E-Tech grinding machines deliver unique
combination of speed and precision for Dawson Shanahan

A dedicated manufacturing cell, comprising four automated high speed grinding machines, is playing a crucial role in helping Dawson Shanahan, the specialist cold forming and precision engineering company, improve the accuracy of finished parts and levels of productivity for components supplied to customers in the medical, automotive and electronics industries. Developed in conjunction with Earlsdon Technology (E-Tech), the grinding machines use specialised tooling to achieve surface finishes with tolerances that the company believes are more accurate than anything previously on high speed systems of this type.

Dawson Shanahan is one of a small number of independent engineering companies to specialise in both cold forming and precision engineering using a wide range of conventional machine tools. The company has production centres in Potters Bar and Welshpool and designs, produces and supplies finished components to customers throughout industry and around the world, with almost 80% of its sales being exported.

The E-Tech grinding machines include groove, slot and centreless grinders, and have been installed as part of an ongoing development programme to increase manufacturing capacity, especially for precision parts that are often based on high performance steels or other exotic engineering materials. Jeff Kiernan, Commercial Director at Dawson Shanahan, explains that, "We've seen a considerable increase in demand in recent years from customers looking for component parts produced to ever tighter tolerances - often to within a few microns - for both small batches and large volume production runs. As a result, we needed to expand our machining facilities, especially our grinding cells, to increase productivity while enhancing levels of quality and repeatability still further."

Dawson Shanahan has worked closely with E-Tech to develop the new slot, groove and centreless grinding machines. Wherever possible, these use common features, to simplify operation and maintenance; for example, twin grinding spindles with dressable and demountable Cubic Boron Nitride (CBN) vitrified grinding wheels, plus automatic part feed and orientation systems, using standard bowl feeders and pneumatic air conveyors.

Key to the successful operation of the machines has been the development of special purpose CBN grinding wheels, carried out by both companies in conjunction with the grinding wheel manufacturer, Asahi Diamond Industrial. These 400mm diameter wheels typically operate at speeds of 4,000rpm and are automatically balanced, to eliminate vibration, and dressed during operation, with the latter using in-situ diamond dressing wheels to maintain exact outer edge profiles and a long operating life. Machine control is via standard Siemens touch screen PLCs, using bespoke programming, which also provides the facility for detailed diagnostics, with data being downloaded for review as part of Dawson Shanahan's extensive ISO quality control procedures.

Combined, these features are enabling Dawson Shanahan to achieve precise and consistent tolerances. "We believe that we are reaching levels of precision for high speed grinding that are currently unrivalled by any other company in Europe", points out Jeff Kiernan. "For example, we're producing finished components in 2.5 seconds that are machined to within 0.7microns over a surface area of just 3.0mm²; there is no need for further polishing or burr removal. Additionally, many of the parts that we manufacture typically incorporate slots with chamfered profiles ground into shafts measuring several millimetres in diameter; here we can hold tolerances of 20 minutes of a degree, which over an extremely small area equates to levels of precision of just a few microns."

The high operating speed of the grinding machines, even with short dwell times, demands that extremely efficient, high pressure temperature controlled cooling systems are used to prevent problems caused by differential expansion of tool parts or burning of components during manufacture. The cooling systems incorporate specially designed, multi-head spray nozzles, with pressure regulated oil being circulated through the machining spindles to maintain a consistent temperature. The coolant systems also feature sophisticated centrifugal filtration, while extraction units ensure that all oil mist is removed safety from the machining areas.

Jeff Kiernan concludes, "The E-Tech machines are enabling us to move our precision grinding operation to a new level, in terms of speed, capacity, flexibility and accuracy. Alongside our overall engineering and cold forming services, this will play a vital role in helping us expand our business in high-technology export markets, especially in North America and the Far East."

Dawson Shanahan in profile
With over 60 years experience, Dawson-Shanahan Limited is the leading global specialist in cold forming and machining of high precision, customer specified copper, aluminium, ferrous and assembled components. Established in 1945, the company is based in Potters Bar, Hertfordshire and currently employs 55 people in its 2800 m² purpose built factory.

Dawson-Shanahan offers a complete solution, with everything from prototype to production, being designed and manufactured in house to reduce both manufacturing lead time and costs for its customers.

With 50% of its business being exported, the company's products meet the demands of a wide range of sectors including aerospace, automotive, electronics, laser, medical, packaging, plasma, power distribution, telecoms and welding.

For further information visit the company's website: www.dawson-shanahan.co.uk or e-mail: info.dawsonshanahan@4cm.co.uk

Small multi-taskers for micro assembly

The new MWPG 20 Miniature Changing Parallel Gripper from SCHUNK is now opening up new application possibilities in the optical engineering and electronic production sectors. The worlds' first quick-change miniature parallel gripper with standardized DIN interfaces has an OD that is less than 20mm. Optical monitoring, a large through-hole and a large range of accessories make this miniature gripper an all-rounder.

This new miniature gripper is made of stainless steel and has a weight of just 26g. In order to avoid frictional loss due to mechanical deflection, two horizontally positioned piston areas provide the jaw drive. The jaw motion is mechanically synchronized via a special ring system. On request, if one of the two fingers should be fixed for example, a forced coupling will not be necessary. Free of scope, smoothly running cylinder pins provide jaw guidance. Therefore gripping forces up to 5N with an adjustable stroke of up to 1mm per finger are possible.

