Efficiency, repeatability and cost reduction become more and more important in today’s container glass manufacturing operations. Clients demand maximum quality and flexibility against minimum costs. At the same time there is a growing environmental pressure on the industry to lower carbon dioxide emissions and energy consumption. The only way to match these internal and external expectations is optimizing the control over the forming process. The new IGC helps taking more control.
The area in which process control can easily be achieved is the weight of product: the gob weight. XPAR Vision has renewed and improved its IGC (Infrared Gob Control) solution for this matter. With the integration of the actual weight of the product into the closed loop of steering the gob weight, the operation becomes easier and more effective.
Where does it fit?
The IGC system basically fits in any container glass production line. It is adaptable for single IS machines with any size sections or gobs. It also supports tandem IS-machine lines, even with more than one product produced at the same production line. NNPB (narrow neck press-blow) forming processes are often equipped with plunger control and its respective weight control loop. The IGC is positioned to provide a control loop in the blow-blow and press-blow (wide-mouth) forming processes.
How does it work?
The Infrared Gob weight Control solution (IGC) monitors the weight of the products and automatically corrects it by adjusting the tube height (or plunger). The ICG is an add-on to the InfraRed Dual camera solution (IR-D). Together, they form an integrated system.
The intensity of the emitted infrared light of each product, measured by the IR-D, is an important factor. It tells everything about the mass of the product. In theory, the total intensity has a linear relationship to the total mass. When, for example, the mass of the products rises over time, the measured IR-intensity will also rise. This information is imported into a control loop, that calculates the ideal position of the tube (or plunger) for that moment. The new IGC also receives weight measurements by the integrated scale. It correlates the weight of the product to the measured IR-intensity. All in all, the closed loop continuously and automatically controls the tube height inside the feeder (Fig. 1).
Fig. 1, IGC control loop
Another important feature of the new IGC is the direct interface to any (servo) tube motor. Until now, the IGC had to be connected to a dedicated motor delivered by XPAR Vision.
Easy to operate
For machine operators the use of IGC system is easy and straight forward. Their tasks in relation to keeping the gob weight stable are reduced to just weighing the product. The IGC system will automatically make the necessary adjustments to the tube settings (Fig. 2).
The IGC system guarantees stability in gob weight. No remedial actions are needed on the floor anymore, so the job becomes easier and safer.
Integration to any Production Information System
The IGC system comes with embedded protocol to share the scale weighing data with commonly used production information systems like Vertech’s SIL and EKF’s iAFIS. Since all measurements are instantly stored in a SQL Database, including the actual scale weights and all corrective actions the IGC has performed, a database connection to any customer production information system can easily be made. With all these data, offline analyses can be performed over a large period of time by the XMIS reporting system. These analyses give better insight in the condition of the complete IS machine, feeder condition, tube condition as well as spout condition.
What does it bring?
The importance of accurate gob weight control over time (low gob weight variation) is obvious. The glass forming process is a result of a number of factors that affect the weight of the gob, such as temperature, viscosity, composition and colour of the glass. Only a proactive adjustable and flexible system can react to sudden or long-term changes in the process and can anticipate on standard operating procedures (like swabbing) at the same time. The self-regulating qualities of the system reduce the operator’s workload and the weight deviation of individual gobs over time. Less deviation of gob weight leads to less glass usage, fewer defects and a more stable production process. It increases efficiency and profit.
Other benefits of the new IGC are:
Less machine downtime
Less weight related defects (e.g.: unfilled finish, over-pressed, thin bottom)
Less volume variation of the products
Less time consuming operator actions
Less overregulation by the operator
Process stability is a must-have for (ultra) light weight container production. The IGC has proven its payback time at numerous installations already. In practice realized weight deviations of 0.2-0.3 % have been reported without exceptions (Fig. 3).
Fig.3, Reduction of gob weight variation with IGC system