TAILIEUCHUNG - Ebook Cam design handbook: Part 2
(BQ) Part 1 book "Cam design handbook" has contents: Cam manufacturing, cam system modeling, cam system dynamics analysis, cam system dynamics response, special cam mechanisms, cams in microelectromechanical systems, automotive camshaft dynamics. | CHAPTER 10 CAM MANUFACTURING Harold A. Rothbart, D. Eng. MANUFACTURING METHODS 285 MASTER CAM ANALOG DUPLICATION CAMS 287 CONTINUOUS NUMERICAL CONTROL (CNC) CAMS 288 MANUFACTURING ERRORS AND DISCUSSION 291 Structural Errors 293 Fixed Backlash Errors 293 Variable Backlash Errors 293 Miscellaneous Errors 293 Probabilistic Model of Cam Profile 294 Manufacturing Discussion 295 CAM SHAPES VERSUS ACCELERATION CURVE 296 DYNAMIC ERRORS BY FINITE DIFFERENCES 297 MATERIAL PROCESSES 301 Melting Practice 302 Heat Treatment 302 Metalworking 302 SPARE PARTS LISTING 303 CAM FOLLOWERS 305 Roller Followers 305 Roller-Follower Installations 306 Sliding Followers 312 CONCLUSION 312 SYMBOLS rc = distance from center to cam, in y = follower displacement, in ¨ = follower acceleration, in/sec2 y ¨m = maximum follower acceleration, in/sec2 y ¨s = follower deviation from theoretical cam curve, in y F = normal force, lb I = moment of inertia of roller, lb-in-sec2 Rc = radius of cutter or grinder, in Rr = roller radius, in a = angular acceleration of roller, rad/sec2 ms = static coefficient of friction between cam and roller s = error or deviation from theoretical cam profile, in q = increment angle, rad w = cam speed, rad/sec MANUFACTURING METHODS It is important that engineers be aware of the fabrication techniques involved in manufacturing and inspecting the actual cam produced from the design information. They should be knowledgeable about the experience and level of dedication of the machine shop workers in making and assembling the parts. To ensure quality (1) errors in fabrication and misalignment in assembly should be eliminated; (2) cam fabrication should be usefully monitored, and (3) tool wear, vibrations, and chatter should be eliminated. Necessary periodic inspection also should be minimized. 285 Copyright 2004 by The McGraw-Hill .
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