FEATURE MECHANICAL COMPONENTS


THE VALUE OF ENGINEERING-GR SMALL SUBSTITUTION COST A


In high-performance automation systems, even the smallest components can carry significant weight. So when shaft collars began causing


failures on the packaging machines at customer sites across Asia, a USA-based OEM turned to Ruland for answers – only to find the problem components were not as they seemed…


in axial applications. Ruland machines the face to within 0.05mm (0.002in) of perpendicularity to the bore and marks the working face with a groove to clearly indicate the correct orientation. “We precision face our shaft collars to TIR ±0.05mm (0.002in) for this reason,” says Chris Gumas, director of customer experience at Ruland. “While shaft collars are viewed as commodity-type components, this is a clear example of why they are not.” Without that level of precision, the substituted part simply couldn’t perform in a motion-critical role. Over time, as the actuator continued to contact the collar at an angle, it pushed the part out of position, eventually leading to failure.


Ruland offers a


diverse range of shaft collars to meet most applications


actuators deployed at customer sites across Asia. The machines began malfunctioning in the field – drifting out of alignment, requiring emergency servicing, and prompting panic from end users – so the OEM turned to Ruland for answers. But what they uncovered was a small substitution with major consequences.


F


A MISIDENTIFIED SHAFT COLLAR, A REAL-WORLD FAILURE The problem surfaced when shaft collars began ‘walking’ down the shaft during use, causing the actuator’s stroke to overshoot its intended limit. These collars weren’t used as hard stops, but rather as precise axial reference points. The moment the actuator reached the collar, it would reverse – meaning even small shifts in the collar position could throw the system out of spec. When the OEM reached out to Ruland, the support team immediately noticed something


or an OEM based in the US, shaft collars, believed to be from Ruland, began causing failures on packaging machines using linear


was off: the collars had no bore size or manufacturer stamp. Ruland includes both on every shaft collar it ships, precisely for situations like this – ensuring traceability in the event of a failure. These parts may have looked like Ruland collars, but they weren’t. Without part markings to confirm their origin, the Ruland team turned to the application details. It was there that the issue became clear.


DIAGNOSING THE PROBLEM Ruland engineers asked how the collars were being used and the customer explained their role in referencing the actuator stroke. In that type of setup, the face of the collar must be precisely perpendicular to the bore. Without that, the actuator meets the collar at an angle, creating uneven pressure on the shaft. That slight imbalance can cause the collar to move or ‘walk’ with each cycle of the actuator. That’s exactly what was happening. The off-brand collars lacked precision facing – a standard operation on all Ruland collars used


24 DESIGN SOLUTIONS NOVEMBER 2025


A $30,000 MISTAKE The customer conducted lab testing and quickly confirmed Ruland’s analysis. When they reproduced the application using the substituted collars, the failures occurred. When they used genuine Ruland collars, the system performed flawlessly. Unfortunately, however, the real damage had already been done. To identify and address the issue, the OEM had to fly engineers to multiple Asian customer sites on short notice – a scramble that racked up tens of thousands of dollars in travel, labour, and component replacement costs. In total, the event cost the company over $30,000 in direct expenses – all stemming from a decision to substitute a low-cost part. The source of the problem was traced back


to a distributor who had approached the OEM’s purchasing team with a lower-cost ‘equivalent’ to the Ruland collar. Without engineering review, the buyer approved the substitution. It wasn’t until field failures occurred that the true cost of the decision became apparent. The buyer was let go; the distributor was


blacklisted; and the company updated its internal processes to ensure that engineering must approve any part substitution going forward.


THE VALUE OF ENGINEERING-GRADE COMPONENTS The customer responded quickly and decisively – not just fixing the issue, but reevaluating how they manage component specifications. Ruland is now the exclusive specified supplier for shaft collars at the company, and the


Ruland shaft collar used as an axial reference to prevent overstroking the cylinder


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