Mumbai University > Mechanical Engineering > Sem 5 > production process 3

Marks: 5M

Year: May 2016

• According to this principle, only the minimum locating points should be used to secure location of the work piece in any one place.
• Considering the “3-2-1” principle, three pins are used in the base of the fixed body.
• This is due to the reason that this is the minimum number of locating points through which a plane can be drawn on which the work piece will seat. The work piece may rock and get strained it more than three locating points are provided.
• Now considering the second plane, it is clear that if one locating point is provided the work piece will swives about this point, but not it these are two such location points.
• These two locating points, establishes a line parallel to the first plane, with the work piece located against a plane and a line, it has only one direction of movement in third plane.
• Therefore, one locating point is sufficient in the third plane to prevent this movement.