In the field of plastic gear mold manufacturing, the laser surface strengthening process is like a magical key, opening up new avenues for improving mold performance and extending its service life. This process stands out among numerous strengthening techniques by enabling the interaction between lasers and mold materials to achieve surface strengthening of the mold. Below is a detailed introduction to this process.
Principle of Laser Phase Transformation Strengthening
Laser phase transformation strengthening is essentially a technology that uses a laser beam to precisely treat a workpiece. Specifically, when the laser beam scans the workpiece, it rapidly raises the surface temperature of the workpiece above the Ac3 critical point. After the light spot moves away, due to the heat conduction effect of the workpiece matrix, the temperature of the heated layer instantly enters the austenite or martensite zone, triggering austenite phase transformation or martensite phase transformation, and ultimately completing the phase transformation strengthening process. This process is akin to putting on a sturdy “armor” on the mold surface, significantly enhancing its surface performance.
Key Points of the Laser Phase Transformation Strengthening Production Process for Plastic Gear Molds
- Raw Material Selection
The selection of raw materials is the foundational step in the laser phase transformation strengthening production of plastic gear molds. Among various steels, low-carbon steel is the ideal choice for plastic gear molds, while high-carbon steel should be avoided. This is because if high-carbon steel is selected, the matrix of the gear will not be able to ensure sufficient compressive strength, thereby reducing its bending fatigue limit. It’s like building a house; if the foundational materials are not strong enough, the overall stability of the house will be seriously affected. Therefore, choosing the right raw materials is the first step in ensuring mold performance. - Initial State Control
The optimal initial state for plastic gear molds is the heat-treated state. In actual production, this step can be closely integrated with the stress-relieving heat treatment process after the forging of gear blanks. Specifically, quenching and high-temperature tempering of the forged blanks are carried out to obtain the desired heat-treated state for laser gears. This approach not only meets the performance requirements of the mold but is also an important way to reduce costs. It’s like a well-planned “optimization campaign” that achieves dual optimization of performance and cost by reasonably arranging the process flow. - Scanning Method Determination
There are mainly two scanning methods for gears: circumferential continuous scanning and radial tooth-by-tooth scanning. Circumferential continuous scanning is like giving the gear surface a comprehensive “massage,” enabling the laser to act uniformly on the gear surface and achieve a relatively uniform strengthening effect. Radial tooth-by-tooth scanning is like a precise “acupressure” technique that targets different teeth of the gear for specific treatment. In actual production, the appropriate scanning method needs to be selected based on the specific shape, size, and performance requirements of the gear to achieve the best strengthening effect. - Pretreatment Technology Key
Suitable pretreatment agents are one of the key factors in ensuring the success of laser strengthening treatment for plastic gear molds and have long been a challenge in the field of laser processing. Appropriate pretreatment agents and process treatments are like a highly skilled “doctor” that can effectively prevent thermal treatment cracks on the gear surface, reduce the sensitivity to surface ablation, ensure the accuracy of the tooth surface after laser treatment, and increase the thickness of the hardened layer. By carefully selecting pretreatment agents and optimizing process treatments, favorable conditions can be created for laser strengthening treatment, enabling the mold surface to obtain more excellent performance.
The laser surface strengthening process for plastic gear molds plays an increasingly important role in the field of mold manufacturing due to its unique principle and significant advantages. By reasonably selecting raw materials, controlling the initial state, determining the scanning method, and applying pretreatment technology, plastic gear molds with better performance and longer service life can be produced, providing strong support for the development of the plastic gear industry.
