Nakamura cuts secondary operations at sub-contractor

The Nakamura-Tome WT150IIF being programmed and prepared for production at Oakley

Despite only opening its doors for business in 2002, Burton On Trent-based Oakley CNC Machining Ltd has undergone a major transitional shift in its machine tool technology in recent years to support its rapid growth trajectory. Initially starting with Herbert capstan lathes and a selection of two-axis CNC turning centres, the company has evolved its investment strategy, with its latest acquisition being a Nakamura-Tome WT150IIF twin-spindle twin-turret turning centre from the Engineering Technology Group (ETG).

Already progressing through a transition period, it was the company acquisition by managing director Ian Oakley in 2015 that led to an acceleration in capital equipment investments. With an order book continually filling and capacity at a premium for the sub-contractor, it searched the market for a twin-spindle turning centre — and it was the Nakamura-Tome WT150IIF that caught the attention of the manufacturing business.

Mr Oakley said: “We have taken full advantage of the 130% super-deduction tax allowance and invested in several high-end CNC turning and milling centres. However, not all acquisitions have performed as we would have liked. As we have several new projects that require production volumes of 10,000-plus, we needed a high-performance turning centre to absorb the volume — the Nakamura was the perfect choice.”

User-friendly machine
The company searched for a twin-spindle twin-turret turning centre with an intuitive CNC interface that could offer both conversational and G-code programming. Mr Oakley added: “We wanted a user-friendly machine that is very capable of machining the range of parts we produce, but we got so much more. One factor that drew us to the Nakamura is the oscillating servo (oscillation cutting) that prevents long stringy swarf and enables us to extend our unmanned running.

“This was particularly important to us as we have a family of nylon parts required in production runs up to 10,000-off. This project for the rail industry is a family of 40mm dia parts up to 100mm long that we can set up on the Nakamura and it will eventually run for days without manual intervention. In fact, it is the swarf-breaking technology and the ability to run long unmanned periods that won this contract for our business.”

However, this project was won due to the Nakamura WT150IIF already being in place. What made the decision to invest in the robust turning centre was a brass electronic component for the construction and earthmoving equipment sector. The brass electronic part is regularly machined in batches of up to 15,000.

Pictured right: the twin-turret twin-spindle Nakamura-Tome WT150IIF

Mr Oakley continued: “The component was being machined on an existing twin-spindle turning centre lights out, but we were having issues keeping the part in pristine condition with no marks. The existing machine has a traditional parts catcher with swarf being deposited in the parts catcher area from machining. The parts when ejected then land on top of the swarf which is far from ideal.

“The Nakamura has a robotic arm which unloads the parts very gently and ‘places’ them into a separate unloading conveyor belt. This in itself is a big bonus to us but coupled with the benefit of having an extra turret, cycle times have been reduced from 3.5 to 1.5min. Considering the batch sizes, we are now saving just over 500hr per batch.”

“Another aluminium part is machined for the food processing industry on our existing twin-spindle machine that is just over 200mm long. This part needed four different operations due to the sub-spindle bar capacity being very limited. This incurred significant set-up times, took a lot of capacity from our machine shop and the overall cycle time was 6.5min. We are now able to produce these on the Nakamura with a cycle time of 3.5min in one-hit.”

As a long-running project that has been ongoing for more than three years, the Staffordshire manufacturer was struggling to keep up with demand prior to the arrival of the WT150IIF. The major saving on this project for the ISO:9001 2015 company is not just the cycle time but the reduction in set-ups, the ability to free capacity from other machines and the reduction in manual intervention.

Swarf-breaking technology
Mr Oakley explained: “It was a labour and machine intense process. Now, we can set the job on the WT150IIF and it will run unmanned 24hr a day for up to two weeks with the swarf-breaking technology. All we have to do is feed the bar into the machine and collect the finished parts from the other end. The stability of the machine also means that we do not even have to change the tools in a two-week long production run.”

As the company gains familiarity with the machine that was installed at the end of 2022, it is moving more parts to the Nakamura. Mr Oakley said: “The brass and nylon parts are long series runs and we are benefitting from the combination of the swarf-breaking technology and the one-hit capabilities of the WT150IIF. We are continually moving more jobs to the Nakamura and we will likely need another machine in the near future.”

Mr Oakley concluded: “We have machine tools here from a range of vendors and the service, and the quality of the machines has been very indifferent. It is only been a matter of months since we installed the Nakamura, but we are delighted with the machine and the service from ETG has been exceptional. If we have ever had any issues, the service team have jumped on the issues immediately. We are currently planning to almost double the size of our facility to nearly 700m² to facilitate our growth. When we have our new building, we will definitely be looking to purchase more Nakamura machines from ETG.”