Product category:
Abrasive machining - manual and CNC machines
News Release from: 600 Centre | Subject: Portal NC surface grinder, VMCs
Edited by the Manufacturingtalk Editorial
Team on 22 August 2005
NC surface grinder and VMCs bring orders
Purchasing a second column-type NC surface grinder - both machines manned by one operator, and adding on new VMCs is keeping a mould maker ahead of the competition.
Coventry based Burnsall Engineering is a company facing an ever-growing demand for machining capacity to satisfy not only its 50 years of expertise in the design and manufacture of injection, transfer and compression tooling for the rubber/plastic moulding industry but also growing business interest from the likes of medical and motorsport sectors for the supply of precision components Indeed, with the recent installation by 600 Centre of Shepshed near Loughborough of an Okamoto ACC208EX column-type NC surface grinder to join an existing ACC157EX machine, the company can now claim to have the two largest Okamoto surface grinding machines in the UK guaranteeing the accuracy of its toolmaking
This article was originally published on Manufacturingtalk on 22 May 2001 at 8.00am (UK)
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Burnsall Engineering has gained a reputation for being very selective in its purchase of machine tools to satisfy its flourishing and diversifying order book, and it was part of its impressive investment policy that led to the first purchase of a large capacity Okamoto surface grinder with a 1500mm by 700mm table size.
Said technical manager Alan Bratby: "We needed a large capacity machine and 600 Centre only had one in Europe that was close to our specification".
"The Okamoto ACC 157 EX was in Okamoto's German showroom and despite the fact that we offered no commitment to buy, 600 Centre transported the machine to Shepshed for us to evaluate under trial conditions, which certainly impressed us to have such a level of service and we bought the machine." However, with the business still growing, Burnsall Engineering decided it needed even greater grinding capacity and so returned again to the 600 Centre and this time ordered an even larger Okamoto 208 EX, with a 2000 mm by 800mm table capacity.
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The Okamoto ACC EX moving column range represents capacities from 1200 mm by 600mm up to 3000 mm by 800mm.
The ACC 157 and 208 EX both have a 510mm by 100mm by 127mm grinding wheel, 15kW wheel head motor, automatic cycle including dressing and Fanuc 21GA control.
Both machines will support a table loading of 2,500kg.
The machines operate on automatic cycle at the company which takes typically two hours to complete.
This means one operator can service both through a 10h shift, 5.1/2 days/week to grind materials that include EN8, P20 and stainless steels to tolerances that are often specified well below 0.010mm.
Burnsall Engineering now employs 48 people and has 27 CNC machine tools to meet its expanding customer base that includes an impressive 25% of turnover created from export.
Alan Bratby explains: "While our core business is still producing mould tools we are now winning regular business contracts from motorsport and medical companies to supply precision engineered components." The company philosophy is to regularly replace and update its machine tools, typically disposing of a machine each year and replacing it with the latest developments.
Burnsall's modern, 19,000ft2 manufacturing centre houses mostly Japanese-built machine tools, to which Alan Bratby comments: "We have found build quality to be consistent and good while their accuracy, durability and low maintenance offer longterm benefits that negate any issue of cost".
"We are truly aware that we can buy machine tools cheaper but our experience teaches us there is no substitute for first class quality and we have no desire to abandon this philosophy." With mould tool complexity increasing, Burnsall also had a requirement for a five-axis machining centre in order to improve efficiency.
Such was the impact of 600 Centre support and service that it soon returned to purchase two Fanuc Alpha vertical machining centres (VMC)s one of which, a five-axis version is saving up to 30% on cycle times.
Almost immediately following installation of the five-axis Fanuc Alpha T21iB Burnsall Engineering started to see an increase in enquiries for contract manufacturing.
Alan Bratby recalled one particular example: "We had an enquiry for 200mm diameter medial components made from 62HRC steel".
"Each part contained 120 apertures positioned to a tolerance of +/-0.01 mm and with a radial pitch that was toleranced to within 5 minutes of arc".
"However, despite the constraint of the component design, these components were machined very successfully." These and other components became part of an ever-increasing workload and led to a further Fanuc VMC purchase in 2003.
However, this time it was a three-axis T21iC version.
Maintains Bratby: "Component tolerances are getting ever tighter and the structure and sensitivity of these machines allows us to use cutters as small as 0.5 mm diameter - an invaluable asset in mouldmaking." Although Burnsall does not operate a night shift it is now running both Fanuc machines unmanned overnight.
For instance, some die profiling work can run for three days on the same cycle and because of the variation in work from toolmaking, the production of a considerable number of copper electrodes for use on the company's EDM machine - has also been undertaken.
A wide range of material is also processed now from stainless steel nickel/chrome steel through to aluminium, copper and plastics".
""Both these machining centres now represent a major acquisition for us," he insists.
The Fanuc Alpha has become popular in the mould and die sector thanks to its compact design coupled with high efficiency milling and hard metal machining capabilities.
Its Fanuc 16iMB CNC incorporates some major software developments by Fanuc such as A1 tool monitoring and life management.
In particular, the Alpha L servo control and A1 nano contouring software is well suited to machining a diverse range of materials from hardened steel to plastics and, through the high levels of auto-intelligence, ensure easy programming using menu-based operation with PC-like operational software for program editing.
The impressive cycle time improvements, witnessed by Burnsall are a feature of the machine's bell-shaped acceleration and deceleration curves that operate at 1.2G with immediate switching between feed and rapid traverse.
The system eliminates servo lag and maintains 'least tracking' error when processing high speed milling data.
The cutter is also automatically lifted from the workpiece when traversing the return path of a cut, further reducing cycle times".
""This is a very competitive industry and it is imperative to invest," concludes Bratby".
""Our business is stronger due, in part, to the roll-on effects of our continued investment".
"We must always look to improve our response times and engineer manufacturing solutions using the very best and latest machine tools".
"With over 50 years of business success behind us, even through difficult times for industry, we consider our philosophy and principles must be working.".
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