Transcript Vertical Mill Operations
PowerPoint to accompany
Technology of Machine Tools
6 th Edition
Krar • Gill • Smid Vertical Mill Operations
Unit 62
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Aligning the Vise
• • When vise aligned on vertical milling machine, dial indicator may be attached to quill or head by clamps or magnetic base Same method of alignment followed as outlined for aligning vise on horizontal milling machine
62-2
Collets
• • • Hold end mills, cutting tools and accessories in machine spindle Spring collet – Pulled into spindle by draw-bar that closes on cutter shank – Driven by means of friction between collet and cutter Solid collet • • • More rigid Pulled into spindle by draw-bar Driven by setscrews that bear against flats of cutter shank
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62-3
To Mount a Cutter in a Spring Collet
1.
2.
Shut off electric power to machine Place proper cutter, collet, and wrench on piece of masonite, wood, or soft plastic on table
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62-4
3.
4.
5.
6.
7.
8.
9.
10.
Clean taper in machine spindle Place draw-bar into hole in spindle top Clean taper and keyway on collet Insert collet into spindle bottom, press up, and turn until keyway aligns with key in spindle Hold collet up with one hand and with other, thread draw-bar clockwise into collet Hold cutting tool with cloth and insert it into collet for full length of shank Tighten draw-bar into collet (clockwise) by hand Hold spindle brake lever and tighten draw-bar tightly as possible with wrench
62-5
Procedure to Remove Cutter from a Collet
• 1.
2.
3.
Operation for removing cutting tools similar to mounting, but in reverse order Shut off electric power to machine Place piece of masonite, wood, or soft plastic on machine table to hold necessary tools Pull on spindle brake lever to lock spindle, loosen draw-bar with wrench (counterclockwise)
62-6
4.
5.
6.
7.
8.
Loosen draw-bar, by hand, only about three full turns Hold cutter with cloth With soft-faced hammer, strike down sharply on head of draw-bar to break taper contact between collet and spindle Remove cutter from collet Clean cutter and replace it in its proper storage place where it will not be damaged by other tools
62-7
Procedure to Machine a Flat Surface
1.
2.
3.
4.
Clean vise and mount work securely in vise, on parallels if necessary Check that vertical head square with table Select cutter that will just overlap edges of work Set proper spindle speed for size and type of cutter and material being machined; check cutter rotation
62-8
5.
6.
7.
8.
9.
Tighten quill clamps Start machine, and adjust table until end of work under edge of cutter Raise table until work surface just touches cutter. Move work clear of cutter.
Raise table about .030 in. and take trial cut for approximately .250 in.
Move work clear of cutter, stop cutter, measure work 10.
Raise table desired amount; lock knee clamp 11.
Mill surface to size using auto feed
62-9
Machining a Block Square and Parallel
•
Machining Side 1
1.
Clean vise thoroughly and remove all burrs from workpiece, vise and parallels 2.
Important that each side be machined in definite order Set work on parallels in center of vise with largest surface (side 1) facing up
62-10
3.
4.
5.
6.
7.
8.
Place short paper feelers under each corner between parallels and work Tighten vise securely With soft-faced hammer, tap workpiece down until all paper feelers are tight Mount fly cutter in milling machine spindle Set machine for proper speed for size of cutter and material to be machined Start machine and raise table until cutter just touches near right-hand end of side 1
62-11
9.
Move work clear of cutter 10.
Raise table about .030 in. and machine side 1 using steady feed rate 11.
Take work out of vise and remove all burrs from edges with file
Machining Side 2
12.
Clean vise, work, and parallels thoroughly 13.
Place work on parallels, if necessary, with side 1 against solid jaw and side 2 up
62-12
14.
Place short paper feelers under each corner between parallels and work 15.
Place round bar between side 4 and movable jaw 16.
Tighten vise securely and tap work down until paper feelers are tight 17.
Follow steps 8 to 11 and machine side 2
Machining Side 3
14.
