It takes a team of real techies to carry through a project like the new CoroDrill DS20, and it took nearly seven years before the techies were satisfied enough to launch what is the longest and most reliable indexable insert drill on the market.
A drill isn’t just a drill – especially not a deep boring indexable insert drill that can drill holes as deep as seven times its own diameter in a single pass and without deflection or overheating. Even so, seven years ago, when Sandvik Coromant started drafting what should be the first 7xD indexable insert drill on the market no one anticipated just how demanding and time-consuming the work ahead was going to be.
“Luckily we are all such techies that none of us ever considered giving up, in spite of several dead ends, unfruitful leads and other unexpected obstacles.” says Håkan Carlberg, lead engineer on the project. “Loving challenges like this is a great driving force, and personally I was always convinced we would achieve what we set out to do.”
Carlberg was proven right. In October 2019 Sandvik Coromant will launch the first of 256 drill body articles for the new series.
The CoroDrill DS20 drill has very little resemblance to the still very successful predecessor CoroDrill 880. Instead of a classic, constant and spiral-shaped helix, the new variable CoroDrill DS20 has one steep turn followed by a straight chip flute. That’s just one of the many clever designs to optimize the performance while maintaining the stability and power balance in such a long, asymmetric drill.
Considerable time and knowledge were invested into every detail of the CoroDrill DS20. R&D developer Tomas Furucrona points to a small insert that he says took about two years to optimize. “Our first big challenge was to give this the right design and position – to determine the optimal net force, as the two indexable inserts are asymmetrically placed.”
In a parallel project, others in the team studied, tested and analysed the drill body, cooling and choice of material to determine the ideal combination.
“Anyone can make one 7xD drill in a specific diameter,” says R&D engineer Fritz Alum Yah, who has been part of the project since it began. “To apply the same reliability to a whole range of drill body articles is a different story. To succeed we had to use completely new ways of thinking and create new calculation methods.”
Meanwhile, there were numerous ups and downs to weather. Lab tests failed. Prototypes broke. Manufacturing ideas had to be binned. Solving the chip flute challenge while maintaining the internal cooling was an undertaking that took about two years to solve. After that there were another 50 different parameters that had to fall into place. If one parameter was changed, 49 others had to be adjusted accordingly.
“One turning point came when our talented calculation engineer Ramus Hemph developed a formula that didn’t leave anything to chance,” says Carlberg. “He saw figures and vectors where we saw a physical product. The new software gave us a logic where all parameters could be controlled, modulated and analysed virtually. After that everything fell into place.”
However, more challenges turned up. The CoroDrill DS20’s drilling ability was field-tested at testing customer SKF’s production plant for slewing rings for the wind turbine industry in Mexico.
“Moving from a competitor’s 6xD drill to our CoroDrill DS20 made it possible for the SKF operators to run a full component without unpredictable stops, without worry and without indexing,” says Furucrona. “They doubled their productivity and were extremely satisfied.”
But the development team was not. “We gave ourselves a list of 15 issues to solve within two months, most of them on the production side,” says Carlberg. “And we did. I guess it’s in our DNA to go above and beyond to prove new solutions and innovations.”
The development of the CoroDrill DS20 was the product of international teamwork. The core team was based in Sandviken, but the project was aided by more than 50 people working in Gimo and Västberga in Sweden and Mebane in the United States.