Product manufacturing

1. PRODUT DESIGN TECHNIQUES OF
MANUFACTURING

2. Cutting by abrasionCutting by abrasion
 An abrasive is a material, often a mineral, that is used to shape or finish a
work piece through rubbing which leads to part of the work piece being
worn away.
 Tool is often made of hard minerals diamond or corundum, however
softer one’s can also be used like calcium carbonate are used as abrasives,
such as "polishing agents" in toothpaste.
 Abrasive substance is usually granular, gritty and sharp

3. Mechanics of abrasionMechanics of abrasion
 These minerals are either crushed or are already of a sufficiently small size
(anywhere from macroscopic grains as large as about 2 mm to
microscopic grains about 0.001 mm in diameter) to permit their use as an
abrasive. These grains, commonly called grit, have rough edges, often
terminating in points which will decrease the surface area in contact and
increase the localised contact pressure. The abrasive and the material to
be worked are brought into contact while in relative motion to each
other. Force applied through the grains causes fragments of the worked
material to break away while simultaneously smoothing the abrasive grain
and/or causing the grain to work loose from the rest of the abrasive.

4. FACTORS AFFECTIONFACTORS AFFECTION
ABRASIONABRASION
 Difference in hardness between the two substances: a much
harder abrasive will cut faster and deeper
 Grain size (grit size): larger grains will cut faster as they also
cut deeper
 Contact force: more force will cause faster abrasion
 Loading: worn abrasive and cast off work material tends to
fill spaces between abrasive grains so reducing cutting
efficiency while increasing friction
 Use of lubricant/coolant/metalworking fluid: Can carry away
swarf (preventing loading), transport heat (which may affect
the physical properties of the workpiece or the abrasive),
decrease friction (with the substrate or matrix), suspend
worn work material and abrasives allowing for a finer finish,
conduct stress to the work piece
 .

5. EXAMPLESEXAMPLES
GrindingGrinding

6. Polishing
Buffing etc

7. Flame CuttingFlame Cutting
 Flame cutting is a combustion process. It is not the heating flame itself that
does the actual cutting but an oxygen jet, which burns the material during
heat formation and transports the combustion products (slag) away from
the cut.
 Before cutting can begin, the steel must be heated to ignition
temperature(combustion temperature) by means of a gas flame. The
choice of fuel gas affects cut quality and the time used for preheating.
When choosing a fuel gas, the thickness of the material must also be
considered.
 When cutting, the purity of the oxygen is of huge importance to the
cutting speed. The purer the gas, the higher the cutting speed and the
better the productivity and cut quality.
 The most important part of cutting equipment is the cutting nozzle. The
higher the outlet speed of the oxygen jet, the better the output of the
nozzle. In turn, the speed depends on the shape of the cutting nozzle.
Nowadays, nozzles with an expansion channel are often used, giving the
oxygen jet a high velocity.

9. ParametersParameters
Proper cutting tip selection
Proper cutting oxygen pressure selection
Proper preheat
Proper cutting speed
Proper selection of the fuel gas
A gas supply system (both fuel gas and Oxygen)
that is sufficient to supply the quantity of gas
required at the pressure required.

10. In cutting a kerf Is formedIn cutting a kerf Is formed

11. Kerf for every process is different
Each cutting process removes a different amount
of material, or kerf. The more precise processes,
like waterjet and laser, remove a smaller amount
of kerf, which is one of the reasons they can be
more precise! A typical example shown here is
for 1/2” thick mild steel.
Plasma: 0.150”
Oxy-Fuel: 0.045”
Waterjet: 0.035”
Laser: 0.025”

13. LASER CUTTINGLASER CUTTING
Concentrated beams of coherent
light(energy) used to cut materials.

14.  Cutting is precise, neat and fast.
 Laser cutting is best suited to high precision cutting of thin
pieces.The cut quality is so high that the pieces can be used
directly, or sent for further processing without the need for post-
cut finishing. Laser cutting is extensively used, especially by
mechanical engineering companies that serve the automotive
industry, as well as in the manufacturing of household equipment,
such as dishwashers, washing machines

15. WORKINGWORKING

16.  The laser beam is a column of very high intensity light, of a single
wavelength, or color.
 The beam is only about 3/4 of an inch in diameter as it travels from
the laser resonator, which creates the beam, through the machine’s
beam path. It may be bounced in different directions by a number of
mirrors, or “beam benders”, before it is finally focused onto the plate.
The focused laser beam goes through the bore of a nozzle right before
it hits the plate. Also flowing through that nozzle bore is a compressed
gas, such as Oxygen or Nitrogen.
 Focusing the laser beam can be done by a special lens, or by a curved
mirror, and this takes place in the laser cutting head. The beam has to
be precisely focused so that the shape of the focus spot and the
density of the energy in that spot are perfectly round and consistent,
and centered in the nozzle.
 By focusing the large beam down to a single pinpoint, the heat density
at that spot is extreme.

17.  The high power density results in rapid heating, melting and partial
or complete vaporizing of the material. When cutting stainless
steel or aluminum, the laser beam simply melts the material, and
high pressure nitrogen is used to blow the molten metal out of the
kerf.

18. Water jet cuttingWater jet cutting
Cutting is operated by a concetrated jet
of water, approximately one tenth of a
millimetre in a diametre hich is propelled
at high pressure ( 5000 to 6000 bars) and
great speed(600 to 100 m/s).
The matter does not get wet at all during
cutting

19. AdvantagesAdvantages
 It is a "cold" cutting process so the material being cut is
not subject to any thermal influence.
 The extremely small cutting gap enables optimum
material exploitation.
 Two- and three-dimensional cutting is possible.
 The "waterjet" tool works independent of direction.
 All materials including soft material can be cut.
 Useful to cut food materials

20. Water jet cuttingWater jet cutting
Two types
1. Pure water jet
 Abrasive water jet

21.  While pure waterjet
cutting relies on the static
pressure of the compact
waterjet and the erosive
effect of the droplets in
order to cut the material,
in abrasive waterjet
applications there are the
solid particles incorporated
in the jet which cause
micro-cutting action on the
material – in this case the
waterjet serves merely to
accelerate the solid
particles.

22. Abrasive water jet
Pure water jet

23.  Typical waterjet cutting applications are:
 Foodstuff portioning (frozen food, bread, cakes and pastries, chocolate,
ice-cream)
 Paper product cutting (nappies, corrugated cardboard)
 Textile cutting (leather, furniture fabrics, carpets)
 Trimming of plastic mouldings and carpet shapes for the automotive
industry
 Cutting of insulation material