In ship main engines, one of the most important safety elements maintaining the delicate balance between the piston skirt and the cylinder liner is the friction bands, known as “rubbing bands.” These bands are sacrificial parts that, in the event of potential oil film thinning, prevent direct contact between the piston and liner, thereby eliminating the risk of “scuffing,” which could lead to hundreds of thousands of dollars in damage. At İntermak, we renew this critical protective shield for your engine in accordance with manufacturer standards and with the highest engineering precision.

• Assessment and Removal: The process begins with a detailed inspection of the pistons upon arrival at our workshop. The wear levels and condition of the existing rubbing bands are carefully assessed. Subsequently, the old and worn-out bronze or special alloy bands are meticulously removed using specialized equipment and methods designed for this task, without causing any damage to the piston skirt.
• Analysis and Component Inspection: After the old bands are removed, the band grooves on the piston skirt are thoroughly cleaned with special solvents. NDT (Non-Destructive Testing) procedures, specifically dye penetrant (PT) testing, are applied to detect any micro-cracks that may have formed in or around the groove surfaces during operation. Critical dimensions such as groove depth and width are checked with precision instruments to confirm compliance with manufacturer tolerances.
• Repair and Assembly: If any deformation or non-standard condition is detected in the band grooves, the necessary repair and machining operations are performed. Following this, the installation of new rubbing bands, made of the highest quality and correct material specifications, begins. The installation is typically carried out using the shrink-fitting method. After the new bands are fully seated and secured in their grooves, they are precisely turned on CNC-controlled lathes, concentric to the piston’s own axis, until they reach the final diameter and surface finish specified by the manufacturer.