Vibratory bowls take over from hand finishing

Galvanometers for laser-beam steering and scanning in surgical, analytical and other applications include a precision-machined housing in which the stator moves. At the Poole factory of Westwind Air Bearings, which manufactures galvanometer components for its US parent group, Novanta, these coil housings are CNC-turned from mild-steel bar to within grinding tolerances.

Dimensional accuracy is down to 5 µm, while surface roughness of the bore and outside diameter are Ra 0.4 and 0.8 µm respectively. It is curious then that such precise components are subsequently rumbled in batches of up to 400 in a pair of vibratory bowls supplied by PDJ Vibro.
Nevertheless, by developing a viable production route that incorporates vibratory finishing, Westwind has been able to save a lot of time and money in comparison with manual finishing. In addition, the uniformity of finish is better using the automated procedure as each component is processed consistently rather than being subjected to the inconsistencies of hand deburring. In total there are 12 part numbers, two-thirds of which are required in relatively high volumes of 3000 per week.
John Bradley, senior manufacturing engineer, says: “Fine fettling of the housing by hand, together with washing cycles before and after finishing, took three people five hours, i.e. 15 operator-hours, to complete a batch of 100 housings.”
Today, it is normally team leader Martin Graham who processes the components in the PDJ Vibro vibratory bowls in a two-hour cycle, without the need to wash the parts at all. They go straight to plating after a quick air blast to remove any media resting in the bore. Overall there is a 7.5-fold saving in labour cost compared with hand processing, and a 60% reduction in finishing lead-time.
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J&S Suprema grinder fits the bill at Bowmill

At its new Tewkesbury manufacturing plant dedicated to the production of Airbus landing gear kits, Bowmill Engineering has installed a Jones & Shipman Suprema Easy cylindrical grinder as part of its multi-million pound machine tool investment programme that includes eight new machining centres and high levels of automation throughout. The factory in Tewkesbury replicates a similar bespoke facility at Bowmill’s headquarters in Poole.

Nick Epps is the managing director of Bowmill and when it came to specifying the grinding machine, he admits a particular affinity with Jones & Shipman: “I’m a time-served toolmaker by trade and a good deal of my apprenticeship was undertaken using J&S manual machines. Here at Bowmill we operate three J&S machines in Poole, while a sister company – Taymar Precision Grinding – also operates a number of J&S machines.
“The Jones & Shipman Suprema Easy is a multi-purpose machine that is known as an ‘all-rounder’ being equally adept at processing high-volume production grinding work or fulfilling high-precision, small batch quantities and one-off work as encountered in environments such as ours,” he continues.
Bowmill has identified nine critical Class 1 kit components that require grinding tolerance finishes – retaining pins, uplock pins and spacers. Some are chrome-plated – a grinding challenge in itself – but all grinding programmes are stored in the memory of the machine’s Easy graphical software which offers a real advantage with its speed of set-up for dressing and grinding cycles utilising touchscreen technology.
Bowmill’s machine has a 650 mm grinding capacity between centres, although longer 1000 and 1500 mm capacities are available.
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Faster surface finishes with stream technology

A new generation of stream-finishing machines built by OTEC Präzisionsfinish is now available in the UK from Fintek. The SF1-Automation with chain loader is typical of the range. The ability to load and unload without stopping ensures the best return on capital investment.

In stream finishing, components are clamped in a holder and lowered into a rotating container filled with grinding or polishing media. The finishing effect is generated by the media flowing around the parts, as well as independent rotation of the components. The process offers very short finishing times.
Smoothing, polishing, edge rounding, deburring and removing coating droplets are all tasks at which the OTEC SF1 is said to excel. A combination of these is usually performed in a single operation, producing surface finish values as low as Ra 0.01 µm.
The SF1-Automation chain loader has 64 positions which can change in diameter according to the workpiece or tool to be processed. Parts ranging from 3 to 32 mm in diameter can be finished in a single batch.
Cycle times depend on the complexity of geometry and standard of finish required, but typically range from 30 to 300 seconds. The SF1 is suitable for both dry and wet finishing.
OTEC stream finishing units are available in different drum sizes and with different media/compounds. Fintek is able to supply all supporting services, including installation, training and support.
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Software and robots from Anca

Visitors to the stand of Anca at EMO (Hanover, Germany) this week will find out how the company’s latest software product launch, Management Suite, aids customers keen on adopting Industry 4.0 strategies (Hall 6, Stand K59). Also in action on the stand will be company’s first Dual Robot technology.

Anca’s Management Suite provides customers with the technology to monitor the performance of their machines no matter where they are in the world. The software also enables companies to run smart factories by providing live production information that enables staff to make data-based decisions about operational improvements.
CNC grinders from Anca now have the capacity to integrate several manufacturing operations into a single production line using the company’s first multi-robot production cell solution. Using a single robot, TXcell can automatically load both the grinding wheel packs and the workpiece. However, with the addition of a second robot in the TXcell, the solution can also complete secondary operations unmanned.
A further innovation in the EMO spotlight will be the new TX Linear, which will be on show for the first time in Europe. Among the stand-out features are Anca’s LinX linear motors on the X, Y and Z axes, an updated Anca AM5X CNC and servo drive system, and a new user-friendly front panel with touch-screen and ergonomic tilt adjustment to suit different operator heights.
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Delivering speed and accuracy to polishing firm

Prompted by increasing demand, Oldham-based North West Polishing Ltd is currently involved in further expanding its production facility and investing in new, highly efficient plant. As a major element in its latest expansion phase, the company recently purchased a VG T-300-3K polishing machine from Ellesco.

Managing director Andrew Marston says: “Having previously purchased polishing machines from other suppliers with somewhat mixed results, we turned to Ellesco. Together, we came to the conclusion that the T-300-3K polishing machine would satisfy our requirements. Following a trouble-free installation and operator training, our new polisher is now enabling us to process much greater quantities of products in a range of high-quality finishes. Furthermore, the speed of the machine ensures that we are able to deliver within the strict timeframes required by our customers.”

The VG T-300-3K uses three abrasive belt heads fitted with 300 mm belts, each driven by individual 7.5 kW motors. According to Ellesco, swapping from one abrasive belt grade to another is both quick and easy. The machine boasts pneumatic floating linishing heads that automatically compensate to ensure consistent pressure is applied to long, non-uniform workpieces. In addition, the T-300-3K provides powered adjustment for different thicknesses of bar and box-section products, while automatic belt tension removes unwanted oscillations.

With a through-feed conveyor, speed adjustment allows slow throughput for demanding applications such as heavy scale removal and pronounced extruder draw lines, through to fast throughput speeds for fine finishing and jobs where minimal heat generation is a requirement.

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