Nowadays, many of products made from plastic materials because of the behavior of plastics. Plastics
are easy to be formed, cheap, and light. Injection molding is a method for making a product from
plastics material. After making a mold for a product, often seen that quality of product which be
resulted from injection is not good or there is a defect in the product, or fail. Of course, this problem
could be bad impact to industry, because they would be needed high cost and time for production.
In the design of mold, there are some things which to be attention when doing design of mold, that are
shape of product, cavity, runner system, gates system, venting of mold and heat exchange system.
Because of that, if a design have made, need to depend on the things in above which has been part of
mold design standard. However, in the decided for the type and condition in above that the most of fit
with the shape of product is very difficult. Example, for decide the location of gate, if location of gate
that has been decided not be good, so the result of product could be not maximum.
To overcome this problem, simulation before made the mold is needed, to improve the quality of
result after injection depend on design that would to be made, so if the mold was made could be result
a good product. Software would be used is Moldflow. When use this software, could be predicted
many things concerning with injection process and could be improved quality of product that resulted
in the injection process.
Case study in this research was a plastic cup, because in the design of a cup, the problem that usually
appears is on the hold of cup. In the location, usually occur defect on the shape of hold of cup. If use
simulation with Moldflow, it could be analysis the optimum location of the gate, so the result of
product after injection process could be better. It is also minimize defect or fails in the product. The
result of simulation that has been done are could show flow of plastic fluid entering all of cavities of
mold, and could find locations which perhaps appears air traps, and could improve quality of product
after injection.
The result of this simulation could improve quality of product. Before use simulation, there is defect
on the product that resulted after injection, but after use simulation, the quality of product is improved.
It is very help in the development of new product plastic cup. The industry could be doing simulation
first, to create the new product or develop existing design. They could be success to carry out the new
design with good quality. It means that they could be saving in production cost and production time.
