Hot runner systems
Nozzles of various standard sizes and modifications ready-assembled, and parts for them: coil heaters and band heaters with the built-in thermocouples and without thermocouples; thermocouples of type J (FeCu-Ni), needle tips, opened, the standard hardness, the raised rigidity with molybdenum inserts; nozzle sealing rings.
Manifolds ready-assembled and accessories to them: cartridge heaters with the built-in thermocouples of type J and without them; bearing washers and nozzle sealing rings (aluminum, titan, ceramics - steatite) T-shaped thermocouples of type J (FeCu-Ni).
Temperature controllers: digital-based, microprocessor-based, PC-based.
General information about the hot runner systems
The basic function of hot runner systems is leading of compressed substance (material) from a nozzle of automatic injection machine to a socket of the mold base and maintenance of stable moulding process. In case of application of hot runner systems (further HRS) moulding is wasteless (the material in small quantities remains on paths of cold channels, and in case of leading of the nozzle to the socket of a detail - a waste is not present in general), also decrease expenses of pressure for injection of a material and for mold base compression, decreases time of cooling and reception of a ready detail, in the general result, provides quality moulding improvement and reduction of means by their manufacturing.
It is possible to single out two main tasks, which decision is assigned in application of HRS:
When in the first case, an overall objective of application HRS is reduction of the cost price of a product. At first sight, initial expenses for HRS purchase, can seem big, and advantage that arises of application HRS completely compensates the previous expenses for short enough time (less power consumption, a short cycle of casting reception, considerable economy of raw materials, low deterioration of HRS, misruns quantity reduction etc.). That in other case, an overall objective becomes reception of a product of appropriate quality, that is the product corresponds to high technical requirements (a split-hair accuracy of the sizes, adequate properties of products, etc.) to receive at application of traditional methods (cold channels) is difficultly, and sometimes it is impossible.
On HRS design can differ very much, but all of them have following general elements:
- Sprue bushing, thanks to which there is a contact-leading - the compressed substance (material) from a nozzle of automatic injection machine to a delimiter. Bushings can be with heating and without heating;
- The delimiter which functions is leading of a material from sprue bushing to a nozzle.
- Nozzle delivers a material to the socket.
The integral part of HRS is the system of regulation of temperature, i.e. temperature regulators. Thanks to system of regulation of temperature the optimum temperature for work of system HRS is reached and contains in the specified limits during all cycle production.
The fundamental advantages of HRS to the relation of traditional methods are:
- High economy of raw materials;
- Reduction of cycletime (cooling time);
- Absence of final processing of molding;
- Quantity limit of wastage;
- Reduction of injection pressure and pressurize;
- Reduction of force of injector locking;
- Energy reduction through injector;
- Reduction of ejection force;
- Identical weight of details (reduction of contraction, details are with the same wall thickness );
- There are less traces after runner (performance of aesthetic runner);
- Reduction of internal pressure;
- Improvement of products quality;
- Less product cost price.