As processors increasingly work with potatoes sourced from more challenging growing conditions, FAM STUMABO introduces StoneExtractor to improve stone evacuation within the cutting head and reduce the operational impact of embedded stones. The solution delivered excellent results under real processing conditions at Kelly Ges.m.b.H., the market leader in Austria.
In potato chips processing, the presence of small stones and foreign materials remains a persistent operational challenge. Even after multiple washing and sorting stages, embedded stones can still reach the cutting process, often hidden within the potato and difficult to detect or remove.
While this risk was traditionally limited through sourcing strategies and favourable growing conditions, it is becoming increasingly difficult to control. Variable weather patterns, harvesting constraints, and supply pressures are pushing processors to work with potatoes grown in less ideal conditions, including rockier soils. As a result, the likelihood of stones entering the slicing stage continues to increase.
When small stones create high operational costs
Despite the use of advanced optical sorting systems and cleaning technologies, a small percentage of foreign materials inevitably reaches the cutting head. Once inside, even small stones can cause disproportionate damage.
The issue is not limited to the initial impact. Stones that are not immediately evacuated may continue moving inside the cutting head and strike multiple blades in succession. This causes cumulative damage, increases maintenance requirements, leads to unplanned downtime, and can affect slice consistency.
A recent project with a European potato chips producer highlighted this challenge under real processing conditions. Faced with sourcing constraints, the company began processing potatoes grown in rockier soils and experienced recurring problems linked to stones reaching the cutting stage. The result was repeated blade damage, increased maintenance frequency, and reduced production stability.
Closing a critical gap in cutting head design and performance
To address this issue, FAM STUMABO has introduced the StoneExtractor, a new development in centrifugal cutting technology specifically designed to improve the evacuation of small stones from the cutting head. Rather than focusing solely on impact resistance or detection, the StoneExtractor addresses a critical but often overlooked aspect of the process: preventing stones from remaining inside the cutting head after impact.
By enabling stones to exit the cutting area immediately, the system helps prevent repeated impacts across multiple blades and helps reduce cumulative damage.
The StoneExtractor is not a standalone machine, but an evolution of the cutting head segment design. It can be implemented by upgrading existing equipment with the new segment geometry, allowing processors to improve stone evacuation and cutting reliability without major modifications to their current setup.
From impact control to stone evacuation: a complete system approach
The StoneExtractor builds on FAM STUMABO’s ongoing development of cutting head technology and forms part of a broader, system-level approach to managing foreign materials during the slicing process.
This evolution can be defined through a complementary “3S” framework developed at FAM STUMABO — Shielding, Sensing, and Separation — with each function addressing a specific stage of the challenge. The StoneDefender provides shielding by absorbing and redirecting the impact of foreign objects toward less critical components; Scalibur™ adds sensing capabilities by detecting abnormal resistance and stopping the cutting process before severe damage can occur; and, completing this approach, the new StoneExtractor introduces separation by efficiently evacuating small stones from the cutting head.
Together, these three functions provide a more comprehensive response to foreign material ingress, helping processors reduce cumulative damage, improve equipment reliability, and maintain stable production conditions.
Designed for effective stone evacuation
At the core of the StoneExtractor is a redesigned segment geometry with deeper, wider grooves and optimized evacuation openings. This design improves the cutting head’s ability to guide stones out of the cutting zone at the moment of impact.
“The key advantage is that stones are removed at the point where the impact occurs. If they exit immediately, they cannot continue circulating and damaging other blades,” explains Jörg Plumanns, Industry Manager Potato Chips, FAM STUMABO.
Field experience confirms a clear change in stone behaviour inside the cutting head. Instead of causing repeated impacts across multiple blades, stones are more likely to make a single contact before being discharged, limiting overall damage.
Validated under industrial processing conditions
Trials conducted under industrial processing conditions demonstrated reduced cumulative blade damage, lower maintenance requirements, improved process stability, and more consistent slice quality. Together, these results contribute to a more predictable production environment, particularly when processing raw materials with higher contamination risks.
Kelly Ges.m.b.H is the market leader in Austria and a specialist in salty snacks, with a brand portfolio that includes Kelly’s, Soletti, funny-frisch, Chio, ültje and Tyrrells.
“As part of our long-standing collaboration in the potato chips segment, Kelly approached us after experiencing recurring operational issues linked to embedded stones reaching the cutting stage, particularly when processing potatoes sourced from more challenging raw material conditions and rockier soils,” explains Jörg Plumanns, Industry Manager Potato Chips, FAM STUMABO. “The result was repeated blade damage, increased maintenance requirements, and reduced production stability. Working closely with the customer under real processing conditions, we analysed the root cause of the issue and developed a solution focused on improving stone evacuation within the cutting head and limiting the operational impact of foreign materials.”
The outcome of implementing StoneExtractor was highly positive. As confirmed by Andreas Steinauer, Line Lead at Kelly Ges.m.b.H., “Since implementing StoneExtractor, we’ve seen a noticeable reduction in blade wear and unplanned stops. It gives us much more predictable performance, especially when processing potatoes under more challenging raw material conditions.”
Adapting to a new raw material reality
As variability in raw material quality continues to increase, processors face new challenges that cannot be fully addressed by upstream sorting alone. Solutions within the cutting process itself are becoming essential to maintain efficiency, product quality, and operational reliability.
With the StoneExtractor, FAM STUMABO expands its approach to managing embedded stones within the cutting process, helping processors maintain reliable slicing performance under increasingly demanding raw material conditions.
