Automatic Locking Mechanism for Plastic Vibration Welding
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Solution Overview
Problem
Current vibration welding machines face limitations in welding larger automotive lights due to dimensional tolerances and aesthetic requirements, leading to macroscopic imperfections and increased production time, as well as mechanical issues with manual adjustment and short operating life of locking mechanisms.
Innovation Solution
A machine with automatic piece locking devices that adapt to the dimensions of the front half-shell, using electrically-operated or hydraulically-operated mechanisms to securely hold the half-shell in place, immune to vibrations, and featuring electronic control for precise locking and vibration control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the amplitude of vibration is increased to accommodate larger dimensional tolerances, then the welding process can handle larger workpieces, but macroscopic imperfections appear along the welding line
Solution Approach 1:
The workpiece is locked in position before the vibration welding process begins. This preliminary locking action ensures that the workpiece cannot shift during vibration, preventing macroscopic imperfections even when using higher vibration amplitudes suitable for larger workpieces
Solution Approach 2:
The locking mechanism is implemented as a separate, independent system from the vibration welding system. The locking device with clamping elements operates independently to secure the workpiece, while the vibration mechanism operates separately to perform the welding, allowing each to be optimized for its specific function
2Reliability
If manual locking mechanisms are used to secure the front half-shell, then the workpiece can be held in place, but the locking mechanisms have short operating life due to mechanical vibrations
Solution Approach 1:
The workpiece is locked in position before the vibration welding process begins. This preliminary locking action ensures that the workpiece cannot shift during vibration, preventing macroscopic imperfections even when using higher vibration amplitudes suitable for larger workpieces
Solution Approach 2:
The clamping elements have curved or rounded surfaces that contact the workpiece, distributing vibrational stresses more evenly and reducing mechanical fatigue on the locking mechanism components compared to sharp-edged rigid contacts
3Adaptability or versatility
If manual adjustment of locking members is required for each front half-shell, then the locking can be adapted to dimensional variations, but production time increases significantly
Solution Approach 1:
The locking mechanism automatically adapts to the workpiece dimensions through the elastic deformation of the clamping elements. The elastic material naturally conforms to different workpiece sizes within the designed range without requiring manual adjustment, enabling the system to serve itself across multiple workpieces
Solution Approach 2:
The clamping elements are made of elastic material that changes its physical parameters (deformation, contact pressure) automatically in response to different workpiece dimensions. This parameter change allows the same locking mechanism to accommodate dimensional variations without manual intervention
4Adaptability or versatility
If the recess of the template is dimensioned to accommodate the larger workpiece, then all workpieces can be held, but the welding area increases leading to visible imperfections
Solution Approach 1:
The locking force is applied locally at specific clamping points on the workpiece rather than distributing force across the entire template recess. This localized approach secures the workpiece without requiring a large welding area, keeping the welding zone minimal and aesthetically pleasing
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
Enables high-quality vibration welding of larger automotive lights by ensuring precise locking and reduced production time, with increased durability of locking mechanisms and improved aesthetic outcomes by minimizing vibration-induced imperfections.
Implementation Method 1
coupled to a vibrating member that can cause the entire template to vibrate in a predetermined horizontal direction, at given amplitude and frequency
Implementation Method 2
coupled to a lifting apparatus that is able to bring the template of the lower fixture in abutment against the template of the upper fixture, so as to forcefully press the peripheral rim of the mouth of the rear body against the facing and complementary peripheral rim of the front half-shell
Data Source
Figure 1
Figure 2~4
Figure 3
AI summary
Machine (1) for welding workpieces made of plastic materials of the type comprising: two workpiece-carrying fixtures (2, 3) each provided with a template (4, 5) having a recess (4a, 5a) adapted to accommodate a respective plastic workpiece to be welded; a moving assembly (6) adapted to selectively couple and press the two workpiece-carrying fixtures (2, 3) to/against each other, so as to tighten the plastic workpieces housed in the templates (4, 5) one against the other; a vibrating member (7) which is adapted to vibrate on command a first workpiece-carrying fixture (2); automatic piece locking means (12) adapted to selectively lock/immobilise the plastic workpiece to be welded inside the template (4) of the first workpiece-carrying fixture (2); and an electronic control unit adapted to drive/control said automatic piece locking means