UNIVERSITY OF SAN CARLOS – TALAMBAN CAMPUS
DEPARTMENT OF MECHANICAL AND MANUFACTURING ENGINEERING
PLATE NO. 1
CAM PROFILE WITH KNIFE EDGE FOLLOWER
ME 3121L – Machine Elements 2 Laboratory
Grp 1 Th 5:30 PM – 8:30 PM
Submitted by
MARIEL KATE D. LUMBACA
BSME – 3
Submitted to
ENGR. JONATHAN COLINA
Instructor
September 23, 2021
PROBLEM
A disc cam is to give SHM (Simple Harmonic Motion) to a knife edge follower during
outstroke of 50mm. The angle ascent is 120°, dwell 60°, and angle of descent 90°. The
minimum radius of cam is 50 mm. Draw the profile of the cam when the axis of the
follower passes through the axis of the camshaft.
Calculate the maximum velocity and acceleration during ascent and descent when the
camshaft revolves at 240 rpm.
SOLUTION
𝜃𝑂 = 120°
SHM
𝜃𝑂𝐷 = 60°
𝜃𝑅 = 90°
SHM
𝜃𝑅𝐷 = 360° − [120° + 60° + 90°] = 90°
h or S = 50 mm
Base Circle Radius = 50 mm
𝑁 = 240 𝑟𝑝𝑚
Angular Velocity 𝜔:
𝜔=
2𝜋𝑁 2𝜋(240 𝑟𝑝𝑚)
=
= 𝟖𝝅 𝒓𝒂𝒅/𝒔
60
60
Maximum Velocity during ascent 𝑣𝑎 :
𝜋ℎ2 𝜔
𝜋(0.05 𝑚)
8𝜋 𝑟𝑎𝑑/𝑠
𝟑𝝅
)(
)=
𝑣𝑎 = (
)( ) = (
𝒎/𝒔 𝒐𝒓 𝟎. 𝟗𝟒𝟐𝟓 𝒎/𝒔
𝜋
2
𝜃𝑂
2
𝟏𝟎
120° × 180°
Maximum Velocity during descent 𝑣𝑑 :
𝑣𝑑 = (
𝜋ℎ2 𝜔
𝜋(0.05 𝑚)
8𝜋 𝑟𝑎𝑑/𝑠
𝟐𝝅
)(
)=
)( ) = (
𝒎/𝒔 𝒐𝒓 𝟏. 𝟐𝟓𝟔𝟔 𝒎/𝒔
𝜋
2
𝜃𝑅
2
𝟓
90° × 180°
Maximum Acceleration during ascent:
2𝑣𝑎2
𝑓𝑚𝑎𝑥,𝑎𝑠𝑐𝑒𝑛𝑡 = (
ℎ
)=(
2
3𝜋
2 ( 10 𝑚/𝑠 )
0.05 𝑚
) = 𝟑𝟓. 𝟓𝟑𝟏 𝒎/𝒔𝟐
Maximum Acceleration during descent:
𝑓𝑚𝑎𝑥,𝑑𝑒𝑠𝑐𝑒𝑛𝑡 = (
2𝑣𝑑2
ℎ
)=(
2
2𝜋
𝑚/𝑠 )
5
) = 𝟔𝟑. 𝟏𝟔𝟓 𝒎/𝒔𝟐
0.025 𝑚
2(
Figure 1. Displacement Diagram
Figure 2. Construction of Cam Profile
Figure 3. Cam Profile