Long exposure image of the printing of a component in the powder bed of a laser melting system. (© KSB AG)
Long exposure image of the printing of a component in the powder bed of a laser melting system. (© KSB AG)
Since the end of the 19th century, industry has focused on products that can be mass-produced. It was not worth investing in expensive automated systems unless they were justified by large lot sizes. The look of a product was determined by those who bought or sold it in large quantities.
Engineers from German pump manufacturer, KSB, began developing selection charts back in the 1930s in order to offer users optimum products designed to fulfil individual operating criteria. The drawback of this system for the manufacturer is that it requires highly efficient complexity management in order to be economically successful. A look at today’s KSB Web-Shop, reveals just how many different centrifugal pump configuration options are available to customers.
Yet the pump factory of the future will go even further than this and will allow many deviations from the standardised design, both large and small. While the possibilities of today’s conventional production methods are limited in terms of economic viability and technical feasibility, new technologies will allow additional functionalities to be offered, which are capable of transforming a pump’s potential.
In the future, production of individualised, tailor-made pumps will require only minimal engineering at each step from contract award to order processing to final commissioning. In extreme cases, a single unit of such a tailor-made pump might be built for a specific system requiring a lot size of one. However, tailor-made pumps should not be confused with untested prototypes. The wealth of experience gained while producing successful models combined with modern development tools make such tailor-made pumps reliable and efficient.
Typically, the demands placed on this type of one-off product are somewhat contradictory. While quality and reliability must be excellent, manufacturing costs must stay low and delivery periods short. And strong competition among pump manufacturers means that the latter are becoming more and more important.
Laser melting method
Laser melting is one of several patternless manufacturing methods which could play an important role in the future. The method involves building up the element to be manufactured layer by layer via micro-welding using metal powder (Figure 1). The result is a physically dense component with excellent contour accuracy produced in a powder bed (Figure. 2). The geometric design data is generated via CAD software, and the 3D printing process itself is completely silent.
Figure 1. Long exposure image of the printing of a component in the powder bed of a laser melting system.
(© KSB AG)
Figure 2. Two physically dense components with excellent contour accuracy printed in a laser melting system. (© KSB AG)
The procedure excels through its extremely economical use of energy and materials, since only the metal actually needed to create the product is thermally treated and consumed. Internal calculations at KSB have shown that savings in materials of 50 to 70% are possible when existing parts are newly calculated, newly designed and optimized for the respective production process. This is due to the fact that almost no waste is generated in 3D printing and all excess powder can be reused. The entire production process takes place in a controlled inert gas atmosphere which ensures that the materials sensitive to oxidation during re-melting are protected. A final product created via 3D printing differs from its conventionally manufactured counterpart in its metallographic microstructure, but not in terms of the metal powder composition which was used to weld it together.
Since the end of 2014, two powerful laser melting systems have been in operation at KSB’s Pegnitz factory (Figure. 3). The company’s materials specialists are examining the potential of 3D printing for development and production by trialling the production of various suitable metal components using CAD data. One question the specialists are still looking to answer is whether the new metal powder-based workpieces offer the same strength and material properties as those produced using traditional methods.
Figure 3. Since the end of 2014, KSB has installed two laser melting systems at its Pegnitz factory. (© KSB AG)
As laser melting is a new field within pump and valve production, it is also necessary to prepare new design guidelines. However, the level of design freedom and the availability of components at any place and any time encourage new approaches to development, production and logistics.
Today’s 3D printing methods still suffer from technological and economic limitations in terms of the size of printable parts and the speed of production. However, the world’s largest laser melting systems already feature build chambers with volumes of 160 litres and given how rapidly this technology is developing, larger printers will not be long coming. The cost efficiency of this manufacturing method is essentially determined by the quantity of molten material required. The manufacture of large, dense parts is thus only economically viable for parts unavailable by other means or prototypes required for the design process.
This has already proved successful for applications including the production of spare parts for old cars, motorcycles and aeroplanes. For the pump manufacturer, exploiting the advantages of the new production process represents an important step towards Industry 4.0 and the maximization of its potential in design and production. Some of 3D printing’s strengths are already clear: It excels in producing small, individual components deviating from the standard or large quantities of parts when they can be manufactured in a single process (Figure 4). Very large, dense components will in the long run continue to be produced via other manufacturing methods.
Figure 4. A battery of test specimens produced in a laser melting system during a single printing process. (© KSB AG)
Exactly which innovations the freedom offered by 3D printing will herald remains one of the most interesting questions for the future. The availability of CAD data allows the production of parts at any place in the world. This means that laser melting will definitely have an impact on the availability of components worldwide and will allow pumps to be individualised in a way that we can hardly imagine today.
Author: Christoph Pauly