Our factory in Hollola manufactured two exceptionally large conveyor screws.

These may well be the largest screws ever made in Finland. Manufacturing screw blades with a diameter of 2.5 meters sounded like a tall order, but we were ready to accept the challenge!

Estonian manufacturing company Estanc contacted Makron because it required two such screw blades for a screw conveyor. These screws had to be made of duplex stainless steel, which is a challenging material and imposed its own requirements on the welding process. Duplex austenitic-ferritic steel is an ideal choice for conveyor screws used at pulp and paper mills. As for the other key characteristics of these 2.5-meter-across screws, the thread material thickness specified is 10–20 mm, and each screw weighs 17–18 tons.

Because of their extraordinarily large size, the process required meticulous planning and preparations prior to the actual manufacture. Makron’s prototype workshop designed and tested the production method in collaboration with the manufacturing department and created the necessary tools. Once the first screw had been welded, the production method was honed still further for the second. In addition, a customized platform was made for transporting the screws.

Makron production