Effect of product flatness on laser welding in plastic laser welding

In the process of plastic laser welding, it is crucial to ensure that two thin film materials can fit tightly without warping, missing welds or false welds. Thin film materials bring many challenges to the welding process due to their thin thickness and easy deformation. This article will explore the key factors and methods to ensure the tight fit of thin film materials in order to improve the quality and reliability of laser welding.

Principle of Plastic Laser Welding

Plastic laser welding uses a laser beam as a heat source to melt and combine the plastic films to be welded on the contact surface through laser energy. Welding usually adopts transmission welding, that is, the upper film is transmitted by the laser, the lower film absorbs the laser energy, generates heat and melts, and then the two films are tightly bonded by applying pressure.

Ensuring a tight fit of the film is the key factor!

1. Choice of film material

Choosing the right film material is the basis for ensuring a tight fit. The materials should have similar melting points and compatibility so that they can be well combined during the melting process. The thickness and thermal expansion coefficient of the materials should also match to reduce thermal deformation and warping.

2. Surface smoothness and cleanliness

The smoothness and cleanliness of the film surface directly affect the welding effect. The surface should be smooth without bumps and clean and dust-free to ensure that the contact surface can fit tightly. The surface quality can be improved through processes such as polishing and cleaning to remove tiny particles and contaminants that may affect the fit.

3. Fixture design and use

鈼員he fixture plays a role of fixing and supporting in the film welding process. Designing a suitable fixture can effectively prevent the film from warping and moving. The fixture should have the following characteristics:

鈼咹igh precision: ensure that the film remains flat and stable during the welding process.

鈼哢niform pressure: The clamp should be able to apply uniform pressure on the welding area to ensure that the film fits tightly.

鈼員hermal stability: The material should be able to withstand the high temperature during the welding process without deformation and maintain the clamping effect.

4. Optimization of laser parameters

Laser welding parameters, such as power, speed, and focus position, have an important influence on the lamination and welding quality of the film. The laser parameters should be optimized according to the characteristics and thickness of the film material to ensure appropriate energy input so that the film can be melted and bonded without overheating or burning through.

5. Preheating

Preheating the film can reduce the internal stress and warping of the material. Preheating can make the film reach a uniform temperature before welding, thereby reducing deformation caused by temperature gradient and improving welding effect.

Methods to prevent warping and false soldering

1.Lamination welding

Lamination welding is to place the film material between two transparent plates for welding, and apply uniform pressure through the transparent plates to prevent the film from warping during the welding process. The transparent plate allows the laser to penetrate, so that the lower film absorbs the laser energy to melt and combine.

2. Vacuum clamp

Using a vacuum clamp to tightly adsorb the film to the surface of the clamp through negative pressure can effectively prevent warping and movement. The vacuum clamp can provide uniform clamping force to keep the film stable and flat throughout the welding process.

3. Control environmental conditions

The temperature and humidity of the welding environment have a significant impact on the stability of the film material. Controlling the temperature and humidity of the welding environment and keeping them within an appropriate range can reduce the thermal expansion and warping of the film and ensure the welding quality.

4. Multi-point welding

For large-area thin film welding, multi-point welding can be used to gradually weld each area. First, weld and fix at several key points, and then perform comprehensive welding, which can reduce the warping and deformation of the film and improve the welding quality.

In the process of plastic laser welding, to ensure that the two films can fit tightly without warping, leaking or false welding, it is necessary to comprehensively consider multiple factors such as material selection, surface flatness, fixture design, laser parameters, preheating treatment, etc. Through reasonable process design and control, the welding quality can be effectively improved to ensure the tight fit and firm bonding of film materials. In the future, with the continuous development and innovation of laser welding technology, the accuracy and reliability of plastic film welding will be further improved to meet more high-precision and high-quality welding needs.