Laser Plastic Welding Using Absorption Profile Energy Control
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Solution Overview
Problem
Existing laser beam plastic welding methods face challenges in producing a qualitatively flawless welded joint due to fluctuations in the properties of molded parts, such as variations in glass fiber accumulation, soot content, absorber additives, water absorption, and temperature control during injection molding, which affect the absorption of laser radiation.
Innovation Solution
A method that focuses on detecting and accounting for the absorption behavior of the molded part that absorbs laser radiation, creating an absorption profile to control energy input during the welding process, ensuring sufficient energy for melting without overheating, using a control device to adjust energy input based on local absorption levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laser beam plastic welding is used without absorption detection, then the welding process is simple and fast, but the weld quality is inconsistent due to material property fluctuations
Solution Approach 1:
The absorption profile of the lower molded part is determined before the welding process begins. This preliminary measurement allows the system to know the absorption characteristics in advance, enabling adaptive energy input control during welding to ensure consistent weld quality despite material variations.
Solution Approach 2:
The system uses the determined absorption profile as feedback to control the energy input during welding. The control device adjusts the laser energy input based on the pre-measured absorption characteristics, creating a closed-loop control system that maintains weld quality consistency.
2Manufacturing precision
If fixed energy input is used during welding, then the welding process is simple and fast, but material damage occurs due to overheating or insufficient energy
Solution Approach 1:
The energy input is made dynamic rather than fixed. The control device continuously adjusts the laser energy input during welding based on the pre-determined absorption profile, allowing the system to adapt to local variations in material absorption properties and prevent both overheating and insufficient welding.
3Measurement precision
If transmission of the upper component is measured, then the measurement process is simple, but it does not provide sufficient information for controlling energy input to the lower absorbing component
Solution Approach 1:
Instead of measuring the transmission of the upper transparent component, the system measures the absorption of the lower component directly. This inversion of the measurement approach provides the critical information needed for energy input control, as the absorbing component's properties are the limiting factor in the welding process.
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 allows for a reliable and precise control of energy input, ensuring a strong and consistent welded connection by matching energy input to the absorption profile of the molded part, preventing material damage and ensuring a high-quality weld.
Implementation Method 1
irradiating the first molded part with an electromagnetic radiation source, detecting the heating of the first molded part using a detector
Implementation Method 2
irradiating both molded parts along the contour of a weld seam to be created with a processing laser such that the energy input generated by the processing laser is controlled depending on the created absorption profile
Implementation Method 3
Through heat conduction, the transparent second molded part is also locally plasticized or melted at a contact surface between the two molded parts
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a method for laser beam plastic welding, having the following steps: arranging a first mold part (3) which substantially absorbs laser radiation on a receiving area (2), irradiating the first mold part (3) using an electromagnetic radiation source, detecting the heat of the first mold part (3) by means of a detector (11), generating an absorption profile of the first mold part (3), arranging a second mold part (16) which is substantially transparent to laser radiation on the first mold part (3), and irradiating the two mold parts (3, 16) along the contour of a welding seam to be produced using a machining laser (8) such that the energy input produced by the machining laser (8) is controlled by a controller (9) on the basis of the generated absorption profile of the first mold part (3).