Sustainably and ergonomically cleaning difficult-to-access deep boreholes:
Machining Aluminium, cast iron and steel to form the core elements of custom-designed hydraulic solutions, POWER-HYDRAULIK manufactures control blocks. Weighing up to 1,000 kilograms, they are crisscrossed by numerous fluid channels. Residual moisture, particles and machining residues need to be removed to ensure precision and operational reliability requirements are met. This task is performed by a BUPI CLEANER® POWERTEC PRO installed in the autumn of 2015. The two-tank cleaning system features an integrated high-pressure cleaning module and a vacuum drier, achieving perfect cleaning results with far less than 500 µm residual dirt and leaving parts spotless. Equipped with a part handling system, it also improves usability. The installation’s superior energy efficiency as well as integrated RTG media treatment systems prolonging the useful life of all cleaning and rinsing liquids protect natural resources and the environment and help maintain reproducibly stable cleaning results.
Hydraulics are used where high forces need to be applied fast and precisely metered, continuous and from zero. Their applications include presses and injection moulding machines for industrial production as well as transmissions and braking systems for lorries, buses and rail vehicles. Self-propelled or tractor-pulled agricultural machines and attachments rely on hydraulic systems for their often complex movements. Excavators, for example, use hydraulics to lift or lower and to open or close their clamshells, to turn the entire machine on its chassis and for propulsion.
Core elements of hydraulic controls
As a leading system supplier, POWER-HYDRAULIK GmbH provides custom-designed hydraulic systems fully fitted with valves and equipped with electronics to industrial customers in the fields of machine tools and construction, environment, communal and agricultural machinery. The mid-sized company based in Sulz on Neckar, Germany, also doubles as a supplier to well-known hydraulic systems OEMs, in many cases supplying them with unequipped hydraulic blocks.
Depending on the application as small as a matchbox or up to one metre on each side, these blocks made of Aluminium, cast iron or steel can weigh up to 1,000 kilograms. Like Swiss cheese, they are crisscrossed by holes, in their case hydraulic channels. POWER-HYDRAULIK manufactures them in 24/7 operations at high levels of precision and cost-effectiveness on CNC machining centres employing a high level of automation. This ensures top productivity and low costs even at low quantities.
“The success of a product depends a lot on planning, as for all the holes to correspond properly, ensuring perfect operation of the block, requires drilling them in the correct sequence”, says production manager Hartmut Strobel. “Perfect part cleaning between settings during machining and prior to surface treatment or assembly is similarly important, as any form of dirt in the channels will compromise the operational reliability of the hydraulic system.”
Rising cleanness requirements
For many years, POWER-HYDRAULIK removed dirt from the hydraulic channels using a spray cleaning system and water-based detergents. “The cleanness levels we achieved were quite agreeable“, says Hartmut Strobel. “As we used water from the municipal mains, this left lime scale on the parts and cleaning effectiveness dwindled rapidly as the liquids assumed pollution. We needed to replace them every six to eight weeks, which led to standstills and considerable recycling costs.”
Cleanness requirements are also continuing to rise. With the aim of reducing residual dirt rates, POWER-HYDRAULIK started looking for a new and better solution in mid-2014. “Along with improving the cleaning results, we were also reviewing the processes related with material handling in order to create a future-proof solution for decades to come“, says Jan Roth who prepared the reconfiguration of POWER-HYDRAULIK’s cleaning installations writing his bachelor’s thesis on the subject. “Aside of the deep bore holes that are difficult to reach due to their different orientation, the great variety of different hydraulic blocks is also decisive.”
During the early stages of researching the Internet to preselect methods and manufacturers worth considering, he ruled out cleaning systems with vertically rotating cages for the parts to clean as they would require the individual blocks to be fastened to the cages. In view of high quantities but low lot sizes, it would have been difficult to do this economically.
Customised standard solution
In his researches, Jan Roth came across BUPI Golser Maschinenbau GmbH, an Austrian premium manufacturer of cleaning equipment. Their sales partner for south-western Germany, RTG cleantec GmbH, is not only a trading firm. Based on decades of experience in industrial part cleaning of its managing partner Oliver Grätz, the company offers comprehensive system consulting as well as custom installations and media treatment systems developed in-house.
The experts at POWER-HYDRAULIK had originally planned to buy a standard system and an external vacuum dryer, a similar configuration to the one they were accustomed with. They selected a BUPI CLEANER® POWERTEC PRO two tank system with separate media circuits for cleaning agent and rinsing water. This allows appropriately covering the often different requirements of cleaning operations during and after machining while optimising the use of energy and detergents.
