Parker Hannifin's hydraulics and pneumatics have been specified for a series of tyre curing presses that machine builder Harburg Freudenberg Maschinenbau GmbH has supplied to Michelin for its plant in Olsztyn, Poland.
With international demand for vehicle tyres heading towards being worth one billion Euros per annum, competition is tough. Companies such as Michelin are therefore constantly striving to improve productivity and efficiency and respond to the expectations of vehicle manufacturers and consumers in terms of safety, respect for the environment, price, comfort and ergonomics. When new investment was planned for its plant in Olsztyn, Poland, Michelin wanted to ensure that all materials, machinery (and components therein) would contribute to these objectives, which meant reliability, quality, low maintenance and cost-effective running. As part of this programme machine builder Harburg Freudenberg Maschinenbau GmbH was chosen to provide tyre curing presses and, in turn, Parker Hannifin products were specified as a single source of hydraulic and pneumatic components because of the company's expertise and proven record of accomplishment within previous projects with both Michelin and Harburg Freudenberg.
The curing process is where tyres get their final shape and tread pattern. Hot moulds shape and vulcanise the tyre. The moulds are engraved with the tread pattern, the sidewall markings of the manufacturer, and other markings required by law. Tyres are cured at about 150degC (300degF) for 12 to 25 minutes, depending on their size, and are then 'popped' from their moulds, taken to final finish and inspection. The demanding specification for the curing presses and the hydraulic and pneumatic components therein was drawn up by Michelin, and was exact, calling for quick start-up, precise positioning, cost savings, high efficiency, low maintenance, and, with future projects in mind, world-wide service support.
Project planning and custom parts
Working alongside other Parker European divisions (France and Germany), Parker Poland co-ordinated all specifications, drawing up the project plan and liaising with all parties concerned, proving the benefits of local support, service (and availability of parts), and has been on-call during the development, production and commissioning stages, even providing tailor-made components via Parker manufacturing plants in Germany. Products include hydraulic control units, power units, hydraulic cylinders, sensors, and valves, together with pneumatic connectors, hoses and couplings.
The column-type presses incorporate customised hydraulic roundline cylinders from Parker. The rod and piston assemblies are fatigue-free at full rated pressure, and the seals are housed in corrosion-resistant steel glands that retain the pressurised fluid while preventing the ingress of contaminants. The heavy-duty polymer bearing rings resist side loadings, and the wide separation of these rings reduces bearing stresses, extending the service life of the bearing itself. Together with a high surface finish to the high-density steel tubing to minimise internal friction and prolong seal life, cushions at the head and cap provide controlled deceleration, thereby reducing noise and shock loading extending machine life. These cylinders will give exceptional service in any rugged, tough, high demanding environment.
Maintenance is simple and easy with the rod bearing and rod seal being replaceable without completely dismantling the cylinder – and, in the event of an emergency, the flanges are spaced away from the head and cap to allow the bolts to be sawn through quickly.
Valves and control
Proportional hydraulic valves (and modular manifold system - NG16 and NG6) for direction, flow and pressure give high performance, comprising two-stage pilot-operated solenoids with electronic spool position feedback, and integrated control electronics. Performance is characterised by high-resolution flow control and repeatability, giving precise and reproducible control of actuator speed in rapid/slow modes, together with smooth acceleration/deceleration. The NG6 version included, for the squeeze cylinder function, a pressure-driven intensifier that allowed 220 bar holding pressure during curing, without the requirement of a high-pressure pump.
For control, monitoring and regulating, a mini pressure sensor (SCP) has been employed for rapid pressure-dependent analogue signals, using a zero point measuring cell with long-term stability, thereby eliminating the need for calibration. The compact unit is robust and the electronics are resistant to the effects of electromagnetic interference, and are protected from vibration and moisture. The standard G1/4 BSPP thread is made of corrosion-resistant stainless steel.
Custom power units
In addition, the power units, made to the customer's specification, meet all international standards, have low noise and filtration to guarantee a long life; the hydraulic piston pumps PV+ have low noise pressure, SensoControl, while the soft-seal (EO-2 chrome free) leak-free hoses and no-skive fittings have a three-year leakage-free guarantee.
Delivery of the first presses took place in the last quarter of 2005, with further deliveries through 2006, and 2007 when the programme will be complete. A key member of the Parker team is Gunther Eberhardt, Account Manager, who says: "With Parker Hannifin being a global player, we are in prime position to handle sales/service around the world. We have met all customer objectives, and in some instances have manufactured special versions of components specifically for this project.
"This project has been proof of Parker's commitment to listening and working closely, not only with the machine builder, but also with the end user, and considering the unique requirements of their particular industry – true teamwork!"
Another key team member, Dominique Marceau, Key Account Manager dedicated to Michelin, echoes these sentiments: "Parker has worked with Michelin for more than 30 years and is a highly valued supplier partner. Michelin needed worldwide duplicable equipment to meets its demanding technical specifications, and our wide range, knowledge and worldwide implantation enabled us to meet their expectations completely.
"This Michelin Olsztyn Poland project has been realised thanks to a team; Parker Poland, Parker Germany and Parker France have been fully involved and worked together to achieve a common goal for our customer and we are very proud."