From one to another!
Precision milling in hot runner technology
GÜNTHER Heisskanaltechnik GmbH maintains quality standards and economic viability in the production of high-precision injection casting nozzles and complex hot runner manifolds with the consistent use of five-axis machining centres from Hermle.
Hot is good, hotter not necessarily better, and regulated hot runner technology is best of all! That is the simple recipe on which the success of the typical medium-sized company GÜNTHER Heisskanaltechnik GmbH and its hot runner technology is based, success that now spans over three decades and regularly keeps raising eyebrows in the injection moulding plastics processing sector. The plastics processing industries were quick to realise the advantages of hot runner technology, which explains the company’s strong growth figures that continue to this day. This has included milestones such as the Hot-Runner-System 230 Volt (1990), 24 Volt-System (1995), the CADHOC-3D configurator for hot runner systems (2006) as well as the thick film heater and BlueFlow® hot runner nozzles (2010) that mark GÜNTHER Heisskanaltechnik GmbH’s progress from a small garage operation to an internationally active enterprise with 250 employees. Part of the company almost from day one and now its sole CEO, Siegrid Sommer has witnessed its growth through various perspectives – in the design department, as Production Manager and then as a member of the executive board. She explains the company philosophy as follows: “We have built up over 30 years of know-how in hot runner technology that ranges from development to production and on to the service coverage. We have always put great emphasis on maintaining highest standards of quality, and therefore we use our excellent production facilities to manufacture all components and systems apart from just a few supplied parts. We produce 18000 to 20000 nozzles and over 2500 manifold systems every year. We are extremely well set up for this with good 130 specialists and an up-to-date machine park. As about 35% of our production involves standard products made to order and around 65% is devoted to special items, we have to be able to deal with flexible output quantities that begin with a batch size of 1. That is only possible with qualified personnel and equipment that provides for maximum availability.
A success factor: Quality production under one’s own aegis.
This is also one of the reasons why seven Hermle milling / CNC machining centres are to be found amongst the 35 CNC machine tools being used in multi-shift operation. The first Hermle machine commenced operation as early as 1990: a UWF 851 universal tool milling machine capable of 4-axis machining with the aid of add-on equipment. Production manager Hartmut Nagel comments on working together with Hermle on the basis of his long-term practical experience: “In the mid-nineties we had machining operations to perform that, unfortunately, could not be provided for by Hermle. Then, in 2000, we returned to Hermle after some negative experiences as far as availability and service are concerned. We purchased a C 600 U machining centre for 4-axis and 5-axis machining. This also had to do with new challenges arising from machining multiple nozzles which we were perfectly able to meet with the innovative kinematics concept of the C series.” Thanks to the vigorous growth, another six Hermle five-axis machining centres followed in the subsequent years: a C 40 U, a C 30 U, a C 40 UP (with pallet changer), a C 42 U and finally the latest C 22 U. This means that almost the entire range hot runner components such as nozzles or plates and manifolds that are manufactured or finished by milling is covered by the Hermle machining centres.
The working ranges in the X-Y-Z axes (three axes in the tool), generous considering the compact size of the machining centre, as well as the absolutely free positioning of the integrated swivelling rotary tables in the C and A axes (two axes in the workpiece) allow for ideal tool deployment, e.g. for drilling deep holes. Whereas smaller manifolds used to have to be clamped in at least two positions, machined on all sides and then moved to special deep drilling machines, all that now happens as full processing involving a single clamping operation, whereby deep hole drilling can be dispensed with in many cases. Thanks to the C 22 five-axis machining centre, similarly dramatic improvements and productivity boosts have taken place in nozzle production as well, as CNC milling manager Jürgen Golde explained: The high degree of accuracy and the 5-axis, 5-side / complete / simultaneous processing with a single clamping operation allows for the high-precision machining of the nozzle tips. Previously, we had to mill them on all sides using a dividing attachment, and then do the finishing by hand – now we just have to clamp the nozzle, work it and then it comes off the machine ready for assembly.