Fig. 4

Cutting contact force analysis. \(O_1\), \(O_2\) are the cutter and turntable center points, respectively; \(R_1\)is the radius of the rotary cutter; \(R_2\) is the radius of rotation of the turntable; \(r_1\) is the radius of the bacterial body; \(F_{1}\) is the thrust of the fixture on the golden needle mushroom and the point of action is G; \(F_2\) is the thrust of the cutter on the golden needle mushroom and the point of action is D; \(F_{N}\) for the pressure of the jig on the golden needle mushrooms; \(F_{a}\) for centripetal force; A is the intersection of the horizontal line through \(O_{1}\) and the vertical line through \(O_2\); B is the intersection of the extension of \(O_{1} D\) with line \(O_{2} C\); C is the center point of the golden needle mushroom; D is the point of intersection of the cutter’s thrust \(F_{2}\) against the golden needle mushroom; G is the point of contact between the edge of the jig and the golden needle; \(\theta_{1}\) is the angle between the rotary cutter and the horizontal line; \(\theta_{2}\) is the angle of \(O_{1} B\) and \(O_{1} O_{2}\); \(\theta_{3}\) is the angle of \(O_{1} O_{2}\) and \(O_{1} A\).