Most of the temperature and stress fields simulations in laser cladding were based on flat surface, while actually cladding
may occur on any curved surface. The difference between cladding on flat surface and curved surface is that the latter
will result in uneven distribution of laser power. Experiments of laser cladding have been done on different material
gears under various technical conditions, and crackles have been observed by SEM. Some factors that affect laser power
actually, such as laser shielding, the incident angle of laser and curved surface of gear are all considered. Based the
analysis of the shape of layer after cladding and the phase transformaion during cladding, temperature and stress fields of
gear surface laser cladding have been simulated by ANSYS in this article. The results indicate that appropriate material
matching and base preheating can decrease the likelihood of crackles, even eliminate it.
Knowing the position of the chute of cargo loading machinery situated in its working environment is a critical element
for effectively accomplishing auto-loading of bulk cargo. This paper presents a novel approach to measure the position
of the chute as well as the status of ship being loaded. A measuring device was designed according to the approach based
on laser scanner and the measuring method was implemented. The system has been installed in actual cargo loading
environment and proved successfully and is believed that it is a good starting point to this kind of usage.
The new idea of the optimum controlling of laser processing technique and parameters with multi-objectives and
multi-variables was put forth. With the comprehensive discussion about the quality index of laser transformation
hardening (LTH), a hierarchical structure of the LTH quality index system and a decision-making framework model of
the quality control were set up. Then, based on the conclusions of the sensitivities of LTH parameters' influences on
the case indexes, the principle of LTH's parameters optimization was discussed by means of fuzzy decision method.
With the combination of the principle and the sectionlly changing scanning velocity technique, which can effectively
the uniformity of longitudinal case-distribution, a decision-making framework for optimal controlling on the laser
scanning technique and the parameters with multi-objectives were put forward. An optimization model was developed
and the validity of the model was verified both by theoretical computation and experimental results.
In laser transformation hardening (LTH), it is a common phenomenon that the discrepancy of hardening effects occurs between the beginning and the end of laser scanning for those parts which have boundaries along the scanning direction, when the laser processing parameters, laser power and scanning velocity, are kept unchanged. The case depth at the end of scanning path is larger than that at the beginning. And sometime the local surface on the end may be melted. The discrepancy, which results in non-uniform hardening effect, will make the process quality bad. This paper study on the discrepancy and the effects of laser power and scanning velocity, then presents the effective method to control the discrepancy and to improve the laser process.
In order to meet the special demands for laser materials processing, after the analysis and design of the resonator parameters and pulse parameters, a mechanical chopper Q-switched CO2 pulse laser unit is developed. At last, a Q-switched CO2 laser pulse with high peak power of more than 10kW and the maximum beam power of 800W (at this time the pulse repetition rate is 20kHz) and TEM00 mode is obtained. The width of the pulse duration is adjustable and in order of μs.
Laser welding of A5083 aluminum alloys with high power CO2 laser is experimental studied in this paper. The study shows that under determinated welding condition, an additional plasma control tube would achieve good plasma suppression, which results in good welding quality. The shielded gas flow acting on the keyhole in CO2 laser welding of A5083 aluminum alloy is numerical simulated by finite element method. From the ANSYS numerical simulation diagrams of the keyhole’s gas flow field, it can be seen that the additional plasma control tube would achieve good plasma suppression to maintain the keyhole.