Ball Screws with internal circulation – compact & precise
When installation space is limited and the highest precision is required, Ball Screws with internal circulation are the ideal choice for you. Thanks to the integrated ball return system within the nut body, an external return tube is no longer needed. The result is an especially compact design combined with high smoothness of operation and reliability.
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Accuracy classes C5–C1
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DN limit value 70,000
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Compact – no external return tubes
What are Ball Screws with internal circulation?
In internal circulation, each ball track is guided individually. After passing through the load-carrying thread grooves, the balls exit the raceway via a guide plate integrated into the nut. From there, they are redirected through a parabolic return channel into the next load-carrying groove.
This patented five-stage parabolic geometry ensures an especially smooth transition. The balls are redirected without abrupt changes in direction, which increases smoothness of operation and minimizes noise – even at high rotational speeds or during frequent reversing movements.
Your benefits at a glance
Compact design
Thanks to the integrated deflection plate within the nut body, external return tubes or end caps are not required. This makes the nut especially slim and ideal for applications with limited installation space.
High smoothness
The five-fold parabolic geometry of the deflection plate ensures a smooth transition of the balls without abrupt changes in direction. This minimizes noise and vibration.
Maximum precision
The independent return of each ball track minimizes axial play. In combination with a preloaded design (zero axial play), accuracy classes up to C1 can be achieved.
Typical applications
In milling, turning, and machining centers, double-nut designs (FDIG, DDIG) are frequently used. Preloading completely eliminates axial play, ensuring high positioning accuracy and repeatability under changing load directions.
In this field, precision is a matter of safety. A surgical robot must position instruments with micrometer-level accuracy. Extremely high positioning precision is also required in tumor radiation therapy.
During wafer exposure, the highest positioning accuracy is required to create structures in the nanometer range. C1 accuracy classes and extremely smooth motion are essential in this application.
In this application, precision is measured directly. Even the smallest inaccuracies in the drive system can distort measurement results. Repeatability is typically in the micrometer or sub-micrometer range. The drive must therefore be extremely low-friction and backlash-free.
Grinding and polishing machines for optical components require drives with the highest path accuracy, as even the smallest micrometer-level errors can affect optical quality.
Type overview
FEIG – Single flange nut with internal circulation
The FEIG series is the most compact solution for flange-mounted applications. It is ideally suited for small to medium loads where installation space is limited.
Nominal-Ø (mm)
Lead (mm)
Dynamic load rating (kN)
Static load rating (kN)
Rigidity K (N/µm)
Nominal-Ø (mm)
Lead (mm)
Dynamic load rating (kN)
Static load rating (kN)
Rigidity K (N/µm)
FDIG – Double flange nut with internal circulation
The FDIG series consists of two separate nuts that are preloaded against each other. This completely eliminates axial play. It is ideal for applications with the highest precision requirements and changing load directions.
Nominal-Ø (mm)
Lead (mm)
Dynamic load rating (kN)
Static load rating (kN)
Rigidity K (N/µm)
Nominal-Ø (mm)
Lead (mm)
Dynamic load rating (kN)
Static load rating (kN)
Rigidity K (N/µm)
DEIG – Cylindrical single nut with internal circulation
The DEIG series doesn't feature a flange and is designed as a cylindrical nut. It is pressed into a housing or nut carrier or secured using retaining rings. This design saves axial installation space and offers maximum flexibility for integration.
Nominal-Ø (mm)
Lead (mm)
Dynamic load rating (kN)
Static load rating (kN)
Rigidity K (N/µm)
Nominal-Ø (mm)
Lead (mm)
Dynamic load rating (kN)
Static load rating (kN)
Rigidity K (N/µm)
DDEG – Cylindrical double nut with internal circulation
The DDIG series combines the advantages of the cylindrical design with the preload of a double nut. It consists of two cylindrical nuts that are preloaded against each other and feature a spacer or clamping washer. Compared to a standard cylindrical nut, this design therefore offers reduced axial compliance and lower backlash.
Nominal-Ø (mm)
Lead (mm)
Dynamic load rating (kN)
Static load rating (kN)
Rigidity K (N/µm)
Nominal-Ø (mm)
Lead (mm)
Dynamic load rating (kN)
Static load rating (kN)
Rigidity K (N/µm)
Design and maintenance guidelines
Design and maintenance guidelines
Materials
Our Ball Screws are manufactured from high-quality case-hardening materials. The screw shafts are made of quenched and tempered steel (according to DIN 17006: 50CrMo4 or Cf53), while the nuts are made of bearing steel (GCr15, GCr15SiMn, or 20CrMo). A precise heat treatment process ensures a consistently high hardness of the raceways of 60 ± 2 HRC.
For special requirements, e.g. in the food or medical technology sectors, stainless steel versions are also available on request.
Installation and design guidelines
To ensure optimal performance and a long service life, please observe the following points during design and installation:
- Screw end: Design the screw end so that at least one end features a full thread. The outer diameter of this end must be at least 0.2 mm smaller than the root diameter of the thread to allow mounting of the nut.
- Alignment: The screw axis must be aligned precisely parallel to the guide rails.
- Mounting position: During assembly, the nut should be positioned as close as possible to the bearing. For long-term storage, we recommend hanging the screw vertically to prevent bending due to its own weight.
- Ambient temperature: The permissible operating range is –20 °C to +80 °C.
Lubrication
Proper lubrication is critical for the performance and service life of your Ball Screw.
- Lubricant selection: The choice between oil and grease lubrication depends on speed, ambient temperature, and load. Please ensure that different lubricant types (especially greases) are not mixed.
- Grease quantity: As a guideline, fill approximately one-third of the free internal volume of the nut with grease.
- Oil quantity (guideline values): The table below shows the recommended oil quantities depending on the screw diameter. The relubrication interval is approximately 3 minutes during operation.