The Crown of Australia
Old tyres have presented an increasing disposal problem in the last 30 years. The number of vehicles on the road around the world has grown enormously. Each year tyre sales worldwide are in the vicinity of 68 billion U.S. dollars.
In the USA alone, 10 million new cars every year represent 50 million new tyres that will need to be disposed of around two years later. Modern tyre designs, including steel belting, have made it more difficult to recycle them. Burning them is definitely not on in this day and age, and there are only so many racetracks in the world where they can be used as impact buffers.
On the other side of the world (down under) an Aussie engineering company, Crown Engineering, has been working with a local design and manufacturing company, Link Pty. Ltd., in manufacturing tyre recycling equipment to turn that old rubber into useable compounds. The granules that exit the tyre recycling machines have numerous uses – as an additive to asphalt in road building, for playground matting and for numerous other experimental projects, such as embankment ground fill.
As an example in the USA, the Texas Department of Transportation has had two notable projects that used immense volumes of recycled tyres. The first job was in Odessa, Texas, where the equivalent of 200,000 old tyres were used to produce 80,000 tonnes of crumb-rubber-modified asphalt pavement, which was overlaid on a 20-mile stretch of U.S. Highway 385. The asphalt-rubber hot mix helps reduce reflective cracking, rutting, surface oxidation and road noise, and lengthens the time between required maintenance. The second project involved using 4,500 tonnes of tyre shreds for embankment fill in various combinations on the loop 375 overpass in El Paso.
Crown Engineering is a 4th-generation family company, and possibly one of the longest surviving family engineering companies in the land down under. It was founded in 1920 by Wilhelm Suchting and his son Doug, who rented premises in an area which is now near the middle of the city of Brisbane. They established a blacksmith’s forge and installed a couple of second-hand flat-belt driven lathes. In 1923 they moved to larger premises at South Brisbane, installed some foundry equipment and began producing machined castings. The Brisbane City Council became one of their larger customers, but in an effort to develop a product of their own, they began producing single-cylinder stationary diesel engines for agricultural applications. Unfortunately, Wilhelm passed away suddenly one day in 1924 on his way to work on a tram, and so Doug was left to carry on the business.
During the “Reds under the Bed” era in the late 1940s, the moulders union caused so much strife in the moulding industry that the foundry had to be shut down. It was losing large amounts of money due to the go-slow work practices of the militant unionists at that time.
When the time came for Doug to step down, his two sons, John and Bill Suchting, took the reins. This was a good combination. Bill, with his university degree in mechanical engineering, was a whiz at mathematics and problem solving, and John, with his engineering apprenticeship behind him, was the practical hands-on man. They decided to move into more specialised areas, such as sprocket and gear cutting. They added milling and gear hobbing machines and found that the business began to grow steadily again.
In 1978, Ray Suchting, the great-grandson of Wilhelm, bought into the business. This was during an era in Australia when NC and CNC machines were starting to become high on the list of budgetary items for manufacturers. At the same time, the resources boom had started, and Australia was becoming a leading supplier to the Asian market of bauxite, iron ore, coal, copper, zinc, lead and almost any mineral you could think of.
The state of Queensland had enormous deposits of high-quality coking and thermal coal with very large seams close to the surface. Ray saw the company’s future in mining industry support, and the manufacture of spares for the huge walking draglines used for open-cut coal mining. Moving into this area was not easy, as the long established giants of medium and heavy engineering usually were first to gobble up the available work building OEM and replacement parts.
However, the unions, bad work practices, high overheads and government indifference caused the large engineering companies to falter, and one by one they began to disappear. This opened the door for Crown Engineering. “In the early 1990s our growth soared,” says Ray Suchting. Crown had developed new and more cost-effective methods of producing large gears and racks in small batch quantities. CNC machining had become an integral part of their production, and they utilized CNCs wherever they could. They upgraded their plant with new machines on a regular basis.
Factory space soon became a big problem. “Although we built a new 40,000-square-foot building in 1996, we have had to continually add to it,” said Ray. “We had orders for large roller circles, which are like huge segmented thrust bearings up to 60 feet in diameter and weighing 150 tonnes. They are used under the revolving cage on the walking draglines. Each roller circle has to be completely assembled and checked before delivery to the mines, and they take up an enormous amount of space when fully assembled.
