Corporate Buyers Guide

The five sided tray is the standard open tray with low side walls. This tray style is increasing in popularity as it is used with shrink wrap to hold the product in place. The tray former for five sided trays uses hot melt glue. The tray is formed in one stroke over a mandrel after glue is applied to the tabs. These machines can form over 10 trays per minute and they are the starting point for packaging cans and bottles.

Special trays have a number of configurations. The most common are with folded corner posts for the fruit and vegetable industry. Another popular tray former is the closed box where a five sided tray is slotted in the middle and folded to create the one piece tray and lid. The meat industry has a deep tray with hand slots. Many of these trays use corrugated cardboard with special, moisture proof coating.

For all tray formers, the most important parameters are the length and width of the tray. The height of the tray is next. Most machines have a range of dimensions for each of these parameters. The layout of the finished trays is on the flat, precut sheet called the “knocked down” (KD) sheet. The location and KD sheet capacity for the sheet feeder is important for easy operation.

Tray formers for five sided trays are available from a catalog, the closed box, fruit and meat trays are more complicated in design and will require close cooperation between the case user, case designer and the machine manufacturer.

All shrink wrap L sealer machines have two things in common. First, they use plastic film which is folded in half as it comes off a roll. Second, they have an L shaped tool which holds two wires or knife shaped blades which are heated. When they come in contact with the plastic film, they melt and seal the film.

The two wires or knife blades are arranged in an L configuration. One blade comes across the width of the folded plastic film. The length of this blade/wire is determined by the wih of the film. The second wire/blade comes along the open edges of the film. The length of this wire/blade is determined by the length of the package to be sealed.

The model names of most shrink wrap sealers give the width and length of the sealing wire/blade. As such, model XXX 2430 means that the seal wire/blade across the film is 24 inches and the length along the edge of the film is 30 inches.

When the wire/blade comes down and seals across the film, the seal package is pulled away, but the film remaining also is sealed across the end. This forms the pocket for the next product to be inserted as the film is advanced into the loading and sealing position. Advancing the film of the shrink wrap L sealer, then inserting the product between the film and then bringing down the L shaped sealing tool can all be done by hand. Or, any or all of these steps can be done by the machine depending on whether the machine is manual, semi automatic or automatic