If small order quantities in a large variant diversity must be delivered just-in-time, all registers must first be considered in the production planning. Secondly, production equipment must be available, using “plug-and-play” as part of the changeover process. One example thereof is the production equipment at the Westphalian plastics processors JD von Hagen AG in Iserlohn.
There, a highly varied range of types of luggage bags and coverings for motorcycles and scooters is produced. In the injection moulding production, the help of EAS‘ magnetic clamping systems enables J.D. von Hagen to enjoy a fast tool change.
Economically diverse production at JD von Hagen
Chairman of the motorcycle supplier J.D. von Hagen, Martin von Hagen, gives their own figures: “Typical motorcycle production volumes per model and year are 12,000 items, with 3,000 to 5,000 annually for a model variant. Those numbers are generally divided into 12 batches, i.e. in monthly release volumes of between 250 and 1000 pieces. To get an impression of the variety with which we deal, it should be mentioned that we have 6,000 “living” products, of which we have to deliver at irregular intervals, in irregular parts or components, but always at short notice. And in quantities of 10 to several thousand items. We therefore need outstanding flexibility on a day to day basis. The consequence in the injection moulding production is, to put it bluntly, that nearly every injection moulding tool must run on each machine. Because of the large number of injection tools, we could not afford to invest in fixed assignments and interfaces between tools and machines. To be able to still produce highly flexibly, we have opted for the combination of standard user-friendly machines and magnetic clamping systems.”
Magnetic clamping provides maximum flexibility
The biggest advantage of the magnetic clamping system is that between tool and machine, nothing more is required than a smooth, clean clamping platen on the tool. The geometric design of the tool plates is secondary in the process. Tools with round plates can likewise be clamped like tools with rectangular or square plates.
Suitable for small and large tools alike
Although the basic requirements – namely the clamping and holding of an injection moulding tool – are identical, two different magnetic clamping plate systems are used for technical reasons. The reason for this is the different conditions for the establishment of an effective magnetic flux in small, medium and large injection moulding tools. This is because the relatively thin sheets of small/medium-sized tools lead to natural barriers in the establishment of an effective magnetic flux, as magnetic field lines do not, or barely, act along plate boundaries. To adapt to these circumstances, EAS has developed two different systems: The Pressmag SP System with square pole technology for injection moulding machines with small and medium clamping forces up to 4,000 kN, and the Pressmag HP System with long pole technology for large machines or Tools with larger plate thicknesses.
In addition to the generous design of the holding force, the function of the system is monitored by sensors. It monitors whether there is permanent contact between the injection moulding tool and the magnetic plates, whether the magnetic flow lies within the prescribed tolerances (to rule out the possibility that a non-magnetic material is being used for the plates), any possible change in the magnetic flux during production (in case an air gap appears), and the operating temperature. The sensors are connected to the injection moulding machines via interfaces. If any of the monitored parameters shows a malfunction, the machine cycle is stopped.
Greater efficiency through collaboration
If type variety and small production batches demand maximum flexibility of production, the way to achieve efficient production is through as universal machines as possible and equipment for shortening the set-up times. More on this from CEO Martin von Hagen: “Flexible usable standard injection moulding machines are the foundation of our business. In order to increase the productivity of these machines in light of the many small production lots, we had to begin with the set-up times. Suggestions for a solution came from our long-standing machinery supplier Wittmann Battenfeld, who took the technicians from EAS Europe on board. The fact that magnet plates would bring the greatest potential for rationalisation for our particular case became clear to us after looking at their long list of references. As a result, we decided to let the majority of our machines be refitted with the EAS magnetic clamping systems. And we were not disappointed. Without having to make any significant changes to the existing injection moulding tools, we were able to reduce set-up times by an average of 30 percent thanks to the magnetic clamping solutions of EAS Change Systems.”