Locating Flashcards
Locating
Properly positions the part, rigidly supports it and restricts movement
Locators and supports are same. Supports bear weight
Basic rules of locating
Positioning the locators
Part tolerance
Fool proofing
Duplicate location
Positioning the locators
Whenever possible locators should contact work on machined surface to ensure repeatability for different parts
Should be spaced as far as possible
Should hold cutting forces
Tolerances
Usually 20 to 50 % of part tolerance
Location from flat surfaces
Solid supports
Adjustable supports
equalizing supports
Location from internal diameter
Single pin can restrict 9 directions of movement
Whenever possible use holes as primary part locators
Locatir to fit MMC
GEN clearance is .0005”
Primary pin locator and secondary
Primary is round and the secondary is diamond shaped
Location from external profile
Completely encompass a circular part
Enclosed in a depression or recess
Plunger
Spring loaded hand retractable
Levelers
Levels the whole fixture and work pieces
Ball plunger
Used for indexing application along with a detent
Referencing
Work properly positioned with respect to the cutting tool (dual process)
