How Five-Axis CNC Machining Solves Five Major Challenges of Complex Surface Machining in Mold Manufacturing?

How Five-Axis CNC Machining Solves Five Major Challenges of Complex Surface Machining in Mold Manufacturing?

In the mold manufacturing industry, machining complex surfaces has always been a technical challenge. Traditional three-axis CNC machine tools often require multiple setups and processes when dealing with complex geometric shapes such as deep cavities, undercuts, and irregular structures, resulting in low efficiency and potential accuracy issues due to cumulative errors. The advent of five-axis CNC machining technology has revolutionized this field. As a professional engineering team at Brightstar Prototype CNC Co., Ltd, we have deeply experienced the transformative impact of five-axis machining in high-precision mold manufacturing across industries such as aerospace, automotive, and medical devices.

This article will delve into how five-axis CNC machining efficiently addresses the five major challenges of complex surface machining in mold manufacturing, showcasing its technical advantages through real-world case studies.

1. Deep Cavity Mold Machining: Avoiding Tool Interference and Improving Cutting Efficiency

Deep cavity structures are commonly found in automotive panel molds, large injection molds, etc., characterized by significant depth and steep sidewalls. On three-axis machines, due to tool length limitations, machining deep cavities often leads to vibration, tool deflection, or even breakage, resulting in poor surface quality.

Five-axis CNC machines dynamically adjust the tool angle to avoid workpiece interference while maintaining the optimal cutting contact point. For example, when machining an automotive bumper mold, Brightstar Prototype CNC Co., Ltd employs five-axis simultaneous side milling technology, ensuring the tool always engages at the best angle, reducing radial cutting forces and improving machining stability. According to research published in the International Journal of Machine Tools and Manufacture, five-axis deep cavity machining can reduce tool wear by over 50% and increase material removal rates by more than 30% compared to three-axis machining (Source: IJMTM, 2021).

2. Undercut Area Machining: One-Step Forming and Reducing Electrode Wear

Undercut structures are prevalent in plastic molds and die-casting molds. Traditional methods rely on electrical discharge machining (EDM), which requires custom electrodes, leading to high costs and long lead times. Five-axis machines use tool axis vector control to approach the workpiece from different angles, enabling direct milling of undercut areas and significantly reducing EDM processes.

For instance, a medical device required a knee joint mold with complex internal undercuts. Using a three-axis machine would necessitate splitting the mold into multiple parts for assembly. However, the Brightstar team adopted a five-axis simultaneous machining strategy, completing the entire mold in a single operation. This not only shortened the delivery time but also enhanced the mold's sealing performance and lifespan.

3. Freeform Surface Machining: High-Precision Smoothing and Reducing Manual Polishing

Freeform surfaces are common in automotive exterior parts and high-end consumer electronics molds. Traditional machining methods often leave visible tool marks, requiring extensive manual polishing, which is time-consuming and inconsistent.

Five-axis CNC machines use continuous path motion (CPM) to keep the tool perpendicular to the surface normal, ensuring uniform cutting. For example, when machining a luxury car brand's grille mold, Brightstar employed a high-speed five-axis finishing strategy, achieving a surface roughness of Ra 0.4μm with almost no post-machining polishing required. According to CIRP Annals, five-axis freeform surface machining can reduce manual finishing time by 80% (Source: CIRP, 2022).

 4. Thin-Wall Part Machining: Minimizing Deformation Risks and Improving Dimensional Stability

Thin-wall molds (e.g., smartphone frames, drone housings) are prone to deformation or even scrapping during machining due to cutting forces. Three-axis machines, with their rigid feed mechanisms, struggle to adapt to the flexible requirements of thin-wall parts.

Five-axis machining employs variable-angle cutting strategies to dynamically adjust feed directions, distributing cutting forces evenly. For example, when machining a titanium alloy thin-wall aerospace component, Brightstar used trochoidal milling combined with five-axis simultaneous machining, controlling deformation to within 0.02mm—far exceeding the customer's 0.05mm tolerance requirement.

5. Multi-Angle Composite Structure Machining: Reducing Setups and Improving Positioning Accuracy

High-end molds (e.g., turbine blades, precision gearboxes) often feature multi-angle composite geometries. Traditional methods require multiple setups, leading to inefficiencies and potential errors from datum shifts. The RTCP (Rotational Tool Center Point) function of five-axis machines allows complete machining in a single setup by rotating the worktable.

For example, a large energy impeller mold with 12 flow channels at different angles, with consistency errors ≤0.03mm. Brightstar utilized dynamic coordinate system transformation technology on a five-axis machine, completing all features in one setup and avoiding repositioning errors. The final inspection yielded a 100% pass rate.

Brightstar Prototype CNC Co., Ltd's Five-Axis Machining Advantages

As a professional five-axis CNC machining service provider, Brightstar Prototype CNC Co., Ltd has extensive experience in mold manufacturing. Our DMG MORI five-axis machining centers are equipped with high-rigidity rotary tables and intelligent anti-collision systems, capable of tackling the most complex mold challenges. Additionally, our engineering team leverages advanced CAM software like Hypermill & PowerMill to optimize toolpaths, ensuring efficient and precise machining results.

If you are looking for a reliable five-axis mold machining solution, contact the Brightstar team for customized services!

References:  

1. International Journal of Machine Tools and Manufacture (2021), "Toolpath Optimization in 5-Axis Machining of Deep Cavities"  

2. CIRP Annals (2022), "Advanced Finishing Strategies for Freeform Surfaces"  

(This article is original by the technical team of Brightstar Prototype CNC Co., Ltd. Please indicate the source for reposting.)