FAQ

Yes, corrosion-resistant ball screws are available for use in humid, aggressive, or hygienic environments. Both the screw and the nut are made of stainless steel, often martensitic or austenitic steels. The balls are also manufactured from stainless steel or ceramic to further reduce corrosion. Additionally, special coatings and corrosion-resistant lubricants are used to increase the service life.

Yes, ball screw drives can generally be repaired, provided the wear or damage is not too severe. Typical repairs include replacing or reconditioning the nut, replacing the balls, readjusting or renewing the preload, and cleaning and relubricating. However, if the thread flanks are severely damaged or high accuracy is required, replacement is often more economical than repair.

Yes, corrosion-resistant ball screw drives made of stainless steel or ceramic can be used in the food industry and in medical technology. It is important that all materials, lubricants, and coatings meet the relevant hygiene and cleanliness requirements, such as FDA or EU standards. Such ball screw drives enable precise, low-wear motion, even in environments with moisture, cleaning processes, or chemical disinfectants.

A ball screw drive can be powered in various ways, depending on the installation situation, spindle length, and dynamic requirements. Often, the spindle itself is rotated by a motor, with the nut remaining stationary, thereby generating linear motion. Alternatively, the nut can be driven directly while the spindle remains fixed, which is particularly advantageous for long spindles or high dynamic demands. Further options include driving via belts, gears, or transmissions to flexibly transfer rotational motion or compensate for deflection angles. The choice of drive type influences the precision, speed, load capacity, and installation flexibility of the ball screw drive.

The bearing arrangement of a ball screw drive should be designed to reliably accommodate axial forces while simultaneously avoiding stresses. In practice, a fixed/floating bearing arrangement is typically employed. The fixed bearing accommodates axial forces in both directions and ensures high rigidity, while the floating bearing guides the spindle radially and compensates for thermal length changes. The bearings must be precisely aligned, preloaded without play, and sufficiently rigidly mounted in the housing to prevent runout, vibrations, and premature wear.

Ball screw drives can be lubricated with either oil or grease. The choice depends heavily on the application. Grease lubrication is used most frequently because it is easy to handle, offers good adhesion, and provides reliable lubrication even at low speeds. It is particularly suitable for standard applications, moderate speeds, and closed systems. Oil lubrication is preferred at high speeds, with high heat generation, or in highly dynamic applications, as oil dissipates friction and heat more effectively and thus enables more uniform lubrication. The key is to match the lubricant type and relubrication concept to speed, load, environment, and the manufacturer’s recommendations in order to achieve optimum service life and smooth running.

Compared to a sliding screw drive, a ball screw drive offers significantly higher efficiency, as the force is transmitted via rolling balls rather than sliding surfaces. This results in less friction, reduced wear, greater positioning accuracy and improved dynamics. Furthermore, ball screw drives can be preloaded with virtually no backlash and are particularly suitable for precise and rapid movements.
On the other hand, they involve higher purchase costs, greater sensitivity to dirt, and greater lubrication and maintenance requirements. Linear guide screws are more robust, cost-effective and, due to their low efficiency, can exhibit self-locking behaviour, which is an advantage in certain applications.

A ball screw drive offers several advantages over a trapezoidal thread: It operates very efficiently because force is transmitted via rolling balls, which keeps friction and wear low. Furthermore, it enables high positioning accuracy and low backlash. Disadvantages include higher acquisition costs, greater sensitivity to dirt and impacts, and a generally more complex design.

A ball screw with a driven nut offers several advantages: Since the screw is stationary and only the nut is moved by a motor, the moving mass is reduced, leading to higher dynamics, faster acceleration, and lower load capacity. This design also allows for the use of long or heavy screws, simplifies installation in cramped or complex machine layouts, and improves the positioning accuracy and precision of the drive through the direct drive of the nut.

The accuracy grades IT1, IT2, IT3, etc. in accordance with ISO 286 specify the manufacturing tolerances for the size, form and position of workpieces. The lower the number, the higher the precision. For thread drives, a distinction is made between lead accuracy, which indicates how precisely the linear feed movement per spindle revolution is, and form and positional tolerances, which define the geometric form of the thread as well as the relative position of spindle and nut. While the IT grades define the manufacturing tolerances, lead and form/positional tolerances influence the functional precision, smooth running and backlash of the thread drive.

The efficiency of trapezoidal screw drives typically ranges from 20 to 40%, as power is transmitted via sliding surfaces. In contrast, ball screw drives achieve efficiencies of 90 to 95%, as power is transmitted via rolling balls. This makes ball screw drives particularly suitable for fast and precise movements, while trapezoidal screw drives are more robust but less efficient.

