Case Studies of Aluminum Molds: Automotive Parts, Home Appliances, and Medical Devices

◆Table of contents

Introduction

Aluminum molds are approximately 40% lighter than steel molds (specific gravity of about 2.7g/cm³) and boast a high thermal conductivity of about 205W/m·K¹, contributing to shorter molding cycles and reduced cooling inconsistencies². Another significant advantage is the ability to reduce initial mold costs by 10-30% compared to conventional methods³. By mastering this “lightness” and “heat,” they demonstrate superiority in both manufacturing costs and lead times.

This article introduces specific case studies of aluminum molds in three major fields: automotive parts, home appliances, and medical devices. Each chapter will explain the following in order:

The background challenges of the case
Improvement points from introducing aluminum molds
Numerical results (cost reduction rate, yield improvement rate, etc.)

Finally, we will summarize the key points for consideration and the future outlook, providing clear decision-making material for our readers on “why” and “how” they should utilize aluminum molds.

¹ Measured values: Specific gravity 2.70g/cm³, Thermal conductivity 205W/m·K

² Cooling time reduction effect: Up to 15%

³ Initial cost reduction range: Manufacturer-reported values

Aluminum Mold Case Studies in Automotive Parts

Improved Fuel Efficiency Through Weight Reduction

The specific gravity of aluminum alloy is about 2.70g/cm³, which is approximately 65% lighter than steel (about 7.85g/cm³)¹⁾. Leveraging this characteristic, the mass of the molds themselves for steering housings and engine mount parts has been reduced by up to 40%. As a result, the molded parts are 5-10 kg lighter, contributing to a 2-3% reduction in total vehicle weight²⁾. In road tests, there are reports of this weight reduction improving actual fuel efficiency by an average of 3.8%³⁾.

Higher Strength and Crash Safety

Aluminum die-cast products can have their tensile strength adjusted to 150-300 MPa through heat treatment or magnesium addition⁴⁾. For automotive door hinges and crash boxes, mold designs using high-strength aluminum alloys have improved crash energy absorption by 20% compared to conventional products⁵⁾. Furthermore, an optimal resin flow path design to suppress crack propagation has been adopted, extending fatigue life by about 1.5 times⁶⁾.

Improved Productivity Through CAE Analysis and Optimal Design

By introducing CAE (Computer-Aided Engineering) analysis and performing flow and stress analyses in the early stages of mold design, the positions of cooling channels and the shape of sprue gates were optimized, shortening the molding cycle by up to 15% compared to conventional methods⁷⁾. Additionally, the average number of mold prototypes was reduced to 2.3, and there are cases where the development lead time was shortened by about 25%⁸⁾. As a result, with 100 molds cast per year, the annual operating days increased by about 20 days, and the yield at mass production startup improved to 98.7%⁹⁾.

¹⁾ Specific gravity comparison data

²⁾ Weight reduction effect and fuel efficiency improvement estimate

³⁾ Road test results (average fuel efficiency improvement of 3.8%)

⁴⁾ Tensile strength adjustment by magnesium addition

⁵⁾ Test showing 20% improvement in crash energy absorption

⁶⁾ Analysis showing 1.5 times extension in fatigue life

⁷⁾ Effect of 15% reduction in cooling time

⁸⁾ Average of 2.3 mold prototypes

⁹⁾ Achievement of 98.7% yield

Aluminum Mold Case Studies in Home Appliances

Enhanced Heat Dissipation Performance in Heatsink Manufacturing

For heatsinks, a typical heat-dissipating component in home appliances, the high thermal conductivity of aluminum (approx. 205W/m·K) is utilized. By optimizing the fin shape, the heat dissipation area was expanded by 20% compared to conventional designs¹⁾. For example, in a heatsink for an air conditioner outdoor unit, there is a case where the fin thickness was reduced from 0.5mm to 0.4mm, while improving heat dissipation efficiency by 15%²⁾. As a result, the overall system’s power consumption is suppressed by 5% annually, contributing to a reduction in the user’s running costs³⁾.

Improved Aesthetics and Durability of Exterior Casings

Aluminum molds can control surface roughness to Ra0.8μm or less, making high-quality mirror finishes and hairline processing easy for the exterior casings of home appliances⁴⁾. For instance, on the front panel of high-end audio equipment, color irregularities after anodic oxidation treatment (anodizing) were suppressed to within ±3%, achieving both aesthetic appeal and corrosion resistance. Furthermore, while thinning the casing wall from 1.2mm to 1.0mm, rigidity was improved by 5% compared to conventional designs⁵⁾. This successfully achieved both product weight reduction and a high-end look.

