National Research Institute of Mechanical Engineering plans to organize the Institute-level defense of the Doctoral Thesis for PhD Candidate Tran Dinh Hieu in early July 2023. The Institute posts the following information about the candidate's doctoral thesis:

Full name of PhD candidate: Tran Dinh Hieu

Collective of scientific supervisors: Assoc. Prof. Dr. Tran Ve Quoc,  Dr. Do Dinh Luong

Major: 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 Archimedean screw on surface roughness and wheel wear"

Summary of new conclusions of the Thesis

- This is the first study in Vietnam investigating 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 Archimedean screw on surface roughness and wheel wear; The alloy steels used in the study are 40Cr, 35CrMo, and 38CrMo.

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

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

Surface roughness:

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

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

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

Wheel wear:

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

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

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

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

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

Detailed content of the thesis of PhD candidate Tran Dinh Hieu can be viewed at here