3D print profits from components "made in Germany"

High running performance, lubrication free, and robust: These are the requirements that are imposed on linear components in 3D printers. In the first series-production printers of Kühling&Kühling, a company based in Kiel Germany, the appropriate special products from igus® must also be able to withstand high accelerations and temperatures of up to 80°C. In this application, high-performance plastics that make the guides fast and quiet, ensure reliable production processes and high-quality end products. The printers from Northern Germany are already proving themselves in many customer applications around the world.

System developers are driving 3D print forward
 
The company Kühling&Kühling, headquartered in Kiel, has been one of these system developers since 2012. The two founders, mechatronics engineers Jonas and Simon Kühling, concentrate on Open Source hardware development and production in the area of 3D printers. After one and a half years of development time, the first product, the "RepRap Industrial", has been running in series production since the end of 2013. It is a cost-effective solution for reliable, as well as high-quality rapid prototyping, particularly in high-load continuous use, emphasize the two founders of the company. The system is being further developed on a constant basis, and with version "v1.1.0" it will get a fundamental update, as well as various improvements. All materials that satisfy several basic specifications can be processed; these materials range from high-strength thermoplastics, to fibre-filled plastics and extend to rubber-elastic materials. Printers that are available for home use or model construction only permit use of a very restricted palette of print materials. For the most part, a so-called "bio-plastic" based on corn is used, which, as a rule, does not withstand the technical requirements that are imposed in industrial use. This plastic fails at temperatures over 45°C – the temperature limits in industrial applications are significantly higher. Compared with other 3D printers for industrial use the "RepRap Industrial" is recommended, primarily due to its price. The price is approximately 25 to 30% below the price of comparable systems. Their success indicates that Kühling&Kühling are on the right track: Quantities are continuously increasing and have quadrupled within one year.

High-quality bought in components from Germany
 
The sales organization is aligned globally, however manufacturing and purchasing occur locally in Germany to the extent possible – particularly, as the components used directly influence the quality of the finished end product. In the area of linear guide components igus® GmbH from Cologne, Germany was a valued partner right from the start. Simon Kühling recalls looking for the right supplier: "When we started the system development, initially we were thinking of classic ball bearings. These have several disadvantages. On one hand, at a unit price of approximately €12 they are too expensive, on the other hand with ball bearings their utility reaches its limits at an operating temperature of 65°C. Then the gaskets start to fail and the lubrication escapes. "This took us to linear plain bearings with plastic sliding surfaces. "For cost reasons we first tested Asian products", explains Simon Kühling. "But in no way did these products meet our requirements, nor did they offer the capability of fast and long-term assured delivery. “

Products from the second major business area at igus®, the plastic energy chains, are also installed in the 3D printer from Kühling&Kühling. The chains of "E2 micro" family used here are characterised by an extremely space-saving design, low weight, and extremely quiet rolling motions. Moreover, the smooth contours of the plastic energy chain protect the cables that are laid-out inside.
 

Economical and easy to install
 
For selection of the suitable components Kühling&Kühling worked closely together with igus®. For Jonas Kühling the consulting service offered by the drive specialist was an important criterion for supplier selection: "Via an online catalogue fromigus® we were able to get a good overview of the product range early on, and an overview of the products that were suitable for us. However, in order to choose the right products from the mass of possibilities the personal consulting was very helpful. “

Advantages for a wide range of applications
 
Extending beyond the application in the 3D printer, for "drylin®" linear plain bearings, thanks to the large-area load distribution, as compared with that of the linear bushing, soft shaft materials can also be used. Thus the hard-coated aluminum shafts offer the best friction and wear coefficients, carbon fiber shafts, the lightest weight and stainless steel shafts, the highest chemical resistance.
 
Contiguous placement of linear guides is possible at all times. To do this the guide rails must merely be slightly chamfered, aligned, and simply placed one next to the other. The sliding element moves over the groove that occurs when linear guides are joined with no problems. Thus stroke lengths of more than 20 m can be implemented. Clear, factory-marked butt joints facilitate assembly.
 
The rolling bodies or balls that are dispensed with make drylin® linear plain bearings independent of the mass inertia of these bodies and permit high speeds of up to 10 m/s and accelerations up to 100 g. Thus the design elements are suitable for applications with light loads, for which cycle rates should be increased. Hard-coated aluminium as friction partner lowers the operating temperature in the bearing point due to its outstanding thermal conductivity. Thus you can work with a high frequency even at very short stroke travel distances. The permissible average surface speed is based on from the load on the bearings: Decreasing service load results in higher speeds.