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GG_775-Regular Member
5-Regular Member
Oct 21, 2026 2:15 PM UTC
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Pressure angle analysis with circular cam

Hi,when with Mechanism I run a pressure angle analysis for a simple circular cam with an eccentric follower, the result is always 0.Instead, it should yield a constant value other than 0.Could someone please explain why Creo provides this incorrect result?Am I doing something wrong?🤔If cam radius is 150mm and follower eccentricity is 100mm, pressure angle should be approximately 41.8 degrees, not zero.Thank you all for your time and help!

Gigi

    Srinivasan-IyerAnswer
    15-Moonstone
    Oct 30, 2026 10:33 AM UTC

    By definition it is between the direction of Motion Velocity of the follower and direction of axis of transmission.

    When the axis of rotation is co-axial to cam surface, there is no transmission; thus, follower velocity is zero.

    Hence pressure angle is zero.

    When Transmission happens, due to an eccentric cam, transmission happens and pressure angle varies.

    Hope I have explained clearly.

     

    Knowing, what we know is just a fistful of Earth, brings in humility.
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    9 replies

    GG_775-Regular MemberAuthor
    5-Regular Member
    Oct 22, 2026 7:10 AM UTC

    Di seguito il modello di riferimento,

    ancora grazie

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    GG_775-Regular MemberAuthor
    5-Regular Member
    Oct 22, 2026 7:13 AM UTC

    Here there are images,

    thanks

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    Catalina
    CatalinaCommunity Manager
    Community Manager
    Oct 26, 2026 1:27 PM UTC

    Hi ​@GG_77 
     
    Thank you for your question.  
     
    Your post has not yet received any response. I am replying to raise awareness. Hopefully, another community member will be able to help. 
     

    Thanks, 

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    Catalina | PTC Community Manager
    GG_775-Regular MemberAuthor
    5-Regular Member
    Oct 27, 2026 6:59 AM UTC

    Hi Catalina,

    thankyou for your interest! I hope to receive a response soon!

    Cheers

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    Srinivasan-Iyer15-Moonstone
    15-Moonstone
    Oct 29, 2026 5:44 AM UTC

    Check the axis of revolution of the cam and the lift of the follower.

     

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    Knowing, what we know is just a fistful of Earth, brings in humility.
    Srinivasan-Iyer15-Moonstone
    15-Moonstone
    Oct 29, 2026 6:57 AM UTC

    Here are the Pressure angles varying for one complete rotation of the cam.

     

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    Knowing, what we know is just a fistful of Earth, brings in humility.
    GG_775-Regular MemberAuthor
    5-Regular Member
    Oct 30, 2026 7:12 AM UTC
    Thankyou for your interest, I don’t understand...Definition of pressure angle:The pressure angle in a cam mechanism is the angle between the direction of motion of the follower (or tappet) and the normal to the cam's pitch curve (or contact profile).

     

    I don’t want eccentricity, the cam is simply circular...in this case the follower has not movement: pressure angle is 41,8 degrees (see attached img3).

    Why Creo’s analyses gives me a zero pressure angle (see img2)???

     

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    Srinivasan-Iyer15-MoonstoneAnswer
    15-Moonstone
    Oct 30, 2026 10:33 AM UTC

    By definition it is between the direction of Motion Velocity of the follower and direction of axis of transmission.

    When the axis of rotation is co-axial to cam surface, there is no transmission; thus, follower velocity is zero.

    Hence pressure angle is zero.

    When Transmission happens, due to an eccentric cam, transmission happens and pressure angle varies.

    Hope I have explained clearly.

     

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    Knowing, what we know is just a fistful of Earth, brings in humility.
    GG_775-Regular MemberAuthor
    5-Regular Member
    Oct 30, 2026 12:02 PM UTC

    Now it is clear...is the movement that makes the difference! If there isn’t follower’s motion pressure angle will be zero.

    Thanks!

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