Injection Moulding Pin Cooling for Automatic Plastic Assembly

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Solution Overview

Problem

Existing injection moulding processes for producing plastic objects with pivotally connected parts, such as containers with handles, require complex apparatuses and long cycle times due to the need for separate steps in mould opening, assembly, and extraction, which can lead to increased productivity and quality challenges.

Innovation Solution

An apparatus that co-moulds plastic objects with a hinge pin and annular element, allowing automatic assembly during mould extraction by exploiting linear movements of the press, and utilizing fluid cooling to stabilize critical areas quickly, thereby reducing extraction times without damaging the parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If separate steps are used for mould opening, assembly, and extraction, then each step can be performed independently, but the working cycle time increases and device complexity increases

Engineering Contradiction:
Improveindependence of process stepsVSAvoidworking cycle time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent combines the mould opening, assembly, and extraction operations into a single integrated sequence. The extraction device performs multiple functions simultaneously: it opens the mould, positions the separate parts, and extracts the assembled product in one continuous motion, eliminating the need for separate command devices and reducing cycle time.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The extraction device is designed as a multi-functional component that serves multiple purposes: it acts as the mould opening mechanism, the assembly device for connecting parts, and the extraction tool for removing the finished product. This universal device replaces multiple specialized devices, reducing complexity while maintaining operational independence.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If assembly is performed after partial removal from injection mould, then assembly can be done with simpler equipment, but the handling complexity and risk of damage increase

Engineering Contradiction:
Improveequipment simplicityVSAvoidhandling complexity
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent performs preliminary positioning and alignment of the separate parts within the mould cavity before extraction. The extraction device prepares the assembly by positioning components in their correct relative positions while still supported by the mould structure, reducing handling complexity during the critical assembly phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The extraction device serves as an intermediary mechanism that facilitates assembly within the protected environment of the mould. It provides controlled movement and positioning of parts during assembly, acting as a mediator between the mould structure and the final extracted product, thereby reducing handling complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If extraction is performed quickly, then productivity increases, but the plastic material may not have sufficient time to cool and stabilize, leading to deformation or damage

Engineering Contradiction:
Improveextraction speedVSAvoidshape stability
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies different cooling strategies to different areas of the molded object. Critical areas that require shape stability are cooled more intensively and for longer durations, while other areas can be extracted more quickly. This localized quality control allows fast extraction overall while ensuring precision where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The mould cooling system performs preliminary cooling of the plastic material during the moulded object formation phase before extraction begins. This pre-cooling ensures that critical areas reach sufficient shape stability before the quick extraction phase starts, preventing deformation while maintaining high productivity.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution significantly decreases working cycle times while ensuring excellent product quality by stabilizing critical areas through rapid cooling, enabling efficient and automatic assembly of parts during the extraction process.

Implementation Method 1

the first and second pin elements are cooled by a cooling fluid 58 by means of cooling means 50

Methodology Applied
Scientific EffectRapid cooling: Cooling

Data Source

PatentEP3352963B1Perfected apparatus to injection co-mould and assemble plastic material objects
Publication Date: 2019.08.28 ABATE BASILIO & C
  • EP3352963B1 patent drawingFigure 1
  • EP3352963B1 patent drawingFigure 2
  • EP3352963B1 patent drawingFigure 3~4

AI summary

It is described a method and an apparatus for injection co-mould and assemble plastic material objects having a first part provided with a hinge pin, and a second part provided with an annular element suitable to be coupled in an articulated manner. The apparatus includes a mould having separated moulding impressions for the two parts to be moulded; a first moulding pin element defining the pin impression and a second moulding pin element defining the annular element impression are provided. The apparatus includes cooling means; particularly the first pin element is internally provided with a channel and a tubular element, being coaxially arranged and defining a cooling gap. A cooling fluid flows through the tubular element and the gap. Cams are provided which axially move the pin elements to cause the automatic assembly of the object during the mould opening and then to allow extracting the moulded object.