Okuma Australia - ROYAL AUSTRALIAN MIND

Details: Published: 28 February 2013

Most people are aware that the Royal Australian Mint makes familiar coins ranging in denomination from 5 cents to $2. What is not so well known is that the Royal Australian Mint is like any other business, manufacturers of a range of products and consequently must develop new designs and improve processes to be more cost effective.

Supporting its own workshop, the Royal Australian Mint requires a vast array of tools and machines to facilitate design, make moulds, create dies, strike coins, package and deliver the final product. Key machines in the tool box are Okuma Australia’s Vertical Machining Centres, model MB56VA.

Increasing demand for higher accuracy, quality and more detailed coins for the collector market requires the Royal Australian Mint to improve productivity and to find machine tools that provide a higher level of precision and throughput. In the past, the Royal Australian Mint had only one vertical machining centre that required a substantial amount of manual input by operators to achieve the end results needed. Recent tenders in late 2011 and 2012 saw the purchase of two Vertical Machining Centres from Okuma Australia – the MB56VA S15 models.

The model is designed to provide greater levels of efficiency, utility and high speeds. Boasting a 15,000-rpm spindle, through-spindle coolant, drum-type filter chip conveyor and the addition of Okuma’s standard feature Thermo-Friendly concept to maximise stability as the machine heats with usage, the Okuma MB56VA ticked all the boxes of the heavily specified tender documentation, including training, service and support.

“We make a number of tools and spare parts to support the production of coins in-house,” says Ashley Moffat, mechanical technician, Royal Australian Mint. “With an inventory of more than 10,000 items, we need machines that are versatile and accurate. This machinery directly or indirectly comes into contact with around 90% of that inventory.”

Of the 200 components made on a more regular basis, it is estimated that the use of the Vertical Machining Centres has given the Royal Australian Mint a 10 - 20% increase in productivity.

In particular, one part made frequently is the coin stacker tubes. These parts are integral to the in-feed system that drops the coin blanks into the press to be stamped with the obverse and reverse designs (‘heads and tails’).

In the past, the coin stacker tubes were sent through a CNC lathe and were then transferred to a milling machine for the final machining processes, requiring several manual operations. The process would take several days, but now can be achieved in a matter of hours on one Okuma MB56VA Vertical Machining Centre.

The thermo-friendly concept and accuracy

The Thermo-Friendly concept featured on the Okuma range of vertical machining centres is designed to compensate for movement in the machine as a result of expansion with heat during operation. Both the spindle and casting have been fitted with this feature. The advantage of this concept is the machine’s ability to maintain exceptional accuracy – down to the micron level.

“Accuracy is vital to the Mint to ensure security markings and delicate text are precise and repeatable,” says Ashley. “The beauty of this concept is that we are not even aware that it is doing it. We know it occurs, but it is so self-managing, that the operators do not need to do a thing. It just happens.”

Service and support

The accuracy and efficiency of the machinery is certainly important to the Royal Australian Mint but so too is service and support. With few engineering firms in Canberra to service the Royal Australian Mint, a key criterion in the tender was the supplier’s ability to support the workshop in training, service and maintenance.

Service in this instance took on a whole new meaning.

The Royal Australian Mint was originally a purpose-built building constructed in the 1960s, but over the years has seen many renovations and refurbishments so that getting equipment to the workshop is no easy task. Therefore, installing a vertical machining centre was a challenge to get through the labyrinth of narrow corridors and doorways.

“At the beginning of the tender process we conducted a site inspection to see just how tight the squeeze might be for the Vertical Machining Centres,” recalls Ian Shaw, Assistant Sales Manager, NSW, Okuma Australia. “It became obvious very quickly that the corridor space would give us no more than 10 millimetres each side to manoeuvre the machine into place.”

On the day of delivery, the machines were stripped of the external guards, automatic tool changer, spindle cooling unit and electrical cabinet so that the body of the machine could fit through the narrow corridors. In some instances the light switches and signage were also removed from the walls.

“There is no doubt that it was a challenge to install the Okuma MB56 into the workshop,” says Ian. “If we had not conducted a site inspection during the tender process we could not have planned how the installation was to be achieved. If you can’t install it, it may as well stay on the truck.”

“The team was very professional when it came to the installation process,” says Ashley. “All the pre-planning paid off and we were up and running within a few days, including the commissioning process.”

Setting the program

As with any CNC-based machining centre, the Okuma MB56VA S15 models utilise coded programs to produce the product features. Using the interactive graphics function (IGF), programs can be manually installed at the machines’ interface or via PC connection to utilise designs developed through CAM software.

In this instance, the Royal Australian Mint has a well established history and workflow using CAM software to create designs offline which are then transferred to the machining interfaces. Okuma Australia was able to provide the necessary interface to maintain the established work procedure, thereby significantly reducing the overall training requirements.

Initial training for the team at the Royal Australian Mint was conducted over a period of three days and provided as part of the tender requirements. Moreover, twelve months “bottomless“ training is also available to the Royal Australian Mint and forms Okuma’s standard training program for all new machine installations.

While much of the Mint is fully automated featuring robotics and AGVs, much of the behind-the-scenes work is not. Gone are the days when many of the spare parts were manufactured manually. There is no doubt in anyone’s mind that improving processes through automated machining centres has had a significant impact on productivity not just in production of spare parts but also in the design of new coins for the circulation and collector markets.

It has made good business sense for the Royal Australian Mint to invest in this type of technology to remain competitive in an increasingly demanding market. The machines provided the necessary precision, speed and reliability and the Okuma Australia team has rounded it out with superior support, training and service.