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Wasting is the term given to material removal (as opposed to additive manufacture) in order to shape a workpiece to a given design. Traditionally, wasting processes have included, drilling, milling and turning. Laser cutting can also be considered a wasting process as there is nearly always material left over from the process that cannot be used without further processing, e.g. recycling
Drilling operations
Drilling operations
Drilling is the process where a rotating tool 'bit' is used to push into a surface and create holes in a range of solid materials including woods, metals, plastics, ceramics and composites.
Drilling is a 2-axis (2 degrees of freedom) operation, however is used to create 3D shapes.
A typical 'twist-drill bit 'abrades' the surface of a given material and extracts the waste along a 'flute'. The 'shank' of the bit is placed inside a rotating 'chuck'. The chuck is rotated by a motor powered within the drill itself.
In this image, you can see the waste material being drawn along the 'flutes' of a twist drill.
A 'chuck key'.
A drill 'chuck'.
This animated .gif demonstrates how a 'chuck key' rotates a geared chuck and allows the 'jaws' of the chuck to open and close by rotating an external 'sleeve'. The jaws grip the drill bit and hold it in position.
The nomenclature 'naming' of a twist drill. Click to enlarge.
Types of twist drill tip and their uses. Click to enlarge.
Related operations often carried out when using a bench or pillar drill.
Related operations often carried out when using a bench or pillar drill.
Machining Operations Related to Drilling.pngReaming: Reaming operations are used to slightly enlarge a hole, to provide a better tolerance on its diameter, and to improve its surface finish. The tool is called a reamer, and it usually has straight flutes.
Tapping: Tapping operations are performed by a tap and are used to provide internal screw threads on an existing hole.
Counterboring: Counterboring operations provide a stepped hole, in which a larger diameter follows a smaller diameter partially into the hole. A counterbored hole is used to seat bolt heads into a hole, so the heads do not protrude above the surface.
Countersinking: countersinking is similar to counterboring, except that the step in the hole is cone-shaped for flat head screws and bolts.
Centering: Centering operation also called centre-drilling, this operation drills a starting hole to establish its location for subsequent drilling accurately. The tool is known as a centre-drill.
Spot-facing: Spot facing operation is similar to milling. This operation is used to provide a flat machined surface on the workpiece in a localised area.
Tapping & threading
(creating holes which are able to insert screws and bolts) Tapping & threading
If you need to insert a screw or a bolt into something, you will also need to have a corresponding receiving thread (otherwise it will just slide or drop straight in and eventually fall back out again). This poster and videos will explain the process of cutting either an internal (inside) or external (outside) thread.
Thread tapping - A video guide
Thread tapping - A video guide
Power tapping using a lathe
Power tapping using a lathe
Milling operations
Milling operations
The term 'milling operations' refers to the types of machining jobs that can be carried out using a milling machine.
Milling is a 6-axis (6 degrees of freedom) process and used to create 3d shapes.
On a milling machine, the cutting tool rotates but stays in the same fixed position. Instead, the 'bed' moves the workpiece along a horizontal (X and Y) axis and the operator adjusts the depth of cut by raising or lowering the bed along the vertical (Z) axis.
X, Y and Z axis.
Notice how the workpiece moves around the cutting tool.
Vertical or 'End' milling
Vertical or 'End' milling
A vertical, or 'end' miller is the most common type of milling machine found in industry. It is distinguished by the fact that the cutter is mounted within a spindle that rotates around a vertical axis. A vertical miller uses 'end' cutters.
The image below explains the 'nomenclature' or engineering description of end cutters.
A typical vertical milling machine
Side milling
Side milling is probably the most common end milling operation. In side milling the tool is engaged both axially and radially. The amount of axial engagement is known as the “stepover” and is often specified in percent of tool diameter.
Face milling
Facing or partial facing is done more efficiently with other types of tools such as fly cutters or face mills, but it can be done with an end mill.
Slot milling
Slotting fully engages the end mill in the workpiece, and creates a slot with a rectangular or rounded profile depending on the end mill shape.
Pocket milling
Pocketing can create round holes, or it can create rectangular or other shaped pockets. Notice that whenever interior corners are created with an end mill they will have a radius at least as large as half the end mill’s diameter.
