TRANSPORT STRAPPING OF THE FREIGHTS

Strapping of the freights is one of inexpensive rather efficient methods of packing. It is widely used in various branches of industry for in making up of freight units, particularly shipping bundles of lumber, fixtures, metal ingots, brick, sectional furniture and other materials and production. It is a "group" packing. Its constituents can have own package (cartons, wooden container, plastic sacks) or be unpacked (brick, saw-timbers). Use of given technology quite often allows to refuse returnable container (pallets, cages, etc.) The examples of such packing are shown on fig. 1-2.

Now strapping of the freights with steel, polypropylene and polyester straps is widely used. The comparative performances of these straps are indicated in tab. 1.

Steel strapping is used for tens of years and it is the most reliable and strongest fastening materials. It is recommended for use where strong fastening is required, where the low extensibility is important and if the packed product is very sharp or hot. Steel strapping is fastened with the help of seals or by a retrosection (sealless joint).

Fig.1Fig.2

Polypropylene strapping has appeared in the market rather recently. Today it is the most frequently used and the cheapest of fastening materials. It has small weight and it does not subjected to corrosion, characterized by high extensibility and elasticity, however it has low tensile strength. Polypropylene strapping can be fastened with buckle, seal or it can be welded (fig. 3,4,5 resp.) It is excellent choice for packing easy packages, blocks and bundles.

Polyester strapping is new and the most rigid of all polymeric fastening materials. Its extensibility is considerably less, than polypropylene has, and the durability is higher. In addition to the positive qualities of polyester it does not form cracks. Thanks to high strength of polyester straps made of it are frequently used for strapping heavy freights, which should be hardly fastened, and this strapping should remain strong during the transportation and storage. Polyester strapping is easy in application and suitable for a reuse.

Table 1. Comparative performances of packing strapping.

Strapping of the freights with steel and polypropylene strapping has received the greatest distribution from all inexpensive kinds of strapping.

The technology of strapping consists in tensioning of the ends of strap winded around the packed object, forming the lock and cutting the free end of strapping.

Devices with the help of which strapping is carried out, can be made as separate tools or combined. In the first case tensioning and cutting of the strap is made with the help of tensioner. Then forming of lock (with the help of seal) is carried out by the sealer. In the second case all operations (with the seal or without it) are carried out with the help of one combination tool. Sealer is not used for fastening of strapping with buckle.

Fig.3Fig.4

Fig.5

The choice of the kind of strapping and accordingly strapping tools and consumption materials depends on many factors. First of all they are weight and volume of freight unit, condition of carriage and handlings, design features of packed production, stability of size and weight parameters during storage and transportation, and also design features of strapping and strength of the lock connecting its ends.

Our specialists will help you to choose the optimal technology of strapping, equipment and suppliers.