Four Heckert machining centres for burner housing production at Weishaupt
At first glance, the new production system at Weishaupt’s main plant jars somewhat: The four Heckert machining centers seem somehow smaller and more compact. At the request of the customer, Starrag built the machines 30 inches into the ground in order to simplify the ergonomics and handling through groundlevel accessibility, which increases productivity. This lower-level installation is just one example of the many details that can be optimized in order to increase productivity by around 10% and improve precision, among other benefits.
The skilled art of good industrial planning is evident not only in the construction of new plants (Greenfield), but above all in the modernisation of an existing plant (Brownfield). This task is made all the more difficult when the transition must take place with no downtime for ongoing operations. In 2015, this was exactly the mammoth task facing Max Weishaupt GmbH, based in Schwendi, Upper Swabia (south of Ulm): The task at hand was to upgrade the existing plant from 1992 with its five machining centres. The new production technology needed to be capable of machining the very large, 1.5-tonne housing of the new WKmono 80 large burner; the old systems were not able to handle a burner of this size.
Excellent machining environment: The optimised supply of coolant plays a decisive role by ensuring a consistent temperature even at high speeds of up to 7,500 rpm and significantly improving the removal of chips.
Visiting Heckert reference customers
Instead of simply replacing individual components of the old plant, Weishaupt decided to design a completely new plant to machine components for industrial burners of all sizes. Before deciding on the Heckert product range from Swiss company Starrag, Weishaupt also considered reference customers from Southern Germany such as Fendt, Vögele and Liebherr, who all specialise in comparable production tasks with similar machining centres.
Ergonomic: At the request of the customer, Starrag built the Heckert machining centers 30 inches into the ground in order to simplify handling through ground-level accessibility, which increases productivity.
In order to prevent production downtime, the conversion was carried out in two stages: The first stage, which took until 2016, involved constructing the first plant with a Heckert HEC 1600 and a Heckert HEC 1000. The second plant followed between 2016 and 2017, with two Heckert HEC 1000s. The new production system can machine components up to a maximum weight of 4 t, a maximum diameter of 110 inches and a maximum height of 87 inches (on the Heckert HEC 1600). A total of more than 100 storage areas – from which two large pallet handling systems supply the four machining centers with components and fixtures – serve as buffers for machining the approximately 450 different components (batch sizes 1 to 250) in two-shift operation. Thanks to this generously proportioned handling and storage system, around 90 clamping devices are available at all times. Each production system has three set-up points, which are adjustable in height between 2 inches and 26 inches. This ensures that the new plant delivers a high degree of flexibility and is extremely ergonomic. As each machining center has 240 tool slots, each tool is available for machining at any time and can be immediately inserted into the spindle – from the 0.2-inch deep-hole drill to the milling cutter with carbide indexable insert.
A handle on downtime: A total of more than 100 storage areas – from which two large pallet handling systems supply the four machining centres with components and fixtures – serve as buffers for machining the approximately 450 different components (batch sizes 1 to 250) in two-shift operation.
The Heckert large-scale machining centres were the answer to smooth interchangeability of pallets and fixtures for the two differently sized machining centres. They allow Weishaupt to switch easily from one machine to another. Starrag was able to make interchangeability a reality.
Burners for heating and process energy worldwide
Precision is the be all and end all when it comes to producing Weishaupt’s burner components, which are generally made from high-quality aluminium die-casting using two clamping operations and six-sided complete machining. The optimised supply of coolant plays a decisive role by ensuring a consistent temperature even at high speeds of up to 7,500 rpm and significantly improving the removal of chips. The use of coolant has already proved its worth with the WKmono 80 housing, for example, for which Weishaupt is for the first time using a very long milling tool for shaping (interpolation) of the reverse of a surface. These industrial burners are used in heating plants and in industrial processing plants all over the world, for example.
Flexible: The new plant with four Heckert machining centres produces using a total of 960 tools each day.
“Starrag made smooth interchangeability of pallets and fixtures a reality.”
Weishaupt was helped with the introduction of the new shaping technique by the tool manufacturer and by Heckert technologists, who created the NC code for this machining. In addition, the Starrag site in Chemnitz helped Weishaupt with the transition from the old production process to the new. The use of a new controller (Siemens 840D sl) meant that the approximately 600 NC programs could not simply be transferred without modifications. With support from Chemnitz, a post-processor was first created to adapt the old NC programs to the new machining centres. The time required to convert the components from the old plant to the new, right up to the start of production, was significantly reduced thanks to this support. Heckert also assisted in the adaptation of the fixtures to the new machine/pallet interface.
Ergonomic: The specialists from Weishaupt enjoy working on both of the new, lower-level production cells.
So taking all the specifics of the order for Weishaupt into account, Starrag has put in a strong performance: The four new Heckert centres are around 10 % faster than the five previous machines and, thanks to power regeneration from motor braking operations, they are also significantly more energy efficient. And, in keeping with the claim “Engineering precisely what you value”, this is exactly one of the goals that Starrag customers can achieve.