Presentation on theme: "Work Holding and Tool Holding"— Presentation transcript:
1 Work Holding and Tool Holding Six degrees of freedom of a body/object in spacePrinciple of work/tool holding (location and restraint)Example of work holding method
2 Six degrees of freedomIf we consider a body/object in space it is free to move in six directions as follows:Back and forth along the X axisSide to side along the Y axisUp and down in the Z axisRotate either way about the X axisRotate either way about the Y axisRotate either way about the Z axis
3 Principle of location and restraint To be able to carry out work on the material/object it is necessary to locate the material in a set position on the machine and restrain it using some form of clamping/fixing device to prevent any linear or rotational movement.The clamping/fixing devices can consist of:(A) positive restraints, where a physical object prevents the material from moving.(B) frictional restraints, where the material is gripped between two or more objects.(C) a combination of positive and frictional restraints.Where possible a positive restraint should be used to resist cutting forces.
4 Location and Restraint If the material is placed on a flat surface as in diagram below some of its states of freedom become restrained
5 When location pins are added as in diagram below it becomes further restrained and also located in set positions
6 If clamping screws are then added as in diagram below the material becomes fully restrained and located in set positions
7 Typical Example of a Work Holding Device (work held between centres on a lathe)