INTRODUCTION FOR PLASTIC INJECTION MOLDING: ROBUST PROCESS DEVELOPMENT & SCIENTIFIC MOLDING

Scientific Injection Molding is typically used in the production of complex parts and components where small variations in molding variables can severely impact the process or finished product. Therefore, the goal of Scientific Injection Molding is twofold:

• Develop a process that produces repeatable results with minimal variation.
• Optimize dimensional or mechanical characteristics of a molded part.

When developing a molding process using Scientific Injection Molding, key inputs such as time (fill, pack/hold, etc.), temperature (melt, barrel, etc.), and pressure (hydraulic, injection melt, cavity, etc.) are meticulously monitored, adjusted, and controlled, to ensure that process robustness is achieved, and a good part is consistently produced. A process can be robust or on the other hand must be changed frequently. A robust process ensures repeatability and a wide processing window for better quality & cost.

COURSE OBJECTIVES

• Material properties that affect processing
• The importance of drying
• Explains specific rules for controlling the plastic during processing
• Injection molding machine selection
• Provides thorough overview of injection molding and troubleshooting techniques.
• Exercise greater control over the molding process
• Reduce rejects and scrap
• Improve part quality
• Increase productivity
• Robust parameter optimization

COURSE CONTENT

DAY 1 

Handling Semi Crystalline & Amorphous Polymers

• Shrinkage
• Mel temperature
• Mold filling speed
• Mold temperatures
• Barrel Heat Profile
• Screw recovery speeds
• Nozzle temperature
• Cooling times
• Mechanical properties
• Optical clarity

Plastic drying

• Degradation
• Drying time
• Drying temperature
• Types of dryers
• Moisture measurement
• Overdrying effect

Injection moulding machine selection

• Clamp force
• Machine platen size
• Shot size
• Screw diameter
• Compression ratio
• Types of screws
• Check ring importance

DAY 2

Process optimization

• Optimization of injection phase
• Cavity balance
• Pressure drop
• Process window
• Gate seal time
• Cooling time
• Screw speed & back pressure

Mold qualification flowchart

• Mold qualification checklist
• Waterline diagrams
• Mold temperature maps
• Setup instructions

Mould cooling, venting & regrind management

• Mould cooling
• Mould venting
• Regrind

DOE to develop robust injection molding parameters

Troubleshooting common issues at customer location

• Short molding – consistent and inconsistent
• Flash