"Follower type The method presented in this Item is applicable to the design of disc cams with any one of the four types of crowned follower illustrated in Sketch 2.1. The algorithm used to calculate the compressive contact stress at the surface (taken from Data Item 78035) is strictly applicable only to static contacts where no traction forces act. In the contact zone between a cam and a domed or a flat-faced follower traction forces (due to friction) are present. However@ if the cam and follower are separated by a film of lubricant@ the coefficient of friction is likely to be very low (less than 0.1) and the values of compressive contact stress predicted by the algorithm will be sufficiently accurate. Therefore this Item is applicable to the analysis of sliding contact (domed or flat-faced) followers only if the lubrication regime can be described as ""mixed"" or ""elastohydrodynamic"" as described in Data Items 94008 and 94017 (see References 20 and 21). If ""boundary"" lubrication is predicted (see Data Items 94008 and 94017) it is more difficult to be certain that the coefficient of friction is less than 0.1 and so results obtained using ESDUpac A9411 should be treated with caution. Follower motion The method presented in this Item can be used to analyse cams with a wide range of profiles. In cam design the relationship between the motion of the cam and the motion of the follower@ during a dwell-rise-dwell (DRD) or a dwell-return-dwell (DRD) motion@ is usually governed by a mathematical equation known as a cam law (see Reference 4). Although the theory (presented in Section 3 of this Item) is general@ in that any mathematical cam law can be specified@ the computer program (ESDUpac A9411) contains only six commonly-used cam laws (identified in Section 7.3.1). If the required cam law for a particular motion segment is not included in the current version of ESDUpac A9411 the FORTRAN source code can be modified (as described in Section 4.1.1) to include the relevant equations. Alternatively the motion of a follower@ throughout a cam cycle@ can be entered to the program via a file. This motion data file must contain values of follower displacement@ follower velocity and follower acceleration at intervals of one degree of cam rotation. The required format of the file is described in Section 7.3.2 and the reasons for specifying motion in this way are explained in Section 4.1.1."