FAILURE ANALYSIS STUDY ON THE CUTTER BLADE OF POLYPROPYLENE PELLETER DRIVE
This report basically discusses the Failure Analysis Study on Cutter Blade of Polypropylene Pelleter Drive. The objective of the project is to conduct failure analysis method on the cutter blade and to determine the causes of its failure. This report also discuss on the types wear and its wear me...
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| Main Author: | |
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| Format: | Final Year Project |
| Language: | English |
| Published: |
Universiti Teknologi Petronas
2009
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| Subjects: | |
| Online Access: | http://utpedia.utp.edu.my/7733/1/2009%20-%20Failure%20analysis%20study%20on%20the%20cutter%20blade%20of%20polypropylene%20pelleter%20drive.pdf http://utpedia.utp.edu.my/7733/ |
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| Summary: | This report basically discusses the Failure Analysis Study on Cutter Blade of
Polypropylene Pelleter Drive. The objective of the project is to conduct failure
analysis method on the cutter blade and to determine the causes of its failure. This
report also discuss on the types wear and its wear mechanism. In this study, the
author had obtained the cutter blades and background data of the sample. The author
had conducted visual inspection of the sample, Vickers hardness test and
microscopic inspection under optical microscope and scanning electron microscope
or SEM. The result obtain from this study confirms that the blade materials is
Titanium Carbide, high wear resistance material but brittle. This material data are
obtained from the manufacturer datasheet. During preliminary stage, the samples
show excessive and uneven wear on its cutting surface, some of the blades had
chipped at titanium carbide tip. The chipped samples are selected and cut using
electric discharge machining to obtain its cross section. These samples then are
mounted to berkelite press then grinded and polished for microscopic evaluation.
Microscopic inspection reveals the materials have voids in its microstructure. These
voids tend to reduce its strength and the tip can break easily upon impact.
Fractography result shows the tip fractures when being hit by foreign particles, the
fractures are consistence with the cutting path of the blades. Mechanical testing
using Vickers Hardness Test, the result obtained is Hv=797. The excessive wear on
the cutter blades is suspected from poor operating procedure. During high melt
index, polymer tends to produce tailings. To counter this problem the operator need
to advance the pelleter rotor forward to the die plate. This resulting higher contact
force and high wear rate. Lack of proper monitoring of cooling water entering the
chamber may have lead to the chipping of TiC tip, debris may have come in between
the blades during operation and collide with the tip. During cleaning of the chamber,
the author had found sand inside the chamber. The outcome of these studies will
provide recommendations in term of modifYing operating procedure and installing
device to prevent from entering the pelleter assembly. |
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