08 May 2012
Increasing productivity — significantly
New sliding-head lathe raises output at precision-parts manufacturer by up to 30%
Neida Blue 62 has continued its investment in the latest mill-turn technology with the acquisition of a 38mm-capacity sliding-head lathe. The Isle of Wight company has 24 CNC machine tools for turning and prismatic machining, including multi-axis sliding-head bar lathes with capacities spanning the range 16, 20 and 32mm — plus the latest 38mm machine.
The Freshwater operation holds accreditations to ISO 9001 and the automotive quality system standard TS 16949. Precision components are produced for a wide range of industry sectors, including aerospace, marine and automotive. A wide variety of materials is machined, including stainless steels, nickel alloys and titanium. The majority of production involves high-added-value close-tolerance work, with less than 10µm dimensional accuracy frequently held.
The company’s first two Star sliding-head machines were inherited from Isle of Wight sub-contractor Blue 62, when Neida Products, Stoke-on-Trent, bought the company in 2005. Neida’s policy is to invest in the latest machine tool technology; in the case of the machines from Melbourne-based Star Micronics GB Ltd (www.stargb.com), this involved the purchase of three 11-axis twin-turret ECAS-32Ts, two of which were installed in 2011, and four SV-series sliders, all with extensive driven-tooling and back-working capabilities.
Larger capacity
The 12-axis triple-turret ST-38 takes sliding-head technology a stage further in terms of productivity, as Simon Fisher — Neida Blue 62’s general manager — confirms: “The 38mm-capacity lathe obviously allows us to turn bigger-diameter bars than on the other Stars. However, the main reason for buying this machine is its greater stability and the associated productivity gains, together with much quicker set-up times, resulting in greater flexibility and competitiveness. The ST-38’s very high mill-turning efficiency is also attributable to the heavy-duty build, as well as the additional power of the spindles and driven tooling, which uses the latest motor-control technology. Compared with the 32mm Star ECAS and SV models, which themselves are capable of impressive throughput, the ST-38 achieves even higher productivity; and whereas a 12mm-diameter indexable-insert carbide mill was the maximum size that we could previously use on our sliders, a 16mm cutter can now be used.”
In practice, the machine — thanks to its robustness — is reserved mainly for cutting 316 and 304 stainless-steel components, for which purpose the machine has been fitted with a high-pressure coolant delivery system. Another factor in the ST-38’s high productivity is its faster acceleration and deceleration rates, which translate into shorter idle times during rapid traverse; and because there are three 10-station turrets, rather than two tool carriers as on Neida Blue 62’s other Stars, there are more cutters in the working area, especially with the multiple tool-holder options in use. In addition, there are more live positions available; this means that fewer cutters have to be changed between batches (normally between 200 and 3,000 parts), so change-overs can be completed within minutes rather than hours, giving the company the flexibility to respond to changing customer requirements more promptly, while reducing the need for large production runs and allowing a quicker response with regard to development and prototype work. The three-turret configuration also maximises the potential for one-hit machining (which is the norm) and minimises cycle times when it is possible to program three tools to be in-cut simultaneously.
Greater productivity
Mr Fisher says: “Taking these factors into account, the ST-38 is up to 30% more productive than our other sliders; the advantage is greater than we thought it was going to be. The latest Star sliding-head lathe technology amounts to a game-changing advance, not to mention the machine’s bigger capacity, which takes it further into fixed-head territory.”
The ST-38 incorporates Star’s advanced motion-control system for programming relatively simple turning operations, resulting in very-high-speed cycles on the machine. For parts involving a combination of simple and complex routines, the complete cycle can be made up from both motion control programming and traditional ISO code.
Stuart Bannister, section leader at the Isle of Wight factory, said that the effect of motion control programs running in the Fanuc 30i-A CNC system is to optimise the position and feed rate of each tool, allowing minimum cycle times to be achieved.
An added advantage is a significant reduction in non-cutting times, as tools are constantly positioned as close as possible to the component, ready for the next cut. This results in tight synchronisation between axis movements, which he estimates can take a further 15-20% out of some cycle times. Star ECAS lathes also feature this facility.
At a recent global presentation attended by Neida, it was suggested that customers now accept that product quality and price are to an extent norms across industry, but that the service provided by supplier companies is still highly variable.
This vindicates Neida’s strategy for growth since it was established in 1969, which has been built on high levels of customer service. The group’s philosophy is to invest in lean manufacture and one-hit machining using the best possible plant, to give customers cost-effective acquisition of components and total flexibility of supply. This approach certainly paid off in 2011 — a year in which turnover at Neida Blue 62 increased by 28%.
However, this level of performance could not have been achieved without investment in people as well. It is noteworthy that six of the company’s 26 staff are in training: three are apprentices, and the others — manual machinists — are being up-skilled to operate CNC machines. Neida finds that training staff internally leads to higher skill levels and better long-term retention.