As the cavity becomes wider and deeper, the remaining structure becomes more responsive to cutting forces, clamping pressure and the release of internal material stress.
An unsuitable machining sequence could affect:

• Flatness across the cavity floor;
• Shape of the rounded side walls;
• Consistency of the perimeter step;
• Position of the side holes and cutouts;
• Location of internal mounting features;
• Overall enclosure geometry.

The cavity was therefore machined progressively. Roughing operations removed the majority of the material, while subsequent toolpaths established the internal surfaces, wall transitions and perimeter features.
This staged approach provided greater control as the housing became less rigid during machining.

Toolpath Planning Across a 450 × 300 mm Surface

Large internal surfaces require a different machining strategy from small pockets.
The visible cutter paths across the cavity show the extensive cutting area involved. On a component of this size, toolpath planning influences machining time, surface consistency and the amount of grinding required before sandblasting.
Particular attention was given to the transitions between the cavity floor and the rounded walls. Unstable cutting or sudden changes in tool engagement could leave deeper marks in these areas. Such marks would require additional manual finishing and might remain visible after clear anodizing.
The final CNC passes were therefore intended to leave a controlled and consistent base surface. The uniform matte appearance would be created later through 150-grit sandblasting rather than by the machining texture alone.

Machining Holes and Openings on Multiple Faces

In addition to the internal cavity, the housing contains holes and openings distributed along its side walls. Their positions needed to remain consistent relative to the main cavity, perimeter and internal mounting features.
Machining features on different faces generally requires secondary positioning or additional setups. With a 450 × 300 mm enclosure, each setup must maintain a reliable reference to the primary housing geometry.
The process controlled the relationship between:

• Internal cavity surfaces;
• Perimeter reference edges;
• Side holes and cutouts;
• Internal mounting positions;
• Other assembly-related features.

The machined openings were also deburred carefully. Remaining burrs could interfere with installation, while excessive manual grinding could enlarge an opening, soften a defined edge or leave an uneven area that became visible after anodizing.

Maintaining Consistency Across 300 Sets

This order required a repeatable production process rather than a one-time machining solution.
Changes in cutting tools, fixture positioning or clamping pressure can gradually influence a large aluminum enclosure. Waiting until the full quantity was completed before inspection would create unnecessary risk, especially because the housings still needed to pass through grinding, sandblasting and anodizing.
In-process inspection focused on:

• Overall length and width;
• Cavity and perimeter geometry;
• Large-surface flatness;
• Side-hole positions;
• Internal mounting features;
• Condition of machined edges.

These checks helped identify dimensional or surface issues before the housings entered finishing.
Once a part has been anodized, machining rework becomes more difficult. A repaired area may also appear different from the surrounding clear anodized surface. Inspecting the parts during production therefore helped reduce both schedule and appearance risks.

Grinding Before 150-Grit Sandblasting

Following CNC machining, the housings were ground to remove burrs, deeper cutter marks and local surface irregularities.
Grinding was a preparation step rather than the final cosmetic finish. Broad surfaces could be blended evenly, while holes, perimeter steps and clearly defined edges required lighter, more controlled treatment.
Excessive grinding could result in:

• Rounded edges around functional openings;
• Reduced definition along the perimeter;
• Low areas on broad surfaces;
• Uneven wall-to-floor transitions;
• Visible hand-finished patches after anodizing.

The objective was to improve the surface condition without altering the functional geometry of the enclosure.
The prepared housings were then sandblasted using 150-grit abrasive media. This produced a fine matte texture across both the internal and external aluminum surfaces.
Consistent blasting coverage was particularly important around the broad cavity floor, rounded walls, perimeter steps, side openings and recessed areas.

Clear Anodizing Retains the Aluminum Appearance

Clear anodizing—also known as natural anodizing—was applied after sandblasting. It retains the metallic appearance of the aluminum while improving surface protection.
Unlike paint or another opaque coating, clear anodizing does not hide the condition of the underlying metal. Deep scratches, dents, aggressive grinding marks or inconsistent sandblasting may remain visible after treatment.
The housings were therefore inspected before anodizing instead of relying only on a final appearance check.
After anodizing, inspection covered:

• Uniformity of the sandblasted texture;
• Scratches and handling marks;
• Noticeable color differences;
• Finish around holes and recessed areas;
• Damage to the perimeter edges;
• Contact marks between components.

The finished housings were separated during packing to reduce rubbing and impact between anodized surfaces during transportation to the United States.

Custom CNC Machining Services for Aluminum Housings

This project demonstrates why a large CNC machined aluminum housing must be evaluated as a complete structure. Cavity machining, secondary setups, edge preparation, sandblasting and anodizing all influence the finished component.
Our aluminum CNC machining service supports non-standard housings, enclosures, frames, brackets and structural parts manufactured from customer-supplied 2D and 3D drawings.
Available project support includes:

• CNC milling and multi-face machining;
• Large aluminum enclosure machining;
• Prototype and batch production;
• Grinding, polishing and deburring;
• Sandblasting and anodizing;
• Dimensional and appearance inspection;
• Assembly-fit checking when required;
• Protective packaging for export.

Our broader custom CNC machining services cover aluminum, stainless steel, brass, copper and engineering plastics for home appliances, automation equipment, medical devices, electronics and other industrial applications.
For large aluminum housings, we consider not only whether the geometry can be machined, but also how the structure may respond as material is removed and how the machined surface will appear after finishing.

Request a Quote for Custom CNC Aluminum Parts

For any custom aluminum housing project, please provide your 2D drawings, 3D model, material grade, order quantity, tolerances and surface-finish requirements.
Whether the design involves a large internal cavity, thin walls, side openings or multiple mounting features, we review the material-removal strategy, workholding method, machining sequence and finishing requirements before production.
By evaluating CNC machining and surface treatment as one connected process, we can identify potential dimensional, assembly and appearance risks before the project moves into batch production.