How we redeveloped a key automation system in a 24/7 operation

At the end of 2016 my team was brought in to manage an engineering project at our Hatfield Customer Fulfilment Centre (CFC). Our CFCs are huge, automated warehouses where we pick and pack hundreds of thousands of customer orders every week.

We first started pilot deliveries from Hatfield CFC1 back in 2001, and today it completes around 165,000 orders per week! Given that our Hatfield CFC has now been fulfilling customer orders for over 16 years, it’s approaching the time in its lifecycle where innovative modifications and updates are needed to squeeze out additional capacity. This is where my team comes in: our aim is to manage either the complete enhancement or installation of mechanical handling equipment that improves the CFC’s output or makes it more efficient and reduces costs.

Our CFCs are split into several temperature zones, including ambient, chill and freezer; this ensures our products stay fresh. The project we were assigned to was the upgrade of the Pallet Infeed Point (or PiP) situated in the chill area.

The goal was to design a system that ensured the safe loading of pallets of goods onto cranes for transportation. This is an important factor within our warehouses, which must run smoothly to facilitate the safe and timely arrival of goods to the pick aisles where our personal shoppers will pick and pack customers’ orders. This project involved the redesign and replacement of the pallet infeed system, which was responsible for moving, weighing and checking the structural safety of approximately 800 pallets a day – this would be the equivalent of almost two million cans of baked beans being inputted into the system each day!

The existing PiP had been in operation for over 10 years, and was approaching the end of its serviceable life. This was made apparent by the increase in time fixing faults, when compared with newer systems within the CFC. As a result, the decision was made to replace the existing conveyor-based system and shuttle car with a newer system capable of providing multiple infeed points. This would mean that the incoming pallets could be placed into or onto the crane and pick aisles more efficiently and reliably.

All of our CFCs are 24/7 operations with little to no down time, therefore it was of huge importance that this project was split into three phases to minimise disruption to the operation. The first phase involved the provision of a new in- and outfeed for the pallet storage cranes; this provided us with the resiliency needed, whilst the later stages were being implemented.


In the second phase, we dealt with the removal of a shuttle car, which transferred pallets from the PiP to a crane. The final phase, which implies the wholesale replacement of the PiP conveyors themselves, is now nearing completion.

As phase one provided a combined in/outfeed, we could both infeed and remove pallets from the CFC while the replacement conveyor run was being installed. This was an essential part of the plan, as there could be no major disruption to the pallets being put into the system. The concept worked well, and the project was completed on schedule, with the minimum possible disruption to the operation.

The in/outfeed was put into action once again for phase three. This time it was used whilst the main pallet conveyors of the chill PiP were removed, and the first infeed was built and commissioned. Once this was in place, we could return the in/outfeed to being an outfeed conveyor and start to use the new infeed. Following quickly on from this, the second infeed point was installed, along with the new reject spur. This is where pallets that fail one of the numerous checks can be stored before they are reworked and put back into the system. During this time, a small part of the old conveyor was kept in operation to feed pallets onto the lift, as the picking of customer orders still needed to go on while we were doing the work.


Finally, the trickiest part of the project was completed: removing that final small section of old conveyor, and connecting all of the new conveyor to the lift. Physically, this is a relatively simple task, but the Ocado Technology developers and PLC engineers had the huge task of ensuring that any pallets destined for pick aisles were diverted at the appropriate place and transferred onto the lift.

The project was completed in October 2017. This has been the most interesting project I have managed to date, and definitely the most rewarding in terms of seeing the end result in operation. It has been great to see a new, shiny, more efficient installation where there was once a tired group of conveyors nearing the end of their serviceable life. The teamwork and flexibility demonstrated by all departments involved has made this a great project to work on, and I am looking forward to the next challenge!

Lee Sample, Engineering Project Manager

george smith