News

Meeting cleaning standards efficiently - No particle larger than 400 µm.

Issued at 2012-09-16



Technical part cleanliness has grown vastly in importance as a quality criterion, especially in the automotive industry. In line with this trend, specifications imposing a maximum particle size of 400 µm are
no longer uncommon.

One international part supplier relies on a multi-stage cleaning process to meet this target, subjecting die-cast aluminium housings for balancer shafts to a high-pressure pre-wash cycle followed by fine cleaning. The performers are two EcoCFlex S cleaning machines of which one is equipped with an innovative high-pressure turret.

The balancer shaft of an internal combustion engine is intended to offset inertia forces produced by rotation of the crankshaft, thereby reducing vibrations and noise levels in the passenger cell. The shaft rotates in oil bearings at very high speeds, so that even ultra-small particles or other abrasive matter may cause damage and shorten its service life.

Cleaning requirements in the micrometer range To prevent this from happening, a German automotive manufacturer
has been raising cleanliness requirements for its die-cast aluminium balancer shaft housings continuously. As of early 2010, no particle present in the shaft housing after cleaning is allowed to exceed 400 µm in size. The shaft manufacturer, an internationally active part supplier, was unable to meet this demand with the cleaning technology employed at the time. Following a thorough review of the market, the project managers ultimately opted for a Dürr Ecoclean solution.

New concept ensures high cleaning quality Together with the specialists from Monschau (Germany), a two-stage
technology was devised to create an optimized cleaning process which could be implemented at short notice. The first cleaning trials based on this tailor-made solution were conducted in September 2010 in the equipment manufacturer's technology center. During the two-day tests, the strengths of the EcoCFlex technology became apparent: unlike the two competitor systems, the equipment was found to meet the ambitious residual contamination targets.

The new cleaning approach is based on two compact EcoCFlex S type machines equipped with 6-axis robots. The pre-wash system features an additional patented turret capable of integrating up to six tools for the high-pressure deburring process. This innovative development ensures high tool availability while minimizing utilities consumption and greatly reducing maintenance needs. "Instead of using several high- maintenance tools that need to be individually controlled, the high-pressure turret requires only one single high-pressure system which is connected so as to pressurize only the active tool at a given time.

The customer thus saves time-consuming tool changes in the cleaning cycle, which significantly reduces set-up times", explains Joachim Wünsch, Key Account Manager at Dürr Ecoclean, thus stressing another advantage of the system. The machines are installed at two of the supplier's production sites.

Pre-wash and fine cleaning perfectly matched At peak times, up to 500,000 die-cast aluminium housings p.a. come off the production line. Oil passages and valve seats are then machined mechanically into each casting. For the subsequent first cleaning step the robot picks the housings individually off the feed conveyor and takes them into the process chamber which is of dirt-repellent design throughout. Using the high-pressure turret system, the parts are then de-burred at a pressure of up to 300 bar. Various tools are employed to access what may be quite small and intricate openings in the casting, treating each of them to specification standards. This is followed by pre-wash cycle with a solid/flat-jet nozzle system that removes coarse chips and process media residues from the parts.

The entire process takes no more than 60 seconds to complete. This short cycle time is owed to the system's very compact design and the associated short conveying distances, among other features. Thus pre-cleaned, the parts are shipped to the assembly plant situated some 60 kilometers away. Here they are subjected to fine cleaning by the second EcoCFlex S. The machine's housing and process chambers have easy-to-clean surfaces yielding very low blank values. Unlike the pre-wash unit, this system cleans two parts at a time, so the cleaning
time (although short already) is reduced by another 50%.

The robot takes the parts off the feed conveyor and moves them into the first process chamber where they are cleaned at up to 50°C by injection flood washing using a WaterKnife. In the second process chamber a
solid/flat-jet nozzle system removes any fine contamination and cleaning agent residue. Each of these two process steps is completed in no more than 20 seconds. In order to avoid re-contamination of the parts before
they are assembled, the drying, cleaning and conveying operations are performed in a controlled environment. For this purpose, a robot conveys each housing into a vacuum chamber specially designed to prevent re-contamination during drying. A convection cooler operating in a clean environment finally cools the parts to room temperature. In
order to prevent any ingress of dirt, cleaned air is passed into the dust-tight enclosure via a HEPA filter so as to build up a positive pressure.

The use of a multi-functional gripper instead of conveyors helps further to keep the environment dust-free and to prevent re-contamination. Moreover, Dürr Ecoclean's engineers optimized the production chain by placing the cleaning system directly adjacent to the relevant assembly and shipping operations.

Forward-looking and energy-efficient This innovative technology enables the supplier to meet his customers' demands safely and reliably while also safeguarding the system's long-term viability. In fact, thanks to their modular design, the systems can be quickly and easily adapted to altered requirements or expanded to suit higher outputs. The same flexibility is inherent in the high-pressure turret whose toolset can be adapted rapidly and straightforwardly to parts of a different geometry.

Apart from their cleaning performance, the EcoCFlex systems impressed through their energy efficiency and minimized consumption of cleaning agents. Accordingly, the customer is highly satisfied with the new equipment and considers the EcoCFlex machines an ideal tool for meeting the ambitious goals imposed by its automotive customers and his own in-house standards.

Further orders placed Over and beyond the current project, this automotive supplier is continuing to expand its cooperation with Dürr Ecoclean. For the next year, the company has already ordered a belt washer for in-house cleaning of diverse steel parts such as cylindrical and bevel gear wheels.

The customer's decision was prompted by the professional project handling as well as by the innovative and highly flexible technology that has long become a hallmark of Dürr Ecoclean. Automotive part suppliers in particular are critically dependent on the capability to respond quickly and cost-efficiently to altered production conditions.

Dürr Ecoclean Group is the leading provider of industrial cleaning, automation and filtration solutions. standard equipment, custom-designed system solutions and services to the automotive industry and its suppliers, as well as to general markets around the globe. As a member of the Dürr group of companies, Dürr Ecoclean maintains operating sites in Germany, France, Czech Republic, the U.S., China and India.

The group provides innovative Dürr is a mechanical and plant engineering group that holds leading positions in the world market in its areas of operation. It generates a good 80% of its sales in business with the automotive industry. It also supplies the aircraft, machinery, chemical, and pharmaceutical industries with innovative production and environmental technology.

The Dürr Group operates in the market with four divisions. Paint and Assembly Systems plans and builds paintshops and final assembly systems for the automobile industry. Application Technology provides automated paint application, sealing, and glueing with its robot technologies. Machinery and systems from the Measuring and Process Systems division are used in engine and transmission manufacturing and in final vehicle assembly, among other areas.

The fourth division, Clean Technology Systems, is focused on processes to improve energy efficiency and on exhaust air purification. Dürr has 50 business locations in 23 countries worldwide and approximately 7,100 employees. The Group achieved sales of € 1.9 billion in 2011.

Contact:

Dürr Ecoclean GmbH, Joachim Wünsch, phone +49 2472 83-173
joachim.wuensch@ecoclean.durr.com, www.durr-ecoclean.com


Source: parts2clean



Related News