Extrusion International 6-2025

49 Extrusion International 6/2025 PIPE EXTRUSION Screw & Barrel Replacement of Third Party Extruders CONEXTRU has been active in the extruder technology market for quite some time. This market is divided into three areas, although it should be noted that there are very few companies operating across this entire spectrum. These three market segments are: Technology transfer Technology transfer of CONEX- TRU screw and groove bushing technology to extruder manufactur- ers. CONEXTRU supplies complete drawings for the manufacture of screws, cylinders and groove bush- ings. This includes calculations of drive power, gear ratio and guar- anteed output for e.g. PE, PP, ABS and other technical polymers. This is a major economic advantage for thesemanufacturers, as there are no development and prototype costs. In the meantime, a large number of manufacturers have taken advan- tage of this opportunity. As a result, there are a considerable number of extruders on the market that are equipped with CONEXTRU technol- ogy. The machine manufacturers using CONEXTRU technology are lo- cated in India, Turkey, Italy, the USA and China, totalling approximately 12 extruder manufacturers. Sale of CONEXTRU single-screw extruders The product range of single- screw extruders with which CON- EXTRU successfully operates on the market consists of: C 25, C 30, extruders up to 20 kg/h for bonding agents, colour stripes and barrier layers C 45, C 60, extruders with 30 L/D from 50 to 200 kg/h, and technical polymers C 45, C 60, C90, C 120 with 37D l/D ratio from 250 kg/h to 1400 kg/h C 45, C 60, C 75, C 90 with 40 L/D ratio from 500 kg/h to 2,000 kg/h. A high-speed extruder with a size of L/D 42 is currently under devel- opment for outputs from 500 kg/h to 1,500 kg/h. All these extruders are equipped with an AC motor and gearbox or a torque motor. Replacement of plasticising units in existing third-party extruders There are many reasons to switch to CONEXTRU units. Examples in- clude: • Special screws for highly lled materials with wear protection. • Replacement of standard plas- ticising units due to high wear and cost-effective replacement of espe- cially wear-protected units. • New screws for quality improve- ment and a slight increase in output capacity. An increasingly important and therefore interesting market segment for CONEXTRU is the re- placement or retro tting of plasticis - ing units in single-screw extruders. This means that the existing design is not remanufactured, but instead this extruder is tted with a completely different designmanufactured using CONEXTRU technology. The following assemblies are af- fected by this replacement: Flange connection to the gear- box, cooled feed section, grooved or smooth with adapter ange so that the existing hopper can be used, cylinder, ange connection to the tool and, of course, the screw. It should be noted that the new plas- ticising units are not copies of the existing design, but rather a switch from existing technology to CONEX- TRU technology. This applies to the groove bushing with length and volume and number and shape of grooves, as well as the screw, which is matched to the feed zone and the cylinder. If possible, the existing heating and cooling units are used – if the cylinder needs to be longer – to improve the melt quality, then new heating/cooling units are also required. These are designed according to the existing electrical system. It is important to note that the mechanical design of the ex- truder, such as motor power, torque, maximum screw speed and required output, must be known, as the screw Pic. 1: 22 L/D long barrier part for best melt quality Pic. 2: Replacement set