Grille Moulding

To make part surface high gloss without weld lines, RHCM(rapid heat cycle molding) technology is an ideal way. And it is necessary to have various aspects function and cooperate such as injection machine, tool, temperature controller, raw material, cooling equipment and so on.

The conception is to use steam and cold water to control mold temperature in a cycle by shifting heating and cooling rapidly. As soon as put in steam or hot water to get mold temperature higher than polymer heat deflection temperature(HDT), inject molten polymer which then flows in the best status so that weld lines and silver marks can be avoided. When the filling is done, to quickly get the mold temperature down lower than polymer HDT by cold water which quickens polymer solidification that shortens the moulding cycle time, effectively having warp and sink problems prevented. Moreover, it makes part surface specular gloss so that subsequent painting procedure can be canceled, saving production cost and cycle time.

We taking using heating rod and polish for example here.

1/ Heating rod:

1.1 to set up heating rods at gate top and bottom, center distance between two rods 20mm and distance between rods and part surface 5mm; to have ∅6 cooling channel(normally) whose wall should be 6-8 mm from heating rod by distance.

1.2 to have heat resistant sealing ring or solid sealing for inside tool cooling channel.

1.3 to set the rod diameter value 5mm in design (actual ∅4.92), using ∅5 ejector pin grinding edge to eliminate burrs of rod before assembly.

1.4 to have the same flow distribution plate at water inlet and outlet with steam injection.

2/ Polishing: working stuffs like good quality oil stone, sand paper and diamond paste, and dust-free workshop if possible. The steps should follow surface status of previous process such as machining, EDM, grinding, etc. The basic procedures for hand polish as following up:

2.1 freehand polish by oil stone with kerosene for lubricant or coolant, normally the sequence of grit 180~240~320~400~600~800~1000

2.2 half-fine polish to use sand paper and kerosene, for sand paper to follow the sequence of grit 400~600~800~1000~1200~1500( #1500 proper for quenching steel over 52HRC)

2.3 fine polish to use diamond paste while if polish bob is used with diamond paste, the sequence normally be 9μm（grit 1800）~6μm（grit 3000）~3μm（grit 8000）

Hot Tags: grille moulding, China grille moulding manufacturers, makers, Console Plastic Mould, Blow Moulding Tools, Rear View Mirror Mould, in mold decoration, Door Panel Mould, Gas Assisted Molding