A Mid-Project Switch from Traditional to CNC Milling

Sometimes projects that appear routine contain hidden flaws that force manufacturers to adjust, adapt and get creative. In this case, our team was tasked with milling a thin, round part. Nothing jumped out to make planners think the job was anything but standard, so instead of setting up a CNC process, we opted for traditional milling. We got started using a large, conventional turning machine, which was about 12 feet in diameter.

The Challenge

The team quickly realized it was going to be incredibly difficult to achieve the size and surface finish we needed. Equally challenging was the fact that the clock was ticking. We had drastically reduced our cutting feeds and speeds to avoid breaking cutters or inserts. It was becoming painfully clear that conventional cutting would require much more time than we had.

The Journey (Approach)

About two-thirds of ENI's CNC projects are pre-planned. The other third, however, are the result of trial and error. Sometimes difficulties in traditional machining force us to adjust and switch to CNC. We soon realized that this may be one of those cases and approached the challenge by considering what was to be gained by switching from manual to CNC milling.

The Discovery

Even though the part was round, which lends itself well to turning, we decided to pull the part from the conventional turning machine. We discovered that by switching to a large, horizontal boring mill, we could use a helical milling technique to create the same diameter.

The Solution

Creativity and imaginative manufacturing. To make it work, we needed to use our equipment in a way that it was not designed to be used. We used the horizontal boring mill to fixture the part more rigidly. This creative adaptation allowed us to engage in simultaneous 3-axis machining to direct the cutting forces on the tool back into the spindle, which is the most rigid situation.

Once we figured this out, the switch to CNC wasn't difficult. Designing and making the fixturing was the most complex part. The software program was fairly simple and our team developed it quickly. In fact, transporting the part from one machine to the other took more time than anything else.

The Results

CNC machining worked right out of the gate. We achieved what was needed in less time and at the same level of quality. The customer got what they needed when they needed it.

Our team also gained valuable insight into our own process. If we ever encounter a similar situation, our team will know to go with CNC from the beginning. We discovered another unconventional way to use one of our machines, which we have since applied to nearly half of our CNC projects in the ensuing years – and will continue to do so for years to come.