Tipos y consejos de los procesos cerámicos.

1. Ceramics
processing
Computer-Aided Manufacturing
• Cervantes Obregòn Jonathan Abraham
• Balderas Cardona Elì Benjamìn
• Herrera Vàzquez Rocìo Elizabeth
• Huerta Castillo Jessica Marlene
• Ledezma Vázquez Leimy Dana
• Loera Hernàndez Selina Yoselin
• Nieto Pachicano Carla
• Torres Tristán José Jesús

2. Shaping ceramics
Several techniques are available
for processing ceramics into useful
products depending on the type of
ceramics involved and their
shapes. Production of some
ceramic parts not involve the same
level of control of materials and
processes as do high-tech
components and cutting tools
(using, for example, aluminum
oxide). Generally, however, the
procedure involves the following
steps:
I. Crushing or grinding the raw
materials into very fine particles
II. Mixing them with additives to
impart certain desirable
characteristics
III. Shaping, drying, and firing the
material.

3. Ceramics may be subjected to additional processing, such as
machining and grinding, for better control of dimensions and surface
finish. The first step in processing ceramics is the crushing of the raw
materials. Crushing generally is done in a ball mill, either dry or wet.
Wet crushing is more effective, because it keeps the particles
together and also prevents the suspension of fine particles in the air.
The ground particles are then mixed with additives-the functions of
which are one or more of the following:

4. 01 Binder
For holding ceramic
particles together
02 Lubricant
To reduce internal friction
between particles during
molding and to help
remove the part from the
mold
03 Wetting agent
To improve mixing
04 Plasticizer
To make the mix more
plastic and formable
05 Agents
To control foaming and
sintering.
06 Deflocculent
To make the ceramic-
water suspension more
uniform by changing the
electrical charges on the
particles of clay

5. Casting

6. The most common casting process is slip casting
(also called drain casting). A slip is a suspension
of colloidal ceramic particles in an immiscible
liquid, which isgenerally water.

7. Plastic
forming

8. Plastic forming (also called soft, wet, or /vydroplastic forming)
can be carried out by various methods, such as extrusion,
injection molding, or molding and jiggering. Plastic forming tends
to orient the layered structure of clay along the direction of
material flow and, hence, tends to cause anisotropic behavior of
the material both in subsequent processing and in the final
properties of the ceramic product. In extrusion, the clay mixture
(containing 20 to 30% water) is forced through a die opening by a
screw-type piece of equipment.

9. Pressing

10. Dry Pressing. This is a technique similar to powder-metal
compaction, as described in Section. Dry pressing is used for
relatively simple shapes, such as Whitevvare, refractories for
furnaces, and abrasive products. The moisture content of the
mixture generally is below 4%, but it may be as high as 12%.
Organic and inorganic bind ers (such as stearic acid, Wax, starch,
and polyvinyl alcohol) usually are added to the mixture; these
additives also act as lubricants.

11. Wet Pressing. In wet pressing, the part is formed in a mold while
under high pressure in a hydraulic or mechanical press. This
process generally is used to make intricate shapes. Moisture
content usually ranges from 10 to 15%.
lsostatic Pressing. Used extensively in powder metallurgy,
isostatic pressing also is used for ceramics in order to obtain a
uniform density distribution throughout the part during
compaction.
Jiggering. A series of steps is needed to make ceramic plates.
First, clay slugs are extruded and formed into a but over a
plaster mold.

12. Injection Molding. Injection molding is used extensively for the
precision forming of ceramics in high-technology applications,
such as for rocket-engine components.
Hot Pressing. In this process (also called pressure sintering), the
pressure and the heat are applied simultaneously, thereby
reducing porosity and making the part denser and stronger.

13. Pressing

14. The next step in ceramic processing is to dry and fire the part to
give it the proper strength and hardness. Drying is a critical stage
because of the tendency for the part to Warp or crack from
variations in moisture content and in thickness. Control of
atmospheric humidity and of ambient temperature is important
in order to reduce warping and cracking. Loss of moisture during
drying causes shrinkage of the part by as much as 20% from the
original, moist size.

15. Finishing
operations

16. Because firing causes dimensional changes, additional
operations may be performed to (a) give the ceramic part its final
shape, (b) improve its surface finish and dimensional tolerances,
and (c) remove any surface flaws. Although they are hard and
brittle, major advances have been made in producing
machinable ceramics and grindable ceramics, thus enabling the
production of ceramic components with high dimensional
accuracy and a good surface finish.

17. 01 Grinding (using a
diamond wheel) 02 Lapping and
honing
03 Ultrasonic
machining 04
Drilling (using a
diamond-coated
drill)
05
Electrical-
discharge
machining
06 Laser-heam
machining
07 Abrasive water-jet
cutting 08
Tumbling (to
remove sharp
edges and
grinding marks)