With the MWPG 20, SCHUNK has found a smart solution for ensuring continuous monitoring of the gripper fingers. It is done via an optical sensor, which is located inside the changing head,  making feed-through of the signal from the gripper to the head no longer necessary. Moreover, the MWPG 20 incorporates a central 7mm diameter through-hole that can be used for feeding components, monitoring with a machine vision system or for laser welding. In case of a sudden energy drop, an externally fitted spring ensures the gripping force is maintained.

The MWPG 20 can be directly mounted to the robot-sided head of the SCHUNK MWS 20 miniature changing system and adapter plates are not needed. It is supplied via two direct hose-free connections with compressed air. The matching MWM changing rack is used for organising and allows a quick, automatic change of tools and grippers.

For further information, e-mail: info@gb.schunk.com or view website: www.gb.schunk.com  Refer to page 162

Schunk: Latest edition of toolholding catalogue

As the market leader for clamping, workholding and gripping systems, Schunk has now issued its latest catalogue for its toolholding systems. The new edition that was launched just before the EMO exhibition with highlight a vast array of new solutions that will appear alongside proven technologies to offer the marketplace a complete toolholding program from the innovative family owned company.

Highlights in the new edition will include the powerful TENDO-E compact hydraulic expansion toolholder and the TRIBOS Mini; the first precision toolholder for direct clamping of very small shank diameters as used in micro machining applications.

Points of focus in the new catalogue will be the TENDO family of hydraulic tool holders, the TRIBOS polygonal clamping technology, the SINO-R expansion toolholders and the CELSIO heat shrinking system. Moreover, the new catalogue comprises information on the universally suitable GZB-S intermediate sleeves, mechanical toolholders such as the ER collet chucks, Weldon end mill holders, CNC Short drill chucks, combined shell end mill adaptors and face mill arbors.

With such a vast selection of innovative new products, view website: www.schunk.com to view and download the new catalogue. It can also be ordered in CD format or alternately emailed to customers upon request.  Refer to next page

VOLLMER sharpens its profile for metalworkers

At EMO 2011 VOLLMER welcomed 'The World of Metalworking' to its stand to view first hand its expanded range of grinding and eroding machines. A major highlight of the exhibition was the automated ExLevel simulation software for the QXD machine tools that enables various PCD (polycrystalline diamond) tools such as drill bits and milling cutters to be machined in one clamping operation. Additionally, Vollmer presented its comprehensive concept for services as well as the new CM200 and CMF200 grinding machines and the exceptional 'Solution K850' grinding machine from the Loroch subsidiary.

The technology and service available from Vollmer at EMO 2011 focused upon introducing the new grinding machines as well as modular expansion options for existing machines. Renowned for its service packages, Vollmer  highlighted the maintenance, servicing and support available which is complemented by first class instruction, training and financing packages that are all geared to the customers' existing machine tool programme. The combination of the 'complete package' to complement the exceptional machine tool range was a major hit at EMO.

QXD 200 - extremely adaptable
The universal QXD 200 and the QXD 400 machines proved a huge success for manufacturers being particularly attentive to modular expansions for PCD machining. Through simple retrofitting or integrating, the QXD 200 can erode and polish the PCD bit in one clamping operation. Face-milling cutters, groove cutters, drill groove cutters and other cutting tools can be polished in an oscillating manner according to the automatic touch mechanism on the PCD bit. The process is set up so that the PCD bit is only polished directly behind the cutting edge. This shortens the machining time and lowers production costs. PCD milling tools can thus be produced automatically and without human intervention in uniform quality and in high quantities.

With the ExLevel simulation software the QXD 200 also proves that the Vollmer machines can sharpen complex geometries of PCD boring tools precisely to the micron. Even less experienced operators can simulate, measure, erode and grind with sandwich panels or sintering techniques in one combined process with the ExLevel PCD boring tools.

Receiving their show premiere, the CM200 and CMF200 are fully automatic grinding machines for manufacturers of hard metal tipped circular saw blades. This heavyweight duo demonstrated how to sharpen the edges of metal circular saw blades with remarkable precision. These new innovations will be available to the marketplace in the near future.

Services - geared to any machine
Another trade fair emphasis from Vollmer was the expanded service concept for grinding machines, which is now strongly integrated into the machine portfolio. From consultation and financing to start-up and training, maintenance and servicing as well as upgrades and software, Vollmer services cover all phases of the machine lifecycle. This topic was presented in terms of contents and also as an architecturally integrated module at the Vollmer stand, a feature that cemented the company's reputation as a complete service provider.

Loroch - a fully-automated grinding machine
At EMO the Loroch subsidiary of Vollmer also had a presence with its saw blade sharpening machines for the CBN-abrasive grinding of metal saw blades. The Loroch showpiece was the 'Solution K850', a fully automatic CNC-controlled grinding machine with four axis movement for the sharpening, re-toothing and automatic chamfering of metal-cutting circular saw blades.

"For EMO, we sharpened our profile even more precisely for the high requirements of the metal cutting industry. We see this trade fair as an ideal platform, not only to present our comprehensive sharpening programme for tool machining, but also to stress the importance of our accompanying services", says Dr. Stefan Brand, Managing Director of the Vollmer Group. For further information, e-mail: admin-uk@vollmer-group.com or view website: www.vollmer-group.com