About Any Ball Transfer
Factors to consider when determining live loading of any manufacturers ball transfers. More important than ball transfer capacity is the ability of the bottom surface of an item to withstand the point loading of the balls. Is the bottom of the item to be moved…
- Hard? Ball transfers are likely to indent soft bottoms and item will act as a brake
- Smooth? Rough bottoms are hard to move and may damage item and ball transfers.
- Flat with no protrusions? Protrusions interfere with movement and may damage ball transfers.
- Non Flexible? Ball transfers will bend bottoms, item will droop and sag between balls. It is difficult at best to move items.
- Conveyable? Ball transfer point loading may break down bottom surface. Constant use recirculating pallets need special consideration.
- Dry, No Water? Water rusts ball transfers. Rust is grit and will destroy ball transfers.
- Clean no dirt, grit or oil? Particulates accumulate, eventually jamming and wearing out bearings. Oils act as a magnet for dust and grit.
- Solid with no holes or voids? Ball transfers under holes or voids will not carry their share of the load. Generic spring loaded ball transfers and Omtec Pop Up Ball Transfers will raise into holes or voids, acting as detents.
- Sub Surface Voids? Ball transfers will break through the false bottom. Same problems as e) & h). Plywood pallets should be specified plugged, sanded, “no sub surface voids.”
- Paint or surface finish? Will metal ball transfers scuff, mar or otherwise ruin the finish? If a concern, plastic balls need to be considered.
- Foot Print (bottom size) and weight? Needed to calculate the most efficient density of ball pattern and path on the work surface or converyor
- Is weight evenly distributed? Uneven distribution will cause item to tilt between ball transfers.
About point loading a major factor in most of the above.
The contact point between the spherical ball and item is very small and subjects the item to an extremely high concentrated point loading.
Example: 50 lb. (22.68kg) item on one ball transfer, Generously say the contact point area was 0.032 inch (0.812mm) diameter. The point load between the ball transfer and item would be 58,100 lbs (26354kg) per sq/in (25.4mm2).
Don’t confuse ball transfer capacity with more important point load capability of the item bottom. A 50 lb. capacity ball transfer is overkill and not a factor if the point load capability of the vast majority of items fall in the range of 5 to 30 lbs. The solution is not higher capacity ball transfers, it is more ball transfers to reduce item point loading!
A heavy item in a corrugated carton is likely to indent and flex, depending on the quality of cardboard, would suggest a live loading of 5 to 10 lbs. (2.27 kg to 4.54 kg) per ball transfer.
The same item on a smooth, hard, solid, flat, non-flexible quality plastic tray would indicate a reasonable live loading of 15 Lbs. (6.8 kg) or less per ball transfer, for successful, minimum effort, movement.
The same item on a smooth, hard, solid, flat and non-flexible steel tray would indicate a reasonable live loading of 30 lbs. (13.61 kg) or less per ball transfer, for successful, minimum effort, movement. Aluminum 15-20 lbs. (6.8 – 9.07 kg)
Experience indicates that the most successful live load rates of ball transfers, falls between 5 to 30 lbs. (2.27 to 13.61 kg) per ball transfer, when all of these factors are considered.