Hyss Metallberarbeitung in Lennestadt, Germany specializes in the machining of large and heavy turning, welding and casting parts.

The machining of long and several tons of heavy turning parts is particularly demanding when at the same time high precision and tightest tolerances are required. It is not only the technical competence of the machine operator that is important, the turning center must also be able to comply the high demands of the machining process for large, accurate and heavy workpieces. In order to be able to produce even small and smallest batch sizes economically and precisely, Hyss Metallberarbeitung has been successfully counting on large turning centers for many years from Hwacheon, a South Korean machine tool manufacturer.

Gerhard Hyss (right) and his son Steffen (left) invested in the extremely robust and precise turn-mill center Hi-TECH 850L YMC

Located in the industrial area of Sachtleben in Lennestadt-Meggen, Hyss Metallverarbeitung GmbH & Co, KG has a combined production area of ​​1,000 m². Workpieces, welded and casted parts for machines, plant and special machine design as well as for the tools, hydraulic, pneumatic, automotive and agricultural machinery industries are manufactured here. In addition, the company offers repairs of defective components, machines, welded or casted parts as well as shafts and bearings. As an option, defective machine parts can also be re-produced according to given samples.

Large Parts – Niche Market. Hyss Metallverarbeitung produces large and heavy turned parts in small and small batch sizes on its XL lathes.

The contract manufacturer has specialized in the machining of large and heavy turning parts, welded and casted parts up to a weight of 8 tons, up to 1,100 mm in diameter and 3,500 mm in length. These are often one-off productions or small series in small quantities. Managing Director Gerhard Hyss has systematically opened up this niche market. In 1982 he started his own business with two partners with the production of small turning parts – but it was hard to make enough money with that. Therefore, investments should be made in a new business field.

“We wanted to manufacture larger parts and decided to invest in machines for processing maximum diameters of 550 mm and peak weights of 1.5 tons”, Gerhard Hyss looks back. “This allowed us to expand our range of services and gain new market segments.”

The concept worked and more and more orders for large precision turned parts were received, so that the previously available production area reached its capacity limits. Against this background, a new production facility was built in 1999 at the current location. The new halls offered space for even larger machines and thus also for machining even larger and heavier workpieces.


With the rigid Hi-TECH 700 from Hwacheon, workpieces up to a diameter of 700 mm and a turning length of 2,000 mm can be processed.

At the Metav exhibition in Düsseldorf, Gerhard Hyss came across the Hi-TECH 700 at the Hwacheon’s booth. It is a horizontal turning center for heavy-duty machining, which offers an extremely rigid spindle design. The high-precision cylindrical roller bearings and the particularly impact-resistant angular roller bearings of the headstock are specially designed for tough and hard turning operations. Torques of up to 3,071 Nm at 115 rpm can be achieved via the integrated gearbox. Gerhard Hyss was immediately enthusiastic about this extremely stable and qualitatively well-processed lathe in XL format and decided, sometime later after comparing the market, to buy his first Korean machine: “With the Hi-TECH 700, new doors opened for us. Now we were also able to machine parts up to a diameter of 700 mm and a turning length of 2,000 mm and achieve more flexibility and speed in production. “

With the new machine, further new orders came for even larger workpieces. The company had found its niche market and at the same time acquired a reputation as a specialist in the manufacture of large parts for machines and industry engineering. In the period that followed, the order backlog continued to grow, so another Hi-TECH 700 was purchased to adjust the production capacity.

Since the first machine had very good experiences, “it was clear,” said Gerhard Hyss, “that the next machine also had to come from Hwacheon”.


Because the signs for the company continued to point to growth and the space available for storing the raw material was no longer sufficient, an additional hall was built on the company property, which offered space for additional machines in addition to a larger storage space. At the same time, the contract manufacturer received more and more inquiries for bigger size turning parts with integrated milling work. Therefore, the procurement of a turning-milling center was planned.

Steffen Hyss, son of the company founder and co-managing director, saw the Hi-TECH 850L YMC turning and milling center at the opening of the new Hwacheon European headquarters in Bochum. With this XXL machine, workpieces up to a weight of eight tons and with diameters of up to 920 mm can be precisely machined up to a turning length of 3,500 mm. In addition to classic turning tasks, milling work can also be carried out in one setup in combination with an additional Y axis. This increases the precision of the machined parts, because clamping errors that can occur when changing from the turning to the milling machine are excluded. The junior manager and the accompanying employee were so impressed by the increased possibilities, the advantages of combining turning-milling and off-set machining and the high flexibility of this turning-milling center that the company decided on this new investment.


The spindle, tailstock and extremely rigid machine bed of the Hwacheon Hi-TECH 850L YMC are designed for large, heavy workpieces. The machine bed is bevelled by 45 degrees for optimal heat management. This prevents excessive heating of the workpiece and machine and ensures the high precision.

The stable and robust machine has a particularly rigid monolithic machine bed with a weight of 23.5 tons, which is manufactured in Hwacheon’s own foundry. For optimal heat management, it is bevelled by 45 degrees so that hot chips can be reliably removed. This means that the machine and workpiece are not excessively heated, even during roughing operations with a large amount of chips. All flat guides of the machine are hand scraped and polished. Especially with this time-consuming work process, the manufacturer’s more than 75 years of mechanical engineering experience become clear. The flat guides have significantly lower vibrations even for heavy-duty machining tasks and thus ensure greater stability for greater precision and longer tool life.

 All flat guides of Hwacheon machines are hand scraped and polished. This means that hardly any vibrations occur even during heavy machining. The resulting increased stability ensures higher precision and availability as well as longer service lives.

Thanks to the massive design of the extra wide turret with a width of 250 mm, even large boring bars up to a diameter of 100 mm and a turning length of 1,000 mm can be clamped. The four-stage main spindle gear offers exceptionally high torque, especially in the lower speed range. The bearings are lubricated and cooled using the oil cooling system specially developed by Hwacheon. The temperature of the four-stage gear is continuously regulated in order to minimize thermal expansion, which ensures the accuracy of machining during long operating times and heavy machining. With a drive power of 45 kW, the machine achieves a maximum torque of 6,873 Nm.

The large Hwacheon Hi-TECH 850L YMC offers an additional integrated Y-axis for combination machining. This means that both turning and milling work can be carried out on the machine in one setup.

Cutting technician Andreas Schöttler was enthusiastic about this tremendous force: He had never had to operate the machine at full load. “Because of our small and single series production, the quality and precision of the machined workpieces is very important to us. We don’t have to drive at full load to achieve faster machining. When it comes to individual parts, it’s not about the minute, the quality has to be right.”

On the Hi-TECH 850, the company has been able to machine all materials from structural steels, tempered steels, quenched and tempered steels, stainless steels, brass to plastics and super duplex steels , “Thanks to the powerful drives and the generously dimensioned flat guides, the HiTech 850 enables us to achieve consistently high quality for our parts,” added Steffen Hyss.

The family company is particularly proud of the fact that the machine park achieves a precision of up to 1/100 mm accuracy and a rejection rate that tends towards zero.


For two years now, the Hwacheon Hi-TECH 850L YMC has been in use at Hyss Metallverarbeitung every day without a significant failure to be reported, and the two older machines are also doing their job reliably. Gerhard and Steffen Hyss are so satisfied with the quality and precision of these machines that they have now bought another Hwacheon lathe into operation with the smaller Hi-TECH 450C. In addition, they are considering investing in a machining center from the same manufacturer. The growth of Hyss Metallerarbeitung, which specializes in large parts, is therefore not yet completed.