Add Magnetic-Joint

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Add Magnetic-Joint

Magnetic-Joint

See also: Magnetic-Joint dialog ( YouTube Video : http://youtu.be/IME9Eb4mpQE )

Use Magnetic-Joints ONLY for special modeling - for example, to reverse-engineer the motion of a Follower from the shape of an imported Cam.

Magnetic-Joints use iterative, root-finding techniques. All other kinematic joints use closed-form equations for exact and fast evaluations. Therefore, a model with a Magnetic-Joint is ~100+ x slower to solve than a model with Slide-Joints, Pin-Joints, and Ball-Joints. Most models (99%?) do not need a Magnetic-Joint.

Terminology

Magnetic-Joint :

A Magnetic-Joint pulls a circular Profile to be in continuous contact with an irregular Profile (or Curve).

The circular Profile and irregular Profile (or Curve) are in different kinematic-chains. After you add a Magnetic-Joint, the motion of the kinematic-chain with the irregular profile (or curve) is are related by the contact between the circular and irregular profiles (or curve).

Point-Cloud :

X-Y or R-Θ coordinates. Use a Point-Cloud FB to import the Point-Cloud coordinates.

Curve :

The smooth shape that we calculate for you from the Point-Cloud coordinates.

Preparation for Add Magnetic-Joint (Typical)

MD-GA-AddMagJoint-Prep-01

The Magnetic-Joint pulls a Circular-ProfileRed-14-4 onto the outside or inside of an Irregular-ProfileRed-14-2.

Red-14-1b A Part (and kinematic-chain) to which the Irregular-ProfileRed-14-2 is a child.

Red-14-2 An Irregular-Profile, which is a

•Profile that you have added to a sketch-loop

or

•Curve that you have fitted to a Point-Cloud

Red-14-5 A Part (and kinematic-chain) to which the Circular ProfileRed-14-4 is a child.

Red-14-3 The Motion-Dimension FB to drive by the action of the Magnetic-Joint.

Add Magnetic-Joint

MD-GA-AddMagJoint-Prep-01

STEP 1: Pre-Position the Circular Profile

1.HOME the model

Select the Home key, or use the ALT+H keyboard shortcut, or do Run menu/toolbar > Home.

2.Edit the Motion-Dimension FBRed-14-3 | Base-Value so that the:

Distance from the Circular-ProfileRed-14-4 to the Irregular-ProfileRed-14-2 ...

... < 0.5 × Radius of Circular-ProfileRed-14-4

Note: See also Magnetic-Joint dialog > Advanced

STEP 2:Start the Add Magnetic-Joint command

1.Mechanism menu > Add Magnetic-Joint

OR

Add Magnetic-Joint icon

1.Kinematic elements toolbar > Add Magnetic-Joint

STEP 3:Select the elements:

1.Click the Irregular ProfileRed-14-2

2.Click the Motion-Dimension FBRed-14-3 that you want to 'drive' with the Magnetic-Joint.

3.Click Circular ProfileRed-14-4

STEP 4: Complete the Command

1.Command-Manager: Click OK-tiny-11-15 in the Command-Manager.

MD-CM-AddMagneticJoint-1
MD-GA-AddMagJoint-Prep-02

Result: (usually)

The Magnetic-Joint pulls the Circular-ProfileRed-14-4 to be in contact with the Irregular-ProfileRed-14-2.

A Point SymbolRed-14-6 is at the contact.

The Magnetic-Joint FBRed-14-7 is near to the Point-SymbolRed-14-6

There is a Magnetic-Joint iconRed-14-8 below and right of the Motion-Dimension FBRed-14-3 that is driven by the Magnetic-Joint.

 

STEP 5: Open the Magnetic-Joint dialog

Video:

Video: Add a Magnetic-Joint