When a monster truck shares the road with a small passenger car, the car driver usually prefers to be pretty sure the truck’s parts were well built and left the factory functioning perfectly – especially the brake system. Chances are that Masport Foundries played a part in ensuring those crucial truck brake systems will do what they must. 

by Jenny Pretorius

Following Masport Foundries’ recently signed contracts to manufacture brake drum and hub subassembly units for three prominent global truck builders, the Masport engineering department acquired a state-of-the-art Okuma VTM65 vertical lathe (VTL) machine to perfect the workshop’s capacity to do this high-end work.

The units will be exported to be used on Kenworth and Paccar’s Bayswater, Melbourne and Volvo’s Brisbane truck assembly lines.

Mt Wellington-based Masport Foundries Ltd, formed in 1911, is New Zealand's largest metal casting production plant. Employing around 100 people at its Auckland plant, the foundry manufactures high-integrity iron castings. Each of these castings requires close monitoring to ensure dimensional accuracy and adherence to the metal's tight metallurgical properties.

The company supplies a wide range of castings and manufactured products into the agricultural, automotive, structural and mineral processing industries, as well as consumer durables, including for the Masport-branded solid fuel heaters. More than 90 percent of the products manufactured are exported to customers in Australia, India, China , Brazil , South Africa and the US.

Masport has extensive and flexible machining capability with 10 CNC machining centres. It specialises in finish-machined automotive cylinder heads, brake drums, hubs and rotors for truck and auto OE and aftermarket sectors. Specialist rock crushing machine spares are another niche market, such as tungsten carbide/iron composite wear parts.

The foundry uses a high speed DISAFORMA green sand moulding system, high efficiency electric furnaces and both shell and cold-box core making. In-house tooling manufacture and heat-treatment furnaces as well as the latest model spectrographic alloy analyser round out the foundry equipment. Magmasoft solidification simulation software is available for special projects.

Masport Foundries general manager Wolf Schmahl says Masport engineers have worked with an Okuma on loan from a sister company before and knew the efficiencies the brand offers were an exact match with what the new production model required. “We sat down with Okuma’s Fred de Jong, and he and his team advised us of our options.

“Okuma is known to be a market leader in all respects, the Rolls Royce of machining centres. We got what we paid for – reliable plant with impeccable workmanship, focused assistance before, throughout and after the sale, a company who kept us appraised and on whose promises we could rely. Even considering Masport is a successful company with an established reputation for excellence, the Okuma is a step up,” he comments.

He explains when making the variety of hub, brake drum and brake rotor castings for light and heavy trucks and trailer applications Masport supplies to the market, dimensional accuracy and very tight tolerances must be achieved. “Our older CNC lathes did not always deliver these specs reliably. The new Okuma VTM65 VTL significantly improves our ability to deliver these tolerances while being able to machine large and heavy hubs and drums, some of which require interrupted cutting and are balanced following assembly.”

Fred de Jong says when considering Masport’s particular requirements for machining larger diameter and quite deep truck brake drums the VTM65 was an obvious superior solution. He explains why: “The VTM-65 has all the features of a vertical lathe but has the distinct advantage of a single tool mount turret with 36 or 60 tool auto tool changer (ATC), which means the issue of interference from adjacent turret mounted tools is completely eliminated.

“In addition, the VTM65 arrangement has highly rigid milling, drilling and tapping capability using standard BT50 taper rotating tools. Turning tools are also BT50 taper mounted via the ATC and are unique so the machine knows to clamp the spindle rigidly with a curvic coupling arrangement to orient it correctly, which results in high accuracy and repeatable turning performance, even with intermittent cutting,” he says.

Mr de Jong reflects on the Okuma machines that the Tiri group of companies, to which Masport belongs, have purchased in the past and says that he is pleased to see that the group has once again found good justification to invest in a higher quality longer-term Okuma solution for this project.

He believes vertical lathes are not considered often enough in the New Zealand market. “VTLs typically have high rigidity and are easier to load work pieces into, with gravity being helpful rather than a problem. VTLs also tend to have a smaller foot print than typical horizontal lathes and because of their simplicity of design tend to be slightly lower cost,” he says.

Okuma produces the full range of VTLs and vertical multi-tasking machines as previously built by the Japanese Okuma and Howa. “Now that these machines are all in the Okuma stable they can be offered with either Fanuc or Okuma OSP controls, which gives the customer even more choice,” he says. He adds the VTM series ranges in turning diameters from 650mm to 2,000mm and respective swing diameters of 750mm to 2,400mm. “For additional flexibility of 5-axis capability the VTM-YB series offers some really good solutions as well.”

Masport has Telarc accreditation in ISO 9001 and ISO 14001 management systems.