Plastics : Combining 3D printing with traditional manufacturing methods in the plastic industry

Additive manufacturing integration means combining 3D printing with traditional plastic manufacturing methods like injection molding, extrusion, and blow molding to create hybrid production systems that leverage the best of both worlds.

What is additive manufacturing integration?

Instead of replacing traditional manufacturing entirely, companies are strategically blending 3D printing with conventional methods. 

Each has its strengths, and sometimes you use them together for the best results.

Traditional manufacturing excels at high-volume production of identical parts, while additive manufacturing (3D printing) shines at customization, complex geometries, and small batches. 

Integration combines these strengths in intelligent ways.

Key integration approaches:

Hybrid tooling and molds:

• Traditional challenge: creating injection molds is expensive and time-consuming, especially for prototypes or low-volume runs.
• Integration solution: companies use 3D printing to create mold inserts, tooling components, or even complete molds for short production runs.
• Example: BMW uses 3D-printed jigs and fixtures alongside traditional injection molding. Instead of machining custom tooling that takes weeks and costs thousands, they 3D print fixtures in days for hundreds of dollars. 

These printed tools guide traditional manufacturing processes for producing car interior components.

Process flow: 

1. Design 
2. 3D print tooling  
3. Use printed tooling in traditional injection molding
4. Produce parts in high volumes

Rapid prototyping to production bridge:

Traditional process: 

1. Design 
2. Prototype 
3. Test 
4. Modify tooling 
5. Production (months of iteration)

Integrated process: 

• Design 
• 3D print prototype
• Test 
• Refine digitally 
• Go straight to traditional production

Procter & Gamble develops new bottle designs by 3D printing prototypes for testing. Once perfected, they use traditional blow molding for mass production. 

This cuts development time from 6 months to 6 weeks while maintaining the cost-effectiveness of traditional manufacturing for large volumes.

Conformal cooling channels:

Traditional limitation: 

Injection molds typically use straight drilled cooling channels, leading to uneven cooling and longer cycle times.

Integration innovation: 

3D print mold inserts with complex, curved cooling channels that follow the part's geometry exactly.

Real impact: 

A automotive parts manufacturer reduced injection molding cycle time by 25% and improved part quality by using 3D-printed mold inserts with conformal cooling. 

The traditional mold frame remains the same, but the 3D-printed inserts provide superior performance.

Integration examples:

Automotive industry (Mercedes-Benz):

• Traditional Process: injection molding plastic interior trim pieces 
• Integration Addition: 3D printing custom assembly jigs and inspection gauges 
• Result: 50% reduction in tooling costs and 75% faster setup times for new model variations

How it works:

• Main parts still produced via injection molding (cost-effective for thousands of units)
• Custom assembly fixtures 3D printed for each car model variation
• Quality control gauges 3D printed and updated as designs evolve
• Traditional and additive processes work together seamlessly

Medical device manufacturing:

• Traditional: Injection molding standard syringe components
• Integration: 3D printing patient-specific modifications and testing prototypes

Example process:

• Standard syringe bodies: Traditional injection molding (millions of identical units)
• Custom grip attachments: 3D printed for patients with limited mobility
• Prototype testing: 3D print new designs before committing to expensive molds
• Final production: Traditional methods for proven designs

Consumer electronics:

Jabil:

Use 3D printing for bridge production while traditional tooling is being prepared following the below timeline:

• Week 1-2: 3D print initial product batches for market testing
• Week 3-8: Traditional tooling development continues
• Week 4-8: 3D print production quantities (hundreds to thousands)
• Week 9+: switch to traditional injection molding for mass production
• Benefits: products reach market 6-8 weeks earlier, customer feedback incorporated before major tooling investment.

Technical integration methods:

Multi-stage manufacturing:

• Concept: combine different manufacturing methods in sequence for a single part.
• Example: smartphone cases 
• Base structure: traditional injection molding for strength and cost
• Custom logos or textures: 3D print and over-mold onto base
• Final assembly: traditional automated assembly lines

Embedded Components:

• Concept: 3D print complex internal structures that would be impossible with traditional methods, then over-mold with traditional processes.
• Example: fluid handling manifolds
• Internal channels: 3D print complex internal geometries
• Outer housing: traditional injection molding for durability and cost
• Result: parts with internal complexity impossible through traditional means alone

Material Property Optimization:

• Strategy: Use each process where its material properties are strongest
• Example: power tool housings
• Load-bearing sections: Traditional injection molding with glass-filled nylon
• Ergonomic grips: 3D printed with flexible TPU materials
• Assembly: Traditional ultrasonic welding

Economic benefits of integration:

Cost Optimization:

• Traditional Only: high setup costs, long lead times, but low per-part costs at high
• volumes Additive Only: low setup costs, short lead times, but high per-part costs
• Integrated: optimal cost structure across the entire product lifecycle

Real Numbers Example:

• Prototype phase: 3D printing costs $50/part versus $10,000 mold setup
• Low volume (1-1000 units): 3D printing costs $25/part versus $15/part traditional
• High volume (10,000+ units): traditional costs $2/part versus $20/part additive
• Integrated approach: use 3D printing for prototypes and bridge production, traditional for volume

Inventory Reduction:

• Traditional problem: must forecast demand and pre-produce inventory 
• Integration solution: 3D print on-demand items while maintaining traditional production for predictable volumes
• Example: replacement parts inventory
• High-demand parts: traditional manufacturing with inventory
• Low-demand parts: 3D print on-demand
• Result: 60% reduction in inventory costs while maintaining part availability

Quality and performance integration:

Testing and Validation (Automotive Example):

• Process: Use 3D printing for extensive testing before committing to traditional tooling.
• Design phase: 3D print 50 different design variations
• Testing phase: physical and performance testing on printed parts
• Optimization: refine design based on test results
• Production: create traditional tooling for optimized design
• Result: first production parts meet specifications without tooling modifications

Hybrid material properties:

• Process: combine materials and processes to achieve properties impossible with single methods.
• Example: drone components
• Frame: traditional carbon fiber molding for strength-to-weight ratio
• Mounting brackets: 3D printed metal for complex geometries
• Housings: traditional injection molding for weather resistance
• Custom connectors: 3D printed for exact fit requirements

Current challenges and solutions:

Workflow Integration:

• Challenge: different software, processes, and quality standards 
• Solution: unified digital workflows that seamlessly transition between additive and traditional processes
• Example Implementation: single CAD file drives both 3D printing for prototypes and traditional tooling design, ensuring consistency.

Material compatibility:

• Challenge: different materials and properties between processes 
• Solution: develop material strategies that work across both manufacturing methods
• Example: use the same base polymer for both 3D printing prototypes and injection molding production to ensure consistent performance characteristics.

Quality consistency:

• Challenge: different quality standards and capabilities Solution: develop integrated quality systems that account for both processes
• Example: aerospace parts use the same inspection protocols whether 3D printed for prototypes or traditionally manufactured for production.

Future of integration:

Smart Manufacturing Systems:

• Vision: automated systems that choose the optimal manufacturing method for each part based on quantity, complexity, and timeline requirements.
• Example: an order management system automatically routes parts to 3D printing for quantities under 100, traditional manufacturing for higher volumes, and hybrid processes for complex geometries regardless of quantity.

Mass Customization:    

• Concept: traditional manufacturing for common components, additive for personalized elements.
• Example: eyeglass frames with traditionally molded base structures and 3D-printed custom-fit elements for individual faces.

The integration of additive and traditional manufacturing in plastics isn't about choosing one over the other . 

It's about creating intelligent production systems that use each method where it performs best, resulting in better products, lower costs, and shorter development cycles.