Hsin-Pao Chen

A Procedure for Measuring Planar Cam Profiles and Their Follower Motions

A procedure that can be used to inspect planar cam contours and to evaluate their follower displacement, velocity, and acceleration curves with a higher degree of accuracy, without the aid of approximating follower displacements in traditional methods, is constructed. Based on the geometric relationships at the contact point between a planar cam profile and its follower, analytical descriptions that can be utilized to determine the follower displacement curve and its derivatives are first identified. To verify the feasibility and accuracy of the proposed procedure, analytical results generated from a theoretical design are compared to those obtained by the application of the procedure. To demonstrate the effectiveness and usefulness of the developed procedure, a measuring test bed has been constructed for a practical application example. Furthermore, the results obtained by using the developed procedure with the built measuring test bed are also compared to those obtained by using a coordinate measuring machine with the proposed algorithms.

Development of a Measuring System for Planar Cam Profiles and Their Follower Motions

A measuring system that can be used to inspect planar cam contours and to evaluate their follower displacement, velocity, and acceleration curves with a higher degree of accuracy without the aid of approximating follower displacements in traditional methods is constructed. Based on the geometric relationships at the contact point between a planar cam profile and its follower, analytical descriptions that can be utilized to determine the follower displacement curve and its derivatives are first identified. To verify the feasibility and accuracy of the algorithms proposed for the measuring system, analytical results generated from a theoretical design are compared to those obtained by the application of the computing procedure. To demonstrate the effectiveness and usefulness of the developed procedure, a measuring test bed has been constructed for a practical application example. Furthermore, the results obtained by using the built measuring system are also compared to those obtained by using a coordinate measuring machine (CMM) with the proposed algorithms.Copyright

Synthesis and Analysis of Slider-Crank Mechanism Motions

Slider-crank mechanisms used in open/close motion from toggle positions can be driven at the crank by many devices. Usually, the slider motion is defined first to synthesize crank motion. When slider motion has acceleration continuity only, crank acceleration is discontinuous causing shock loading at high speeds. To avoid such behavior, motion constraints must be assigned up to ping continuity at the limiting positions. This paper presents kinematic motion equations of slider-crank mechanisms with input from both the slider and crank. Toggle and limiting positions having required transmission angles at varied link ratios are determined. Motion functions that yield continuous crank acceleration are demonstrated.Copyright

Benefit Evaluation for Manufacturing of Marine Propellers

To increase productivity of marine propellers by raising machining efficiency, this paper presents the zigzag/spiral tool paths generation algorithm based on the arc base curve approach for three-axis machining of curved surfaces of propellers. By considering the shapes of selected cutters with different types of tool paths generated by the proposed procedure, machining efficiency can be calculated and simulated. To verify the accuracy and effectiveness of the developed approach, numerical and experimental results of machining of propeller surfaces are compared. It was proved that the machining time can be cut down up to 19% by using zigzag tool paths with a toroidal cutter. In addition, the machining knowledge revealed here can be accumulated for benefit evaluation in the manufacturing process with existing CAD/CAM systems. From the cost model, design, and process views, the overall cost savings after 5 years are investigated, and the expected benefit yield is about 45%.Copyright

Removing Tool Marks for Impellers in Five-Axis Machining With Improved Interference-Free Tool Paths

The paper deals with the procedure of removing a gouge phenomenon on impeller surfaces in 5-axis machining. That is, when an impeller of a centrifugal compressor is being cut, tool marks on its surfaces may exist in finish milling due to reverse movements of moving axes along a 5-axis interference-free tool path. For generating interference-free cutter location (CL) data needed in rough and semi-finish 5-axis cutting processes, first, a simple yet useful approach is proposed. To identify the potential gouge area and to solve the problem for a tool path having reverse motion directions with its moving axes in finish milling, the CL data are further smoothed to remove the reverse movements about its rotating and tilting axes. The effectiveness of this procedure has been experimentally confirmed by successful 5-axis finish milling of an impeller without leaving tool marks on its surfaces.Copyright