Machined Stainless Steel Rail Profiles for the Dairy Industry
Dairy machinery operates in a permanently wet environment with aggressive cleaning agents, making stainless steel the mandatory material choice for structural and functional components. A manufacturer of dairy processing machinery needed a stainless steel rail guide profile that would be easy to clean and maintain, with a special cross-section geometry featuring half-round machined grooves to Ra 1.2 µm maximum roughness. The initial specification pointed toward hot rolling, but given the required quantities and the tightness of the roughness tolerance inside the grooves, Montanstahl proposed milling as a more cost-effective and technically appropriate production route. The solution delivered a prototype followed by a batch of over 700 kg, with dimensional and roughness checks performed by the customer at Montanstahl’s production plant, and delivery completed ahead of schedule.
Why Hot Rolling Could Not Meet the Groove Roughness Requirement
The rail guide cross-section included two half-round grooves with a radius of R5 ±0.1 mm and a surface roughness inside the grooves not exceeding Ra 1.2 µm. Hot rolling produces dimensional accuracy in the overall cross-section but cannot control the surface roughness inside a groove to this level: the rolled surface in a concave feature carries the texture of the roll surface, which does not reach the Ra 1.2 µm threshold without post-rolling machining. For the required batch size of just over 700 kg, a combined hot rolling and finishing operation would have been more expensive than direct milling from flat bar. Milling also gave Montanstahl control over the groove geometry and roughness in a single production sequence, without the die and setup cost of a rolling campaign for a non-standard section.
Multi-Step Milling, Customer QA at the Plant, Delivery Ahead of Schedule
The profiles were produced by milling in multiple steps to achieve the specified groove geometry and bring the roughness inside the machined slots within the Ra 1.2 µm tolerance. The multi-step approach allowed progressive stock removal and surface refinement without the thermal distortion that aggressive single-pass milling can introduce in thin sections. Before the full batch was released for shipment, the customer performed dimensional and roughness checks directly at Montanstahl’s production plant, verifying compliance against the specification on site. The complete batch was packed in wooden boxes and wrapped in bubble wrap to protect the machined surfaces during transport, and delivery was completed ahead of the agreed schedule.
Application Context
This project sits within Montanstahl’s Food & Beverage segment, where machined and special stainless steel profiles are produced for dairy machinery, food processing equipment, and hygienic structural applications where surface roughness, cleanability, and corrosion resistance are all part of the functional specification. The dairy and food processing sectors regularly require section geometries that combine a structural profile with precision machined surfaces, a combination that cannot be achieved by rolling alone at small batch quantities. Montanstahl’s machining capability covers this need from prototype to small and medium production batches, with customer inspection available at the production facility before dispatch.