Types and Functions of Moulds

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Questions and Answers

What is the source of the information about isolation boards?

LK Präzisionswerkzeuge (Coburg)

Mould Design/WS 2024/2025

Meusburger Georg GmbH / Wolfurt (A) (correct)

Michael Kaisser

What is the application temperature of composites made from resin bonded glass fibres and fillers?

270°C

180°C

240°C

210°C (correct)

What is the main difference between a basic mould and a slider mould?

A slider mould uses hydraulic force, while a basic mould uses mechanic force.

A slider mould has a single opening direction, while a basic mould has two.

A slider mould uses mechanic force, while a basic mould uses hydraulic force.

A slider mould has two opening directions, while a basic mould has only one. (correct)

What is the purpose of the wedge area in a slider mould?

To allow for the creation of undercuts and breakthroughs. (A) Signup and view all the answers

Why is αb = αw - 2° in a slider mould?

To ensure that the wedge area is properly aligned. (D) Signup and view all the answers

What is the tolerance of the guide pin?

690+ 70 HV 30 (A) Signup and view all the answers

What type of steel is C15?

Case-hardening steel (C) Signup and view all the answers

What is the hardness of the guide pin material?

HV 30 (C) Signup and view all the answers

What is the typical material used for a guide pin in a basic injection mold?

C15 (B) Signup and view all the answers

What is the primary function of the centring element in a basic injection mold?

Guiding the mold halves during closing (A) Signup and view all the answers

What is one advantage of a basic injection mold?

Easy design and production (B) Signup and view all the answers

What is a potential challenge associated with using ejector pins and sockets in a basic injection mold?

Difficulty in achieving precise ejection (C) Signup and view all the answers

What feature is typically NOT present in a basic injection mold?

Undercuts (C) Signup and view all the answers

Which steel type is recommended for a sprue bushing, seeking a soft annealed state?

56NiCrMoV7 (C) Signup and view all the answers

What is the recommended steel type for a retaining plate if a high strength is desired?

55NiCrMoV6 (A) Signup and view all the answers

What does the 'Location Ring' component do in an injection molding machine?

Ensures proper alignment between the fixed half platen and the injection molding machine. (B) Signup and view all the answers

Which of these steels is not specifically recommended for ejector pins?

Ck 45 (C) Signup and view all the answers

What is the typical mechanical property expected from a boltster sleeve?

Surface hardness of 60 HRC (A) Signup and view all the answers

Which steel type is commonly used for ejector pins, and is considered a 'cold work' steel?

115CrV3 (A) Signup and view all the answers

What is the typical expected strength of a back plate made of Ck 22 steel?

400-500 N/mm² (A) Signup and view all the answers

Which of these steels is considered a 'hot work' steel?

1.2713 (B) Signup and view all the answers

What is a primary characteristic of a core-puller mould?

It uses hydraulic or pneumatic actuation for moving parts. (D) Signup and view all the answers

What is the primary function of ejector pins and sockets in a split-mould?

They are used to remove the molded part from the cavity. (D) Signup and view all the answers

Which of these features is NOT commonly found in split-moulds?

A complex system of multiple parting lines (D) Signup and view all the answers

What is the primary function of the "Klinke" (ratchet) in a 3-plate mould?

It controls the movement of the plates during the molding process. (D) Signup and view all the answers

What is the main advantage of using a 3-plate mould over other types?

It allows for the creation of parts with extremely complex shapes. (B) Signup and view all the answers

What distinguishes a slider mould from a split-mould?

Slider moulds have a more complex design that allows for the creation of intricate details. (B) Signup and view all the answers

Which of the following is NOT a common feature of a 3-plate mould?

A simple, straightforward design (A) Signup and view all the answers

Why is maintenance and lubrication crucial for core-puller moulds?

It improves the quality and precision of the molded parts. (A) Signup and view all the answers

Which of these effects is a result of using undercuts in a slider mold? (Select all that apply)

Increases the cost of the mold by 15-30%. (A), May increase the cycle time of the injection molding process. (C) Signup and view all the answers

Why are sliders typically placed on the moving half of a mould?

To provide a means for creating undercuts within the molded part. (B) Signup and view all the answers

What is the primary function of a slider in a mold?

To allow for the creation of undercuts in the molded part. (C) Signup and view all the answers

Which of the following is NOT a potential drawback of using undercuts in a mold?

Potential for shorter cycle times. (C) Signup and view all the answers

What is the main purpose of the additional opening direction in a slider mold?

To allow for the removal of parts with undercut features. (A) Signup and view all the answers

Why might a hydraulic cylinder instead of mechanical force be used for the demoulding of undercuts?

To allow for larger strokes and more complex movements. (D) Signup and view all the answers

In a slider mold, how does the slider move in relation to the fixed half and the moving half?