“At the same time, it became necessary to move into gear grinding and checking, which meant more machine tools and more space.
We also had to become self-sufficient in heat treatment, as lead times and quality control for our large parts became an issue. So we put in our own oil quenching plant in a new factory separate to the main plant. We can now do case carburising of gears up to 2 metres in diameter and shafts up to 3 metres long and weighing up to 6 tonnes. Then we had to move the fabrication shop into its own area to make more room in the machine shop. We now have around 65,000 square feet.”
With the onset of the Asian economic crisis in 1997, and restructuring by some of Australia’s largest mining companies, the signs became ominous for Crown Engineering. “We had to look to other sources of work to supplement our order book – work that would fit the envelope of the CNC machines we had purchased for our mining part production,” says Ray. “Essentially, we had purchased large-capacity double column CNC machining centers, ram-type milling machines and larger CNC vertical turning machines. In saying this, we had always had a hole in our machining center capacity by not having a smaller vertical machine. We always crammed the small parts into the large machines, which were relatively slow, and inefficient to set up and break down on this type of work,” explained Ray.
“During 1997, we forged an alliance with Link Pty. Ltd. and started building tyre recycling machines. There were a number of smaller internal parts to be machined that we just could not afford to put on our large CNCs. We decided that we had to buy a smaller VMC to keep the larger machines free. We had been buying larger machines for nearly 10 years, and were not familiar with what was available in VMCs of around 1 meter travel,” Ray explains. “Our main criteria was that the machine would need to be easy to set up, be able to produce simple programmes easily on the machine control, have enough grunt to drill and tap large holes, take a decent cut in tool steel and have flexibility in program uploading and downloading,” he said.
Ron Newton, who runs Ray’s CNC department, was asked to make a recommendation. “At the end of the day, we chose a Haas VF-3,” said Ron. “It fit all the criteria and had a number of options which made it that bit more attractive. I reckon that it was a good value-for-money package, particularly with the 4th-axis drive included and the fact that the Haas dealer, Alfex CNC, is quite close to us. They have a full complement of spare parts in store, and they have factory-trained technicians on staff as well,” said Ron.
The tyre recycling process involves up to three separate machines for truck tyres or two machines for car tyres. In the case of car tyres, the first machine shreds the tyre into small pieces about 16 mm square and simultaneously strips the steel belting away from the rubber. The steel is separated from the rubber by magnetic conveyor belts. The second machine grinds the rubber into granules to a maximum diameter of 2 mm.
The first job Crown had to do on the VF-3 was produce 38 sets of grinding discs, which the grinding machine uses to grind the chunks of rubber into small granules. These sets comprise both fixed and rotating discs, which need to have pockets milled right through to allow the large chunks to be progressively ground into smaller granules as they pass through the grinding discs. There are 3 different rotating discs with 7, 9 and 10 pockets, and the fixed discs have 8 pockets. The principle of operation is probably similar to the hand-operated mincing machine that Mum used when she minced up the leftover roast to make a shepherd’s pie.
The discs are made from D2 tool steel, and 70% of their starting weight is machined away during the process. After using a 24 mm U-drill to drill a start hole in each pocket, a 20 mm diameter tipped endmill was used to cut each pocket out, taking 5 mm deep cuts at 2,000 rpm and 700 mm per minute feed. There were also 6 holes drilled and tapped 6 mm on a 259 mm diameter.
“As a testament to the accuracy and rigidity of the Haas VF-3, we didn’t need to take a final cleanup cut after cutting through the 20 mm thick discs,” said Ron. “Each 5 mm step-down was hardly noticeable, and the surface finish was more than acceptable for the application.” After machining, the rotor discs were oil hardened and tempered in the heat treatment plant.
Finally, the disc faces are ground flat, and then down into the bowels of the large fabricated steel frame they go, in an assembly with the shafts and gears.
It is not easy to find engineering companies in Australia that have experienced the sort of expansion in the last 10 years that Crown Engineering has. Ray Suchting says that remaining focused on keeping the business moving ahead, targeting niche markets, and taking calculated risks while keeping the overhead costs to a minimum are some of the main contributing factors.
At the end of the day, it is no different than most other successful businesses, and can be summed up by two words: “good management.”