Widespread Application of Laser Plastic Welding Technology in the Automotive Manufacturing Sector

With the rapid development of society, there is an increasing demand for energy conservation, emission reduction, and safety in automobiles. Automotive manufacturers are actively seeking lightweight manufacturing processes and transforming traditional component packaging techniques. In this context, laser plastic welding technology has emerged as an ideal solution. Below, Songsheng Optoelectronics will briefly share the applications of plastic laser welding technology in the automotive manufacturing sector.                                              

Illustration of Automotive Plastic Component

A finished plastic product in a car may be composed of multiple materials or parts. To combine these components, methods such as mechanical fasteners, adhesives, and welding processes can be employed. Among these three joining techniques, mechanical fasteners allow for quick connection of two parts but offer poor leak-proof performance at the seams. Localized stress can also easily cause separation between polymer materials. Adhesives can create seams with excellent leak-proof functionality; however, they are difficult to handle and have slow curing speeds. Additionally, when using adhesives, the seam preparation process and surface cleanliness requirements are higher. In contrast, welding processes yield better results, producing robust and stable seams with mechanical properties close to those of the base material. Moreover, welding offers diverse forms, allowing for the selection of different welding techniques based on material type, size, and application.

Welding of Plastic Components

The so-called welding of plastic components refers to the process of heating the surfaces of two thermoplastic parts simultaneously until they melt, and then bonding them into a single entity under external force.

Welding Processes for Plastic Components

Plastic welding processes can be divided into two categories: first, mechanical movement-based welding processes, including ultrasonic welding, friction welding, and vibration welding; second, external heating-based welding processes, including hot plate welding, hot gas welding, and implant welding. Depending on the heating method, they can also be classified as heated tool welding, induction welding, ultrasonic welding, high-frequency welding, hot plate welding, laser welding, vibration friction welding, infrared welding, hot stake welding, and hot air welding.

In modern vehicles, plastic components can be found everywhere in exterior trim parts, interior trim parts, functional parts, and structural parts. Replacing traditional metal materials with plastics has achieved significant weight reduction effects, which is of great importance for saving energy and reducing greenhouse gas emissions.

For example, replacing metal with plastic intake manifolds in automobiles can reduce weight by 40% to 60%. Additionally, the smooth surface and low flow resistance of plastic manifolds can improve engine performance, enhance combustion efficiency, reduce fuel consumption, and dampen vibrations and noise. According to statistics, dozens of types of plastics are currently used in automobiles, including polypropylene, polyethylene, polyurethane, polyvinyl chloride, ABS, nylon, and thermoset composites. On average, plastics account for 5% to 10% of a vehicle's total weight. The demands for lightweighting, safety, and aesthetics have also driven the advancement of plastic laser welding technology in the automotive field.

Currently, plastic laser welding technology has been successfully applied in the manufacturing of automotive bumpers, dashboards and instrument panels, brake lights, airbags, automotive toolboxes, door panels, and other engine-related components. As many traditionally metal-based parts, such as intake manifolds, instrument pointers, radiator reinforcements, fuel tanks, and filters, are being replaced by plastics, the application of new technologies and technical research in the field of plastic welding have gained excellent development opportunities. Welding equipment with low energy consumption, high efficiency, non-toxicity, and pollution-free operation will become the trend of technological advancement in automotive welding lines in the future.

Left: Single Focus Constant Temperature Plastic Welding System
Right: Contour Welding

Main Advantages of Songsheng Optoelectronics' Laser Plastic Welding:

1. Utilizes a high-energy-density laser heat source to optimize the temperature at the plastic joint interface, ensuring high speed and precision in the plastic laser welding process.

2. By adjusting the shape and size of the laser beam, the heat-affected zone and joint area can be minimized. The exterior surface of the welded area shows no visible traces or damage from the welding process.

3. Optional 976nm/2μm multi-band welding heads with integrated CCD coaxial temperature measurement interfaces enable real-time monitoring and constant-temperature welding of solder joints.

4. No restrictions on the shape or size of components, significantly enhancing design flexibility for parts.

5. Non-contact processing (no physical contact between the connected components and the heat source), making it easier to maintain hygiene and safety standards for medical and food equipment.

6. High degree of freedom in laser beam delivery, facilitating automation.