JEB Takes-off with Nakamura Turning CentrePosted on May 18, 2021
When JEB Precision Ltd won an order to manufacture a complex component for an aerospace air handling system, the Northwich subcontract manufacturer recognised that its existing production method needed to be upgraded to improve productivity. The solution was a Nakamura-Tome AS200LMYS turning centre from the Engineering Technology Group (ETG).
In 2019, the Cheshire manufacturer that primarily produces components for the scientific instrument and aerospace sectors had won a substantial order that initially resulted in the complex aerospace parts being machined via three turning operations and two milling operations. The S130 grade stainless steel parts were required in batches of more than 100 per month and the five set-ups on multiple machines was an unsustainable long-term solution.
Founded in 1974, the ISO: 9001 certified company offers a comprehensive service that encompasses CNC milling up to 5-axis, turning, wire erosion, jig boring, honing, surface and cylindrical grinding as well as full scientific instrument assembly. Despite this comprehensive versatility, the challenging aerospace part required a new process to improve throughput, precision and quality. With six ETG turning centres on-site, JEB Precision was already familiar with the extensive solutions available from the Wellesbourne machine tool experts – but this was the first Nakamura-Tome machine to be installed at JEB.
Discussing the project, JEB Operations Director Mr Michael Bebbington recalls: “Whilst our Hardinge turning centres are very capable machines, the Nakamura-Tome AS200LMYS is a twin-spindle machine with milling capability and Y-axis machining that is built on a very robust platform. By investing in this technology, we were immediately able to reduce set-ups, increase throughput, improve process reliability and quality and free capacity on our other machine tools.”
Before the arrival of the Nakamura-Tome AS200LMYS in January 2020, the 83mm diameter by 23mm aerospace part was precisely machined on two turning centres with the third operation incorporating turning on a third machine with an expanding mandrel to ensure the thin-walled part achieved the concentricity and precision required. The three operations were followed by a milling process that required four reamed and counterbored holes to a tolerance of +0.012/-0mm with final machining on a second machining centre that milled features on the final face.
“The set-up time for the components was 2 hours for the first turning operation, 1 hour for the next and 1.5 hours for the third op. Then we had two milling set-ups of 1.5 and 1 hour respectively, giving us a total setup time of seven hours. Despite this extensive 7 hour set-up time, the combined cycle time was only 30 minutes. However, almost all dimensions were tied to a tolerance of +/-10 microns with some features having tolerances below that. What made this part more challenging was the behavioural characteristics of the material between processes with extensive machining and thin wall features creating a susceptibility to deformation.”
The Nakamura-Tome AS200LMYS was installed at JEB Precision with a Hainbuch collet chuck in the main spindle and a Hainbuch expanding mandrel on the sub-spindle for ID clamping to ensure complete machining in a single operation. The part is machined complete in just 20 minutes on the Nakamura-Tome AS200LMYS and in the early days of gaining familiarity with the twin-spindle workhorse, JEB had slashed 30% off its programming time – a figure that is destined to improve as the company enhances its understanding of the machine.
….and then the pandemic struck
Just two months after installing the Nakamura-Tome AS200LMYS, the world went into lockdown with the aerospace industry and its supply chain heaviest hit. For JEB Precision, the new order that justified the Nakamura purchase was put on hold. Commenting upon this, Michael Bebbington continues: “The family of aerospace air handling system components was forecast to be 25% of the capacity of the Nakamura. Whilst this work has not been lost long-term, we needed to fill the capacity of the Nakamura throughout the pandemic. As a business, the impact of Covid-19 has not been as devastating for us as it has been for many others. The majority of our work is in the scientific instrument industry and we manufacture a lot of parts and assemblies for mass spectrometers and electron microscopes which have been required by the scientific community throughout the pandemic. We looked at some of our existing parts with multiple set-ups and how we could transfer those parts to the Nakamura to reduce set-ups and improve throughput and productivity.”
With increased availability on its new Nakamura-Tome AS200LMYS, JEB identified a scientific part that is used on a quadrupole analyser assembly that could be transferred to the new turning centre. The long-term 304L stainless part had historically been machined with three turning operations and an additional two milling operations. This process included one rough turning operation with two subsequent finish turning operations on Hardinge turning centres that were followed by 4th axis drilling, countersinking and 3.2mm wide slotting on a machining centre with a final operation of drilling holes on a PCD around the flange face on a fifth machine. By transferring this job from a multitude of machines to a single operation on the Nakamura-Tome AS200LMYS, JEB Precision reduced the machining time by almost 30% from 28 minutes to 20 minutes.
Once again, the major savings arrived from reduced set-ups, improved throughput and quality as well as the freeing of capacity throughout the facility. The previous process required 8 hours of set-ups across the respective 5 machines, something that has been cut to less than 5 hours. Commenting upon the benefits, Michael Bebbington says: “As our familiarity with the Nakamura improves, so will our set-up times. It has instantly improved productivity and reduced set-up times by more than 30%. However, this is not the only reason behind the purchase. Single set-up machining has reduced manual handling and improved process reliability, throughput, precision and overall quality.”
Looking at lead times, Michael Bebbington adds: “With the considerable complexity of many parts and the number of set-ups, the Nakamura has made an evident impact on lead times. For example, the quadrupole analyser component would have taken at least 3 to 4 weeks for us to get the first parts through the shop floor – with the Nakamura we can set the machine and finished parts can be out of the door in 24 hours. As we get more parts programmed and stored on the Nakamura, we will improve the lead times for many more of our complex parts. The overall benefit to our business will be huge as we free capacity on several older machines and we reduce the pressure on our skilled engineers to programme, set and produce parts on a number of machines.”
JEB Precision is delighted with the capabilities and benefits of its Nakamura-Tome AS200LMYS and the company has no qualms about buying more Nakamura machines in the future. As the world exits the pandemic and gradually returns to some semblance of normality, the 25 employee Cheshire company has continued its investment strategy with a twin-spindle turning centre with Y-axis milling capacity which arrived from ETG in February 2021. This was installed to replace an older machine. Commenting on this, Michael Bebbington concludes: “We’ve had Hardinge turning centres for over 25 years and some of our existing machines are 20 years old. The new machine was a direct replacement for a Hardinge machine that was at the end of its life.”
“The 51mm diameter capacity machine replaces a 20-year-old machine of similar specification that was at the end of its life. The Nakamura machine has proven invaluable for our business and as we continue to exit the pandemic and grow our business, we have no doubt we’ll be investing in more machines from ETG.”