New control system solutions for injection modling

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.

Easy Sensor Mounting with Priafit

The use of cavity pressure and cavity temperature sensors directly at the molded part is a permanently growing market since many years. This is not surprising considering that a bad part cannot be detected only by machine parameters due to various reasons.

The sensors are therefore commodity items which are applied in high quantities.And the ease of use during installation becomes even more important.
In the past decades two simple rules have been applied: a cavity pressure sensor was usually mounted with the help of a mounting nut in order to ensure an installation situation as stiff as possible. This is necessary to avoid measuring errors. A cavity temperature sensor however was clamped with the help of a distance sleeve as a standard because this has no influence on the temperature measurement. Both methods are not always ideal because the thread for the mounting nut must often be tapped deep in the bore hole and the distance sleeve must be cut to the exact length.

The new Priafit mounting sleeve consists of a combination of mounting nut and distance sleeve and combines the advantages of both methods. The thread for the mounting of the sensor can easily be tapped near the borehole top and the length of the sleeve must not be cut exact but only approximate. A simple but very efficient and cost-saving method.

BlueLine Voltage Module for Injection Molding Machines

The Priamus Fillcontrol systems monitor and control the injection molding process on the basis of real process parameters such as cavity pressure and cavity temperature measured directly on the molded part inside the injection mold. For process analysis, process documentation and also for the monitoring of the machine itself very often it does make sense to measure the set and actual values of single machine parameters such as injection speed, screw position or hydraulic pressure in addition.

For this purpose Priamus developed a new voltage module which measures the analog machine signals where they are actually available - which is in the control cabinet of the molding machine. At this place the analog signals are converted into digital signals and finally connected with the BlueLine devices by one single Hybrid-Bus cable. Since this is a bus system the different BlueLine modules such as pressure and temperature amplifiers or machine interfaces for process control can be complemented and designed in any order. The device is galvanically isolated and also designed to provide the required supply voltage for independent sensors such as pressure transmitters.

On request or in case of confined space conditions the device can also be mounted outside of the control cabinet in a sealed housing.