The castor housing is redesigned so that only the worn rollers require replacement instead of exchanging the entire sliding‑door carriage section. The new construction, produced through additive manufacturing and combined with machined metal elements, separates the rollers so they function as individual plain‑bearing components. With compact dimensions of 40 × 50 × 70 mm and a weight of 110 g, the redesigned housing reduces costs to around 25% of the original solution. When only the rollers wear, the replacement cost drops to roughly 2% of the previous expense, delivering substantial annual savings.