Information on the doctoral thesis of PhD candidate Trần Đình Hiếu (revised version after the Institute-level Thesis Evaluation Committee):

Full name of PhD candidate: Trần Đình Hiếu

Scientific supervisors: Assoc. Prof. Dr. Trần Vệ Quốc and Dr. Đỗ Đình Lương

Field: Mechanical Engineering - Code: 9520103

Training institution: National Research Institute of Mechanical Engineering - Ministry of Industry and Trade

Thesis title: “Research on the influence of grinding parameters of alloy steel Archimedes screw on surface roughness and wheel wear”

Summary of new conclusions of the thesis

- This is the first work in Vietnam to study the influence of workpiece rotational speed (n: rpm), grinding wheel speed (v: m/s), and axial feed rate (S: µm/stroke) when grinding alloy steel Archimedes screw on surface roughness and wheel wear; The alloy steels used in the study are 40Cr, 35CrMo, and 38CrMo.

- Determining the wheel profile for grinding Archimedes screw using digital method.

- The study elucidated the influence of workpiece rotational speed, grinding wheel speed, and axial feed rate on surface roughness and wheel wear when grinding alloy steel Archimedes screw. The central composite rotatable design method combined with ANOVA analysis was used to optimize the technological parameters affecting output quality indicators. A set of technological parameters including workpiece rotational speed (n: rpm), grinding wheel speed (v: m/s), and axial feed rate (S: µm/stroke) was established for:

Surface roughness:

+ 35CrMo steel: optimum achieved at: R_amin = 1,025, n = 4, 412 rpm; S = 4,727 µm/stroke;  v = 23,495 m/s

+ 38CrMo steel: optimum achieved at: Ra_min = 1,0253, n = 4,5 rpm; S = 4,72 µm/stroke;  v = 23,51 m/s;

+ 40Cr steel: optimum achieved at: R_amin = 1,0255. when n = 4,34 rpm; S = 4 µm/stroke; v = 25,63 m/s;

Wheel wear:

+ 35CrMo steel: optimum achieved at k_{td min} = 62,21; n = 5,063 rpm; S = 6,848 µm/stroke;  v = 24,465 m/s;

+ 38CrMo steel: optimum achieved at k_tdmin = 97,84; n = 2,8 rpm; S = 10 µm/stroke;  v = 26 m/s;

+ 40Cr steel: optimum achieved at: k_{td min} = 97,44 when: n = 2,8 rpm; S = 10 µm/stroke;  v = 26 m/s.

- Experimental testing of contact pattern between screw and worm wheel to evaluate the optimization results using the central composite rotatable design method.

- The research results of the thesis are applied in production practice, contributing to improving expertise and supplementing technical documentation for grinding technology.

Detailed information of the thesis can be viewed at here