Chemical Machining Power Point Prensentation.
PRESENTED BY:
ATRIA INSTITUTE OF TECHNOLOGY
MECHANICAL DEPARTMENT 2018 BATCH
1AT18ME003 Adwaith Krishna
1AT18ME004 Aishwarya s
1AT18ME006 Ashish B Raikar
1AT18ME008 Avdhesh Kumar Singh
1AT18ME009 Avinash V
Cybercrimes in the Darknet and Their Detections: A Comprehensive Analysis and...
NTM: Chemical Machining
1. Atria Institute Of Technology
Department of Mechanical Engineering
Topic:
Chemical Machining(CHM)
Under guidance of Anjan Kumar. D
Presented by:
•1AT18ME003 Adwaith Krishna
•1AT18ME004 Aishwarya s
•1AT18ME006 Ashish B Raikar
•1AT18ME008 Avdhesh Kumar Singh
•1AT18ME009 Avinash V
2. What is
Chemical
machining ?
Chemical machining is the
material removal process for
the production of desired
shapes and dimensions. It is
done by selective or overall
removal of material by a
controlled chemical attack
with acids or Alkalies.
3. Working Principle
•The main working principle of chemical
machining is chemical etching. The part of the
workpiece whose material is to be removed, is
brought into the contact of chemical called
enchant. The metal is removed by the chemical
attack of enchant. The method of making contact
of metal with the enchant is masking. The portion
of workpiece where no material is to be removed,
is mashed before chemical etching
4. Schematic Setup and process parameters.
The process can be applied to different types of
operations such as milling, blanking, and engraving. The
different chemical machining processes can be
classified as:
1.Chemical milling
2.Chemical blanking
3.Chemical engraving
5. Chemical machining for some special purposes can also be achieved by using a jet of reactive gas, e.g.,
chlorine on the machining zone. This is known as Gaseous Chemical Machining or Hot Chlorine
Machining and can be used for deburring of metal parts.
Chemical Milling
Chemical milling sometimes called Chem milling or contour machining or etching. It is used to produce
shapes by selective or overall removal of metal parts from relatively large surface areas.
The main purpose is to achieve shallow but complex profiles, reduction in weight by removing unwanted
material from the surface as in the skin of an aircraft. The components are cleaned and degreased by
immersion in trichloroethylene vapour. Or some alternative chemical cleaner followed by washing in clean
water.
6. The component is then coated with a cut and peel maskant by brushing, dipping or spraying (up to 0.2 mm).
This can be a suitable fluid with a neoprene base. Or some alternative plastics solution impervious to the
action of the etching agent (permitting etching depths up to 10 mm
7. When this has dried, by mild heating otherwise, the desired shape to be processed on the
work material is cut on the maskant with a scribing knife and the unmachined portions of
the maskant are peeled away. Usually, a template is used to portray. The desired
machining shape within tolerance.
The parts are then dipped completely into a tank of chemicals which will dissolve (etch)
away from the exposed metal. After etching to the required depth, and washing to remove
all traces of the etchant, the entire masking is stripped from the component and their
surfaces are anodised or treated with a temporary protective agent as necessary.
8. Chemical Blanking
Chemical blanking, chem-blanking, photo forming, photofabrication or
photo etching is a variation of chemical milling. In this process, the material
is completely removed from several areas by chemical action. The process
is used chiefly on their sheets and foils. Almost any metal can be worked by
this process, however, it is not recommended for material thinner than 2
mm.
The workpiece is cleaned, degreased and pickled by acid or alkalis. The
cleaned metal is dried and photoresist material is applied to the workpiece
by dipping, whirl coating or spraying. It is then dried and cured. The
method of photography has been used to produce etchant resistant images
in photoresist materials.
9. This type of maskant is sensitive to light of a particular frequency, normally
ultraviolet light, and not to room light. This surface is now exposed to the light
through the negative i.e., a photographic plate of the required design, just as in
exposure, the image is developed. The unexposed portions are separated out
showing the bare metal.
The used metal is next placed into a machine which sprays it with a chemical
solution. The etching solution may be hydrofluoric acid (for titanium), or one of
1 to 15 min, the unwanted metal has been eaten away, and the finished part is
remove the etchant.
Printed circuit cards, other engraving operations and blanking of intricate designs
can be suitably made by chemical blanking by using photoresist maskants.
•Very thin metal (0.005 mm) can be well etched.
•High accuracy of the order of +0.015 mm can be maintained.
•High production rate can be met by using an automatic photographic technique.
10. Advantages
•Burr-free components are produced.
•Most difficult to machine materials can be processed.
•High surface finish is obtained.
•Any metal can be machined.
•Stress free components are produced.
•Since the process is comparatively simple, there is no need of
highly skilled labour.
•Both faces of the workpiece can be machined simultaneously.
•Hard and brittle materials can be machined.
•Tooling cost is very low.
•Complex contours can be easily machined.
11. Limitations
•Since the process is slow, metal removal rate is low.
•Manufacturing cost is high.
•Workpiece thickness, that can be machined, is limited.
•Large floor area is needed.
•It is not possible to produce sharp corners.
