19-10-2010, 04:20 PM
CRYOGENIC GRINDING :
CRYOGENIC GRINDING PRESENTED BY BINAY SHAW 4TH YEAR MECHANICAL ENGINEERING ROLL NO. 10207051016 KALYANI GOVT. ENGINEERING COLLEGE GUIDED BY PROF. S. DAS Head, DEPT. OF MECHANICAL ENGINEERING KALYANI GOVT. ENGINEERING COLLEGE KALYANI NADIA
GRINDING :
GRINDING Grinding is one of the most popular finishing processes. This process is carried out with a grinding wheel made up of grits for removing materials from workpiece surface.
The problems in conventional grinding process: :
The problems in conventional grinding process: High heat generation Introduction of tensile residual stress and micro-cracks occur High level of surface quality can not be reached Problems in hard materials. Less tool life Sometimes M.R.R. is not satisfactory.
Now… elimination of all those problems are required…but… :
Now… elimination of all those problems are required…but… HOW…???
Here comes the introduction of _ :
Here comes the introduction of _ C R Y O G E N I C G R I N D I N G …also known as Freeze Grinding
How it is done… :
How it is done… The cryogen like liquid nitrogen is applied onto the cutting point mostly in the form of jet. At low temperature (-196°C) of the cryogen, the temperature at the cutting zone is controlled more effectively than the other methods of applying cutting fluid.
Experimental set-up :
Experimental set-up
Slide 8:
. Ground chips of different steels under different environments: (a) MS 30 µm; (b) HCS 40 µm; © CDS 40 µm; (d) HDS 30 µm; (e) HSS 40 µm
Slide 9:
Surface conditions of different steels ground under different environmental: (a) MS 30 µm; (b) HCS 40 µm; © CDS 40 µm; (d) HDS 30 µm; (e) HSS 40 µm.
discussing in course of viewing the advantages… :
discussing in course of viewing the advantages… The cryogenic grinding lowers the thermal related problems Reduced grinding forces High M.R.R. can be achieved Minimizing residual stress and micro-cracks Retention of wheel grit sharpness (i.e. low rate of grit wear) Surface finish, dimensional accuracy and tool life improved Difficult-to-machine materials can also be machined Moreover, use of liquid nitrogen as a grinding fluid facilitates clean and pollution free working environment
Cryo-grinding do have distinctive advantages over the conventional cooling processes, but… :
Cryo-grinding do have distinctive advantages over the conventional cooling processes, but… The application of the cryogen in the moist atmosphere may cause formation of ice and around the delivery nozzle and the piping system carrying the cryogen. This may result in the possible blockage of the liquid nitrogen delivery system. Economic considerations should be solved
Hence we can conclude… :
Hence we can conclude… Cryo-grinding improves product quality by controlling thermal effects Oxidation and surface burning are eliminated Surface damage is absent The surface roughness in cryo grinding is found to be greater than in conventional grinding Reduction in forces and specific energy The benefits of cryo-grinding are greater for harder materials and higher infeeds
http://studentbank.in/report-cryogenic-grinding--2990
http://studentbank.in/report-cryogenic-grinding--5136
http://studentbank.in/report-cryogenic-grinding
http://studentbank.in/report-cryogenic-g...?pid=23600
