ADVANTAGES, QUALITIES AND METHODS OF APPLICATION OF ARMOURED LAYERS

• Increased wear of surfaces (of screws, barrels, etc.) is caused by a continuously increasing share of fillers in the plastics (e.g. glass, mineral fillers, flame retardants, etc.) which are included in 20 % up to 60 % of total volume of the plastics.
• Armouring of surfaces with hard metal materials shows several times higher mechanical and chemical resistance to wear in comparison with nitrided parts (according to the type of hard metal overlay and the kind of material to be processed). The armoured areas acquire increased resistance to excessive wear, high temperatures and pressures as well as to all non-plastic materials.
• Armoured overlay of hard metal material of thickness up to 2,5 mm (according to the type of armoured layer) shows in its whole thickness a uniform indicated high hardness and resistance to wear compared to the nitrided layer (thickness of approx. 0,3 to 0,5 mm) showing higher hardness only on the surface compared to the remaining cross section of the layer. With increasing depth of nitration the hardness of the nitrided layer decreases. Service life of armoured parts is min. three times or more higher in comparison with the nitrided parts of higher qualities.
• One of the options for renovation of the worn-out nitrided set consisting of the screw and barrel is grinding through and honing of the inner diameter to the net diameter (to the largest possible worn-out diameter) with consecutive new nitration and welding on of the appropriate screw by means of the hard metal material on the dimension in accordance with the renovated barrel.
• The technology of welding on enables to realize the further repeated consecutive repairs (a number of revisions depends on the way of wear out, basic material, chosen type of hard metal overlay, etc.).
• The welding-on of screws is materialized not only on the upper part of screw thread but also on the side part and on the screw body.
• We constructionally design new shapes of screws and barrels. These constructinal designs enable to increase output even of the older extruders by 10 % up to 30 % of melt (kg/hour) and to improve its mixing.
• As our free of charge service we check the measures of parts (e.g. the outer diameters of screws, the inner diameters of barrels by means of specially prolonged subites accurate to hundredths of a milimeter etc.) in your firm and provide the suggestions for several options of the consecutive repairs.
• Our firm has been involved in welding-on technology with consecutive grinding of the inner diameters of barrels, as one of a few such companies in Europe.