Which type of Compression Molding does the figure below desc

Which type of Compression Molding does the figure below describe? a. Positive b. Semipositive c. Negative. d. Flash Which type of thermosets process does the figure below describe? a. Compression Molding b. Pultrusion c. Vacuum-Bag Forming d. Transfer Molding Which type of Compression Molding fits tor forming shallow or flat parts? a. Positive b. Semipositive c. Negative d. Flash

Solution

solution:

Q40:b-1)answer to Q.40 is semipositive compression molding as in figure small clearance is present between plunger and die and such clearance is present in semipositive compression molding.

compression molding has three type as flash,positive and semipositive compression molding,in case of flash molding excess powder is placed in female die cavity and it will move out of die cavity and formed flashed part at boundary of main part,in case of positive molding exact powder amount is placed in die cavity and it will not moving out of die and for semipositive certain clearance is present to beahave as combinely as flash and positive molding.

Q.41.b paltrusion as this figure is not showing any press hence it is not a compression or transfer compression molding process as they require it to perform operation as placing molten powder in die and pressed it to desire shape ,and it is also not showing vaccum bag forming in which heated plastic in sagging state is pulled by vaccum down ward and create necessary component.

it is showing paltrusion which is process of forming composite by adding resin to fibre by passing fibre over roller and through resin tank to get coating of resin and it will give composite of resin and fiber which has good strength as in figure number of roller are shown hence it is pultrusion

Q.42.d flash-generally positive and semipositve compression molding are used to produce intricate shape and they require high pressure for operation nad hence there operation are costly and hence for simple flat and shallow part flash comprssion molding is used which required less pressure and hence less costly and negative compression molding doesnt exist.