Efficiency through the right manufacturing process
Flange screws are a structurally unassuming component—and yet the choice of manufacturing process has a decisive impact on load-bearing capacity, surface finish, and cost-effectiveness. The cold rolling process has proven to be superior in this regard: it improves the mechanical properties of the thread, increases fatigue strength, and is material-efficient. The development of a cold-rolled flanged spindle Tr 16 × 2 demonstrates that this process is also feasible for demanding specialty materials such as duplex steel 1.4462—a manufacturing example that redefines the boundaries of what is possible.
What Makes a Bund Spindle Unique
flanged lead screw is a threaded screw with an integrated flange—a ring-shaped shoulder that directly absorbs axial forces and secures the screw in its installed position. This design feature makes it the preferred solution in many linear drives when installation space is limited or when bearing assemblies need to be eliminated.
The Tr 16 × 2 trapezoidal thread is a classic thread size for applications involving moderate loads and a defined lead—precise enough for positioning tasks and robust enough for continuous operation under load.
Central spindle with rolled thread
Rolling Instead of Machining: The Key Benefits
The cold rolling process creates a thread not by removing material, but through controlled plastic deformation. This results in advantages that cannot be achieved through grinding or whirling:
- Fiber orientation: The fiber orientation of the material is preserved during rolling and follows the thread contour. This significantly increases the fatigue strength of the thread compared to thread profiles produced by machining. This significantly increases the fatigue strength of the thread compared to thread profiles produced by machining.
- Surface compaction: The edges are compacted during the rolling process—the resulting surface is smoother and more wear-resistant.
- Material usage: Since no chips are produced, the raw material is used more efficiently.
- Reproducibility: Once the rolling parameters are set, they ensure consistently high thread quality across large production runs.
For a flanged spindle that combines both a thread and a precise flange, the rolling process is therefore not only cost-effective but also the technically superior choice.
The Challenge: Duplex Steel as a Material
It is standard practice to roll drive spindles from standard steels. The challenge becomes greater when the material must meet specific requirements. In this case, the material specified was 1.4462—a duplex stainless steel (X2CrNiMoN22-5-3). The reason: The spindle is designed for use in a corrosive environment where standard stainless steels are not sufficiently resistant. 1.4462 offers the necessary properties for this—excellent corrosion resistance, high strength, and resistance to stress corrosion cracking.
However, this material is known for being difficult to form. This becomes particularly evident during rolling: the rolling force of conventional rolling mills was insufficient to shape the material into the thread profile in a controlled manner. The flow behavior of duplex steel resists the standard rolling process.
Rolling process using a collar spindle as an example
The solution: Process adaptation instead of changing the method
Switching to machining would have been the obvious solution—but that would have meant giving up the advantages of the rolling process. Instead, we further refined the rolling process itself: We developed a custom set of rollers with a special coating that specifically influences the flow behavior of the duplex steel, enabling the required forming to be achieved consistently even with this material.
In addition, the cutting parameters for turning and milling the flange contour were individually optimized for 1.4462—cutting speed, feed rate, and tool geometry were selected to ensure that tool life and dimensional accuracy remain consistent even when machining this tough material.
The result is a rolled Tr 16 x 2 spindle that meets the geometric tolerances and surface finish standards of a rolled product—in a material that previously allowed for this process only to a limited extent.
Conclusion: Process knowledge is essential
Switching to machining would have been the obvious solution—but that would have meant giving up the advantages of the rolling process. Instead, we further refined the rolling process itself: We developed a custom set of rollers with a special coating that specifically influences the flow behavior of the duplex steel, enabling the required forming to be achieved consistently even with this material.
In addition, the cutting parameters for turning and milling the flange contour were individually optimized for 1.4462—cutting speed, feed rate, and tool geometry were selected to ensure that tool life and dimensional accuracy remain consistent even when machining this tough material.
The result is a rolled Tr 16 × 2 spindle that meets the geometric tolerances and surface finish standards of a rolled product—in a material that previously allowed for this process only to a limited extent.
