Mould Base Decompression Channels for Air Evacuation

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Solution Overview

Problem

Existing mold bases manufactured by machining face challenges in increasing air evacuation flow rates without interfering with coolant circulation pipes, which is a limitation in blow molding and stretch blow molding processes for polyolefin containers.

Innovation Solution

A mold base design featuring raised molding faces with decompression vents comprising shallow side channels and central channels that extend into ribs, connected by a fillet, and a gap between the mold wall and mold base for efficient air evacuation, allowing trapped air to escape through the peripheral upper edge, enhancing air flow without compromising coolant circulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If decompression vents are made as single holes in the mold base, then the structure is simple, but the air evacuation flow rate is insufficient

Engineering Contradiction:

Improveair evacuation flow rateVSAvoidvent structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The decompression vent system is segmented into multiple shallow channels distributed across the mold base, with each channel contributing to the overall air evacuation capacity. This segmentation increases the total flow rate while keeping individual channel structures simple and easy to manufacture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from point-like single hole vents to planar shallow channel structures, effectively moving from zero-dimensional to two-dimensional vent configuration. This dimensional change dramatically increases the surface area available for air evacuation while maintaining shallow depth for ease of manufacturing.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If decompression vents are made as slots in additive manufactured bases, then the air evacuation flow rate increases, but it interferes with coolant circulation pipes

Engineering Contradiction:

Improveair evacuation flow rateVSAvoidcompatibility with coolant circulation

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The vent channels are designed with locally optimized characteristics - shallow depth (less than or equal to 5/10 mm) in the regions where coolant pipes are present, while maintaining adequate width and distribution to ensure sufficient air evacuation flow rate. This local quality adjustment resolves the conflict between flow rate and pipe compatibility.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the geometric parameters of the decompression vents, specifically controlling the depth to be shallow (≤5mm) and adjusting the width and distribution pattern of channels. These parameter changes enable the system to achieve high air evacuation rates while maintaining compatibility with coolant circulation infrastructure.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If shallow channels are used in machined mold bases, then air evacuation efficiency improves without interfering with coolant pipes, but manufacturing precision requirements increase

Engineering Contradiction:

Improveair evacuation efficiencyVSAvoidchannel depth and width tolerance

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Rather than requiring precise control of channel depth throughout, the design uses intentionally shallow channels (≤5mm) where excessive depth control would be problematic. The shallow nature provides a built-in margin that accommodates manufacturing variations while still achieving adequate air evacuation performance.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The channel patterns are designed to be replicated across the mold base surface, using standardized geometries that can be efficiently manufactured and maintained within acceptable precision tolerances. This replication approach reduces the cumulative impact of manufacturing variations.

Inventive Principle:

Principle #26Copying

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 design significantly improves air evacuation efficiency, preventing air pockets and ensuring better impression-taking of container bases, resulting in improved mechanical strength and reduced bead formation during the blow molding process.

Implementation Method 1

the air that is trapped and then compressed between the blank and the mold base circulates in the channels and is evacuated via the peripheral upper edge

Methodology Applied

Scientific EffectAir evacuation through decompression channels:

Data Source

PatentUS10556375B2Mould base provided with decompression channels opening on to a peripheral upper face

Publication Date: 2020.02.11 SIDEL PARTICIPATIONS SAS

AI summary

Mold base including a base wall and a peripheral side wall which is connected to the base wall by a fillet, this mould base ending with a peripheral upper edge and including ribs forming cavities for grooves for strengthening the base of a container to be formed and which each straddle the fillet, this mould base also including decompression vents hollowed out of the moulding face and which include, for each rib, at least one pair of shallow side channels which extend on either side of the rib and open, at an upper end, on to the peripheral upper edge.