DOD coder for Cheetham Salt

Cheetham Salt is Australia's largest producer and refiner of salt. Its 12 solar salt fields nationally produce an annual total of more than 1.4 million tonnes, which is processed at six refineries. Together, the fields and refineries supply salt from consumer packs of cooking and table product right through to entire shiploads of industrial salt.

Rob Williams, from Cheetham's Price plant in SA, says, "Cheetham codes bagged product with human-readable text, which is mainly for traceability purposes. We needed to replace a coder in our Price plant because the old system was outdated and the ink tended to run through the woven bag, leaving a blurry image."

The salt is packed into polypropylene bags, so the ink needs to dry very quickly. If too slow, the bag's open-weave nature and rougher surface will allow wet ink to spread quickly and become illegible.

Cheetham packages many different grades of salt. Product codes are printed on the side of 10, 15, 20 and 25 kg bags - and the grade of the packaging itself also varies dramatically. Key among Cheetham's requirements were to change codes quickly - they use up to 20 different ones - and that these codes are visible from 10 m, so forklift operators can read them.

"Included in the coding we print are the date and where the bag was packed. We have many different sites and we need to identify each one for QA traceability reasons. Basically, we need flexibility in what we want to print on the bag."

Added top that, the environment can be harsh for printers.

To meet all those requirements, Cheetham installed a DOD 3200 printer from Matthews Intelligent Identification.

"The operator-friendly access panel allows easy selection of codes,"

Cleaning the 3000 print-head is also simple. This print-head was chosen as it gave a print height of 20 mm, which is highly visible. Using DPI 201 ink, combined with the 3000's small drop size, gave fast-drying ink, thus eliminating any bleed issues.

Because another requirement was to reduce consumable costs, Matthews ran trials on the installation, setting up a counter to check the number of bags that could be printed with 1 L of ink. The results were pleasing: 71,000 bags were printed, with an average of 20 characters using a 14x10 matrix. Matthews also supplied a Fluid Pump System (with low-level warning system), allowing Cheetham to buy ink in 20 L pails.

The system has been so successful, Cheetham Salt has installed Matthews 3400 systems into plants in Queensland and Sea Lake (Vic) as well.