Ball screw nuts accurate to the hundredth of a millimeter
In the manufacture of ball screw nuts, hundredths of a millimeter can mean the difference between a functional part and a reject. Achieving the correct tolerances between the thread and the guide system is one of the most challenging tasks in precision machining—and one that cannot be solved by compromising on either the tool or the machine. Manufacturers in this field require stability, repeatability, and a system they can trust even during unmanned operation.
That was precisely the reason we decided to invest in another MILLTURN machine from WFL—this time the M30-G, featuring full automation and a storage tower.
What makes ball screw nuts so challenging
A ball screw nut is not a mass-produced component—even though it is manufactured in large batches. The requirements for geometry and surface accuracy are high: outer contour, through-hole, thread cutting, pocket milling, deburring, deflection system, holes for connections and lubrication ports—all of this in a single process across multiple bearings, with tolerances of ± one-hundredth of a millimeter.
Materials such as 100CrMo7 for standard applications or 1.4112 stainless steel for the food industry place additional demands on cutting parameters and process stability. Any errors that creep in cannot be corrected later—they lead directly to scrap..
Why the decision was made to choose WFL again
We have been operating a WFL M40 MILLTURN since 2021—and the experience we’ve gained over the years has been a major factor in our decision to choose the M30-G. Complex thread profiles, tight tolerances, and stable processes—even for tools that didn’t run reliably on other machines.
Added to this was a structural advantage: machinery and automation from a single source. A single point of contact, an integrated system, and clearly defined areas of responsibility. This not only reduces the effort required for integration but also minimizes risks during ongoing operations.
Photo: Joshua Rzepka; WFL M30 with automation
Automation that makes even single-unit production runs cost-effective
We primarily manufacture batch sizes ranging from ten to 15 ball screw nuts—a scale at which automation is traditionally considered uneconomical. The M30-G proves that this doesn’t have to be the case.
Photo: Joshua Rzepka; Kardex Storage Tower
The integrated Kardex storage tower can hold up to 300 workpieces across 28 shelves. In combination with the articulated-arm robot, which removes parts and loads new raw material, the entire machining process—starting from a quantity of one—can be handled fully automatically. Up to 21 hours of autonomous production are not the exception, but the norm: started on a Friday evening, the system ran unattended until Saturday noon.
In terms of numbers, this means that out of 600 parts produced, six were rejected. A rate that speaks for itself.
What automation means for our workforce
Automation is changing the nature of work—but it isn’t replacing it. Thanks to reduced setup times, the operators who oversee the M30-G have gained capacity that they can now devote to other machines and processes. Planning, quality assurance, and process optimization—these are tasks that require specialized knowledge and are rarely compatible with manual single-part machining.
For us, automation does not primarily mean staff reductions, but rather stability: the ability to consistently deliver high quality despite limited human resources—while remaining an attractive employer.
A cycle that brings us particular joy
Here’s a little detail that really brings our partnership with WFL to life: the ball screws we manufacture are used in WFL machines—most recently in the M200 MILLTURN. These spindles are designed with a specially adapted pitch that allows for a larger ball screw profile, enabling them to handle higher axial loads while maintaining a compact footprint.
The machine on which our ball screw nuts are manufactured is itself driven by our ball screws. It’s a cycle that illustrates just how closely precision and partnership are intertwined in this business.
Results that speak for themselves
Six die components for 600 manufactured nuts, 21 hours of autonomous production, batch sizes starting at a single unit—all fully automated. By combining MILLTURN technology, sophisticated automation, and a partnership model that draws on the expertise of both sides, we have been able to take our manufacturing to a new level.
Photo: Joshua Rzepka; robotic gripper operating the WFL M30
