Injection Molding

We have more than 30 units injection machine, ranging from 60 tons until 350 tons clamping force. These machines are used to make plastic cabinet for our product. Just to inform, our factory serve total solution for consumer electronic manufacturing, from plastic cabinet, PCB assembly until ready to export product.

We do not inject our own product. We inject customer product. They give injection mold and plastic resin. We make it into plastic cabinet. Manufacturing cost per hour depend on machine clamping force tonnage and number of mold cavities. We group our machines into 4 groups:
• Group 1 : 350 tons
• Group 2 : 200, 220 and 250 tons
• Group 2A : 170 tons
• Group 4 : 60 and 80 tons

Group 1 is the most expensive manufacturing cost, while group 4 is the cheapest price. Group 1 needs highest electric power consumption. Manufacturing cost already consider manpower cost, electrical consumption, maintenance cost and expected profit, etc.

Above picture show some plastic cabinet we make. Please observe the biggest plastic cabinet. This part is made from injection machine group 1. Let’s say, this machine is only able to perform 70 shoots in one hour. Because of its dimension, mold only consist of 1 cavity so, in one hour, this machine is only able to produce 70 pieces. If manufacturing cost per hour is USD 7, manufacturing cost for one piece become USD 7 / 70 or USD 0.1. Lets say, for another smaller plastic cabinet which also use group 1. Because of plastic part dimension, mold consist of 2 cavities so in one hour the machine can make 140 pieces. Manufacturing cost for each piece become USD 7 / 140 or USD 0.05.

There are two main units on injection mold machine :
- injection unit, in simple concept, consist of
o hopper (arrow 1)
is used to minimize plastic resin humidity
o barrel (arrow 2)
is a screw tunnel and to melt plastic resin by heating process
o screw (arrow 2)
to deliver melting plastic into mould
- clamping unit
to push moving platen of mould in high force
- mold (arrow 3)
is the most important part of injection mold system, and is use to form melting plastic material into plastic cabinet

Our factory has two type clamping system : hydraulic clamping system and Toggle system

Mold. Standard mold consist of two plates :
- Cavity side
is connected to nozzle of injection unit to deliver melted plastic material (from screw) into sprue of cavity side
- Core side
is connected to clamping system so it is called moving plate. Inside this side, there are some ejector that is use to release plastic part from machine. Operator can take out plastic part manually or using robot arm in automatic system.

Above picture show 2 cavities mold. Picture A is core side and picture B is cavity side. Arrow 1A and 1B are used to form cabinet top while 2A and 2B are used to make cabinet bottom. This kind of mold is called pairing mold.

..analisa mold

Part come from injection machine consist of part itself (arrow 1 below picture) and sprue and gating (arrow 2). Part’s weight will be based on part itself. Sprue and gating will be recycled to make new part. The number of recycling process is purely depend on expected quality. The high class plastic cabinet will be made from virgin plastic resin, while very cheap plastic cabinet may come from 100% recycled material.

Another factor to consider to weight plastic cabinet is barrel cleansing process. Every time injection mold use new material, especially new color, barrel has to be cleaned by plastic resin until expected color / material can be achieved.