Milling Flashcards
Use paper towel when handling_____?
Cutters
What is the most time consuming but the most crucial part of milling?
Set up
What are the four types of knee and column milling machines?
Plain Horizontal
Universal horizontal
Standard vertical
Ram type vertical
What are the characteristics of a plain horizontal milling machine?
- most basic
- can do most milling jobs
- main spindle is horizontal
- table moves at right angles
What are the characteristics of a universal horizontal milling machine?
- same a plain milling machine but table can swivel.
What are the characteristics of a standard verticals milling machine?
- vertical spindle
- spindle can be fed in and out like a drill press
- vertical spindle allows for use of endmills, drills, and other chuck mounted cutting tools.
-more versatile then horizontal but not as rigid.
How are knee type milling machines sized?
Range of movement
Horsepower
What are the parts of a knee column milling machine?
Base - supports column
Column - provides support for the horizontal spindle
Overarm - supports the arbour
Saddle - houses table feed mechanism
Knee - houses the saddle and knee feed mechanisms
Table - rides in dovetail ways on top of the saddle supports work pieces
Backlash eliminator - used when climb milling to prevent workpiece from being pulled into the cutter.
When should a backlash eliminator be used?
Before climb milling
What drives the cutter?
Spindle
How is spindle speed controlled?
Gear box
When a part cannot be taken apart easily what milling machine is best suited?
Portable key seat mill.
Can be taken to the shaft and used to cut on shaft diameters from .5” to 24”
Arbour mounted cutters are for?
Horizontal type milling machines
Shank mounted cutters are for?
Vertical milling machines
What are 4 shank styles of endmill cutters?
Straight style - light machining
Weldon shank - light machining
Threaded shank - heavy duty cuts
Double ended - less costly
How many cutting edges can a endmill have?
2- large chip space, ideal for cutting soft materials
3/4 - higher feed rates, typically not for plunge cutting unless teeth extend to the centre of the bit
All end mills can cut sideways through a workpiece. Centre cutting end mills can cut straight down. If cutting edges extend to the centre it can be used for plunge cutting.
Greater number of teeth permits higher feed rate.
Most three of four flute cutters are NOT for end cutting.
When do you use a fly cutter?
When very flat surface with a good finish is desired.
What is an arbour?
The long or short bar that holds the milling cutter in place
Describe a collet?
Hardened steel bushings with a series of slits cut into them. Used to grip the shank of the cutting tool
When should a backlash eliminator be used?
Before climb milling
What drives the cutter?
Spindle
How is spindle speed controlled?
Gear box
When a part cannot be taken apart easily what milling machine is best suited?
Portable key seat mill.
Can be taken to the shaft and used to cut on shaft diameters from .5” to 24”
Arbour mounted cutters are for?
Horizontal type milling machines
Shank mounted cutters are for?
Vertical milling machines
What are 4 shank styles?
Straight style - light machining
Weldon shank - light machining
Threaded shank - heavy duty cuts
Double ended - less costly
How many cutting edges can a endmill have?
2- large chip space, ideal for cutting soft materials
3/4 - higher feed rates, typically not for plunge cutting unless teeth extend to the centre of the bit
When do you use a fly cutter?
When very flat surface with a good finish is desired.
What is an arbour?
The long or short bar that holds the milling cutter in place
What is a jacobs taper adapter?
What is a Morse tape adapter?
Makes it possible to fit a drill chuck to the spindle of the milling machine
Makes it possible to fit a large drill having a Morse taper shank into the spindle of the milling machine.
What are the characteristics of a good holding device?
Easy to set up
Grip the workpiece
Allow coolant to cool the cutter
What is the best way to clamp large or awkward pieces to the milling machine?
Clamp straight to the table
Chip load x spindle speed x number of teeth =
Feed rate
Work piece fed against the rotation of the cutter?
Conventional milling
- set up must be ridged as cutter tends to lift material off the table
- use conventional milling with ever there is no backlash eliminator in the machining table
Workpiece feeds the rotation of the cutter?
Climb milling
- leaves good surface finish
- not suitable for castings or other workpieces with hard scale on the surface. Cutter dulls quickly
Length of key seat does not include____?
Any runout or radius left.
When changing spindle speed (gear box) it is important to?
Adjusting variable speed wheel it is important to adjust while ?
Shut machine down before changing.
