Fillcontrol: Automatic Valve Gate Control for Cold Runners
In hotrunner technology control systems are successfully used since many years for the automatic balancing of multi cavity molds. This is because the simultaneous filling of all cavities is a precondition for the optimum part quality. These conditions are achieved by automatically detecting the melt front in the single cavities and by controlling the temperature of the hotrunner nozzles in case of deviations.For cold runner molds - for instance in case of liquid silicone rubber applications - it is even more important to achieve an equal filling because otherwise the different volumes in the cavities will also cause a different compression after cross-linking. The results are unfilled respectively inhomogeneous parts which sporadically occur in one or the other cavity.
The solution for this problem is again the automatic detection of the melt front via cavity pressure or cavity temperature sensors and the automatic delay of the valve gate opening until an equal filling will be achieved. There is a choice of either balancing the average fill time or to control the desired target fill time.
This control method can be used for thermoplastics as well as for liquid silicone rubbers or elastomers. Likewise it can be used to balance and control conventional multi cavity molds as well as family molds.
Fillcontrol is a modular system to monitor and control the injection molding process. For the automatic valve gate control the new Control V module comes into operation.
Robust Temperature Sensors for the Injection Molding Process
In order to fulfill the ever increasing requirements in the injection molding process Priamus as the market leader in the area of cavity temperature sensors has come up with an idea.The existing range of products has been extended with a new line of so called "Heavy Duty" cavity temperature sensors which now can also be used at mold temperatures up to 320°C. The proved and tested PRIAMUS systems for the monitoring and control of the injection molding process can therefore also be applied for demanding processes without difficulty today. This involves processes in the field of thermoset, elastomer and liquid silicone processing as well as the molding of technical plastics in the area of thermoplastics. "Heavy Duty" sensors dispose of robust connecting cables which were designed for the use in a rough and industrial environment and can be ordered with a hardened sensor front for the use with abrasive media.As another new development Priamus introduces a melt temperature sensor for the employment in the machine nozzle or in the hotrunner manifold. This sensor has been especially designed for the temperature measurement of plastic melts under high pressure why it is provided with a special seal.
The ambient temperature at the place of installation can permanently reach 450°C.
The sensor is delivered with a hardened sensor front as standard, in order to withstand also high filled melts.
