Week 14 challenge
- In the three steps of the 3-2-1 method, three mutually perpendicular planes, called datum planes, are introduced, one at each step. These three planes define the workpiece position, and together with opposing clamping forces fully constrain the part.
- The 3-2-1 principle of location (six point location principle) is used to constrain the movement of workpiece along the three axes XX, YY, and ZZ. This is achieved by providing six locating points, 3 pins in base plate, 2 pins in vertical plane and 1 pin in a plane which is perpendicular to first two planes.
Degree of freedom controlled by 3-2-1 location principle
In this method, 9 degrees of freedom is controlled.
Pins A, B, C on the base plane ( a plane parallel to the plane which contains X and Y axis) restrict the rotation of component about X axis and Y axis. It also limit the downward movement of component along z axis. Ie. 1,2,3,4 and 5 degrees of freedom is restricted.
Pins D, E is in plane parallel to the plane containing X and Z axes. It prevents the rotation of component about Z axis (6, 7 degree of freedom) and the movement of the body in along Y axis towards one direction (8 degree of freedom).
- Basic Rules For Location
- Choosing Locating Surfaces
The last pin F is in a plane parallel to plane contains Y and Z axes. It restricts the movement component along X axis in one direction.
Three remaining degree of freedom 10, 11, 12 is unrestricted. It facilitates the loading of the component in the fixture. This three degree of freedom may restrict after loading of component by using clamping devices.
