## 6 Conclusions and Future Work  
(1) Based on the analysis of the process and difficulties of multiple laser scribing, this paper analyzes the process requirements of adaptive matching of laser scribing process parameters and motion parameters in the process of laser scribing. The physical theoretical model of scribing depth and laser scribing process parameters was established for a continuous laser and a quasi-continuous laser. Experimental results show that the theoretical model is in good agreement with experimental data. The laser scribing depth is positively proportional to the laser power and inversely proportional to the laser speed and has little relationship with the laser frequency.  
(2) There is an obvious positive linear correlation with the laser power density. The predicted accuracy of mathematical equations regarding the laser power density and scribing depth which is calculated by the laser power, speed and scribing depths experimental data, are 88.53% and 90.79%. The relationship model of laser scribing depth with laser power and laser scribing speed can realize the adaptive adjustment of laser energy according to the laser speed so as to realize the precise control of scribing depth in the application.  
(3) Under the condition of the same laser power, scribing speed and scribing frequency, the laser scribing depth at a forward angle of 6\({}^{\circ}\) and a side slope angle of 7\({}^{\circ}\) is the deepest compared with the vertical incident scribing depth, and the angle is also the recommended angle of laser scribing. With the increase of the incidence angle, the laser scribing depth will decrease linearly. The scribing depth at each angle can be conveniently calculated for practical laser scribing applications. The influence of laser scribing angle for scribing depth is also explained and analyzed, which includes many factors. Further systematic research is needed in the follow-up study.  
In this paper, a laser sublimation model based on energy conservation is established, and the influence of laser engraving process parameters on engraving depth is analyzed only by a single factor. The techniques can be used to guide the setting of process parameters during laser scribing processing, which will help improve processing accuracy and efficiency. However, the comprehensive influence of multiple parameters in laser engraving also needs to be further analyzed and studied. Meanwhile, the theoretical model of incident angle and laser engraving depth also needs to be further studied. In the future, our group will conduct research on precise removal models and multiparameter regression methods of laser scribing, or even the influence of fumes and plumes, which is a more complex task.  
Conceptualization, Q.L. and J.W.; methodology, J.W., P.S. and Q.L.; validation, J.W. and P.S.; formal analysis, J.W.; investigation, P.S. and L.W.; data curation, P.S.; writing--original draft preparation, Z.N.; writing--review and editing, J.W. and Z.N.; visualization, J.W.; supervision, Q.L.; project administration, Q.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the project \"Research and development of laser scribing technology and equipment for annular thin-walled milled parts of aeroengine\" from the national key R&D plan \"special project of additive manufacturing and laser manufacturing\" (Project No.: 2016 YFB1102500).  
Not applicable.  
The authors acknowledge [PERSON] from the Xi'an Institute of Optics and precision mechanics of CAS, and [PERSON] from AECC Shenyang Liming Aero-Engine Co. Ltd.  
The authors declare no conflict of interest.