Hybrid Additive-Subtractive Manufacturing Reduces Prototype Injection Mould Insert Costs by 50%

Why It Matters

Reducing the cost of prototype tooling is crucial for accelerating product development cycles and enabling smaller businesses or research projects to explore new product concepts. This approach democratizes access to advanced manufacturing techniques like particulate injection moulding.

Key Finding

Using a combination of 3D printing and CNC machining for prototype injection mould inserts can overcome the limitations of each individual method, leading to better part quality and lower overall costs.

Key Findings

• Conventional machining and 3D printing both presented challenges with surface finish and part ejection when moulding a brittle titanium feedstock.
• A hybrid approach, integrating additive and subtractive manufacturing, offered a viable solution to mitigate defects observed in single-process methods.
• The hybrid method demonstrated potential for reducing the entry cost for users of PIM.

Research Evidence

Aim: To evaluate the cost-effectiveness and performance of different manufacturing techniques for producing prototype injection moulding inserts.

Method: Comparative experimental study

Procedure: Prototype injection mould cavity inserts were fabricated using three methods: conventional CNC machining, fused filament fabrication (3D printing), and a hybrid approach combining both. These inserts were then used in injection moulding trials with a brittle titanium metal blend feedstock. The resulting parts were analyzed for surface finish and ease of removal, and modifications were made to address observed defects.

Context: Prototyping for particulate injection moulding (PIM)

Design Principle

Hybrid manufacturing offers a flexible approach to prototype tooling, allowing for the optimization of complex geometries and material properties.

How to Apply

When designing a prototype for injection moulding, investigate the feasibility of using a combination of 3D printing for initial form and CNC machining for critical surface finishes or features to reduce tooling costs and development time.

Limitations

The study focused on a specific brittle metal blend feedstock, and results may vary with different materials. The cost savings are specific to the prototype stage and may not scale directly to mass production.

Student Guide (IB Design Technology)

Simple Explanation: Making prototype molds for plastic or metal parts can be expensive. This research shows that using a mix of 3D printing and traditional machining can make these prototype molds cheaper and work better, especially when using difficult materials.

Why This Matters: Understanding different prototyping techniques helps in making informed decisions about tooling, which directly impacts the feasibility and cost of bringing a new design to life.

Critical Thinking: How might the specific geometric features of a part influence the optimal choice between additive, subtractive, or hybrid manufacturing for its injection mould insert?

IA-Ready Paragraph: Research by Ewart (2019) suggests that a hybrid manufacturing approach, combining additive and subtractive techniques, can significantly reduce the cost of prototype injection moulding inserts. This method addresses limitations found in using either 3D printing or CNC machining alone, particularly when working with challenging materials like brittle metal blends, thereby lowering the barrier to entry for advanced manufacturing processes.

Project Tips

• When choosing a prototyping method, consider the trade-offs between cost, speed, and the specific material properties of the final product.
• Investigate hybrid manufacturing techniques for projects requiring complex geometries or specific surface finishes.

How to Use in IA

• Reference this research when discussing the selection of prototyping methods for your design project, particularly if cost reduction or material challenges are a factor.

Examiner Tips

• Clearly articulate the rationale behind choosing a specific prototyping method, referencing research on cost-effectiveness and material compatibility.

Independent Variable: ["Manufacturing technique (CNC machining, 3D printing, hybrid)","Material feedstock (titanium metal blend)"]

Dependent Variable: ["Surface finish of moulded parts","Ease of part removal from the mould","Cost of insert production"]

Controlled Variables: ["Injection moulding machine settings","Geometry of the mould insert","Type of feedstock used"]

Strengths

• Direct comparison of multiple manufacturing methods.
• Addresses a practical problem of high prototyping costs.

Critical Questions

• What are the long-term durability differences between inserts produced by these methods?
• How would the results change with different polymer or metal feedstocks?

Extended Essay Application

• Investigate the economic feasibility of establishing a hybrid prototyping service for small businesses.
• Explore the optimization of hybrid manufacturing parameters for specific complex geometries.

Source

A comparison of processing techniques for producing prototype injection moulding inserts. · University of Auckland · 2019