Milling hard steel (500 HB)

Steel with a Brinell hardness of 500 is tough in every aspect, including in regards to its machinability VST Verschleißtechnik conquers this challenge by using conventional gantry-type milling machines from KNUTH.

Steel with a Brinell hardness of 500 is tough in every aspect, including in regards to its machinability VST Verschleißtechnik conquers this challenge by using conventional gantry-type milling machine...

read more

Specialist for custom solutions

For three generations Josef Schulte’s family has been in the steel machining business. Since 1985 the business shifted its focus increasingly to the production of custom wear plates for the recycling industry. “Our customers are mainly scrap metal processors, shredders or general recycling operations, and increasingly wood processing operations that want to convert their waste to energy, or also agricultural operations with focus on soil cultivation,” explained Josef Schulte. Today, Josef Schulte runs VST Verschleißtechnik together with his business partner, Johannes Stiens.

Stability – a fundamental success factor

With 30 employees at its headquarters in Warburg, Germany, the company processes 1000 tons of materials per year for their customers. Their main customer base is in Germany, only about 20 % of their orders come from neighboring European countries. “We serve a wide variety of customers, from machine manufacturers all the way to end users such as stone quarries,” said Schulte. “Our customers appreciate our speedy response. And if needed, we also will deliver overnight.” However, the major criterium in wear protection technology is stability and high-precision machining of the protective shields. “Our shields are supposed to protect machinery and equipment as long as possible in an extremely rough environment during shredding of metals, electronics, wood, tires, or glass,” explained Schulte. In order to offer his customers the best possible solutions and most suitable materials, Schulte familiarizes himself in depth with their processes. 

Portamill Duo, Conventional Gantry-Type Milling Machine
Portamill Duo, Conventional Gantry-Type Milling Machine
Even materials with 500 Brinell hardness are no challenge for the Portamill Duo. This gantry-type milling machine handles any wear bar with superior power and precision.
Even materials with 500 Brinell hardness are no challenge for the Portamill Duo. This gantry-type milling machine handles any wear bar with superior power and precision.

Conventional vs. CNC

Demands are becoming increasingly exacting. Materials are constantly advancing and become increasingly harder. For VST Verschleißtechnik that means a constant flow of new challenges. “Our customers expect to receive the newest materials with the highest durability from us, and we must constantly work on maintaining our capacity to machine these extremely hard materials,” said Schulte. The most widely used steel is Hardox 500 from Sweden. These steel plates have a Brinell hardness of 500 and must be machined to a precisely fitting final shape by flame cutting, milling, drilling and countersinking. For this purpose, the company utilizes almost exclusively premium CNC machines. But there are wear bars that require circumferential adaptations, and for those requirements Schulte relies on conventional milling machines. “A CNC machine’s automatic, rotating milling cutter heads would wear out quickly, if exposed to this extremely hard material,” said Schulte.

Power meets Precision

In 2016, Schulte was looking for a replacement for their old milling machine and turned to KNUTH Machine Tools in Wasbek, Germany. KNUTH project manager, Andreas Hendrich, remembers: “After careful examination of all their criteria, we recommended our Portamill Duo 4012 as an ideal solution to Mr. Schulte.” This gantry-type milling machine provides high machining power and X-axis feed rates up to 2.620 mm/min. Machine bed, columns, and traverse form a solid cast-iron frame structure that is firmly integrated into the machine base. This especially rigid construction ensures the Portamill Duo’s utmost stability even during extreme machining loads. In addition, it features two driven cutter heads (horizontal and vertical).

Andreas Hendrich (center) of the KNUTH Sales Team arranged a visit at the site of a reference customer to convince Josef Schulte (right) of the power this gantry-type milling machine has to offer. Josef Schulte runs VST Verschleißtechnik together with his business partner, Johannes Stiens.
Andreas Hendrich (center) of the KNUTH Sales Team arranged a visit at the site of a reference customer to convince Josef Schulte (right) of the power this gantry-type milling machine has to offer. Josef Schulte runs VST Verschleißtechnik together with his business partner, Johannes Stiens.

Convincing Milling Performance

Schulte was interested, but still had some doubts, if the Portamill Duo could reliably handle material with a Brinell hardness of 500. “KNUTH was straightforward, and took us to a close-by reference customer, where we could try out a smaller, but equally powerful machine using our own materials and tools,” Schulte said. “And after that we were convinced.” Andreas Hendrich also joined them during their test: “The hard material was no problem for the machine, the chips were just flying off the bars.” The Portamill Duo was adapted slightly for the specialized requirements at VST. Now, the cutter heads can be rotated both horizontally and vertically at an angle of 45 degrees in both directions. Adjustments are made via a handwheel-operated worm gear and controlled on a 1-degree scale. “In addition to the standard position indicator, we also added a digital position indicator for the horizontal cutter head,” stated Hendrich. Subsequently, the machine was transported via special carrier to Warburg, where it was set up and put into operation by a KNUTH technician. Now the Portamill Duo has been milling extremely hard steel materials for VST since the end of 2016, and today it is fully utilized in a two-shift operation. Josef Schulte is very satisfied with his purchase: “The machine meets all our requirements and expectations.”

Portamill Duo 3012 - Moving table design, tilting milling head and horizontal milling head for large workpieces

Portamill Duo 3012

Moving table design, tilting milling head and horizontal milling head for large workpieces

  • Rigid structure with firmly integrated gantry
  • Vertical and horizontal spindle head
  • Setup table is supported across the entire travel distance
  • Hydrostatic table guide
  • For workpiece weights up to 6,000 kg (13,228 lbs)
View Machine