A ball screw assembly contains precision-ground or rolled raceways, recirculating balls, seals and accurately machined shaft ends. Even when the assembly has passed production inspection, unsuitable packaging, handling or storage can cause bending, corrosion, contamination or impact damage before installation.
Transportation protection becomes especially important for long ball screws because their weight and unsupported length make them more sensitive to bending and handling forces. Packaging should therefore be designed according to the screw diameter, total length, nut structure, shaft-end machining and shipping method.
Main Transportation Risks
Ball screw assemblies can be affected by several conditions during handling and international transportation:
- Bending caused by insufficient support under a long screw shaft;
- Impact damage to the screw raceway or machined shaft ends;
- Movement of the nut along the shaft during transportation;
- Moisture entering the package and causing corrosion;
- Dust, metal particles or packaging debris entering the nut;
- Damage to the nut flange, return components or seals;
- Excessive stacking pressure or contact between separate assemblies.
Packaging must control these risks without placing concentrated pressure directly on the precision raceway, ball-return components or finished shaft ends.
Protect the Screw Raceway Before Packing
Before packaging, the exposed screw surface should be clean and protected with a suitable rust-preventive material. The lubricant and rust protection must be compatible with the ball screw materials, seals and expected storage period.
The raceway should then be covered with clean protective material to reduce contact with moisture, dust and packaging debris. Materials that shed fibres or particles should not be placed directly against the precision surface or ball nut opening.
Where moisture exposure is a concern, the assembly can be enclosed in a sealed moisture-resistant layer. Suitable desiccant may be added for export shipments or extended storage, provided it does not directly contact the screw surface.
Secure the Ball Nut
The ball nut should not be allowed to move freely along the screw during transportation. Repeated uncontrolled movement can cause the nut to strike the machined shaft end or packaging structure.
The nut should be secured in a suitable position without applying damaging pressure to the flange, seals or return components. The fixing method must also prevent the nut from being rotated off the screw shaft.
Never remove a ball nut from the screw merely to reduce the package size. If separation is necessary, a suitable transfer sleeve must remain inside the nut to retain the recirculating balls in their correct positions.
Support Long Ball Screws at Multiple Positions
A long screw should not be supported only at its two ends. Its own weight can produce deflection during storage or transportation, while vehicle vibration can repeatedly load the unsupported centre section.
Support points should be distributed along the shaft according to its diameter and length. The supports should hold the assembly securely while avoiding concentrated contact with the precision raceway.
For wooden-case or frame packaging, the internal supports must be fixed so that they cannot shift during handling. Additional protection should be provided around the machined shaft ends, which can be damaged if the package is dropped or struck.
Prevent Parts from Contacting Each Other
When several ball screws are packed together, each assembly should be separated and restrained. Direct metal-to-metal contact can damage the raceways, nut flanges or machined ends during vibration.
Heavy components, support units or tools should not be placed loosely on top of a ball screw. Accessories should have their own fixed positions inside the package.
Labels can be used to identify the model, quantity, shaft-end orientation and package handling requirements. This is particularly useful when one shipment contains several similar ball screws with different machining dimensions.
Handling During Loading and Unloading
Long ball screw packages should be lifted at suitable supporting positions rather than pulled from one end. Lifting a long assembly from a single point can allow it to bend under its own weight.
The ball nut, return tube, seals and machined shaft ends should never be used as lifting points. For heavy or long assemblies, appropriate lifting equipment and more than one support position may be required.
Packages should remain horizontal unless a different orientation has been specifically designed and marked. They should also be secured inside the transport vehicle or container to prevent sliding and collision.
Inspection After Delivery
The package and ball screw should be checked after arrival, particularly after long-distance or international transportation. The receiving inspection can include:
- Damage, deformation or moisture on the outer package;
- Movement or failure of the internal supports;
- Rust, scratches or impact marks on exposed surfaces;
- Damage to the nut seals, flange or return components;
- Damage to threads, bearing seats or other machined ends;
- Abnormal resistance when the nut is moved carefully along the screw.
If the package has suffered a strong impact or the screw appears bent, the assembly should be inspected before installation. Forcing a damaged nut or screw to operate may cause further damage to the raceways and recirculating components.
Storage Before Installation
Ball screws should preferably remain in their original protective packaging until they are ready for installation. The storage area should be clean and dry, with protection from rain, condensation, corrosive chemicals and large temperature changes.
Long assemblies should be stored horizontally with suitable support along their length. They should not be leaned against a wall or left unsupported between widely spaced points.
Packages should not be stacked in a way that places excessive load on the screw or internal supports. If the storage period is extended, the condition of the packaging and rust protection should be checked periodically.
Before installation after long-term storage, inspect the raceway, nut, seals and lubrication condition. Any temporary rust-preventive coating should be handled according to the relevant product and lubricant requirements.
Packaging Should Match the Actual Assembly
A short standard ball screw and a long custom-machined assembly do not require the same packaging structure. Diameter, length, weight, nut quantity, machined-end geometry, shipment method and destination all affect the appropriate protection.
DLY supplies standard and customized ball screw assemblies with export packaging selected according to product length and order configuration.
Separate or replacement ball screw nuts also require suitable transfer sleeves and protective packaging to keep the internal balls in position.
Need a long or custom-machined ball screw shipped internationally?
Send DLY the screw diameter, lead, total length, nut type, shaft-end drawing, quantity and destination for product and packaging confirmation.
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