What do a tunnel and hiking boot have in common? Both have a membrane that prevents the ingress of rain. In the case of the tunnel, the Norwegian company Oldroyd is an expert for the membrane and its injection-molded fixing product. It uses CX machines from KraussMaffei and 100% sea plastics.
Tunnels are an everyday phenomenon in Scandinavia because they are used to get around the many fjords. Norway alone has over 900 tunnels, and the world's longest road tunnel is also located there. The enclosures for the traffic are more complex than one might think because a sophisticated membrane system lies behind the pipes visible to the driver. This system prevents water penetrating the soil causing damage to the concrete.
Oldroyd is the top dog in the area of waterproofing against rain and holds over 90% of the market share in the Nordic countries. The key to success lies in the innovative strength of the family business in Stathelle (around 160 kilometers south-west of Oslo). Originally concentrating on film extrusion, founder John Oldroyd Cheetham also accessed the injection molding technology with the help of KraussMaffei and now successfully operates three hydraulic CX 160-750 with a clamping force of 1600 kN.
So-called spacers, curved products with grid structure, which create a distance between rock and membrane, are produced on these machines in a cycle time of roughly 15 seconds. They weigh approximately 150 grams, whereby there are around 20 different models, varying in diameter and height.
Working together to promote sustainable tunnel construction (from left): John Oldroyd Cheetham (founder of Oldroyd), Linda A Celin (CEO Oldroyd), Rolf Kjønnerud (KraussMaffei Agent SAXE) and Carl Kremer (Product Development/Operator Oldroyd) in front of one of the CX 160-750
100% sea plastics300,000 to 400,000 of the spacers are required for one tunnel alone. For these quantities it pays off ecologically to use recycled materials. Oldroyd uses 100% sea plastics, consisting of roughly half PP and half PE. The remnants of broken fishing nets and plastic ropes are collected on the coast of Norway by specialist companies and crushed, washed, and regranulated. The subtle fish scent does not need to be removed for the tunnel construction.
The APCplus machine feature is very helpful for the changing material compositions and resulting viscosity fluctuations. It ensures a very constant shot weight by adapting the switchover point and the pressure level from shot to shot.
The construction of the Stockholm Bypass (a series of underground motorway tunnels) is currently the world's largest tunnel project. Thousands of spacers from Oldroyd are also used here.