There is no universal minimum operating temperature for every ball screw or ball screw bearing system. The safe minimum temperature is determined by the complete assembly, including the ball nut, lubricant, seals, fixed-side and supported-side bearings, coupling, motor and surrounding machine structure.
In many standard industrial systems, the lubricant becomes the first practical limitation as temperature falls. Grease thickens, starting torque rises and lubricant distribution becomes slower. However, selecting a low-temperature grease does not automatically make the entire ball screw assembly suitable for the same temperature.
Contents
- What Does "Ball Screw Bearing" Mean?
- Why There Is No Single Minimum Temperature
- Why Lubrication Is Usually the First Check
- Other Components That Set the Temperature Limit
- What Happens to a Ball Screw at Low Temperature?
- Cold-Start Procedure and Verification
- Low-Temperature Selection Checklist
- What DLY Can Confirm
- FAQ
What Does "Ball Screw Bearing" Mean?
The phrase "ball screw bearing" is commonly used for different parts, so the component should be identified before discussing its temperature range.
| Component | Function | Low-temperature concern |
|---|---|---|
| Balls inside the ball nut | Roll between the screw and nut raceways | Lubricant viscosity, internal clearance or preload, and material contraction |
| Ball nut assembly | Converts screw rotation into linear movement | Grease, seals, return components and starting torque |
| Fixed-side support bearing | Locates the screw axially and supports thrust load | Bearing grease, seal material, preload and housing fit |
| Supported-side bearing | Supports the opposite end while allowing the intended axial arrangement | Lubricant, seal drag and allowance for thermal movement |
A complete low-temperature review must include both the rolling elements inside the ball nut and the bearings used in BK/BF, FK/FF, EK/EF or other support arrangements.
The minimum operating temperature must be confirmed for the complete ball screw assembly, not only for the screw shaft.
Why There Is No Single Minimum Temperature
A temperature printed on one component's datasheet does not automatically become the rating of the assembled axis. Each component may have a different permissible range.
The system minimum can be expressed as:
For example, suppose the mechanical steel parts remain usable at a low temperature, but the selected ball nut grease is only specified down to a higher temperature. The grease limit controls the system unless another approved lubricant is selected and the assembly is revalidated.
The following information is required before a minimum temperature can be confirmed:
- Lowest ambient temperature while the system is stopped.
- Lowest temperature at which the motor must start the axis.
- Continuous operating temperature after warm-up.
- Cooling rate and frequency of temperature cycling.
- Whether the system develops internal heat during operation.
- Load, speed, stroke, acceleration and duty cycle.
- Required positioning accuracy at the lowest temperature.
A machine stored at −30°C but started only after warming to −10°C has a different requirement from a machine that must start immediately and carry its full load at −30°C.
Why Lubrication Is Usually the First Check
As temperature falls, the base oil in grease becomes more viscous. The grease may resist movement and distribute more slowly through the ball circulation path. This can increase motor demand before the system reaches a stable operating condition.
Cold-start torque can rise sharply
The axis may require considerably more torque at startup than during normal warm operation. If the motor and drive were selected only from room-temperature running torque, the machine may stall, trigger an overload alarm or move unevenly during a cold start.
The grease temperature rating is not the only criterion
A lubricant datasheet may provide an operating-temperature range, but the lowest printed temperature does not guarantee acceptable starting torque in every ball screw. Grease type, fill quantity, screw size, nut preload, speed and motor torque all affect actual behaviour.
Do not mix lubricants without checking compatibility
Replacing standard grease with a low-temperature product requires confirmation of base-oil viscosity, thickener compatibility, load capacity, material compatibility and relubrication procedure. Mixing incompatible greases may cause separation, softening or hardening.
Excess grease can worsen cold-start resistance
Overfilling the ball nut or support bearing can create unnecessary churning resistance. At low temperature, this resistance becomes more noticeable. Lubricant quantity should follow the component or lubrication supplier's recommendation.
Other Components That Set the Temperature Limit
Changing only the ball nut grease is insufficient if another component has a higher minimum temperature.
| Component | What to verify | Possible low-temperature problem |
|---|---|---|
| Ball nut seals and wipers | Material and minimum temperature | Hardening, reduced sealing performance or increased drag |
| Support bearings | Bearing type, internal grease, seals and preload | High starting torque, altered preload or insufficient lubrication |
| Coupling | Elastomer or flexible-element temperature rating | Loss of flexibility, cracking or increased torsional stiffness |
| Motor and brake | Starting torque, encoder and brake specifications | Failure to release, insufficient torque or unstable feedback |
| Limit switches and cables | Cable jacket and sensor temperature ranges | Brittleness, signal problems or mechanical damage |
| Protective bellows | Fabric, polymer and fold performance | Cracking or resistance to movement |
What Happens to a Ball Screw at Low Temperature?
