Traditional vs. Modern Mold Manufacturing

Mold manufacturing is an important part of many industries producing everything from automotive spares to consumer goods. Traditional methods have been reliable for decades. Methods like CNC machining and Electrical Discharge Machining offered precision and durability. However, these methods are time consuming and costly majorly for complex designs.

Modern techniques, like 3D printing, are transforming the field as they allow faster production, reduced waste and greater design flexibility. Comprehending both traditional and modern methods gives manufacturers a competitive edge and optimizes their production.

In this article, we will go through the differences between the two molding techniques and examine the benefits and limitations of each in order to help you choose the best method for your specific needs.

CNC Machining Vs 3D printing  (Image Source: Diversified Machine Systems)

Traditional Mold Manufacturing

Traditional custom injection molding encompasses several key processes which in include: 

1. Machining (CNC milling, turning, EDM)

Machining involves the use of CNC milling, turning, and electrical discharge machining (EDM). CNC milling and turning shapes the mold from a solid block of material. EDM uses electric discharge to undermine materials and thus provide complex details and shapes.

2. Casting

Casting involves pouring molten metal into a mold to form a specific shape. When the metal cools and solidifies, the mold is removed and leaves the casting. This method is suitable for the rapid production of large quantities of molds.

3. Hand Finishing and Polishing

After machining or casting, molds often require manual processing and polishing. Skilled technicians smooth out imperfections and ensure themold’s surface is precise and clean. This step is essential to achieve a high quality finish on your molded product.

Materials Used

There are various materials used in traditional mold manufacturing. They are as follows: 

1. Steel (P20, H13)

One of the most commonly used materials used in traditional mold manufacturing is steel. The P20 steel is known for its ability to provide good polishing and machining.

H13 offers brilliant rigidness and heat resistance, making it exceptional for high-temperature.

2. Aluminum

Aluminum is another popular form material. It is lighter and easier to work with than steel. Compared to steel molds, aluminum molds have a shorter life, so they are suitable for small and medium batches.

3. Copper Alloys

Copper alloys are specified for mold components that require excellent thermal conductivity. These alloys ensure heat dissipates rapidly thus improving cycle times and part quality.

Advantages

• Proven and Reliable Techniques: Over time, traditional methods have stood the test of reliability and service delivery. These techniques are well-understood and accepted at large by the industries.
• High Precision and Durability: Traditional methods offer accurate results. The end products are robust and can withstand repeated use, making them suitable for high-volume production.
• Established Industry Standards: Traditional mold manufacturing follows established industry standards. This ensures compatibility and reliability across different production setups and industries.

Disadvantages

• Longer Lead Times: this is a major drawback in industry that is time-sensitive as the process of machining, casting and hand-finishing can take weeks or even months.
• Higher Costs for Complex Designs: Setting up equipment for complex designs is usually high. The need for specialized machining and skilled labor increases the overall production costs.
• Limited Design Flexibility: Traditional manufacturing has limited design flexibility. Certain complex geometries and intricate details are challenging or impossible to achieve with these methods. This limits the scope for innovation and customization in mold design.

Modern Mold Manufacturing

Modern mold manufacturing uses advanced technologies to increase efficiency and capabilities. These processes include 3D printing and hybrid manufacturing. Let’s explore them in more detail.

1. 3D Printing/Additive Manufacturing (FDM, SLA, SLS, DMLS)

In 3D printing, molds are built layer by layer from digital models. It is also known as Additive manufacturing.  Fused Deposition modeling(FDM) uses thermoplastic filaments to create parts.

3D printing (Image Source: Freepik)

Stereolithography (SLA), on the other hand, uses lasers to solidify liquid resin into solid plastic, while selective laser sintering (SLS) and direct metal laser sintering (DMLS) use lasers to sinter powdered materials to create strong and durable components.

2. Hybrid Manufacturing (combining traditional and additive methods)

Hybrid manufacturing uses a combinational method of CNC machining with additive manufacturing. This approach leverages the strengths of both methods, allowing for rapid prototyping and detailed finishing. It offers the flexibility of 3D printing with the precision and durability of traditional machining.

Materials Used

Some of the materials used in modern mold manufacturing include: 

1. Advanced Polymers

Advanced polymers are commonly used in modern mold manufacturing. These materials have high strength, are flexible, and resistant to wear and tear. They are suitable for creating detailed and durable molds.

2. Metal Powders (stainless steel, titanium)

Metal powders like stainless steel and titanium are used in additive manufacturing processes like DMLS. These materials provide excellent strength and durability. They are ideal for molds that need to withstand high temperatures and pressures.

3. Composites

With a combination of different materials, Composite materials improve the performance of the mold. They offer a balance between strength, flexibility and durability. Composites are used in applications that require special material properties.

Advantages

• Greater Design Flexibility: Modern manufacturing methods are greatly flexible especially for molds with complex geometries and intricate details. This allows room for innovation and customization.
• Reduced Lead Times and Costs: Additive manufacturing offers minimal lead times and costs. Molds can be produced quickly without the need for extensive tooling. This makes it cost-effective, especially for small to medium production runs.
• Ability to Create Complex Geometries: 3D printing is prominent in creating complex designs that would otherwise be difficult to design with traditional methods.This capability enables the production of highly detailed and functional molds.
• Rapid Prototyping and Iterative Design: One useful advantage of modern methods are their abilities to provide rapid prototyping and designing iteratively. Designers quickly produce and test multiple iterations simultaneously thus refining the mold designs to meet exact requirements.

This accelerates the development process and improves product quality.

Disadvantages

• Material Limitations and Higher Costs for Certain Materials: Materials like, high-strength metals can be expensive and challenging to work with, increasing production costs for specific applications.
• Surface Finish and Precision Challenges: To achieve high precision can be a challenge as often post-processing steps like sanding and polishing are required to meet desired standards.
• Durability and Strength Considerations: Products manufactured using modern methods may not always match the durability and strength of traditional methods as some of them tend to wear out faster or cannot withstand constant high-pressure.

Comparative Analysis 

Traditional and modern mold manufacturing can be compared based on various aspects. Below we will explore these comparative factors!

Design Flexibility

Traditional mold manufacturing offers limited design flexibility. Complex geometries are hard to achieve and often require multiple steps. Modern methods like 3D printing allow for intricate designs and customization. 

Lead Times and Costs

As stated earlier, traditional methods have longer lead times since the process has multiple stages of production, increasing costs especially for complex molds. Modern techniques like 3D  printing minimize lead times thus being cost-effective.

Precision and Quality

When it comes to precision and quality, traditional methods reign as the top contenders. Machining and EDM ensure high accuracy and excellent surface finishes. Consequently, modern methods have also enhanced in these areas i.e 3D printing can achieve high precision with post-processing for optimum surface quality.

Material Selection

Traditional manufacturing uses material such as aluminum, steel, and copper alloys which are strong and durable. As much as they offer the durability advantage, these materials can be expensive and difficult to work with for complex designs.

Environmental Impact

Traditional manufacturing produces more waste because of its subtractive processes.It also consumes significant energy, especially in machining and EDM. Modern methods like 3D printing are eco-friendly and are more energy-efficient thus less waste is released to the environment.

CNC machining (Image Source: Istock)

Conclusion 

Both traditional and modern mold making methods have their advantages and disadvantages. Traditional technologies provide accuracy and reliability, while modern methods such as 3D printing provide design flexibility and efficiency. You need to understand both ways to optimize production, improve innovation and stay competitive in the industry.