Hot Runner Balancing with the Aid of Mold Cavity Pressure: Fast, Automatic and Extremely Precise

As the "fingerprint" of molding, cavity pressure is the critical variable for evaluating process control and the quality of molding. The new Kistler MultiFlow system now also uses this pressure as the most efficient of all of the potential controlled variables for balancing hot runner systems.

Cavity pressure sensors are the only means of measuring the injection molding process extremely accurately - from the injection - through the compression and holding pressure - to the cooling phase. It is precisely this accurate measurement of the entire injection and compression phase through the actual pressure regime that is important for balancing hot runner molds, as the filling of the mold is not complete until after the compression phase. A snapshot, such as that used for manual optimization, which is used to set the temperatures of the hot runner nozzles with the aid of melt front positions during partial filling, is not sufficient for good balancing. The Kistler MultiFlow system offers cycle-by-cycle analysis of the injection and compression phase of the variation in pressure in all cavities, and automatically optimizes hot runner nozzle temperatures as a manipulated variable with the aim of achieving identical filling of all cavities and thus synchronization of the variation in pressures in all cavities.

This method of control completely eliminates the need for involved manual optimization of the conditions in the hot runner on the basis of case studies. It also obviates time-consuming optimization and adjustment of the hot runner temperatures before and during production. In the course of production the Kistler MultiFlow system automatically corrects the hot runner temperatures to guarantee continuously stable filling conditions in all cavities. At the same time, with the aid of the cavity pressure curve, the MultiFlow system monitors the quality of all of the moldings produced and signals any need for automatic separation of rejects.

The new MultiFlow system from Kistler balances multicavity injection molds quickly and extremely accurately. The MultiFlow system enhances tried and tested process and quality assurance based on the cavity pressure curve with additional functionality that cuts costs. Kistler MultiFlow will be available as a module in the proven DataFlow software 2805A… and in the DataFlow System 2865B… . In 2008 Kistler will also integrate its MultiFlow system into the CoMo Injection process monitoring system Type 2869B… .

Kistler at K 2007

Kistler will present its portfolio of products on Stand 10F04 in Hall 10 at K 2007 (International Trade Fair for Plastics and Rubber), which is to be held in Düsseldorf from 24 to 31 October 2007.

Background: Cavity Pressure Curve

The cavity pressure curve serves as a "fingerprint" of the injection molding process. It is the most significant variable in evaluating the quality of the molding.

As the supplier with the largest and widest range of sensors for all methods of injection molding, simple connection technology and user-friendly, networkable systems, Kistler is the only manufacturer to offer complete monitoring of injection molding from a single source. The company is the world's leading manufacturer of pressure and temperature sensors for use in the plastics processing industry.

Kistler Group

Kistler’s core competence is the development, production and use of sensors for measuring pressure, force, torque and acceleration. Kistler’s know-how and electronic systems can be used to prepare measuring signals for use in analyzing physical processes, controlling and optimizing industrial processes, improving product quality in manufacturing and improving performance in sports and rehabilitation.

Kistler offers a comprehensive range of sensors and systems for engine development, automotive engineering, plastics and metal processing, installation technology and biomechanics.

A worldwide sales presence in the form of 20 group companies and 30 distributors ensures customer proximity, application support on an individual level and short lead times..

With a staff of more than 800, the Kistler Group is one of the world’s leading providers of dynamic measuring instrumentation. The Kistler Group achieved turnover of 174 million Swiss Francs in the 2006 financial year.