Dimensions contract
The screw shaft, nut, balls, bearing housings and machine frame contract as temperature decreases. When the components use similar materials and reach the same temperature uniformly, some dimensional changes may be similar. In real machines, however, different materials and temperature gradients can change alignment, fits and preload.
Screw length changes
For an approximate calculation, the thermal length change can be estimated as:
For steel, a typical engineering estimate for the coefficient of thermal expansion is approximately 11–12 × 10−6/°C. A 1,000mm steel screw cooled by 30°C contracts by approximately 0.35mm. The exact system error depends on reference temperature, mounting arrangement and compensation method.
Preload and clearance may change
It is not correct to state that low temperature always increases or always decreases preload. The result depends on the materials, dimensions, temperature distribution and nut structure. Any precision or preloaded assembly intended for a wide temperature range should be evaluated at its actual operating temperatures.
Condensation can occur during warm-up
When a cold machine is moved into warmer, humid air, condensation may form on the screw shaft, inside housings or near seals. Moisture can create corrosion and contaminate the lubricant. Controlled warming and environmental protection may be required.
Impact loading becomes more critical
A cold system with thick grease and reduced material flexibility should not immediately receive maximum acceleration or shock load. Even when the steel components remain within their permissible range, high startup resistance can increase stress on the nut, support bearings, coupling and motor.
Cold-Start Procedure and Verification
A controlled cold-start procedure helps determine whether the selected assembly operates smoothly at the required minimum temperature.
- Condition the complete assembly: Allow the screw, nut, supports and machine structure to reach the specified test temperature.
- Inspect before movement: Check seals, covers, visible grease condition, condensation and possible ice formation.
- Measure breakaway torque: Confirm the torque required to initiate movement rather than relying only on warm running torque.
- Start at reduced speed: Move through a controlled stroke without immediately applying maximum acceleration.
- Monitor motor current: Compare cold-start current with the drive and motor limits.
- Check the full stroke: Make sure resistance does not change abnormally along the travel.
- Repeat temperature cycles: One successful cold start does not demonstrate long-term reliability through repeated cooling and warming.
- Recheck accuracy: Measure positioning performance at the required operating temperature rather than only at room temperature.
Low-Temperature Selection Checklist
| Information | What to provide |
|---|---|
| Temperature | Storage minimum, cold-start minimum, continuous operating range and maximum temperature |
| Ball screw | Diameter, lead, length, accuracy grade, nut type and preload or clearance requirement |
| Motion | Load, speed, acceleration, stroke, cycle frequency and installation direction |
| Lubrication | Required grease or oil, temperature range, fill quantity and relubrication method |
| Supports | BK/BF, FK/FF, EK/EF or drawing-based bearing arrangement |
| Environment | Humidity, condensation, frost, washdown, dust, vacuum or chemical exposure |
| Verification | Cold-start torque, motor-current limit, positioning accuracy and required temperature-cycle test |
What DLY Can Confirm
DLY supplies rolled and ground ball screws with matched ball nuts. Common accuracy options include rolled C7 and C10 and ground C5, C3 or C0 according to the required specification. The ball screw shaft material is S55C, and the ball nut material is 20CrMo.
Available manufacturing support includes:
- Diameter, lead, nut type and accuracy-grade confirmation.
- Custom total length up to 6 metres where manufacturing and transportation conditions permit.
- BK/BF, FK/FF and EK/EF shaft-end machining.
- Drawing-based custom shaft-end machining.
- Ball screw and nut matching before shipment.
- Rust-preventive oil and export packaging.
View the DLY ball screw range, or review how temperature affects a rotating ball nut system.
FAQ
Can a standard ball screw operate at −20°C?
Possibly, but the temperature alone is insufficient to confirm suitability. The ball nut grease, support-bearing grease, seals, motor torque, load, speed and cold-start requirements must all be checked.
Does synthetic grease automatically allow operation at −40°C?
No. A lubricant may have a low published minimum temperature, but actual ball screw starting torque, load capacity, seal performance and support-bearing limits still require verification.
Should the motor be larger for low-temperature operation?
The motor and drive must provide sufficient cold-start torque without exceeding component load limits. Do not simply increase motor size before measuring breakaway torque and identifying the source of resistance.
Can a ball screw be preheated before starting?
Controlled preheating may be used in some machines, but the heating method must avoid uneven thermal expansion, lubricant damage and local overheating. The warm-up procedure should be part of the machine design.
What is the difference between storage and operating temperature?
Storage temperature applies while the system is stationary. Operating temperature applies while it must start, move and carry load. A component may survive storage at a temperature where it cannot start reliably.
Contact DLY
Send us the minimum storage and startup temperatures, ball screw size, load, speed, stroke, accuracy, lubricant requirement and shaft-end drawing for technical confirmation.
Email: dlyexport2@dlybearing.com | WhatsApp: +86 166 0578 8856
