The propeller manufacturer Oshaug Metall is in the process of finalizing a research project where they will use robots to make molds directly from digital formats instead of making models from plywood.

Oshaug Metall in Molde is a mechanical engineering company that manufactures molded propeller components from an alloy consisting of nickel, aluminum and bronze (NiAl-Bronze).
“Our core competence lies in the actual casting process. We are a very specialized company and, in fact, are the only manufacturer in the whole of Scandinavia to manufacture ready-made propeller blades carrying out all process steps in our own right. This means that we have total control of all the production processes. Our customers in this area include Rolls-Royce, Wärtsila and Brunvoll, to name a few,” explains Stein Berg Oshaug, CEO of Oshaug Metall.

CEO of Oshaug Metall

Business Development Representative at Digitread

Robotized model-free molding
Oshaug Metall is participating in an R & D project supported by public innovation aimed at maritime clusters. The project is called “Robotized Model Free Formation” and concentrates on the work that happens before the actual casting process starts:
“Traditionally, we have made the propeller blade models out of plywood using a milling machine. In this method, the model is placed into a sand mold and then the vacuum which forms the required pattern is filled with molten metal. The research project we are participating in now aims at forgoing the plywood model, hence making it obsolete and instead the mold will be made using Siemens NX CAM Robotics and a robot cell without having to make a model out of plywood first. This will result in less time and resources being consumed on making the model, as well as the added benefit of increased mold precision,” asserts Berg Oshaug.

The robot performs the milling process
The robot will act as a milling machine and will mill the casting mold into tempered sand, a material that is suitable for machine-forming. Martin Eie from Digitread explains:
“This solution is more flexible and has greater range than typical CNC machines. Moreover, this solution becomes more cost-effective in comparison to using a large machine system. Now that Siemens has implemented its robot programming technology in NX CAM, the threshold for utilizing robots for tasks like milling, drilling and grinding has been greatly reduced. What’s new is that it is possible to handle more than five axes which are typical of CNC machines. Oshaug Metall is also using its long term experience with NX to its advantage. The designers can work in the same user interface from product definition right up to production,” reports Martin Eie, Business Development Representative at Digitread.
“Another challenge is to achieve sufficient accuracy by using robots in this way. Robots are particularly suitable for this type of low force machining, which do not create excessive vibrations. With the aid of NX technology like adaptive milling and intelligent tool paths, we could also see robots gradually being used for more demanding machining operations,” he continues.

NTNU, Digitread and Viddal Automation
The design of the propeller takes place using Siemens NX while NX CAM Robotics creates the data that the robot needs to do the job properly. The project is being carried out in close cooperation with NTNU, where PhD candidate Eirik Njåstad is developing the geometrical specifications that are needed. One of the biggest challenges is to move the actual milling operation to a robot which has traditionally been done by CNC machines. For this purpose, Viddal Automation is collaborating in the project as another important player:
“We deliver the robot itself and relay the data from the systems to make the robot work. NX CAM Robotics creates the path that the robot will follow. In addition to the actual milling, the robot will perform different logistical tasks, which will also be programmed in NX CAM Robotics. Our job is to design and build the entire robot cell, calibrate the equipment and make the whole process work in real life,” states Steffen Viddal, CEO at Viddal Automation.

Ready to go live at the turn of the year
Today, the project is in the pre-project phase, which means, among other things, that Viddal Automation is in the process of solving all the challenges that the robot has to overcome in the robot cell itself. These challenges must be uncovered and solved in order for the entire robot cell to work properly when put into operation:
“The project started in 2016, and around the turn of the year 2018/19 we expect the robot cell to be installed and ready to start trials. The preliminary results look very promising and we think it’s very good to be able to participate in the development and experience how the power of digital solutions can solve new issues and contribute to efficiency,” Berg Oshaug concludes.
Berg Oshaug states that the project has a total cost framework of around 13 million kroner, around half of which is being borne by Oshaug Metall.

PUBLISHED: October 25th 2018