| Laser marker is a machine-electricity facility applying many techniques referring to laser, optics, mechanism, electricity, and computer. Laser marking is a kind of technique of marking permanent mark on the objective surface by using laser beam with high density. Laser marking is a new branch of laser processing technology. It has been widely used in many fields of industry, and furthermore, it is becoming a new industry standard. For the present, in the laser marking market, on-line laser marking have the most prospect. But the on-line marking requires the laser marking system has high marking speed. In our country, now most company's products can only be used in slow speed on-1 ine marking. Foreign company dominates the high-speed on-line marking system. It's on-line laser marking product can marking at the speed of 2000 characters per second. The product we designed can be applied for high speed marking then can substitute some type of foreign products.The design of two types on-line marking system is studied in detail in this thesis. The marking control software, laser system and optical system are introduced. The innovat ions of this thesis are as follow: By using dots marking method we achieve high on-line marking, and we design the accurate orientation project, the high scan project, and the step scan project, each of them can be applied for different marking requirement The main contents of thesis are as follows:1 The development of laser industry, the prospect and technically advantage of laser marking is reviewed.2 For the design of laser marking system, this paperintroduces the design of the RF excited CO2 marking system and the Nd: YAG marking system.( 1 ) The laser criterion for on-line marking is analyzed. The principle of the Sonical-optical Q-switched Nd: YAG laser, the design of its resonant cavity and the determine of its Q-switch frequency is analyzed. The design of optic transmitting system and its work principle is reported. The method of expanding, focusing and collimating the beam of light and its effect for laser marking is discussed. The principle of two axes scanning by using optical scanner is analyzed. The control system that is to control the laser system, optical scanner and inspect system by using computer is also reported. In this paper the design of cool ing system and power system to make the whole system work steadily is also introduced.(2) The reasons of chosen RF excited CO2 laser as the on-line marking system's laser is analyzed. The principle of the RF excited CO2 and its superior performance is introduced. And the design for the parts of RF excited CO2 marking system is also introduced.3 For dots marking, we design a convenient software, it can pick-up the characters dots information directly from dots characters-library, then make it more convenient for user.4 Two type of laser markers have been used to some product-lines. Three different projects are developed. Every of them can be used for on-line marking, and can be applied for different marking requirement. The accurate orientation project is a commonly used marking method, it can mark character accurately, but its marking speed is comparatively slow. The high scan project can mark character highly, but the laser system musthave high property, and furthermore, it can't mark normally on some special objects. By analyzing the first two projects, we design the step scan project. The step scan project can solve the speed and accurate problem effectively, and can be applied for most requirements.5 The principle of vectorial marking and filling marking is introduced and these two marking methods are achieved in static mode. And the difficulties for these two marking methods being used for on-line marking are discussed. |
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