They were pleased to learn that cleaning equipment in the BUPI CLEANER® POWERTEC product range is also available with non-standard dimensions of the cleaning chamber and with a higher load capacity. “Without changes to the depth of the installation, this allows us to clean all types of hydraulic blocks produced in-house using a uniform process”, says Jan Roth. “While the high pressure cold cleaning process previously used for big parts prevented this, we can now vacuum-dry all parts, removing all moisture and leaving them absolutely spotless.”
Boreholes in very big hydraulic blocks can be particularly difficult to access. To facilitate individual cleaning of those with warm cleaning agent, Oliver Grätz suggested equipping the BUPI CLEANER® POWERTEC with a high-pressure module providing spraying pressures up to 250 bar. This optional equipment was integrated complete with intervention gloves, a viewing window and LED cleaning chamber illumination as well as a compressed-air gun for manual for operations with the loading gate closed. “Initially, we were sceptical as we have had some bad experiences with hot water pressure-cleaning in the past”, Jan Roth recalls. “BUPI Golser were able to prove that the proposed equipment would fulfil if not exceed our requirements.”
Durable and sustainable
“We were impressed by the obvious robustness and longevity of BUPI CLEANER® cleaning equipment. After all, there is an installed base of more than 14,000 systems, many of which have been doing their jobs for several decades, and none of the users we have asked are considering investments to replace them in the near future”, says Hartmut Strobel. “The decisive factor in our decision, though, was the sustainability of the cleaning operation these Austrian systems facilitate if equipped with the RTG media treatment systems while improving technical cleanness.”
Installed in the media reflow circuit, the RTG systems permanently separate cleaning agent and rinsing water from oil and particles, adding builder and tensides as required. This automated removal of particles and dirt and the particular cascading maintains cleaning and rinsing media quality at nearly constant levels. This significantly reduces residual dirt on the parts. It also extends useful media life before replacement to anything between six months and a whole year. This is good for the environment and avoids cleaning system standstills resulting from this maintenance work, reduces disposal costs and minimizes waste.
All BUPI CLEANER® cleaning systems are equipped with Siemens control systems featuring an energy-saving standby mode and with powerful Grundfos pumps with an IE3 energy efficiency rating, contributing further to their favourable environmental and energy balance. “In this context, BUPI Golser’s flexibility to equip these systems with media heaters utilising alternative methods is least as important“, Hartmut Strobel notes. “As we are an environmentally conscious business, we heat the media tanks using a natural gas condensing boiler integrated with the cleaning installation. We also use excess heat from our air supply compressors that we feed back to the media tanks via stainless steel pipe bundle heat exchangers.”
Jointly developed spray jet deflectors
The bore holes in the hydraulic blocks must be flushed with 1000 litres of cleaning solution and 700 litres of rinsing liquid per minute even in case of horizontal holes, although the parts are situated on the grate in the cleaning chamber at small distances and with no particular orientation without moving during cleaning. To fulfil this requirement, RTG cleantec und BUPI Golser jointly developed saucer-shaped deflectors. They form a fine, high-energy spray jet to flush the holes. “As other customers have similar requirements, these spray jet deflectors were not merely implemented as a custom solution“, says BUPI Golser marketing manager Gerhard Bernauer. “They will be added to the comprehensive BUPI CLEANER® range of options as a standard product.”
With the new cleaning system, POWER-HYDRAULIK also meant to improve the part flow. “We had to handle the individual parts too often around the cleaning and drying processes”, Jan Roth points out one of the reasons. “The selected custom solution BUPI Golser realised for us enables us to substantially improve parts handling and ergonomics associated with the cleaning processes.” To this end, the cleaning system and the vacuum cleaner as well as two enclosed manual workstations were linked with a transport system. This conveys the grates on which the parts stay during cleaning and drying and on which they go to and from the machining centres on specific trolleys.
Fully transparent to a perfect result
“Coming across BUPI Golser turned out a real bonanza“, says Hartmut Strobel. “We enjoyed full transparency during the making of the system, always finding open ears and doors at the company’s Hallein headquarters and were effectively treated like family members.” This was of particular importance to the production manager who was keen on involving the colleagues now working with the equipment at an early phase. “I was also impressed by the thoroughness with which BUPI Golser pursued the project”, he adds. “To facilitate realistic trial operations using the gas boilers we provided, the premium manufacturer had two gas lines installed at the factory.”
These preparations during which the project was co-ordinated and supported by RTG cleantec resulted in a thoroughly satisfying result: “Cleaning cycles were reduced by about one third. The process was also unified, big and small parts now receive equal treatment, entirely in the closed cleaning chamber”, says Hartmut Strobel. “Machine operators can now perform the task of cleaning the parts between machining operations after minimal training, allowing a much more flexible workforce deployment.” Jan Roth adds: “That we replace the cleaning media for the first time after six months rather than every six to eight weeks is a great benefit for operations as well as the environment that only BUPI-CLEANER® systems equipped with RTG media treatment systems can offer.”