11. Advantages of broaching
• High production rates, suitable for mass production
• Provides high surface finish and accuracy
• No need of skilled operator
• Design, operation and maintenance of broaching machine is
easy
• Roughing and finishing operation takes place in a single stroke
• Irregular surfaces can also be easily broached
• Broaching facilitates efficient coolant circulation resulting in
good surface finish and longer tool life
12. Disadvantages of broaching
• Tool cost is high
• Surface to be broached must be accessible, hence the process
is suitable for through holes and surfaces
• Large sized workpieces cannot be broached
• Parts o be broached must be strong enough to withstand the
forces during cutting
• Economical only for mass production operation
14. Lapping
Low speed, low pressure final abrasion finishing operation that
produces extreme dimensional accuracy, corrects minor
imperfections of shape, refines surface finish and produces
close fit between mating surfaces.
Lapping methods
1. Hand lapping
2. Machine lapping
21. Lapping
Advantages:
• Any material, hard or soft, can be lapped, as well as any shape,
as long as the surface is flat.
• There is no warping (bend) since the parts are not clamped and
very little heat is generated.
• No burrs are created. In fact, the process removes light burrs.
• Any size, diameter, and thickness from a few thousands thick
up to any height the machine will handle can be lapped.
• Any material hard or soft, mattalic or non-metallic can be
lapped
22. Lapping
Limitations.
• Requires skilled and experienced operators to obtain consistent
and accurate results
• Even though there are general recommendations and
assistance from manufacturers and past experience is useful,
trial and error may still be needed to get the optimal results.
• Costlier process
23. Applications
• Various parts produced by lapping process include
1. Gauges
2. Piston rings
3. Valves
4. Gears
5. Roller bearings
6. Dies and metal moulds
7. Surface plates
24. Honing
Honing is a low-velocity abrading process. Material removal is
accomplished at lower cutting speeds than in grinding.
Therefore, heat and pressure are minimized, resulting in
excellent size and geometry control.
The most common application of honing is on internal
cylindrical surfaces.
27. Horizontal spindle machine
• Horizontal-spindle honing machines, for hand-held work with
bores up to 6 in., are among the most widely used. The
machine rotates the hone at from 100 to 250 rpm.
• The machine operator moves the work back and forth (strokes
it) over the rotating hone. The operator must ”float” the work
that is, not press it against the hone or the hole will be slightly
oval. Sometimes the work piece must be rotated.
29. • Vertical spindle machines. Vertical-spindle honing
machines are used especially for larger, heavier work.
• These all have power stroking at speeds from 20 to
120 rpm. The length of the stroke is also machine
controlled by stops set up by the operator.
Vertical spindle machine
30. Honing
• Advantages:
• The workpiece need not be rotated by power, hence chucks,
faceplates, or rotating tables are not required.
• The hone is driven from a central shaft, so bending of the shaft
cannot cause tapered holes .The result is a truly round hole.
• Honing uses a large contact area at slow speed compared with
grinding or fine boring.
• Because of the combined rotating and reciprocating motion
used, a crosshatched pattern is created which is excellent for
holding lubrication.
• Good surface finish and close dimensional tolerances can be
achieved
31. Honing
Limitations:
• Honing is though of as a slow process.
• Horizontal honing may create oval holes unless the
work is rotated or supported.
