Laser Plastic Welding Using Absorption Profile Feedback
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Solution Overview
Problem
Existing laser beam plastic welding methods face challenges in producing high-quality, fault-free connections due to fluctuations in material properties such as glass fiber accumulation, carbon black content, water uptake, and temperature control, which affect the absorption and transmission of laser radiation.
Innovation Solution
A method that detects the absorption profile of the mold part absorbing laser radiation, using a detector to control the energy input from a machining laser based on the absorption profile, ensuring precise energy dosing to prevent overheating and material damage, while using a single machining laser for both profile generation and welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmission of the transparent mold part is detected before welding, then the energy input can be pre-calculated, but the absorption fluctuations of the absorbing mold part are not accounted for, leading to unreliable welding quality
Solution Approach 1:
Instead of measuring the transmission of the transparent mold part as in conventional methods, the invention inverts the approach by measuring the absorption characteristics of the absorbing mold part. This is achieved by irradiating the absorbing mold part with a laser beam and detecting the reflected radiation, thereby directly capturing the absorption fluctuations that affect welding quality.
Solution Approach 2:
The invention implements a feedback mechanism where the absorption profile measured from the absorbing mold part is used to dynamically adjust the energy input during welding. The controller receives the absorption data and modifies the laser parameters in real-time, ensuring that welding energy is precisely dosed according to the actual absorption characteristics, thus compensating for material property fluctuations.
2Reliability
If the energy input is increased to ensure sufficient plasticization of the absorbing mold part, then reliable welding is achieved, but material damage and overheating occur
Solution Approach 1:
The invention dynamically changes the laser parameters (energy input, power, duration) based on the measured absorption profile. By adjusting these parameters according to the actual absorption characteristics detected before welding, the system ensures sufficient energy for reliable plasticization while avoiding excessive energy input that would cause material damage or overheating.
Solution Approach 2:
The invention performs a preliminary measurement of the absorption characteristics before the actual welding process. This preliminary action allows the system to pre-calculate the appropriate energy input required for reliable welding, thereby preventing both insufficient plasticization and excessive energy input that would lead to material damage.
3Object-affected harmful factors
If the energy input is decreased to prevent overheating, then material damage is avoided, but insufficient plasticization occurs leading to poor welding quality
Solution Approach 1:
The system dynamically adjusts the laser energy parameters based on the measured absorption profile, ensuring that the energy input is precisely matched to the actual absorption characteristics of the absorbing mold part. This prevents both overheating and insufficient plasticization by optimizing the energy dosage according to real-time measurements.
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 approach enables reliable and high-quality welded connections by accurately adjusting energy input according to the absorption behavior of the mold parts, ensuring consistent bonding without material damage.
Implementation Method 1
a first mold part which substantially absorbs laser radiation
Implementation Method 2
irradiating the first mold part using an electromagnetic radiation source
Implementation Method 3
detecting the heat of the first mold part by means of a detector
Implementation Method 4
irradiating the two mold parts along the contour of a welding seam to be produced using a machining laser
Implementation Method 5
By means of thermal conduction, the transparent second part is also plasticized or melted locally at a contact area between the two mold parts
Data Source
AI summary
The invention relates to a method for laser beam plastic welding, having the following steps: arranging a first mold part which substantially absorbs laser radiation on a receiving area, irradiating the first mold part using an electromagnetic radiation source, detecting the heat of the first mold part by means of a detector, generating an absorption profile of the first mold part, arranging a second mold part which is substantially transparent to laser radiation on the first mold part, and irradiating the two mold parts along the contour of a welding seam to be produced using a machining laser such that the energy input produced by the machining laser is controlled by a controller on the basis of the generated absorption profile of the first mold part.