Analysis of Causes of Marking Plastic Products
The main purpose of marking plastic products is to ensure that personnel are able to read the information on the plastic products quickly, accurately, and visually. Plastic products are generally non-rigid and easily deformable materials, while lasers used to mark plastic products are generally high-power devices that generate high energy through focusing. Therefore, when the laser beam scans plastic products, the heat generated at the focus point is high during scanning, causing the plastic product to rapidly expand and contract, forming a curing phenomenon. During the contraction process, voids are formed under the focus point and the surface of the plastic product, leaving a visible marking of the marking information. This marking phenomenon is called product marking.
The reasons for the shock waves of plastic product marking are mainly caused by the expansion and contraction of the marked plastic product due to the heat generated by the laser during marking. The expansion and contraction process generally consists of four stages: laser irradiation, melting, vaporization and cooling. When the laser is irradiated on the plastic products, the materials close to the laser focus point will be first instantaneously heated and melted, and the heat will rapidly spread out, and the plastic product will expand in a very short time, thus generating such seismic waves.
The intensity of shaking caused by the marking of plastic products is affected by many factors, including but not limited to, marking content, marking speed, beam power, focal length and material properties. Therefore, in order to reduce the risk of shock waves caused by marking of plastic products, operators should select appropriate marking parameters, carefully adjust the working distance between the focus point and the plastic product, appropriately set the marking speed, and select the appropriate power and beam multiplier.
In addition, the thermal conductivity of the plastic product also affects the severity of the shock waves caused by the marking of plastic products. Generally, the thermal conductivity of plastic products increases as the temperature increases, so when the marking power reaches a certain level, the shock wave can be suppressed by increasing the speed of the marking. Because higher speed leads to a smaller temperature gradient and a lower temperature difference between the focus point and the general structure of the plastic product, thus reducing the expansion and contraction and the impact of the shock wave.
In summary, controlling the parameters of laser marking and selecting the appropriate materials can reduce the shock waves caused by marking plastic products. Operators should adjust the relevant parameters or materials reasonably in the following situations. The amount of marking information is large, the marking speed is slow and the laser power is low. During marking of plastic bottles and other objects, in order to reduce the residual stress, plastic materials with good thermal conductivity should be used. With appropriate adjustments, the severe shock waves caused by marking can be effectively prevented, which can protect the health of the operators and ensure the accuracy of the marking information.
