Corporate Buyers Guide

As stated previously, all L sealers use folded plastic film and heat sealing wires/blades which are arranged in an L shape. The product is placed between the folded sections of the film. The heated L is then brought down to seal across the film plus along the open side where the product was inserted. The seal across the film is wide enough and strong enough to separate the section containing the product and seal the film producing a sealed end for the next product insertion.

In a manual L sealer, the plastic film comes off a roll already folded and is pulled by hand over the sealing station. The first end has to be sealed from the previous sealing operation. The product is then placed between the sheets of film and the sealing L is brought down sealing the other end plus the opening where the product was inserted.

Sealing the end also separated the product package from the roll of film. The product package can now be pushed by hand into a heating tunnel to shrink the film.

A semi-automatic sealer requires that the product is placed into the film pocket by hand. The heating L bar is lowered by hand. When the bar is raised, the sealed package moves automatically to the end of the conveyor and the film advances in the sealing station ready for the next filling operation.

With an automatic L sealer, the shrink film with one end sealed lies in the sealing station. The product is brought by conveyor and is inserted into the film pocket with a push rod. The L sealer bar is lowered mechanically and is raised when the seal is completed. The sealed package is then moved ready for heat shrinking. With the automatic L sealer the feeding of the product at the input end plus the shrink tunnel at the output end have to carefully integrated for the process to operated without difficulty.    

Two types of palletizers are on the market. One type handles cases, trays and totes, the other type handles bags. The two are not interchangeable. This is true for the traditional automatic palletizer which uses mechanical means to arrange the location of the products. The newer, robotic palletizers are more flexible because the end effector (gripper) determines what products can be handled.

The palletizer specifications are similar for both types.

1. The models are either low level or high level loading.
2. The speed of cases or bags per minute
3. Capacity of pallet dispenser
4. Maximum weight of loaded pallet.

Additional items to consider:

1. Is a slip sheet dispenser available or part of the palletizer?
2. Do the controls have case/bag size and layout pre-programmed?
3. What type of control and operator interface (touch screen)?

The palletizer for cases, trays and totes has an in-feed that lines up the product for proper alignment in the layout. The bag palletizer has a longer in-feed which pats all bag surfaces and edges to make sure that when the bag enters the layout, it is the correct shape. The need for different automatic palletizers for cases, trays and totes and for bags because of the mechanical alignments needed in each type.

Robotic palletizers require unique end effectors (grippers) to lift and locate a product. The gripper can be for either a case or a bag. This makes the robot more versatile. Also, the robot can load more than one pallet at a time.