Clean vise, work, and parallels thoroughly
62-13
19.
Place side 1 against solid vise jaw, with side 2 resting on parallels if necessary 20.
Push parallel to left so that right edge of work extends about .250 in beyond parallel 21.
Place short paper feelers under each end of corner between parallels and work 22.
Place round bar between side 4 and movable jaw, making sure round bar in center of amount of work held inside vise 23.
Tighten vise securely and tap work down until paper feelers are tight
62-14
24.
Start machine and raise table until cutter just touches near right-hand end of side 3 25.
Move work clear of cutter and raise table about .010 in.
26.
Take trial cut about .250 in. long, stop machine, and measure width of work 27.
Raise table required amount and machine side 3 to correct width 28.
Remove work and file off all burrs
62-15
62-16 Machining Side 4
29.
Clean vise, work, and parallels thoroughly 30.
– Place side 1 down on parallels with side 4 up and tighten vise securely Round bar not required on side 4 31.
Place short paper feelers under each corner between parallels and work 32.
Tighten vise securely 33.
Tap work down until paper feelers tight 34.
Follow steps 24 to 27 and machine side 4 to correct thickness
Machining the Ends Square
• – Two common methods Short pieces held vertically in vise and machined with end mill or fly cutter – Long pieces held flat in vise, one end extending past end of vise; end surface cut square with body of end mill
Procedure for Short Work
1.
Set work in center of vise with one end up and tighten vise lightly
62-17
2.
3.
4.
5.
6.
Hold square down firmly on top of vise jaws and bring blade into light contact with side of work Tap work until edge aligned with blade of square Tighten vise securely and recheck squareness of side Take about .030 in. deep cut and machine end square Remove burrs from end of machined surface
62-18
7.
8.
Clean vise and set machined end on paper feelers in bottom of vise Tighten vise securely and tap work down until paper feelers are tight 9.
Take trial cut from end until surface cleans up 10.
Measure length of workpiece with depth micrometer 11.
Raise table required amount and machine work to length
62-19
Procedure to Machine an Angular Surface
1.
2.
Lay out angular surface Clean vise 3.
• Align vise with direction of feed Utmost importance 4.
Mount work on parallels in the vise
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62-20
5.
6.
Swivel vertical head to required angle Tighten quill clamp 7.
• Start machine and raise table until cutter touches work Raise table until cut desired depth 8.
9.
Take trial cut for about .50 in.
Check angle with protractor 10.
If angle correct, continue cut 11.
Machine to required depth, taking several cuts if necessary
62-21
Alternate Method Milling an Angular Surface
62-22
1.
2.
3.
4.
5.
Check if vertical head is square with table Clean vise Lock quill clamp Set workpiece in vise with layout line parallel to top of vise jaws and about .250 in. above them Adjust work so cut will start at narrow side of taper and progress into thicker metal
6.
7.
8.
Take successive cuts of about .125 to .150 in. or until cut is about .030 in. above layout line Check to see that cut and layout line parallel Raise table until cutter just touches layout line 9.
Clamp knee at this setting 10.
Take finishing cut
62-23
To Tap a Hole on Vertical Mill
• Can be performed either by hand or with use of tapping attachment
Procedure
1.
Mount work in vise, or clamp it to machine table 2.
Mount center drill in drill chuck, adjust machine table until center-punch mark on work aligns with point of center drill
62-24
62-25
3.
4.
5.
With center drill spot each hole to be tapped to slightly larger than tap diameter Drill hole to correct tap drill size for size of tap to be used Mount stub center in drill chuck
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62-26
6.
7.
8.
9.
Fasten tap wrench on correct-size tap and place it into hole Lower spindle using quill handfeed lever until stub center point fits into center hole in end of tap shank Turn tap wrench clockwise to start tap into hole; at same time, keep stub center in light contact with tap by applying pressure on handfeed lever Continue to tap hole while keeping tap aligned by applying light pressure on handfeed lever