Case Study: Pallets and Conveyor Interactions

The Nelson Tech Center was recently called into a warehouse to review pallets and solve pallet problems in a flow rack system. 

Problem
The pallets were not flowing as intended within the rack system. Even worse, the pallets were actually damaging the rack system components. The system was rated to support much heavier weights, but something was causing higher than expected stress between the loaded pallets and the flow rack.

Flow rack system. Loaded Pallets from manufacturing are placed at the back and flow towards the front as unloaded. This is a common type of high density pallet storage system. In this system, the pallets are supported by the 3 rows of skate wheels.

Skate wheels were being damaged by the pallets.

Bolts that held some of the wheels were being bent by the loaded pallets.

On paper everything added up. We had a flow rack system that was strong enough to support the loads, and we had a heavy duty wood pallet that was strong enough to support the loads. But something was not working well together. 

Tech Center Evaluation
During our evaluation, we keyed in on one main area where these two components did not “match” - the middle of the rack.

The outside skate wheel rails were directly under the rigid pallet stringers (2x4’s). The outer skate wheels were not over stressed, and these rows were not damaged. The middle rail, however, was under deckboards only and between the rigid stringers. These deckboards were bending under load around the middle skate wheels. This resulted in the rack component damage and a system that did not flow as intended.

Tech Center Recommendations 
We suggested two recommendations to fix this issue:

• Use two center skate wheel rails, rather than one, so that the pallet is supported by wheels under each of the four stringers.
• Convert to a three stringer pallet with a middle stringer directly over the middle rail.
  
  

Since the rack system was already in place, the more economical solution was to change the pallet design to a three stringer design. We used wider stringers to maintain the previous durability levels, and the rack damage issues and flow issues went away.

Do you have damage to your rack system? Let us know the issue by commenting below. We can find you a solution! 

Post by: John Clarke, Technical Director