Ballscrews convert rotary motion to linear motion. Balls are the anti-friction element between the ballscrew spindle and nut. Ballscrew dynamics and positioning accuracy primarily depend on the accuracy of production and the technical implementation of the stipulated tolerances.
Advantages of ballscrews over leadscrews
- No axial play
- High positioning accuracy
- Low heat generation
- High efficiency
- Very high traverse speeds
- Long lifetime
- No stick-slip effect
- Low-play single nut
- Anti-backlash pre-loaded single nut (4-point pre-loading)
- Anti-backlash, pre-loaded double nut
- Spring pre-loaded double nut
As pre-loading results in absence of play and increased stiffness of the ballscrew, but also significantly affects the service life and rolling characteristics, it should be applied “as little as possible but as much as required”. If you have any questions, please contact us for consultation.
On request, we can supply test reports regarding:
- Lead accuracy
- Dimensional tolerances
- Shape and positional tolerances
|Tolerance classes||IT 1||IT 3||IT 5||IT 7|
|Thread length||Tolerances( µm )|
|316 - 400||7||13||25||57|
|401 - 500||8||15||27||63|
|501 - 630||9||16||30||70|
|631 - 800||10||18||35||80|
|801 - 1000||11||21||40||90|
Materials for standard versions
Steel 1.1213 (Cf53) , ball track hardened to 60 +/-2 HRC
|Ballscrew nut:||Steel 1.3505 (100Cr6), hardened to 60 +/-2 HRC|
|Balls:||Steel 1.3505 (100Cr6), hardened to 60 +/-2 HRC|
Materials for stainless versions
|Ballscrew spindle:||Steel 1.4112, ball track hardened to 56 +/-2 HRC|
|Mutter:||Steel 1.4034, hardened to 56 +/-2 HRC|
|Balls:||Steel 1.4034, hardened to 56 +/-2 HRC|
The rigidity can be increased and adjusted via pre-loading and the ball oversize. Please note that high pre-loading will have a negative effect on the lifetime.
The static rating describes the maximum possible static load on the ballscrew. Reaching or exceeding this value will result in lasting deformation of the ball or thread profile, which will result in irreparable damage.
This value should be used when designing a ballscrew. Karl Hipp GmbH recommends a maximum load of approx. 30% of the dynamic rating for continuous operation.
Guidelines for maximum speeds
Karl Hipp GmbH recommends a maximum load of approx. 30% of the dynamic rating for continuous operation.
Initial lubrication is done as standard with Staburags NBU12/300KP.
As a rule, a single lifelong lubrication is not sufficient for the ballscrew, as, despite the use of appropriate wipers, the ballscrew spindle continually removes grease.
Karl Hipp GmbH therefore explicitly recommends an appropriate maintenance interval, which should be adapted to the application. If manually relubricating the system, make sure that the ballscrew spindle is carefully cleaned. Further information can be found in our general lubricating instructions.
Several factors determine the selection of a lubricant. The most important ones are spindle speed, ball speed, operating temperature, and ballscrew load. Special lubricants for use in vacuums and clean rooms are also available. Please contact us if you have an questions.
When assembled, the nut should easily move at any position on the ballscrew. Possible misalignments and the resulting tension can be easily detected near the bearing or at the outermost end of the spindle. The ballscrew must be assembled with extreme care, as tension and misalignments will reduce the lifetime and may lead to premature breakdown.
Wipers made of POM plastic are used in normal applications. A special plastic made of PTFE may also be used if there are higher requirements for temperature stability.
Vulkollan wipers are set apart by very good dynamic characteristics and high wear-resistance. The edges of the wipers are very close to the ballscrew spindle, thus reducing the loss of lubricant. The frictional torque of the ballscrew will be increased. These wipers are not available for all dimensions.
If the ballscrew requires special protection from fine dust, we recommend using a felt wiper. Please note that the frictional torque of the ballscrew will be increased. These wipers are not available for all dimensions.
If an application does not use wipers, implement a regular lubrication interval or relubrication in accordance with our lubrication instructions.
To prevent the nut system from being contaminated, additional protective measures, such as a pair of bellows, may be necessary.