Simple structure, high on the material of the limitations of open mode, leaks of wire drawing and easily, the surface quality is poor, abroad application in high precision mould is less, the same pair of mould and a mixture of different manufacturer of needle valve type.Many companies can make their own.
Needle valve type
The needle valve type hot runner saves material, the plastic part surface is beautiful, the internal quality is tight, the strength is high.
.There are two types of needle valves in the world (according to the principle of injection) : cylinders and springs.The cylinder type dependent controller and the timing controller control the cylinder to push the closure of the needle valve, the structure is more complicated, but the design itself is simple.There are DME(USA), INCOE (USA), MOLD-MASTER(Canada - hot runner), HUSKY(Canada), HOTSYS (Korea), YUDO (Korea), JTM(JTM), and hotflow plastic.Because of the characteristics of its structure, the cylinder type determines the precision of the MOLD, while debugging and maintenance are relatively miscellaneous, among which the MOLD-MASTER is the Rolls-Royce in the hot runner - the heating part is on the nozzle.The large cost of them in debugging and maintenance, the customer can not maintain themselves.Spring type was a -- FISA (Japan), the biggest characteristic, depend on the needle valve spring and the balance of the injection pressure control switch, debugging and maintenance simple assembly, mold precision is not high, the Japanese domestic customers basic maintenance ability, is widely used in household appliances, automotive trim, precision multi-cavity mold.The difference between spring and cylinder is that it cannot be controlled in sequence and can not solve the problem of welding seam.The small diameter wear-resistant nozzle was developed by the plastic American hot runner.Spring needle valve and internal heating nozzle.