1908HDM011 Top Housing Processing Case: Die Casting + CNC Machining with Black Painting

This article shares the actual processing case of 1908HDM011 top housing, a structural component for intelligent equipment. The part is produced in full accordance with customer drawing requirements, using a combined process of die casting, CNC machining, and surface black painting. The whole production focuses on dimensional accuracy, surface quality, and batch stability, realizing stable mass production of high-quality structural housing.

Part & Material Introduction

The 1908HDM011 top housing is a thin-wall enclosed shell with multiple mounting positions, reinforcing ribs, and assembly limit structures.

According to structural strength, casting formability and post-machining performance, the material is determined to be ADC12 die-casting aluminum alloy. This material has good fluidity, high density after casting, small internal stress, and is suitable for making complex structural shells while ensuring stable CNC machining accuracy.

Full Processing Flow of 1908HDM011 Top Housing

The entire production adopts a step-by-step process to ensure precision and surface effect at each stage.

1. Die Casting Forming

• Process: High-pressure die casting
• Equipment: 800T die-casting machine
• Key points: Controlled casting temperature, pressure and holding time to reduce porosity and shrinkage; formed the overall shape, inner ribs, and basic outline of the housing in one step
• Purpose: Obtain near-net-shape blank with high consistency, laying a foundation for subsequent CNC machining

2. Deburring & Stress Relieving Treatment

• Removed casting flashes, sharp edges and excess material manually and mechanically
• Conducted low-temperature stress relief to reduce deformation caused by internal stress in subsequent CNC machining

3. CNC Precision Machining

This is the core link to ensure assembly accuracy. The contents include:

• CNC milling of the top and bottom mating surfaces to ensure flatness
• Drilling and reaming of mounting holes
• Tapping of threaded holes
• Milling of positioning grooves and limit notches
• Trimming of appearance profile and corner rounding

Controlled tolerance range:

• Mating surface flatness: within 0.05mm
• Mounting hole position tolerance: ±0.05mm
• Thread hole position accuracy: ±0.08mm
• Overall outline dimension tolerance: ±0.1mm

4. Cleaning & Surface Preparation

• Ultrasonic cleaning to remove oil, aluminum chips and cutting fluid
• Sanding and smoothing local surfaces to improve painting adhesion

5. Black Painting Surface Treatment

• Process: Electrostatic spraying + high-temperature curing
• Paint type: Matte black structural paint
• Requirements: Uniform film thickness, no sagging, no missing spray, good adhesion
• Function: Improve corrosion resistance, anti-scratch performance and appearance consistency

6. Full Dimensional Inspection & Appearance Testing

• Used vernier calipers, height gauges and thread gauges for full inspection
• Sampling inspection with coordinate measuring machine (CMM) for key dimensions
• Appearance inspection under standard light source to ensure painting quality

Processing Difficulties & Solutions

1. Thin-wall deformation controlThe housing wall thickness is only 1.8–2.2mm, which is easy to deform during casting and machining. We optimized die-casting parameters and adopted layered milling in CNC to reduce cutting stress, and finally controlled deformation within 0.08mm.
2. Hole position accuracy stabilityMultiple mounting holes require high coaxiality and position degree. We used special fixtures and one-time clamping processing to avoid repeated positioning errors.
3. Painting appearance consistencyIn order to avoid color difference and orange peel in batch products, we unified spraying parameters and curing temperature, and realized consistent matte black appearance.

Batch Production Performance

After stable mass production, the one-time pass rate of size inspection is above 98.5%, the appearance pass rate is above 99%, and the parts can be directly assembled without secondary repair, meeting the customer’s mass production and supply requirements.

FAQ

Q1: What material is 1908HDM011 top housing?

It uses ADC12 die-casting aluminum alloy, which has good casting performance and suitable for thin-wall shell structure.

Q2: What is the full processing technology?

High-pressure die casting → deburring & stress relief → CNC precision milling / drilling / tapping → ultrasonic cleaning → electrostatic black painting → curing → full inspection.

Q3: What tolerance can be achieved in CNC machining?

Mating surface flatness within 0.05mm, hole position tolerance ±0.05mm, outline dimension tolerance ±0.1mm.

Q4: What surface treatment is used?

Matte black electrostatic spraying with high-temperature curing, with good adhesion and anti-corrosion performance.

Q5: What are the key dimensions controlled in this case?

Mainly including mounting hole position, thread hole position, mating surface flatness and overall outline dimensions, all within the required tolerance range.