The slider moves independently of both the fixed and moving halves. (B) Signup and view all the answers

Why are undercuts considered a more expensive aspect in mold design?

All of the above. (D) Signup and view all the answers

What is the purpose of the first step opening in a 3-Plate mold?

To break the gate and pull the sprue (D) Signup and view all the answers

What is the main purpose of the bushes in a 3-Plate mold?

To restrict the movement of the ejector system during mold opening (D) Signup and view all the answers

Which of the following is NOT a type of screw-mold?

Hydraulically driven mold (C) Signup and view all the answers

What is the main purpose of the stripper plate in a 3-plate mold?

To eject the molded part from the mold cavity (C) Signup and view all the answers

Which of the following mechanisms is used for demolding with a screw mold with a collapsing core?

The mold opens and the core retracts (C) Signup and view all the answers

What is the primary difference between a 3-Plate mold and a screw mold?

The 3-Plate mold utilizes a rotating mechanism, while a screw mold utilizes a linear mechanism (B) Signup and view all the answers

Which of the following is a characteristic of a 3-Plate mold?

The mold has a separate stripper plate for removing the runner (B) Signup and view all the answers

What is the main advantage of using a screw mold?

They can be used for larger and more complex parts (B) Signup and view all the answers

Study Notes

Different Kinds of Moulds

Various types of molds exist, each with unique characteristics and applications.
Standard molds are readily available and have been tested extensively.
Functional guarantee is assured for standard parts.
These parts are readily available for replacements and repair.
CAD data is accessible for various components.

Tasks and Functions of a Mould

Transfer motion: Molds facilitate the movement of components during the injection molding process.
Absorb forces/retain shape: Molds absorb forces exerted during molding and maintain the shape of the components.
Guiding of mold parts: Guiding components prevent misalignment and ensure proper positioning.
Long lifetime: Molds are designed to withstand repeated use and have long operational lifespans.
Gating: Conduits which direct molten plastic into the mold cavity.
Venting: Channels that allow gases to escape during the molding process.
Tempering: Cooling or heating of the mold to maintain temperature control.
Demoulding: Removing molded components from the mold cavity.
Undercuts: A component that may require additional steps for removal.
Guides & center: Essential for proper alignment.

Parts of an Injection Mould

Mould Core: Provides support and shape to the workpiece.
Mould Cavity: The cavity/container where the workpiece is created.
Bolts: Used to secure components in the mould.
Guide Pins: Enable proper alignment of components in the mold.
Risers: Channels for efficient material flow during molding.
Ejector Plate: Plate responsible for ejection of the molded workpiece.
Ejector Locating Plate & Retainer: Ensures correct ejector pin placement.
Bolster Sleeves: Maintains alignment during operations.
Moving half support plate: Maintains the structural integrity of the moving half.
Guide Bushes: Offer bearing surface to avoid wear.
Retaining Plate: Prevents ejector pins from shifting.

Steels for Functional Parts/Standard Parts

Steels are chosen based on their mechanical properties for specific functional parts within molds.
Application related properties such as Hardness, Strengthen and Strengthened properties are required.
Specific steel types are detailed such as alloys and their composition which determines their strength and usage.
Data like hardness values and strengthening values are detailed for each part.

Tolerances of Shafts and Bushes

Precision control during manufacturing via tolerances.
Clearances are specified and dimensions are detailed for precision assembly.
Specifications of tolerance range for shafts and bushes are provided.

Kinds of Injection Moulds

Basic Mould: This type is characterized by its simple design and straightforward demolding mechanisms using gravity and ejectors.
Slider Mould: Multiple opening directions for a range of components.
Split Mould: Ideal for larger molds with threads or undercuts.
3-Plate Mould: Specifically for complex shapes with multiple gating points.

Core Puller

It uses hydraulic or pneumatic mechanisms to eject large components (such as cores).
Controlled by switches which automate the process.
Quality depends on guided surfaces.

Screw-Mould

Uses a collapsing core to demold threads.
Multiple cavities enable diverse component production.
Rack Steering: Threads rotate by mechanical or electric means.
Spindle: The core is driven by gear spindles.

Multi Cavity Mould

This allows multiple components to be produced simultaneously.

IMD Moulding/IML Moulding

A manufacturing process that inserts different materials like films or parts into the main section.
Various types of insertion methods ensure precision control during the molding process.

Stack Mould

A complex structure with at least two parting lines.
High production output on one machine
Mostly for flat components due to suitable design.

Change Mould

Allows simple changes and quick conversion for different molds.

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Description

Explore the different kinds of moulds and their specific tasks in the injection molding process. This quiz will cover the characteristics, functionalities, and the operational lifespan of various molds. Test your knowledge on how molds facilitate component movement and ensure shape retention.