A CAD/CAM System for High Performance Precision Drum Cams

Masood, Syed H.

doi:10.1007/s001700050036

Cited by 6 publications

(5 citation statements)

References 6 publications

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“…Simple harmonic motion (Masood 1999) which has smoothness in velocity and acceleration during the stroke is an advantage inherent in the curve. However, the instantaneous changes in the acceleration at the beginning and end of the stroke tend to cause vibration, noise, and wear.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to general polynomial curves, these NURBS curves have the useful property that offset are of the same type, and hence also have an exact NURBS representation. Masood (1999) describes a computer-aided design and manufacturing system for the design and production of complex profiles for high-performance drum cams within the specified tolerance. The system graphically generates the cam profile on the cylindrical drum after performing an analysis of the kinematic performance for the prescribed follower motion, using a B-spline representation of follower curves.…”

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confidence: 99%

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Optimisation of cam-follower motion using B-splines

Sateesh¹,

Rao

Reddy

2009

International Journal of Computer Integrated Manufacturing

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This paper proposes design of cam-follower velocity curve by using B-spline polynomials. B-spline polynomials are smooth curves defined by control points. Curve shape can be modified by changing the control points. The traditional design method for improving the motion characteristics of the follower is to find an optimum displacement curve for which follower velocity, acceleration curves to be continuous and their peak values as small as possible (i.e. minimum jerk). B-spline polynomials of degree three and six control points are used in design of follower velocity curve. The B-spline curve is used to approximate the various basic curves which have better motion characteristics. A computer-aided design and computer-aided manufacturing (CAD/CAM) system is developed which generates follower motion curves, i.e. displacement, velocity, acceleration, jerk and cam profiles. An analysis is carried out on B-splines with basic curves for maximum accelerations to select the best cam follower motion. It also provides cam profile coordinates to manufacture a cam on computer numerical control (CNC) machines.Keywords: disc-cams; cam profile, B-spline; computer numerical control (CNC); computer-aided design and computer-aided manufacturing (CAD/CAM); R-D-R-D (rise-dwell-return-dwell) IntroductionA cam is mechanical member used to transform rotary motion into translating or oscillating motion to its follower by direct contact (Roth Bart 1956, Jensen 1965. Cam may be a plate cam or a disc cam which is cut out of a piece of flat metal, drum cam in which a groove is cut on the surface of cylinder, globoidal cam and circular cam. Applications of these cams are found in packaging machines, wire-forming machines, internal combustion engines, mechanical and electronic computers. Requirements for high performance of such machinery demands efficient methods for the design and manufacture of cams.In a cam-follower mechanism, the load produced by inertia forces induces deflections and creates vibrations. These affect the operating life of the cam. So the design of motion curves to minimise dynamic loading is of importance for high-speed cam mechanisms. It is well known that the velocity and acceleration curves are required to be continuous and to have the peak values as small as possible (i.e. minimum jerk). The purpose of this paper is to develop a CAD/CAM system for cam-follower mechanisms and to design follower velocity curve using B-splines in view of improving motion characteristics.

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Optimisation of cam-follower motion using B-splines

Sateesh¹,

Rao

Reddy

2009

International Journal of Computer Integrated Manufacturing

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“…In order to obtain kinematic curves with good dynamic properties under arbitrary design requirements, the kinematic model parameters are obtained by optimising the dynamic performance [20,21]. Currently, there are also many relevant software packages to create cam systems to facilitate the design of cam mechanisms, e.g., CAD/CAM [22][23][24], UG [25], and SOLIDWORKS [26,27].…”

Section: Introductionmentioning

confidence: 99%

“…The Cartesian coordinate system is the main tool for the graphical methods [29][30][31][32]. Wu et al [24] proposed a design of a variable speed translational cam profile [33]. Two approximate analysis methods were given to determine the plate cam profile with a roller follower [34].…”

Section: Introductionmentioning

confidence: 99%

A General Design Method of Cam Profile Based on Cubic Splines and Dynamic Model: Case Study of a Gravity-Driven Tricycle

et al. 2022

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This paper proposes a general design method for cams based on the kinematics and dynamics of a mechanical system. According to the actuator’s trajectory, the cam profile is generated in reverse based on the kinematic model of the system. Firstly, the cam design’s optimising problem is converted into the execution trajectory’s optimisation to obtain the optimum operation trajectory according to the actuator’s requirements. Secondly, the relationship between the cam profile and the actuation trajectory is modelled based on the kinematics and dynamics of the mechanical system. Then, applying the cubic spline interpolation method, the cam profile is generated, and the error compensation methods are illustrated through numerical analysis. Finally, the validity of the presented design method is verified through experiments, which demonstrate the reliability of this method.

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“…In 1992, Yang [5] integrated the design and manufacture in cylindrical cam, index barrel cam, and roller gear cam with cylinder rollers. In 1999, Masood [6] did a drum cam study of CAD/CAM integration, and discussed the dynamic attributes. As for the CAD for spatial cams, in 1994, Angeles [7,8] developed the CAD systems in spherical cam with oscillating roller follower.…”

Section: Introductionmentioning

confidence: 99%

Surface Generation and Fabrication of Roller Gear Cam with Spherical Rollers

Chen

Hong

2008

JAMDSM

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This paper derived the surface profile equations and the meshing equations of the spherical meshing elements from the homogeneous coordinate transformation matrix and the conjugate surface theory proved by the envelope theory. In the machining aspect, we demonstrated the position equation of cam profile using the coordinate transformation theory and obtained the perfected controlling position point of the tool path under the limitation of the chord errors. Finally, the design and the machining module was developed via Visual Basic that generated the cam profile points and the tool path points. The curves from UNIGRAPHICS to test and verify the cam profile equation. To verify the validation of the tool path, a cutting simulation software, VERICUT, is used to simulate the cutting geometry and kinematics of the roller gear cam, and demonstrate the practical application of the developed method.

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A CAD/CAM System for High Performance Precision Drum Cams

Cited by 6 publications

References 6 publications

Optimisation of cam-follower motion using B-splines

Optimisation of cam-follower motion using B-splines

A General Design Method of Cam Profile Based on Cubic Splines and Dynamic Model: Case Study of a Gravity-Driven Tricycle

Surface Generation and Fabrication of Roller Gear Cam with Spherical Rollers

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