CASE STUDIES

Margron Hip Prosthesis

When leading Australian orthopaedic surgeon Dr Ron Sekel wanted assistance to develop his revolutionary hip prosthesis, he turned to Westray Engineering. The US FDA approved Margron™ Hip Replacement System has a number of advantages over existing prostheses, including:

• a significant reduction in post-operative thigh pain
• easier alignment to eliminate risk of dislocation
• easier replacement when revision surgery is required (10-20 years after the initial surgery).

Westray was involved in the design and manufacture of the “neck” component, which together with the stem and femoral head, make up the prosthesis. The neck is forged in chrome-cobalt alloy, an extremely difficult metal to forge requiring very close temperature control. Material lubrication and control over the trimming operation are also critical to minimize the possibility of cracking. 

Flight Bars for Longwall Coal Mining

Westray is the only Australian manufacturer of fully forged bars for AFC applications in underground longwall coal mining.

Working with our customer back in 1998, we jointly developed a flight bar that:

•  had superior mechanical and wear properties compared to other bars on the market. This meant that the bars had higher resistance to breakage and lasted longer between changeovers.
• could be manufactured and supplied more quickly than bars sourced from European suppliers.
• Westray could manufacture small quantities of spare parts as and when required – compared to a full set quantity (typically 460-500 bars).

In succeeding years, Westray developed other one piece and two piece flight bars for use on 30mm, 34mm, 38mm and 42mm chain. All bars are closed die drop forged and are produced to a thickness tolerance of 2mm and a flatness of 1mm. The maximum forged mass per bar is typically 30-38kg – ie, up to approx 75kg for a two piece construction bar.

In addition, Westray supplies tee head spillplate bolts, hex head bolts and swage type fastening systems to secure the bars to the chain.

60kg Asymmetric Rail Forging

This project resulted in considerable cost saving to our customer.

Asymmetric rail is used in switches & turnouts where it is necessary to machine the rail so as to allow a train to smoothly (and safely), change direction from one set of tracks to another. If standard profile rail were to be used for this purpose, the vertical web would have insufficient strength to carry the weight of the train, so a special asymmetrical profile is used.

However, where the switch rail is required to be welded to the next length of rail in the track, the rail end must be the same (standard), profile so that it can be welded into place.

Westray has successfully developed a forging sequence to convert the asymmetric profile to the standard profile. The transition length is approx 750mm and the total length of each rail can be up to 20 metres. This has necessitated special handling procedures and equipment to do this job – all of which have been developed in-house by Westray. In fact, we even modified our factory layout so as to accommodate the rail lengths involved.

The major challenge of this job was to obtain a rail end profile that exactly matched the standard 60kg profile – variations from standard are unacceptable to the rail Authority engineers. There is very little room for error as we “massage” the metal from one profile to the other.

Prior to undertaking this project, our customer had to send the rail lengths to Europe to be forged. Needless to say therefore, having an Australian supplier has saved considerable cost and time compared to the previous practice.