Mold-press forming apparatus with stepped pressure reduction

Solution Overview

Problem

The existing mold-press forming apparatuses face issues with displacement of forming materials during pressure reduction, leading to uneven thickness and defective shapes in formed products, particularly due to rapid evacuation and mold vibration, which affects the precision and accuracy of optical elements like glass lenses.

Innovation Solution

A mold-press forming apparatus with a pressure reducing member that controls the pressure reduction rate stepwise, using a combination of valves and pumps to manage the evacuation process, ensuring the forming material remains centered and preventing displacement, thereby maintaining even thickness and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rapid evacuation is performed to reduce pressure in the airtight chamber, then productivity is improved by shorter processing time, but manufacturing precision deteriorates due to material displacement and mold vibration

Engineering Contradiction:

Improveprocessing speedVSAvoidprofile accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The evacuation process is divided into multiple stages with different pressure reduction rates. The first stage uses a first pressure reduction rate, and the second stage uses a second pressure reduction rate that is lower than the first, allowing controlled material positioning followed by efficient pressure reduction

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The forming material is positioned at the center of the mold before the main evacuation process begins. This preliminary positioning prevents displacement during pressure reduction and ensures accurate profile formation in the final product

Inventive Principle:

Principle #10Preliminary action

2Productivity

If rapid evacuation is performed to reduce pressure in the airtight chamber, then productivity is improved by shorter processing time, but manufacturing precision deteriorates due to uneven thickness in formed products

Engineering Contradiction:

Improveprocessing speedVSAvoidsurface accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The evacuation process is divided into multiple stages with different pressure reduction rates. The first stage uses a first pressure reduction rate, and the second stage uses a second pressure reduction rate that is lower than the first, allowing controlled material positioning followed by efficient pressure reduction

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The forming material is positioned at the center of the mold before the main evacuation process begins. This preliminary positioning prevents displacement during pressure reduction and ensures accurate profile formation in the final product

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If stepped pressure reduction with multiple stages is implemented, then manufacturing precision is improved by preventing material displacement, but device complexity increases due to additional control mechanisms

Engineering Contradiction:

Improveprofile accuracyVSAvoidcontrol system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The pressure reduction rate is made dynamic by switching between different rates during the evacuation process. The system transitions from a first pressure reduction rate to a second pressure reduction rate based on process requirements, optimizing both precision and efficiency

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The pressure reduction rate parameter is changed during the evacuation process. By adjusting this parameter from a first rate to a second rate, the system achieves precise material positioning while maintaining operational simplicity

Inventive Principle:

Principle #35Parameter changes

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 effectively prevents material displacement during pressure reduction, ensuring consistent product quality by maintaining the forming material's position, thus enhancing the profile and surface accuracy of optical elements like glass lenses without extending the forming cycle time.

Implementation Method 1

each processing chamber heated to a high temperature, such as a pressing chamber in which press forming is performed, is evacuated to vacuum by evacuating air

Methodology Applied

Scientific EffectVacuum evacuation: Vacuum

Data Source

PatentUS7682537B2Mold-press forming apparatus and method of manufacturing a formed product

Publication Date: 2010.03.23 HOYA CORPORATION

AI summary

A mold-press forming apparatus for applying a molding pressure to a mold containing a forming material to perform press forming includes a loading chamber (that is, an airtight chamber) P1 kept airtight. The loading chamber P1 is connected to a pressure reducing member which includes evacuating members 14 and 13 arranged in an evacuating path 7 connected to the loading chamber P1 for evacuating a gas in the loading chamber P1, and a plurality of valves 11 and 12 arranged in the evacuating path 7 in parallel to each other. When the loading chamber P1 is evacuated, the pressure reducing member changes a pressure reducing rate in the course of pressure reduction.