IMHO, it means when loading the cargo onto the pallets, half the cargo is aligned in one direction, and the other half is 90 degrees in the other direction. Grating refers to the parallel bars of the packaging crates.

4 entries found for grating.
To select an entry, click on it.
grate[1,verb]grate[3,transitive verb]gratingdiffraction grating

Main Entry: grat·ing
Pronunciation: 'grA-ti[ng]
Function: noun
1 : a wooden or metal lattice used to close or floor an opening
2 : a partition, covering, or frame of parallel bars or crossbars
3 : a system of close equidistant and parallel lines or bars ruled on a polished surface to produce spectra by diffraction


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Note added at 8 hrs 6 mins (2005-09-12 14:39:03 GMT)
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>>> 您能不能用汉语解释，half gratings one direction and half the other direction on each pallet到底应该怎样解释吗？

就是说把成品装在运输台架(pallet) 上时， 一半的箱子顺同一方向排列放置，另一半货交错 90 度排列放置。 这样摞起来比较稳定。