Chris Strikes Long Raining Sixes!
C - clamping
S - strikes
L - locating
R - raining
S - safety
Clamp:
- Used for miscellaneous supports at miscellaneous positions.
- Used when jig and fixture fail to perform requisite.
Jigs:
- Hold and support workpiece
- Guides the tool for machining at a specific position.
- Lighter in construction
- Not fixed with machine
- eg: jig plate - interference fit , drill- bush: clearance fit
Fixtures:
- Holds and support workpiece
- Heavier in construction
- Fixed with machine
- Do not judge the tool but provides reference for machining w.r.t. workpiece.
- Continuous path operation can be performed.
- eg : setting block - milling fixture , 3 jaw chuck - turning fixture
V - locator : it is used to locate or support circular and semi circular objects.
3-2-1 principle:
- A - primary datum
- B - secondary datum
- C - tertiary datum
- 3,2, 1 are number of locating positions
- Total 6 supports are there: 3 - A , 2 - B , 1 - C
- Providing support to the primary datum translational motion along negative z axis , rotational motion about x and y axis will be restricted so 5 DOF will be arrested.
- Providing support to secondary datum , translational motion along negative y and rotational motion about z axis will be restricted so 3 DOF will be arrested.
- Providing support to tertiary datum , translational motion along negative x will be restricted so one DOF will be arrested.
Note: using 3-2-1 principle all together 9 DOF will be arrested and 3 DOF will be allowed that too along cartesian axis , for loading / unloading , clamping /unclamping and for necessary machining motions.
Pins:
- Supporting pins: fixed pin , adjustable pin , for workpiece without holes
- Locating pins: for workpiece carrying holes
- Jack pin : adjustable gaps used in screw jack , in salloon chair
- Diamond pin : it controls the variation in centre position between two holes
Ejectors:
- Easy removal of workpiece from the support after machining is performed.
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