Machine is running
To use a friction collet you:
1: determine the diameter of the cutter shank
2: choose the corresponding collet from the set
3: clean all grit from the collet, cutting tool shank, chuck body and nut
4: snap the collet into the chuck nut using the palm of your hand
5: turn the chuck/nut assembly onto the thread of the chuck body but do not tighten it.
6: slide shank of cutter into the collet
7: use chuck wrench to tighten the chuck nut.
Heavy duty collet chuck parts
Each time a vertical head is installed it must be dialled in to ensure the vertical spindle is perpendicular to the surface of the table. Remember these points:
- loosen vertical head slightly to allow for adjustments
- dial indicator extensions are set up in the spindle. With the dial on the table surface. Rotate the dial by hand and adjust the head in small increments. Rechecking many times
- a total runout of .001 - .002 “ is required for good machining performance.
Best tool to find prick punch centre on milling machine?
Cone point edge finder is best
Wiggler works to
Dialling in a vice on the milling machine.
1: set vice on table making sure table and bottom of vice are clean
2: clean jaws of vice and clamp a parallel extending past the top of the vice.
3: set base of dial indicator on a flat part of the milling machine. (Usually the column) adjust indicator to ride either on the front or back side of the parallel.
4: tighten one of the hold down bolts with a wrench. Leave the second bolt hand tight.
5: move the table so the indicator is positioned with the tight-end bolt and zero dial.
6: move table so the parallel runs across the indicator stopping at the opposite end.
7: use the change in dial reading to determine which way the vice is out and strike the vice with a soft faced hammer to knock the vise closer to true alignment.
8: repeat steps 5, 6 and 7 until dial shows no run run out.
9: tighten second bolt and double check runout.
Setting up for face milling consists of?
1: choose a face mill slightly wider than the face to me machined. Check condition of cutter.
2: mount cutter
3: secure workpiece to the table using clamps or vice. IF CLAMPING FLAME CUT WORK PIECE TO TABLE MAKE SURE TO CLAMP OVER KEYSTOCK TO PREVENT DAMAGE TO TABLE.
4: set spindle and feed rate
5: start spindle and raise table until the cutter just touches the workpiece.
6: move workpiece away from cutter and raise table just enough to clean the face around .050”
7: engage feed and take a cut. When cut is finished use rapid feed to return table to the start of cut
8: stop spindle measure work piece and determine how much material needs to be cut away
9: take one or more cuts to finish workpiece to size.
When cutting keyseats entire length of shaft what cutter is best?
Side milling cutter
When keyseats run up to a feature what tool is needed to cut the key seat?
End mill.
End mills tend to deflect so they can take much longer to cut the keyseats
Wood ruff key cutting is down with what tools?
Using standard cutters and fit with readily available keys having standard sizes
Depth of keyseat is always measure from ?
The flat
What are the two ways to set the cutter to depth when milling keyseats?
1: raise the workpiece until it just touches the cutter. Carefully raise the table further until the cutter appears to be cutting to its full width. Set the knee dial to zero then raise the table to the amount equal to the depth of keayseat. Not the best but good enough
2: consult a reference (machinery’s handbook) for the depth of the keyseat measured from the outside of the shaft rather the. The flat.
When cutting the length of a keyseat and the plans call for 1 1/4 length how do you measure the length?
Length is measure by the straight portion of the cut and not taking the radius measurement into account.
Centring the shaft under the cutter steps:
1: test off a strip of paper 6” long
2: hold paper between the rotating cutter and workpiece. Hold paper loosely so it slips out of fingers easily.
3: move workpiece toward the cutter until cutter grabs the paper. Zero dial.
4: lower work piece so it clears the cutter and move it to a distance equal to half the diameter of the cutter plus half the diameter of the work piece
When finding centre of the shaft with the cutter what is the formula for endmill?
Cutter D/2 + shaft D/2
Cutter diameter
Shaft diameter
When using a milling machine why do you not want to use a unusually slow feed?
Dulls the cutting bit
Why should you never stop a cutter while in contact with a work piece?
Will chip the cutting edges
Max cut for endmill is?
1/2 diameter of the cutter.
I would do less than that though
Why is cleaning and oiling machines very important?
Prevents rusting which results in loss of accuracy
Feed rate equals?
Original spindle speed formula
CS x 12/ 3.14 x diameter of cutter
Chip load x spindle speed x number of teeth
Inches per minute
Why must cutter tools be stored to not make contact?
Protects their cutting edges from chips and wear
