Question

You will select 1 defect (this will be your output) in injection molding process. Of course you will investigate the causes of this defect and select 2 of them as inputs. You will create the following: Basic block of the program Set of rules if/then to derive your output (fuzzyfication) Create one Membership function for one of your inputs (no need to program in Matlab or any software just a regular graph)

Answer 1

In process of manufacturing of molded prototypes require art and science skills. There should be high level of technical experience and attention required to prevent mistakes. Lack of experience could bring the error and defects in molded injections. These defects could be very costly if production was performed at large scale. There are the following defects could occur in injection molding process.

1. Flow Lines
2. Sink Marks
3. Vacuum voids
4. Surface Delaminating
5. Weld lines
6. Flash

These mistakes happen because of lack of right tools and experience personnel. Second one is incorrect combination of Software and hardware.

Flow Lines: - These are the lines, pattern and streaks occur on prototype occur because of physical path and cooling temperature of molten plastic passed through injection mold tool. This defect occurs because of slow speed and varying thickness of mold injection tool. It can be prevented through increasing the speed and maintaining the required pressure through adequate filling.

Sink Marks. These marks occur when cooling time and mechanism are insufficient to cool down the mold. These could be happen because of excessive temperature at gate and inadequate pressure in molding tool cavity. These can be prevented using the thin wall section to faster cooling.

Surface delaminating occurs because of contamination in mold through foreign particles in mold. There will be lack of bonding in between mold and foreign particle so they get separated from finished product. This can be prevented through increased temperature and pre drying of plastic before molding.