Milling Fixture

Fixtures, Types of fixtures, Milling fixture, Elements of fixtures

1. Milling Fixture

2. Overview
•Fixtures
•Typesoffixtures
•Millingfixture
•Elementsoffixtures

3. Fixtures
•Fixturesarestrongandrigidmechanicaldeviceswhichenableeasy,quickand
consistentlyaccuratelocating,supportingandclampingofworkpiecesagainst
cuttingtool(s)andresultfasterandaccuratemachiningwithconsistentquality,
functionalabilityandinterchangeability.
•Fixturesaredesignedspecificallyforanoperationandsothesearenamedonthe
baseoftheoperationtobecarriedoutwiththeirhelp.
•Fixturesareusedtoholdtheworkpieceproperlytocarryouttheoperations.

4. Types of Fixtures
•Differenttypesoffixturesarelistedbelow.
oTurning fixtures
oMilling fixtures
oFixture for grinding
oFixture for broaching
oTapping fixture
oFixture for welding
oAssembling fixture
oInspection fixture

5. Elements of Fixtures
•Fixturesaremanuallyorpartiallypoweroperateddevices.
•Tofulfiltheirbasicpurposes,fixturesarecomprisedofseveralelementssuchas,
obaseandbodyorframewithclampingfeatures
olocatingelementsforproperpositioningandorientationoftheblank
osupportingsurfacesandbase
oclampingelements
oauxiliaryelements
ofasteningparts

6. Milling Fixture
•Fixturesusedtoperformdifferenttypesofmillingoperationsarecalledmilling
fixtures.
•Millingfixtureisaccuratelylocatedandboltedonthemachinetablebyusing
boltsandnuts.
•Thecutterisnotguidedduringcuttingoperation.
•Locationandclampingsystemsaresimilartothoseusedfordrilljigs.
•Cuttingforcesinfixturesarehighandtendtolifttheworkpiecethereforethe
clampingforcesneedtobehightoo.
•Thefixturesformillingoperationsaredesignedanddescribedonthebasisof
millingoperations,millingtechniquesandclampingpowertechniques.

7. Types of Milling Fixtures
•Onthebasisoftypesofoperationsthemillingfixturemaybeofdifferenttypes
are-facemilling,slotmilling,plainmilling,sidemilling,formmillingandgang
millingfixtures,etc.
•Onthebasisontechniqueofmillingmachining,millingfixturesarenamedas
singlepiecemillingfixture,stringmilling,indexmilling,etc.
•Onthebasisofclampingpowerandclampingmethodmillingfixturesarenamed
asfixturewithmechanicalclamping,hydraulicclamping,pneumaticclamping,
automaticclampingandvicejawclampingfixture.

8. Setting Block
•Table of the milling fixture is positioned relative to the cutter with the help of
setting block.
•The setting block is located relative to the workpiece location system
•It is retained on its position on the fixture by using screws.

9. Setting Block
•It has two hardened setting faces.
•The table setting is done with 0.25mm feeler between the cutter and setting face.
•Feeler is used so that block will not be damaged while machining.
•Setting block is positioned so that the cutter is between the vertical face of the
block and the operator during setting.

10. Tenons
•Two tenons are locatedon the underside of the fixture base.
•They are made from casehardened steel.
•Tenons sit in T-slots that run along the length of the machine table.
•They locate the fixture relative to the table feed.
•Two tenons are placed as far as possible to have maximum accuracy.

11. Milling Machine Table and Tenons

12. Base of Milling Fixture
•Millingfixturehasaheavybaseon
whichthecompletefixtureis
constructed.

13. T-bolt
•Fixture is bolted / secured to the machine table by two or four t-blots.
•T-bolts are placed int-slots on machine table.
•They are not a part of the fixture.

14. Machine Vice
•The machine vice is simplest milling fixture.
•Location system can be incorporated in it.
•It can be adapted to accommodate awkwardly shaped workpieces.

15. Machine Vice
•Themachineviceismountedon
themachinetableT-slotsbyusing
T-bolt,hexnutandwasher.

16. Machine Vice

17. Machine Vice
•Special jaws-shaped to accommodate the workpiece and with workpiece location.

18. Milling Fixture

19. Simple Milling Fixture
•The fixture is located on machine table by two tenons that locate in the same
machine slot.
•Fixture is bolted to the machine using T slot.

20. Simple Milling Fixture
•The workpiece is located from two holes by using one location pin and one
diamond pin.
•Workpiece is clamped using two spanner-tightened heavy duty clamps because of
the high forces during milling.
•The cutter is set using setting block. Setting block has two setting faces one for the
depth and other for the transverse-setting.

21. Line or String Milling Fixture
•Five cylindrical workpiece are located in line.
•The workpieces are located and clamped with one spanner-tightened screw.

22. Line or String Milling Fixture
•The fixture is located on machine table by using two tenons.

23. Thank you!
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