Mould Core Movement Protection in Injection Moulding

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Solution Overview

Problem

In injection moulding, the mould core can cause permanent impressions on the inner side of the nozzle-side mould platen, leading to damage and visible defects on the moulded parts, especially when producing high-gloss surfaces.

Innovation Solution

The implementation of a movable mould core with protective measures such as damping elements, adjustable gaps, and two-stage advance control to prevent mechanical damage during its movement, along with using a protective element with lower wear resistance and monitoring systems to maintain the gap between the mould core and the nozzle-side platen.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the mould core is positioned in the mould cavity to manufacture moulded parts with breakthrough, then the breakthrough feature is achieved, but the mould core leaves permanent impressions on the inner side of the nozzle-side mould platen causing surface defects

Engineering Contradiction:

Improvecapability to manufacture parts with breakthroughVSAvoidsurface quality of moulded parts

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

A protective element is introduced as an intermediary component between the mould core and the nozzle-side mould platen. This protective element absorbs the mechanical contact and prevents direct interaction that causes surface impressions, while still allowing the mould core to perform its function of creating breakthroughs in the moulded parts.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective element is positioned in advance on the nozzle-side mould platen to cushion the impending contact with the mould core. This prior cushioning measure prevents damage before it occurs, protecting the platen surface from permanent impressions during the breakthrough manufacturing process.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If the mould core is moved in the advance direction to occupy the mould cavity area, then the breakthrough is formed, but mechanical damage occurs to the inner side of the nozzle-side mould platen

Engineering Contradiction:

Improvemanufacturing efficiency of breakthrough partsVSAvoidintegrity of the mould platen

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The protective element serves as a mediator that allows the mould core to move into the mould cavity and form breakthroughs without directly damaging the nozzle-side mould platen. The protective element absorbs the mechanical stress, maintaining both productivity and platen reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective element is designed as a sacrificial component with lower wear resistance than the mould platen. It is intended to wear or be replaced periodically, protecting the more valuable and critical mould platen from damage while maintaining continuous production capability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If the mould core is removed from the mould cavity to manufacture parts without breakthrough, then high-gloss surfaces are achieved, but the risk of platen damage from core movement remains

Engineering Contradiction:

Improveoptical quality of high-gloss surfacesVSAvoidmechanical damage risk to mould platen

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The protective element remains in place on the nozzle-side mould platen even when manufacturing high-gloss parts without breakthrough. It continues to serve as a protective intermediary, preventing any potential contact damage between the mould core and platen during the core's movement, while allowing the production of defect-free high-gloss surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9034226B2Injection moulding method for optional manufacturing of moulded parts with or without a breakthrough

Publication Date: 2015.05.19 BOSCH SIEMENS HAUSGERATE GMBH

AI summary

An injection-molding method for selectively manufacturing molded parts with and without a breakthrough is disclosed. A molded part with a breakthrough is manufactured by positioning a mold core in a mold cavity, whereas a molded part without breakthrough is manufactured by removing the mold core at least partly from the mold cavity. The mold cavity delimited by a nozzle-side mold platen and an ejector-side mold platen. The mold core is movable relative to at least one of the mold platens, in particularly the nozzle-side mold platen, in an advance direction, where the mold core is closer to the nozzle-side mold platen and an opposite withdrawal direction.At least one protective measure is provided for protecting the inner surface facing the mold cavity of the respective mold platen, in particularly the nozzle-side mold platen, from adverse mechanical effects during movement of the mold core in the advance direction.