Mack is part of Fresca Group Ltd, one of the UK’s largest importers and distributors of fresh fruit and vegetables.

The division’s Mack Service facility in Southamtpon specialises in producing a range of value added products such as freshly prepared fruits, vegetables and salads for the retail and food service sectors. It also has contracts rights for airline catering services and specialist bespoke customer fruit baskets.

Mack production process

One of the problems facing Mack Service was the accurate weighing of its produce. Previously, Mack Service had to resort to weighing some products by hand and this proved costly in time, labour and giveaway. To counter these problems, Mack Service automated the weighing process by installing a mini-packaging line, an Ishida QX-775 tray sealer and a DACS-W checkweigher.

The line has successfully packaged a variety of mixed and single fresh fruit products into tray sizes of between 160g to 460g.

“Mack Service automated the weighing process by installing a mini-packaging line, an Ishida QX-775 tray sealer and a DACS-W checkweigher.”

The facility’s lines were enhanced in August 2007 with the installation of two Ishida Fresh Food Weighers (FFWs). These have improved the accuracy of weighing and should reduce giveaway from 7% to around 1% (paying for themselves in 18 months).

Food products such as meat, poultry, seafood and fresh produce require accurate weighing technologies to reduce giveaway. Ishida’s weighers help manufacturers of these products to automate their weighing processes and reduce labour costs. They also help in increasing the speed and accuracy of processing, thereby increasing efficiency.

Ishida’s weighers provide manufacturers with complete or semi-automatic feed system choices. The weighers conform to hygiene regulations and are easy to clean. Fast product changeover and quick return on investment are also possible through the installation of the weighers.

Workers have to move the product along linear belt feeders, which distribute them evenly to the weighing units. Using Ishida’s multi-head weighing technology, the computer determines the best combination of hoppers to meet the target weight. In addition to the weigh hoppers, a set of booster hoppers are also placed as part of the FFW. The booster hoppers hold the product that has not been selected by the computer. This approach enables the weigh hoppers to admit more fruit and produce different weight combinations. The booster hoppers help in increasing speed and accuracy of the system.

Mack service line

The FFWs were developed to quickly and accurately weigh ‘difficult’ fresh food products on assembly lines. The weighers were designed to handle sticky, wet and fragile food such as fruit and are equipped with special hoppers with anti-stick scrapper gates to insure a smooth flow of produce through the weigher.

“The packaging line can now handle up to ten different product variations daily.”

The packaging line can now handle up to ten different product variations daily. Changeovers and specifications are called up from the unit’s memory by using a touchscreen control.

Each of the FFWs at the Mack Service facility have two sections allowing four types of fruit of different weights to be handled (for the same pack).

The line speed is 25 packs per minute (ppm) but can go as high as 30 ppm and even 40 ppm for single fruits.

The line works by presenting each of the pack trays under four ‘dipping’ funnels from the FFWs. These then move to be sealed and checkweighed before labelling and secondary packaging.

Following automation, the number of people required on the line has halved, freeing up personnel for other duties.

Installation

Ishida project managed the whole installation process. Ishida were able to provide custom-made gantries for the weighers, conveyors and an extended infeed for the QX-775 tray sealer which allowed it to be included in the new line.