In a ball screw drive, the ball recirculation system is the mechanism that returns the balls to the end of the screw or nut, allowing them to move continuously in a circle without falling out of the nut. This can be achieved either via a closed tube or through deflectors within the nut. The return system ensures that the ball screw drive operates with minimal wear, provides high running smoothness, and enables precise movements.

A driven nut is a threaded nut that is rotated directly by a motor or drive while the spindle remains stationary. This creates the linear motion of the screw drive without the spindle rotating. It is mainly used in mechanical engineering, robotics, or machine tools, especially when long spindles or precise positioning are required. Advantages include lower inertia, higher dynamics and faster acceleration, as well as easier handling of heavily loaded or long spindles.

A high-lead thread is a thread with a particularly large lead, meaning a significant distance between the thread turns. This allows it to transmit axial movements more quickly, as more advancement is achieved with each revolution. However, high-lead threads have lower load capacity and higher wear compared to standard threads, but they are well suited for rapid adjustments and linear movements.

The difference between axial and radial recirculation in ball screws lies in the direction in which the balls are returned within the nut. In axial recirculation, the balls are redirected along the screw axis and return parallel to it, allowing for a compact design and high running smoothness. In radial recirculation, the balls are guided outwards across the screw axis and returned radially, which allows for a robust construction but typically requires more installation space and can cause higher recirculation noise.

The optimal relubrication cycle for a ball screw drive depends on operating conditions, load, speed, environment, and the lubricant used. For lightly loaded applications, lubrication can be performed at longer intervals, whereas for high speeds, heavy loads, or aggressive environments, shorter intervals are required. Automatic or central lubrication systems are particularly advantageous for dynamic or hard-to-reach ball screw drives, as they ensure a constant supply of lubricant. It is crucial to always adapt the relubrication cycle to the manufacturer’s specifications, grease type, and specific operating conditions.

When designing a ball screw drive (BSD), factors such as loads and forces, the required accuracy, speed and lead, service life, as well as the installation situation, lubrication, and environmental conditions must be taken into account. Only if these factors are coordinated will the BSD operate reliably and with a long service life.

Noise development in a ball screw drive depends on speed, pitch, preload, the recirculation system, lubrication, and the installation situation. At low speeds, ball screws generally run very quietly, usually producing only a steady running noise. As the speed increases, the rolling and deflection noises of the balls increase, causing a slight whirring or hissing sound, which is considered normal. At very high speeds, additional flow and resonance noises may occur. Grinding or pulsating noises, on the other hand, are unusual, as they indicate insufficient lubrication, wear, contamination or assembly errors.

When mounting a ball screw (KGT), it is crucial that the spindle and nut are aligned precisely to avoid lateral forces, tilting moments, or tension, which impair precision and service life. The preload must be set correctly so that the nut runs without backlash without unnecessarily increasing friction. Equally important are firm bearing, fastening, and lubrication to ensure the screw drive runs smoothly and wear is minimized. For vertically installed ball screws, the dead weight of the moving part must also be taken into account, if necessary, through safety nuts or additional holding devices. Thermal expansion, installation lengths, and space conditions should also be considered to ensure long-term functionality.

Different types of grease are used for the lubrication of ball screws and lead screws, depending on the application, environment, and load.
In general mechanical engineering, high-performance or multi-purpose lithium- or calcium-based greases are frequently used, as they withstand high loads, temperatures, and speeds. For corrosion-resistant or stainless steel ball screws, synthetic polyalphaolefin (PAO) or ester-based greases are suitable, often combined with anti-corrosion additives.
In food, pharmaceutical, or medical technology, only food-grade lubricants (FDA or NSF-H1 approved) may be used. Synthetic silicone- or ester-based greases are used here, which also withstand cleaning and disinfection processes without affecting the function of the thread drive.
The correct selection significantly influences the service life, smooth running, friction, and wear of the thread drive.

Kammerer Gewindetechnik employs turning, milling, rolling, and grinding for thread production.

Kammerer Gewindetechnik focuses on the production of ball screws and trapezoidal threads. Custom forms can also be implemented upon request.
The pitch depends on the thread type and size and can vary from very fine to coarse. These are also manufactured specifically according to customer requirements.

The optimal thread type varies depending on customer requirements. If you want to keep friction as low as possible, a ball screw drive is used, whereas if high self-locking is required, a sliding or trapezoidal thread is used.
We will be happy to advise you on selecting the thread drive!

If you experience any issues with your Kammerer thread drive, you can contact your regular contact person at our company or email qsba@kammerer-gewinde.com.