Ecoclean's high-efficiency EcoCdry vacuum drier reduces robot cell workload
Meeting stricter cleanliness standards within the same cycle time – to meet this requirement repeatably in cleaning diesel engine crankcases, a German automotive manufacturer fitted its robot cells with EcoCdry high-efficiency vacuum driers made by Ecoclean. The units eliminate the need for pre-drying inside the cell, thus freeing valuable cycle time for the actual cleaning and high-pressure deburring treatment.
In the automotive industry, engine and transmission parts are often subjected to high-pressure deburring and cleaning. These operations are carried out in cells affording a high degree of flexibility to process workpieces such as cylinder heads, engine blocks and crankcases to high cleanliness standards within short cycle times. If the requirements on residual contamination are raised, e.g., for a new engine generation, the robot will need more time to clean and debur the part in the cell. Accordingly, additional robot cells will become necessary in most cases since the assembly line timing is set to a given throughput. Such was the situation faced by a major German automotive manufacturer, but the company found a more efficient solution in cooperation with Ecoclean of Monschau.
The crankcases are cleaned and deburred in EcoCflex Classic robot cells. Before each workpiece leaves the cell, it is pre-dried to remove most of the water adhering to its surfaces. To this end, the robot positions the crankcase in front of a blowing device within the cell. This step takes up to 10 seconds off the overall cycle time.
In order to make more meaningful use of this interval "wasted" on pre-drying, an EcoCdry unit was assigned to each robot cell. Ecoclean had developed this highly efficient vacuum drier roughly 1 year ago, along with the new EcoCflex 3 system. This robot cell – successor to the EocCflex Classic – was designed from the start for a drying process performed entirely outside the cleaning machine. The EcoCdry is part of the standard equipment package. However, thanks to its modular design, the vacuum drier can also be retrofitted to existing robot cells.
Apart from the commonly used vacuum pump, the EcoCdry possesses an additional accumulator vessel in which a vacuum is perpetually generated by the pump. Since the pump runs continuously anyway due to the rapid cycle times used in automotive manufacturing, this feature involves no additional energy consumption but merely makes more efficient use of the power input.
The crankcase is placed in the vacuum chamber by a gantry loader. Next, the chamber is closed and then evacuated abruptly. This creates a vacuum of around 500 mbar within one second. A very strong airflow will form as a result. The water adhering to the part is literally "sucked" off the surface and piped into a tank. For reliable drying of the part, the existing vacuum is then raised to 30 mbar.
Since the EcoCdry unit easily copes with any residual water adhering to the product, pre-drying in the robot cell is no longer necessary. The German OEM thus gained an additional 10 seconds of cleaning time. These are used to increase the cleaning time of critical crankshaft areas and to focus on the removal of any stuck chips. It is thus possible to achieve more stringent cleanliness standards efficiently without investing in additional cleaning machines. Needless to say, the high-efficiency vacuum driers come at an additional expenditure, too. However, this expenditure falls far short of the cost of an extra robot cell that would otherwise be needed.
Author: Doris Schulz