Product category:
Machinery and Production Equipment
News Release from: StarragHeckert UK | Subject: Durr Ecoclean 81W
Edited by the Engineeringtalk Editorial
Team on 05 February 2002
Washing machines keep production clean
While the thorough cleaning of machined parts may not be that high on everyone's list of priorities, it's an essential element of the manufacturing programme operated by JL French in Essex.
While the thorough cleaning of machined parts may not be that high on everyone's list of priorities, it's an essential element of the manufacturing programme operated by JL French in Essex This is reflected in two of its automotive component machining cells, where the 300-strong Witham-based company has selected front-loading Durr Ecoclean 81W aqueous washing machines
This article was originally published on Engineeringtalk on 21 Feb 2001 at 8.00am (UK)
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Supplied by UK agent Traub-Heckert UK of Brackley, the machines were selected to remove all swarf, debris and cutting fluids from precision aluminium castings.
Says Ken Worsfold engineering manager: "The first cell has been running with the Durr Ecoclean for over two years.
It has run round-the-clock for five days a week, and with the addition of our latest project, which involves even higher cleaning standards, we decided an improved specification Durr wash should be included which is currently under final commissioning".
Such has been the performance and reliability of the first Durr machine that Ken Worsfold reflects: "We have consistently achieved the levels of wash efficiency and the self-cleaning system has recorded an uptime of 95%.
We have also found the specially designed stainless steel Durr baskets, for example, have shown no signs of wear after more than two years in service.
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Whereas on one of our other washing machines, the baskets had to be replaced after just six months".
As well as producing pressure die castings for a range of automotive components such as mounting brackets, cam caps, housings, and various engine parts, JL French also adds value by machining these castings on a range of special-purpose CNC rotary transfer machines and machining centres.
In several of these dedicated production cells, which have been set-up for high volume projects, effective cleaning is crucial before the machined castings are transferred to other stations in the cell for inspection and test procedures.
This means the standard of cleanliness has to be high and consistent to ensure that secondary operations are not compromised, the castings are not damaged on location faces by any remaining particulate matter and any swarf is removed from holes and threads.
When the company secured the contract in 1999 from a leading automotive manufacturer to produce the intricate castings for ladder frames, which hold the cam caps together on a new V6 engine, a key element in the production philosophy was the integration of a highly efficient cleaning system.
With two frames required for each engine, production quantities are around 200,000 a year.
JL French already had experience of different cleaning systems but for the ladder frame project the requirement was for a high efficiency aqueous washing in order to meet the strict performance criteria of cleanliness and productivity.
Says Ken Worsfold: "We wanted a well-engineered aqueous washing system which would guarantee a level of cleanliness.
It had to feature fully automatic wash, rinse and dry cycles; and satisfy our production demands.
However, the intricate nature of these castings created numerous swarf traps which meant that the cleaning process would have to be particularly effective".
The company set the standard so that the particle size of any remaining debris was less than 10mg.
Following discussions with several different manufacturers, the company decided that the Durr 81 W modular aqueous cleaning system best met its all-round specification.
Off-site trials at the Durr headquarters in Germany on ladder frame castings confirmed the performance, repeatability and output of the complete washing and drying cycle and resulted in the machine's installation in July 1999.
As a guide to the complexity of the cleaning tasks Traub Heckert and Durr faced, the aluminium ladder frames are 300 mm by 201 mm by 25 mm thick and the castings consist of thin section, lattice type webs and feature a number of detailed forms and profiles which have to be thoroughly cleaned.
These include: three main bores, 30 plain holes, nine radius half-bores, each with small diameter oil holes, a 300 mm long by 6mm diameter gun drilled oil gallery, 18 blind M6 tapped holes and various grooves and recessed features.
To meet planned machining schedules, the complete washing and drying cycle had to be completed within a 60 second cycle per part.
While JL French had considered an automatic tunnel-type cleaning system, it decided that the rotary/dip cycle of Durr system provided the best engineering solution in terms of high and consistent cleaning standards, practical operation, productivity and cost.
In order to meet the production cycle time, 10 ladder frames are processed at a time in the special stainless steel baskets.
With the exception of loading the castings into a basket and moving this on a roller conveyor into the main chamber of washing machine, all other elements of the cleaning cycle are fully automatic.
This comprises a series of dip processing steps including high efficiency vacuum hot air drying in a sealed chamber at 100C.
Loading is carried out by the same operator as the CNC rotary transfer machine in the cell which minimises labour requirements and gives the operator total control over the process.
As each part is finished machined, the operator removes the component from the machining fixture and places it into one of 10 slots in the cleaning basket.
This positions the castings at a 60-degree angle to aid the wash cycle and ensure equal spacing for the washing media to flow between the components.
A lid is automatically lowered onto the basket which retains the ladder frames in position and enables the basket to be oscillated in a rotary motion without damaging the parts during the various stages of the washing cycle.
The actual cleaning process takes 10min for the 10 components and involves flooding the work, rinsing, spray washing, further rinsing and hot air drying at 100C in the vacuum chamber.
After cleaning, each ladder frame goes sequentially into laser inspection, a ball insertion process and final pressure test stations within the cell.
Based on the service and support of Traub Heckert and Durr, JL French is installing the second Durr 81 W washing system for its new production cell which is being set-up to manufacture variable valve cam carrier bush assemblies.
Production quantities are scheduled to be around 170,000 per year and the aluminium castings will be machined on a CNC machining centre and then transferred to the 81W system in batches of 16 a time, for washing.
However, faced with ever-higher cleaning standards the new installation has to meet a standard particle size that any remaining debris is less than 2mg.
As part of the upgraded performance package, the new machine has an extra tank to provide an ultra-fine wash cycle.
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