Abstract: A mechanical press shapes parts by driving a ram into metal to deform it into a desired form. Because this process is widely used—from forming pop cans to shaping car fenders—mechanical presses play a crucial role in global manufacturing. The objective of this research is to develop alternative drivetrain designs for mechanical presses that generate specialized ram motions while meeting industry demands for optimal joint forces. By focusing on mechanical presses, this study leverages their advantages over other forming methods, including higher speeds, lower costs, enhanced accuracy, greater precision, and improved energy efficiency. Even small improvements can significantly reduce processing time and energy consumption. The research evaluates five drivetrain designs under realistic industrial conditions to enhance the dwell phase and achieve the required joint forces. Two of these designs are currently prevalent in industry, while the remaining three offer potential advancements.
Novel High-Speed Mechanical Press Designs Optimized for Improved Ram Dwell Limited by Joint Force Considerations
Tianze Xu
Advisors: Andrew Murray & David Myszka
Department of Mechanical & Aerospace Engineering
Press Machine Structure Designs
(a) Slider
(d) Knuckle - Ternary
(c) Geared Five-Bar Sliding (GFBS)
(b) GFBS - Ternary
Numerical Optimization of Structure
Fig. (i) illustrates the input-output plot generated using the proposed optimization method under varying maximum joint load-force constraints. The horizontal axis represents the angle (driving angle of linkage a), while the vertical axis denotes the stroke trajectory of the press slider (with 0 indicating contact with the workpiece). The plot shows that as the allowable maximum force decreases, the effective stroke range correspondingly reduces.
Knuckle Structure Equations
(e) Knuckle Kinematic Diagram
The four equations correspond to the position, velocity, and acceleration calculations of the knuckle structure. They enable us to efficiently construct the required mathematical model in MATLAB, serving as a foundational basis for further in-depth analysis and research.
Figures (e) through (j) illustrate the kinematic diagram of the knuckle structure, along with its corresponding force analysis. The kinematic diagram facilitates our understanding and derivation of Equations (1) through (4), which represent the position, velocity, and acceleration relationships of the system. These equations form the basis for constructing the corresponding mathematical model in MATLAB. On the right side, the force analysis diagrams further support the evaluation of maximum joint forces within the press structure during operation, providing critical insights into the mechanical performance of each linkage and node throughout the working cycle.
In Fig. (g), a geometric approach is illustrated for determining the optimal value of {e} corresponding to a given set of four-bar linkage parameters {a, b, c, d}. This method aims to minimize the calculated positional error (EE) while simultaneously maximizing the load-bearing capacity (F_i) of each joint. Fig. (h) presents the corresponding optimization process flow diagram.
(f) Knuckle Force Analysis
Eq(1)&(2) Knuckle Structure Position Loops
Eq(3) Knuckle Structure Velocity Matrix Equation
Eq(4) Knuckle Structure Accelerate Matrix Equation
(g) The process to decide best by four bar link {a, b, c, d}
(h) Optimization Process Flow-Diagram
(i)The Input-Output Plot for different max load-force constrain