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Lesson 1: The Molding Machine

In this lesson we will review various components of a molding machine. Then see how the machine, peripherals and set-ups provide process engineers with the tools to produce the highest quality parts possible.

Topics in this lesson include: the functionality of a molding machine, different molding machine set-ups, the role of peripherals in machine set-ups, various pieces of equipment integral to successful molding, and the interaction of process set-up parameters in a molding cell.

Molding Machine Play Screen

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Begin with the basics! Learn what happens inside a mold during the injection molding process. Build your own Circle of Knowledge lesson by lesson. 

Goals of Molding Fundamentals: Inside the Mold (Level 1): 

  • Learn the fundamentals of what goes on inside a mold during the injection molding process
  • Get a basic understanding of how a molding machine functions and its various components
  • Analyze real-life molded parts and learn the cause and effect behaviors of design and process

Section Description: 
Having the foundational understanding of what happens inside a mold during the injection molding process is key for a successful career in the plastics industry. From part designers to mold designers to process engineers, having a good grasp of these molding fundamentals is essential to designing and produce high quality parts.

Explanations, simulations, cause and effect analyses, and the introduction of various injection molding concepts are covered in this section. The relationship between various factors inside the mold during injection molding are evaluated and analyzed. Fundamental training is important to understand the complex part and mold designs that are commonplace in the injection molding industry.

Recommended For: Entry Level Personnel, All Personnel

Length: Lessons are approximately 15-20 minutes long each

The Kruse Training platform delivers knowledge and expertise developed over two decades in the plastic injection molding industry. Now companies and individuals can access a state-of-the-art online training program, suited for all levels of knowledge.

The Molding Machine Discussions

Andres Mora

March 14, 2021 5:32 pm

1. Is there any knock-out rod specification for injection machines?
2. What are the differences between a LSR injection machine and a conventional one?
3. How is the injection process in a micro-molding machine?
4. How can I specify a rhombus mixing element? Is there any specific characteristic? Can it be assemble in a gp screw even though it is not needed?

Nathalie Fischer Andres Mora

March 15, 2021 9:08 am

Please see the responses to your questions below:

1. Is there any knock-out rod specification for injection machines?

There are common ejection layout specifications but generally machine manufacturers will have their own ejector rod size specifications. A mold maker should confirm the mold ejection system is compatible with the machine requirements.

2. What are the differences between a LSR injection machine and a conventional one?

LSR molding is thermoset molding. The material is kept cold in the machine cylinder assembly and cured inside the mold with a hot mold. The main differences between the LSR and conventional machines are the injection unit, which is water cooled and the screw, which is a specific LSR screw combined with a spring-operated check ring assembly. Most cylinder assemblies also have a shut-off nozzle controlled by the molding machine.

3. How is the injection process in a micro-molding machine?

Micro-molding is a very specific technique whereby the entire molding machine, especially the cylinder assembly, must accommodate high precision molding and small shot sizes.

4. How can I specify a rhombus mixing element? Is there any specific characteristic? Can it be assemble in a gp screw even though it is not needed?

The mixing element needs to be part of the screw assembly and must be specific to the molding machine manufacturer. The mixing element should only be used for special molding applications that require very thorough material
mixing inside the cylinder assembly.

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