Horizontal boring and milling machines are currently imported into the USA by the overwhelming majority of manufacturers. UnionChemnitz has presented its first HBM built in the USA in cooperation with its sister company KPM at the IMTS 2016. The floor-type horizontal boring mill with 6.4” (162 mm) spindle diameter (PCR 160) is unique in the market: it is the first one built in the USA with a complete hydrostatic guidance system. Thanks to the hydrostatic guidance of both the column and the RAM, the machine operates virtually wear-freely and with outstanding precision.
UnionChemnitz is the oldest existing machine tool manufacturer in Europe, drawing on more than 160 years’ experience. In the past 15 years, the company has delivered more than 60 HBMs to North American customers. Now, the state-of-the-art horizontal boring mills are manufactured in the USA. Construction and assembly of the machines take place at UnionChemnitz’s sister company KPM in close cooperation with the design department in Germany.
The PCR 160 has been installed at Herkules USA in Ford City, Pennsylvania, in late 2016. Herkules USA is a leading manufacturer of machine tools. The main challenge here is machining large and demanding workpieces to very high standards in terms of accuracy and reproducibility. The machine concept was therefore specifically tailored to the customer’s requirements by the UnionChemnitz design department. With an X-axis of 138” (3,500 mm) and a Y-axis of 157” (4,000 mm), the horizontal boring mill is designed for effective five-side machining of medium-size to large and heavy workpieces. “The HBM will machine high-precision lathe headstock castings and other machine tool components to very tight tolerances,” says Jakob Scheiffarth, Plant Manager at KPM. “These headstock castings are part of 110-ton capacity lathes that will machine large gas and steam turbine rotors. Headstock castings can weigh up to 15 tons. They have an intricate geometry, combined with very high requirements in terms of accuracy, especially eccentricity and parallelism, to achieve the perfect fit for high-precision radial and thrust bearings.”
To guarantee the required precision even when performing heavy-duty machining tasks, the machine bed is a special design of welded steel which absorbs vibrations, and the column is strongly ribbed for extraordinary stiffness. The PCR 160 reliably compensates spindle and RAM droop as well as column tilt. In addition to stable heavy-duty machining, the machine is therefore suitable for extremely precise finishing tasks. The rotary and traversing table of the PCR 160 with a length of 98” (2,500 mm) and a width of 79” (2,000 mm) effortlessly handles workpiece weights of 20 t. The table traverses up to 59” (1,500 mm) deep in the V-axis. The B-axis of the table can be adjusted in increments of 0,001 degrees, allowing for very precise positioning of the workpiece and hence excellent machining accuracy.
Flexibility is essential for the machining of the components manufactured at Herkules USA. The W-axis (boring spindle) and Z-axis (RAM) of the PCR 160 have a combined length of 87” (2,200 mm), allowing for machining operation deep within the workpiece. Imported HBMs often come with a major disadvantage: they are standard, mass-produced machines which can be customized only to a very limited degree. The PCR 160, in contrast, has been custom-designed by UnionChemnitz experts and built by KPM in close cooperation with the German colleagues specifically according to Herkules USA’s requirements: “As short machining times are an important factor in the overall efficiency of Herkules USA’s production facility, we added special equipment to reduce machining times in the HBM’s specific area of application – a pick-up station to switch between milling units for various machining tasks and a 60-pocket tool magazine with an automatic tool changer,” says Dr. Benedikt Sitte, President and COO of UnionChemnitz. The horizontal boring mill is operated with a Heidenhain iTNC 530 HSCI control and can alternatively be equipped with FANUC and Siemens controls.
KPM is an expert in implementing customized solutions. “We are a vertically integrated supplier of most components in our machine tools,” Jakob Scheiffarth says. “We manufacture rotary tables, gearboxes, milling heads and other critical assemblies. We take internally produced, proven modular components and combine them to develop custom, economical manufacturing solutions for our customers.” The components are produced with the help of a modern machine inventory comprising a wide range of lathes, milling and grinding machines, as well as measuring devices – all in all, the headquarters in Ford City cover 81,000 ft2 (7,525 m2). Both mechanical and electrical engineering take place in-house. The engineers and technicians at KPM draw on many years’ experience in manufacturing and assembling machine tools to build the boring and milling machines designed by UnionChemnitz. “We have a very skilled team of 110 employees who are experts at machine tools, machining and controls integration,” confirms Sam Kube, President of KPM. “We even teach the art of hand-scraping to our apprentices.”
By combining their competences, UnionChemnitz and KPM have reached the goal of their collaborative effort: They are now the only North American manufacturers of fully hydrostatic horizontal boring mills. “American customers will benefit from reduced delivery times of these high-performance machines. This is a great potential advantage for their American operations requiring horizontal boring mills,” Jakob Scheiffarth states.