Flexibility for Small-Lot, High-Mix Production

The home appliance industry requires frequent model changes and the ability to handle small-lot, high-mix production. The manufacturing lead time for aluminum molds is about 30% shorter than for steel molds, and simple prototype molds can be delivered in as little as two weeks⁶⁾. Initial mold costs can also be reduced by 10-30%, ensuring profitability for small-lot production. Furthermore, by adopting modular split molds, there are cases where the mold change time per part was reduced from the conventional 2 hours to 30 minutes, reducing line stoppage time and enabling diverse design development⁷⁾.

¹⁾ Effect of expanding heat dissipation area by fin optimization

²⁾ Test showing 15% improvement in heat dissipation efficiency by fin thinning

³⁾ Simulation of 5% annual power consumption reduction effect

⁴⁾ Surface roughness Ra0.8μm control technology

⁵⁾ Test of color irregularity and rigidity improvement after anodizing treatment

⁶⁾ Delivery time comparison for simple aluminum molds (vs. steel molds)

⁷⁾ Case study of mold change time reduction using modular split molds

Aluminum Mold Case Studies in Medical Devices

Dimensional Stability Through High-Precision CNC Machining

Medical device parts, such as syringe pistons and catheter insertion points, require high dimensional accuracy of ±0.01mm or less. At Daiwa, the cavities and cores of the mold body are finished with high precision using CNC (Computer Numerical Control) machining to reproduce the shape exactly as designed. Furthermore, by using EDM (Electrical Discharge Machining) in conjunction to supplement the processing accuracy of fine shapes and sharp corners, the risk of product fitting failures and leaks is significantly reduced.

Biocompatible and Sterilization-Resistant Surface Treatments

Parts that come into contact with the human body require biocompatibility and resistance to sterilization. Aluminum molds are given a special surface treatment of anodic oxidation (anodizing) to enhance corrosion resistance. By suppressing the surface roughness after treatment to Ra0.4µm or less, bacterial adhesion is prevented, and the design is made to withstand autoclave sterilization. Additionally, after mold production, deburring and ultrasonic cleaning are thoroughly performed to ensure the cleanliness of the mold surface, reducing secondary processing costs on the product side.

Quality Management System Compliant with ISO 13485

The reliability of medical device molds is supported by a quality management system based on the international standard ISO 13485. At Daiwa, all processes from design to processing, inspection, and shipping are documented and recorded to ensure traceability. During mold production, verification is carried out using dimensional inspection instruments and 3D scanning, and if a non-conformance is found, the process is stopped for cause analysis. This suppresses the post-delivery defect rate to 0.02% or less, strongly supporting the quality assurance operations of medical device manufacturers.

Summary

Overall Summary of Benefits of Introducing Aluminum Molds from Case Studies in Each FieldIn automotive parts, we achieved improved fuel efficiency (average 3.8% improvement) through weight reduction of molds and parts, a 20% increase in crash energy absorption, a 15% reduction in molding cycle time, and a 25% reduction in development lead time by utilizing CAE analysis. In the appliance sector, we achieved a 15% improvement in heatsink heat dissipation performance, and improved aesthetics and weight reduction through high-end mirror finishing and thinning of exterior casings, enabling delivery of prototype molds in as little as two weeks. In the medical device field, we achieved a defect rate of 0.02% or less with high-precision machining of ±0.01mm and an ISO 13485 quality management system, ensuring safety and traceability.
Future Outlook and Key Points for Introduction
- With the advancement of EVs and autonomous driving, the demand for more advanced lightweight and high-strength parts will increase. The fusion of CAE simulation and multi-material design is key.
- In smart appliances and IoT devices, flexibility for small-lot, high-mix production will determine competitiveness. Modular molds and rapid shortening of prototype lead times are essential.
- For personalized medicine in medical devices, fine processing accuracy and strict quality control will become even more important. In addition to ISO 13485, the introduction of clean manufacturing processes and real-time traceability functions is recommended.
- As key points for consideration, plan early for material selection (aluminum alloy), CAE introduction and design flow整備, and establishing a system for compliance with quality management standards.

Aluminum casting & mold design services