Every hole in a corrugated polypropylene panel is a potential crack origin, so the idea of reinforcing it with an eyelet sounds universally sensible. In practice eyelets add cost and a failure point of their own, and they pay for themselves in three fairly narrow situations.
Situation one: repeated rope or strap contact
Anything that takes a rope, a bungee, a cable tie or a strap through it repeatedly benefits from reinforcement. The load is localised, it moves, and it abrades. A raw hole in that duty grows steadily until the panel tears free, while a metal or moulded eyelet takes the abrasion indefinitely.
Situation two: drainage in a wet stream
Drain holes in crates that carry wet product get poked, scraped and jet-washed. The hole edge is the first thing to fray and the first place biofilm builds up. A drainage eyelet with a smooth bore stays cleaner and resists the mechanical damage of cleaning, which is a genuine hygiene argument rather than a durability one.
Situation three: hanging and handling points
Panels that hang on hooks, whether in a wash line, a drying rack or a storage system, concentrate their whole weight on a small feature. Here the eyelet is not an upgrade, it is necessary – and the backing washer matters as much as the eyelet itself.
When they are a liability
Eyelets fail when they introduce a second material into a stream that does not want it. In recycling terms a metal eyelet in a polymer panel is contamination unless it is designed to be removed. In food contact applications the crevice between eyelet and board collects product residue. Both are arguments for a moulded polymer eyelet or, better, no eyelet at all.
Metal versus polymer
Metal eyelets are stronger, cheaper and recyclable-separated. Polymer eyelets avoid corrosion and galvanic issues, integrate better with eventual recycling, and are gentler on whatever passes through them. In a wash tunnel at elevated temperature every cycle, metal wins on life and loses on cleanliness risk.
Setting quality decides everything
A badly set eyelet is worse than no eyelet. Under-set it spins and enlarges the hole; over-set it cracks the flange or deforms the surrounding board, creating exactly the stress concentration you were trying to prevent. Hand-set eyelets with a hammer and no anvil are the single most common cause of eyelets that fail early.
Ask to see a set sample sectioned, or at least flexed hard. If the board around the eyelet has a visible ring or whitening, the setting pressure is too high.
Placement rules that prevent most problems
Keep clearance from the panel edge, keep clearance from fold lines, and do not place an eyelet across a flute in a way that lets it rock. Those three rules, plus a backing washer where anything bears on it, remove most of the failures we get asked about. The general spacing and edge distance logic is the same as described for holes in PP board.
Testing before committing
Fit eyelets to three sample panels and abuse them the way service will: pull a strap through repeatedly, wash them, freeze them, and then pull again. Most eyelet problems appear within twenty cycles of realistic abuse, and none of them appear on a bench.
Then open one up. Look at whether the flange has cracked the surrounding board, whether it has deformed the flutes, and whether the setting has produced a clean bore. That single inspection tells you more than any specification sheet about how it will behave in service.
What we can do
We fit reinforcement to corrugated PP sheet fabrications and will tell you when to skip it. Describe what passes through the hole and how often, and we will recommend an eyelet, a reinforcing patch, or a different hole position that makes the whole question go away.