machining and machine tool (types of milling machine)
TRANSCRIPT
Milling Machine
Contents
• Basic functions & purposes
• Classifications
• Kinematic system & working principle
• Applications
Functions of Milling M/c
• Producing flat surfaces at any orientation
• Inclined surfaces
• Special contours on m/c elements
Principles
• Up milling:
– More clamping forces
– No effect with back clash in screw-nut systems
• Down milling
– Proper clamping is ensured
– back clash affects the process & product
Major uses
• Making flat surfaces (diff. orientations)
• Slots and steps
• Slitting
• Rotary turning
• Threads
• Helical surfaces
• Gushing in drills
Classifications
• Purpose
• Configuration
• Spindle orientation
• Automation
• CNC
According to purpose
– General purpose :
• most versatile, non-automated
• Low vol. of production
– Single purpose :
• specific operation , automated to some degree
• Lot production
– Special purpose :
• Making special features using attachments
• Batch production (automatic)
According to configuration
• Knee type :
– Non-automated
– Piece production
– Small size m/c
-contd.
• Bed type :
– Rigid & robust
– Vertical spindle
– Depth is given to cutter
– Batch wise production
- contd.
• Plano miller:
– Many cutters simultaneously can work
– (for large jobs having many plane surfaces)
– Fast production
Contd.
• Rotary table type:
– Open / closed type
– Work table rotates
– High productivity
– More than 1 spindle
According to spindle orientation-Contd.
horizontal Vertical spindle Universal head
Base
Ram
Arbour Speed chain
Feed chain
Over running clutch
Milling cutters
classifications
• Profile sharpened cutters – surface geometry doesn’t depend on tool shape
– Slab or plain milling cutter
– Side milling cutter
– Slitting cutters
– End milling cutter
– Face milling cutter
Plain or slab milling cutter
• Hollow straight HSS cylinders
• 4 to 16 straight or helical flutes
Feed
Side milling cutters
• Large cutting teeth on periphery
• Each tooth has peripheral cutting edge
– Single sided milling cutter
– Double sided milling cutter
Slitting cutters
• Only one peripheral cutting edge
• Cutter is larger in φ & thin
• Large nos. but smaller in size
• Only for slitting
End mills & shell mill
Face milling cutter
• Larger φ:80 to 800 mm
• Coated or uncoated carbide inserts
• For larger jobs like lathe bed, planer beds
Contd.
• Form relieved cutters – surface generated is the replica of the tool shape
– Form cutters
– Gear milling cutter
– Spline shaft cutter
– T-slot cutter
– Thread milling cutter
characteristics
• Flank surface is Archimedean spiral shape
• Tooth are sharpened by grinding the rake face
• To make 2D or 3D contours
Form cutters
• Made of HSS or carbides
Gear teeth milling cutter
Disc type cutter End mill type form cutter
Spline cutter
• To make spline shaft
• The cutter has the same shape to be produced
• Indexing helps to generate the spline over the circumference
Thread milling
• Short thread
• Long thread