Infrared Heater Feedback Control for Plastic Welding Uniformity

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Solution Overview

Problem

Conventional infrared heating systems in the plastic welding industry face challenges in maintaining uniform heating across multiple weld cycles due to variance in heater functionality over time, requiring manual adjustments that are inefficient and prone to errors.

Innovation Solution

A surface temperature and infrared feedback adjustment system using sensors and cameras to monitor part surface temperatures, adjusting infrared heater outputs automatically to maintain a specific surface temperature related to the melting temperature of plastic, thereby compensating for heater functionality variance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual adjustment of heater output values is used, then initial heating control is simple, but heating uniformity deteriorates over time due to heater functionality variance

Engineering Contradiction:

Improveheater control simplicityVSAvoidheating uniformity

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The system employs a feedback mechanism where a sensor array measures the actual surface temperature of the part, and the controller uses this measurement to automatically adjust the output values of infrared heaters for subsequent heating cycles. This closed-loop control compensates for heater functionality variance (such as degradation over time or increased transmissivity when warm) and maintains consistent heating uniformity across multiple weld cycles without requiring manual intervention.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If automatic feedback control is implemented, then heating uniformity is maintained, but system complexity increases

Engineering Contradiction:

Improveheating uniformityVSAvoidcontrol system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system replaces manual mechanical adjustment of heater controls with an automated electronic feedback control system. The sensor array electronically measures surface temperature, and the controller automatically calculates and applies output value adjustments to the infrared heaters, eliminating the need for manual intervention while maintaining heating uniformity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-adjustment by using the sensor array to monitor its own heating performance and automatically modifying its operation through the controller. The system serves itself by detecting temperature variations and correcting heater output values without external intervention, thereby maintaining consistent heating uniformity.

Inventive Principle:

Principle #25Self-service

3Reliability

If heater output is increased to compensate for degradation, then heating effectiveness improves, but energy consumption increases

Engineering Contradiction:

Improveheating effectivenessVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The feedback control system applies partial adjustments to heater output values based on actual temperature measurements. Rather than uniformly increasing all heater outputs, the controller selectively adjusts only the heaters that require compensation, applying the minimum necessary correction to maintain heating effectiveness while avoiding excessive energy consumption.

Inventive Principle:

Principle #16Partial or excessive 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 system ensures consistent and efficient heating by automatically adjusting infrared outputs based on real-time temperature measurements, improving the reliability and efficiency of the welding process by maintaining the desired surface temperature across multiple cycles.

Implementation Method 1

a first plurality of infrared heaters configured to output infrared energy toward the upper nest in a welding cycle, the movable heating platen having on a lower surface thereof a second plurality of infrared heaters configured to output infrared energy toward the lower nest

Methodology Applied

Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 2

a first imaging sensor arranged to have a field of view that encompasses heated portions of the first part in response to the movable heating platen being retracted away from an area between the upper nest and the lower nest

Methodology Applied

Scientific EffectThermal radiation detection: Thermal Radiation

Data Source

PatentUS11654640B1Feedback system and method for automatically adjusting and controlling infrared heating of parts

Publication Date: 2023.05.23 DUKANE IAS LLC

AI summary

Systems and methods of controlling outputs of infrared heaters used to join a first part to a second part, and a component made thereby. Upper and lower nests hold the first and second parts, respectively. A movable heating platen has infrared heaters on opposite surfaces. Imaging sensors have fields of view encompassing heated portions of the first and second parts, respectively, when the platen is retracted away from an area between the upper and lower nests. A controller causes the upper and lower nests to move while causing the platen to extend into and retract away from the area between the upper and lower nests. The first imaging sensor takes a first image of the heated portions of the first part, which causes an adjustment to be made to an output of the infrared heaters in a subsequent welding cycle.