Turning centres Twin-spindle turning centre reduces secondary operations
UK — Thread rolling expert Dobson & Beaumont machines highly demanding materials for a variety of industries. In order to reduce secondary operations the company invested in a twin-spindle turning centre that now replaces two machines.
Founded over a hundred years ago, Blackburn based Dobson & Beaumont is a subcontractor with a distinct niche. The longstanding company are experts in thread rolling, a process that cold forms threads to work harden the thread, strengthen the grain flow and improve overall thread strength by more than 25 percent when compared to typical thread cutting operations. Before thread rolling, Dobson & Beaumont has to machine some of the most challenging materials known to the industry — this is one of the many reasons the company has just purchased a Nakamura-Tome AS200 twin-spindle turning centre from the Engineering Technology Group (ETG).
Appointed Managing Director of the family business last year following the unfortunate passing of previous company Managing Director Phil Dobson who had served the company with distinction for 50 years, Richard Guest comments on the position the company was in during the pandemic: “Like all subcontract manufacturers, we were impacted by the pandemic. Luckily for us, our niche offering sees our business work across the fastener, pump and flow control, automotive, motorsport, oil and gas and petrochemical, marine and defence, subsea, wind energy and aerospace markets — this means that we were not too heavily impacted by one particular industry segment.”
The pandemic allowed the company to review its processes and ageing plant list and instigate a plan for investing in new technology. The company machines a lot of parts in batches that can vary from 4 or 5-off through to 50, 100 and beyond, and their turning centres were all single spindle machines. This meant that most of the turned parts required secondary operations. “We knew we needed a twin-spindle turning centre to reduce secondary operations and following a comprehensive review of the market, the Nakamura-Tome AS200 twin-spindle turning centre from ETG was a perfect choice”, Dobson said.
The company machines “normal” materials but increasingly processes more challenging materials such as Titanium, Inconel, Stainless Steel, Super Duplex, Duraheat to tolerances in the region of +/-0.0125 mm with the thread rolled parts often being critical components in their respective assemblies. “We have 6 Hardinge lathes and have been using Hardinge for over 20 years, so we understand the build quality, rigidity and stability they offer. Out of the available vendors, the Nakamura-Tome from ETG was sensibly priced, it had the same Fanuc programming language as existing machines and it was supplied as a long-bed version for our 400-500 mm parts with a bar feed, part catcher, the twin spindle for one-hit machining and of course a highly recognised reputation for build quality, stability and precision.”
Installed at the Lancashire company in April, the new Nakamura-Tome AS200 twin-spindle turning centre immediately replaced two ageing machines to:
- free up shop floor space,
- free up machine capacity,
- reduce power consumption,
- reduce set-ups and the subsequent labour requirement.
In the few weeks since the machine has been installed, it has reduced the cycle time for a number of parts including connecting rods from two minutes ten seconds to just under one minute on parts that used to require a secondary turning cycle to complete the parts. The company has also reduced the cycle time of double-ended bolts from one minute 30 seconds to less than 45 seconds. The ease of use of the Nakamura-Tome AS200 and its Fanuc CNC control have immediately impacted the 14 employees Dobson & Beaumont.
The most dramatic saving has arrived on hexagonal head bolts where the cycle time has fallen from eight minutes to one minute 30 seconds. Commenting upon this, Richard Guest says: “We produce a lot of bolts where we have to machine the hexagonal heads, and this is a perfect example of the savings that we can achieve with the Nakamura-Tome machine. The combination of twin-spindle machining, powerful and robust milling capability and automated production through the bar feed and part catcher has made a significant difference on this component — and it will do on future parts too. This machine is a step-change in technology for our business and as we move forward, we will be aiming to move legacy work from existing machines to the new Nakamura.”
The robust Nakamura-Tome AS200 features:
- A spacious work envelope with a maximum turning diameter of 340 mm and a turning length of 570 mm with a bar capacity of up to 65 mm diameter.
- Flexibility provided by a 15-station tooling turret with a 5.5/3.7 kW driven tooling motor that achieves a speed of 6000 rpm.
- The main spindle is driven by a 15 kW spindle motor with the sub-spindle driven by an 11 kW motor — both high-torque units are capable of reaching a maximum speed of 4500 rpm.
Concluding on the acquisition, Richard Guest says: “We are still in the early days of this installation, but so far, it is clear we have bought the right machine for our business. We have drastically cut cycle times on many parts and we are eliminating secondary operations throughout the shop floor. ETG has been extremely helpful in getting us up and running and we are still enlisting their help for more complicated parts. We have one part that is currently five operations and the ETG engineers will help us to bring that to one-hit machining on the Nakamura. This is a perfect example of why we have moved to twin-spindle turning with Y-axis milling.”
The next step for Dobson & Beaumont is to put increasingly more new and legacy work through the Nakamura to reduce the burden on their other turning centres as well as in the milling department. With the barfeed and part-catcher, they also have the opportunity to automate the production of complex work, so unmanned and lights-out running will create another opportunity for the company.