Cutting cycle times for sintered parts by more than a half

Paul Boughton

Superabrasive machining technology is drastically reducing the cycle times for producing parts manufactured from sintered metals.

Sintered metals are used increasingly in the automotive industry, due to the requirement for vehicles to go longer intervals between services. As a result, there is a move away from engine drive technology based on rubber belts and pulleys, to chain drives and sprockets. It is precisely these latter components - and gears - where sintering comes into its own. The technology offers the advantage that it can be tailored to suit all requirements, enabling it to become established as a highly efficient and economical manufacturing process.

Although valued for their homogeneous and stress-free composition, materials that have undergone the sintering process are notoriously difficult to machine and are totally unsuitable for conventional turning.

However, the High Efficiency Deep Grinding (HEDG) techniques provided by Holroyd's Edgetek machines (Fig. 1) are an effective answer to this problem.

This superabrasive machining technology (is drastically reducing the cycle times for producing automotive parts manufactured from sintered metals, in one case from 1 minute 10secs per component to just 22 seconds.

Holroyd's Paul Hannah explains: "The use of an Edgetek SAT (Superabrasive Turning System) has enabled one automotive manufacturer to machine powdered metal timing sprockets and reduce tooling costs by 75 per cent as a result of the ability of Edgetek's ability to perform interrupted cuts successfully."

"In another automotive application a sintered triple drive sprocket was extremely difficult to turn conventionally due to the requirement for interrupted cuts. Previously, our customer was using tooling with CBN inserts costing from 50 to 75 dollars each. These were turning each sprocket groove in 1 minute 10 seconds, but were lasting only a maximum of 50 components, resulting in a consumable parts cost of around $1US. Machining the same component on one of our Edgetek SAT machines has reduced the cycle time from 1 minute 10 seconds to just 22 seconds. Moreover, throughput has been increased greatly to 15000 components per CBN wheel (costing US$500), and set-up and consumable parts costs have been reduced commensurately, the latter to just 3.3 cents per component".

In addition to sintered sprockets and gears, the Holroyd Edgetek machines provide unparalleled levels of productivity in the manufacture of rotors and impellers, medical instruments, hand tools, air foils, nozzle guides, airframe actuation components, ducting supports, mechanical seals and many more. These components are often manufactured from among the most difficult to machine materials available, including Ceramics, Nickel, Tool Steel, Waspalloy, Inconel, Hastelloy and Stellite.

The flexibility of the design and the wide range of configurations available enable the Holroyd Edgetek machines to serve the broadest spectrum of industry types, including power generation, automotive, aerospace, medicals, tools and general engineering. The machines can be tailored by Holroyd to suit specific applications and be supplied as complete turnkey solutions as part of a manufacturing cell.

Holroyd has expanded its technical support team and introduced a new product-wide support structure to help customers get the best from their machines in terms of performance, reliability and whole life costs.

All areas of production and machining using Holroyd machine tools are also subject to a pro-active approach to improved tooling and software, from updates to retrofits, upgrades, service, maintenance, preventative maintenance and breakdown support.

The introduction of the technical support team is an answer to the production pressures of a highly competitive global manufacturing base. It provides a mechanism whereby customers can ensure that their production can be maintained at its most efficient and profitable level.

Advice and support for any production or service issues can be dealt with quickly and efficiently by Holroyd's experienced mechanical, electrical, software and commissioning Engineers who, between them, are able to provide the ideal solution, regardless of when the need arises, or how complicated the issue.

The experience of the team means that often a phone call is enough to solve an issue with any machine. This is because the engineers have been involved in the design, operation and set up of all Holroyd machines, providing a pool of knowledge and experience that customers can draw upon at any time of the day or night.

In cases where problems cannot be resolved over the phone, Holroyd engineers are able to travel at short notice to ensure that machines are returned to full production as soon as possible. This is also the primary objective in cases where the onsite work involves complex retrofitting and upgrade work, which is undertaken by Holroyd's experienced team and fully guaranteed.

The technical support team also helps companies to maintain competitiveness, by providing advice on new tooling and software developments. Holroyd is in the unique position of employing the same machines in its own production as it sells to the world market. This means that the company is always at the leading edge of tooling and software developments, providing an ongoing database of manufacturing experience, which benefits users of Holroyd products worldwide. The dynamic nature of the database enables Holroyd to offer the latest advice and solutions on any tooling issue, and also on the latest developments in machine code and profiling software which are available to customers.

Complementing the technical, support and maintenance facilities provided by Holroyd's new team is direct access to all stocked parts for Holroyd and Edgetek machines. This facility is crucial in breakdown or pressurised maintenance situations, allowing replacement parts to be despatched the same-day to restore production or to meet tight maintenance deadlines.

Commenting upon the introduction of the new service, Paul Hannah, said: "Holroyd is constantly developing the capability of its machines to ensure that they offer performance that is comparable to, or better than, any in the world. However, the fast moving nature of the global manufacturing economy means that new barriers are being broken all the time, bringing improvements in manufacturing that our technical support team can provide to our customers. At the same time, the need to ensure maximum uptimes for production means that we are always looking at ways to improve our service. The combination of our best technical engineers into a elite support group seems to us a good way of achieving this."l

Holroyd is based in Milnrow, Rochdale, England.

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