Profile milling
Profiling is done on the perimeter of a workpiece and can produce nearly any shape that has interior radii at least as large as that of the cutter.
Contour milling
Contour milling is often done with a rounded tool called a ball end mill, contour milling can produce shapes with a three dimensional contour. Contouring can be used to produce tooling such as injection moulds and forming dies.
Horizontal milling
Horizontal milling
A horizontal milling machine differs from a vertical miller in that the spindle / cutting tool rotates along a horizontal axis. Horizontal milling can be generally thought of as a more 'heavy-duty' milling as they are constructed of more rigid frames. As such horizontal milling is usually seen in heavy industry to remove large amounts of material from substantially sized workpieces.
A typical horizontal milling machine
Slab milling
Slab milling is similar to face milling in that it removes material to make the surface of a workpiece flat and or to reduce the overall thickness of a part.
Profile milling
Profile milling creates an exterior contour with a desired shape.
Slot milling
Slot milling or slotting produces rectangular or rounded channels in a workpiece.
Straddle milling
Straddle milling may use two or more cutters on the same arbor to create a rectangular pad of a desired width. Using two or more cutters simultaneously in this way is known as gang milling. Gang milling can be used to create more complex shapes, such as v-ways and cooling fins.
Slit milling
Slitting is similar to slotting but cuts completely through the workpiece.
End milling cutter nomenclature.
Milling operations videos
Milling operations videos
The following 'crash course' videos were originally released on YouTube by Glacern Machine Tools and provide a nice visual introduction to basic milling operations.
Chapter 1 - Basic Machine Anatomy.mp4Introduction to Milling Operations - Part 1
Introduction to Milling Operations - Part 1
Milling machine 'anatomy'
Chapter 2 - Basic Operations.mp4Introduction to Milling Operations - Part 2
Introduction to Milling Operations - Part 2
Basic operation of a milling machine
Chapter 3 - CNC Mill Operation.mp4Introduction to Milling Operations - Part 3
Introduction to Milling Operations - Part 3
CNC (Computer Numerically Controlled) Milling
Chapter 4 - Work Holding.mp4Introduction to Milling Operations - Part 4
Introduction to Milling Operations - Part 4
Work holding methods
Chapter 5 - Work Locating.mp4Introduction to Milling Operations - Part 5
Introduction to Milling Operations - Part 5
Work locating methods
Chapter 6 - Tool Holding.mp4Introduction to Milling Operations - Part 6
Introduction to Milling Operations - Part 6
Tool holding methods
Chapter 7 - Face Milling.mp4Introduction to Milling Operations - Part 7
Introduction to Milling Operations - Part 7
Face milling
Chapter 8 - Choosing & Using Endmill.mp4Introduction to Milling Operations - Part 8
Introduction to Milling Operations - Part 8
Choosing and using 'endmills'
Chapter 9 - Drilling, Tapping, and Boring.mp4Introduction to Milling Operations - Part 9
Introduction to Milling Operations - Part 9
Drilling, Tapping and Boring
CNC machines - The Types of CNC Machines Explained (3 and 5 axis).mp4CNC Machines
CNC Machines
The types of CNC machines explained
Turning operations
Turning operations
The term 'turning operations' refers to those carried out by a lathe. Lathes are used to create cylindrical shapes from larger stock.
Animation of a 3-jaw chuck mechanism
The Centre Lathe
The Centre Lathe
Lathe turning operations can be carried out using a manual lathe or using a more modern, CNC lathe.
The lathe is often called a 'centre' lathe because it operates by rotating the workpiece to be machined about a central axis.
For this reason, lathe turning operations are only suitable for components or parts that have rotational symmetry about its longitudinal axis, e.g. the X axis in the image below.
Essential Machining Skills_ Working with a Lathe, Part One.mp4Working with a lathe 1
Essential Machining Skills_ Working with a Lathe, Part Two.mp4Working with a lathe 2
Essential Machining Skills_ Working with a Lathe, Part Three.mp4Working with a lathe 3
Quick-view Posters -to aid in revision
Quick-view Posters -to aid in revision
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