The fear behind every carton-to-crate conversation is that the packing line will have to be rebuilt. In most packhouses it does not. Crates run on roller conveyors, they go through the same weighing and labelling stations, and they stack on the same pallets. What does change is smaller and easier to miss.
What usually works as-is
Roller and belt conveyors take crates without complaint, provided the crate base has a flat bearing surface rather than feet that catch between rollers. Checkweighers do not care what the product is sitting in. Labelling heads can be set for a crate wall instead of a carton panel. Palletising by hand is unchanged. If the line is a conventional grading and packing line, the mechanical part of the switch is usually a setting change rather than a purchase.
The three things that do change
First, accumulation. Cartons absorb small timing differences because they deform slightly and gripping surfaces grip them; rigid crates do not, so a line that was tolerant of a surge may become noisy and scuffing. Second, height. A stack of crates is usually taller than the same weight of produce in cartons, which matters at a door height, on a truck, and at the grader infeed. Third, wash and return – the crate has to come back, and that is a logistics job that did not exist when cartons were being skipped.
Changing the foot, not the line
The single most common mechanical problem is the crate base catching on a roller or a transfer plate. It is usually solved by choosing a crate with a continuous rim rather than one with separate feet, or by fitting a transfer plate at the one place where the line steps. That is a small fabrication job, not a line rebuild, and it is worth walking the line with a single sample crate before ordering anything.
A phased change is usually better
Running one line or one crop on crates for a season, while the rest of the packhouse stays on cartons, answers every question the switch raises – how many crates are needed, how many come back, what the wash load is – without betting the season on it. The fleet sizing question is the one that usually surprises people, and working out crate fleet size for a season sets out why the first estimate is nearly always low.
What to tell the supplier
Conveyor type and roller pitch, whether there is an accumulator, the pallet pattern in use, and the door and truck heights available. Those four determine which crate will run on the line. Area and crop determine how many. Most enquiries arrive with the second and not the first, which is why quotations get revised.
The thing to do before ordering anything
Walk the line with one sample crate, by hand, through every transfer. Push it over each roller junction, each plate and each drop. The places where it catches are the places that will need a transfer plate or a different base – and finding them takes an hour on a quiet day rather than a week during the season.
Do the same with a loaded crate at the grader infeed and at the palletising point, because those are where the crate is lifted and set down most often, and therefore where an awkward crate costs the most time. Most line problems with crates are found in this walk or not at all.
What we can do
We supply PP produce crates in footprints that run on standard packing lines, and we will send sample crates to walk your line before you commit to a fleet. Tell us the conveyor pitch and the pallet pattern and we will say which base design suits it.