Dynamic Mold Clamping Force Control for Injection Molding

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional methods for setting mold clamping force in injection molding machines are inaccurate and unreliable, often leading to excessive force application, mold degradation, and energy inefficiency, as they primarily rely on monitoring a single factor, the opening of the movable mold, which is insufficient for determining a proper clamping force.

Innovation Solution

A method that sequentially lowers the mold clamping force from the maximum force, monitoring multiple elements such as mold clamping pressure, its differential value, and reduction rate, and adjusting the force when these elements exceed predetermined thresholds to set a proper clamping force, preventing flash and optimizing energy usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If maximum mold clamping force is applied to achieve secure clamping without flash, then clamping reliability is improved, but mold degradation accelerates and energy consumption increases

Engineering Contradiction:

Improveclamping reliabilityVSAvoidmold life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention changes the parameter of mold clamping force from fixed maximum value to dynamically adjusted values based on multiple monitored factors. By monitoring mold clamping pressure, differential pressure, and pressure reduction rate simultaneously, the system determines the minimum adequate clamping force rather than always applying maximum force, thus extending mold life while maintaining sufficient clamping reliability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If maximum mold clamping force is applied to prevent flash, then sealing performance is improved, but energy consumption increases unnecessarily

Engineering Contradiction:

Improvesealing performanceVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the mold clamping force parameter based on real-time monitoring of multiple factors including mold clamping pressure, differential pressure, and pressure reduction rate. This allows the system to use the minimum necessary force to prevent flash rather than always applying maximum force, significantly reducing energy consumption while maintaining adequate sealing performance.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If single monitored factor (mold opening) is used to determine clamping force, then system complexity is reduced, but determination accuracy is insufficient

Engineering Contradiction:

Improvemonitoring system complexityVSAvoidclamping force determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The invention segments the monitoring function into multiple independent monitored factors: mold clamping pressure, differential pressure, and pressure reduction rate. Each factor is monitored separately by dedicated sensors, and their combined information provides comprehensive and accurate determination of adequate clamping force, overcoming the limitations of single-factor monitoring.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system transitions from one-dimensional monitoring (single factor) to multi-dimensional monitoring by simultaneously tracking multiple parameters. This dimensional expansion allows for more accurate and reliable determination of proper clamping force through comprehensive analysis of pressure characteristics over time.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Ease of operation

If mold opening detection is used as the basis for setting clamping force, then detection simplicity is maintained, but setting accuracy deteriorates due to flash occurrence

Engineering Contradiction:

Improvedetection simplicityVSAvoidclamping force setting accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The invention performs preliminary analysis of pressure characteristics (mold clamping pressure, differential pressure, and pressure reduction rate) before flash occurs. By monitoring the rate of pressure reduction and differential pressure trends, the system can determine adequate clamping force in advance, rather than waiting for mold opening detection after flash has already occurred.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback monitoring of multiple pressure parameters during the molding process. By analyzing the real-time feedback from pressure sensors, the system can dynamically adjust and optimize clamping force settings based on actual process conditions, achieving high accuracy without relying on post-factum mold opening detection.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7943069B2Method of setting mold clamping force of injection molding machine

Publication Date: 2011.05.17 NISSEI PLASTIC IND CO LTD

AI summary

When test molding is performed by sequentially clamping a mold with a mold clamping force (100%, 80%, 70%, . . .) obtained by sequentially lowering a mold clamping force by a predetermined amount from the maximum mold clamping force (100%), a mold clamping pressure Pc in an injection process is detected and a plurality of different monitored elements (Pc, Pcd and Per) corresponding to the variation of the mold clamping pressure Pc are monitored, and thus it is detected that at least one of the monitored elements is varied to exceed a predetermined threshold, a mold clamping force obtained by increasing a mold clamping force at the time of the production of the variation by a predetermined amount is set as a proper mold clamping force Fs.