GROB 5-axis technology: a detailed look at the horizontal spindle and the tunnel concept

5-axis machining has been a significant step forward for the metalworking industry, enabling highly complex components to be produced in a single operation.

However, not all 5-axis technology is the same. The pursuit of unique machine concepts that optimise every aspect of the machining process is essential to reach high manufacturing standards. This is where GROB engineering makes the difference, developing designs that solve technical challenges in innovative ways.

These 5-axis machining centres are a feat of engineering designed to deliver outstanding productivity and accuracy, thanks to an intelligent and distinctive design.

A detailed look at GROB's unique machine concept

The high efficiency of GROB machining centres lies in a set of design features that work in harmony to improve every stage of machining.

• Horizontal spindle position. Unlike many conventional configurations, the GROB design positions the spindle horizontally. This arrangement offers a twofold advantage:
  
  — It provides a considerably longer Z-axis travel, making it easier to machine deep parts.
  
  — It optimises swarf fall by gravity. Free, constant swarf evacuation prevents build-up on the part and the tool, avoiding overheating and premature wear. This contributes directly to greater efficiency, longer tool life and a higher-quality surface finish.

• Maximum stability. The machine architecture is designed to minimise the distance between the guideways and the tool tip. This approach, which keeps the lever effect during cutting to a minimum, gives the whole machine superior stability. The result is reduced vibration, allowing the machine to operate at higher speeds and accelerations while always maintaining first-class accuracy and repeatability, even in the most demanding operations.

• Tunnel concept. This design feature, patented by GROB, is an ingenious solution for maximising the working area. The tunnel concept makes it possible to machine 100% of the machinable area for any part size, even when using very long tools. The part can swivel and rotate through the "tunnel" without losing travel or risking collisions. This greatly increases the machine's versatility and ensures full use of the working space.

• Wide swivel range. The kinematics of GROB machining centres, with three linear and two rotary axes, allow not only 5-sided machining but also simultaneous 5-axis interpolation. This is achieved with an impressive swivel range of 230 degrees in the A axis and 360 degrees in the B axis. This range of movement significantly improves process versatility, allowing the most complex geometries to be machined efficiently without repositioning the part.

Technical relevance in specific models

These design concepts are applied across the entire range, from the most compact models to the largest.

• The Grob G150, ideal for high-precision parts, benefits directly from this engineering. With X/Y/Z travels of 450/670/665 mm and rapid traverses of 50/40/60 m/min, its stable design achieves a positioning accuracy of 0.006 mm. Its agility is shown by a chip-to-chip tool change time of just 2.6 seconds, minimising idle time.
• At the other end of the range, the Grob G750 shows how these technologies scale up for large parts. Its travels of 1,000/1,100/1,170 mm and its interference diameter of 1,280 mm are made possible by the tunnel concept. Despite its size, it maintains the same positioning accuracy of 0.006 mm and a high working speed, with rapid traverses of up to 75 m/min.

Applications in high-demand industries

Thanks to this advanced technology, GROB machining centres are highly valued in industries with strict quality and productivity requirements. In aerospace, stability and the tunnel concept are ideal for structural parts. In the medical sector, accuracy is paramount. In automotive, speed and cycle efficiency are key. Other industries such as renewable energy, mould and die and engineering and contract manufacturing services also benefit from their versatility and high performance.

Ferrotall's added value

Acquiring a machine of this calibre is an important decision. That is why Ferrotall offers complete solutions for the machining sector. This support includes technical support available 24 hours a day, 7 days a week, to ensure continuity of our customers' production. In addition, Ferrotall provides machining centre programming training, so that our customers' teams can master and make the most of the capabilities of their new machinery.

Choosing a GROB 5-axis machining centre is a smart investment in production capacity. Understanding its distinctive technical features, such as the horizontal spindle and the tunnel concept, shows why these machines offer superior efficiency, accuracy and use of space. With the backing and training provided by Ferrotall, metalworking companies can integrate this advanced technology with complete confidence that it will perform optimally.