One of the largest deep drawn parts manufacturer in the UK, has decided to respond to their customer demands by installing a Höckh Multi Clean degreasing system.
In order to meet these demands they had a requirement for a washing and degreasing plant capable of removing oil, lubricants and coolants from deep drawn parts, whilst also achieving high cleanliness levels specified by its customers. With current systems consuming large quantities of solvent, and being very labour intensive, the key objective was to rationalise the current equipment to provide a cost-effective solution whilst also meeting the environmental obligations.
“We were faced with the environmental challenges, as well as increasing solvent and labour costs associated with degreasing parts in six ageing cleaning plants,”
“Furthermore, increasing demand from customers to provide high levels of particulate and residue cleanliness meant that the old processes could not compete with the latest available technology.”
As this machine was to replace a number of other plants, it had to be flexible to meet the requirements of a varied product range from ultra-clean, precision ABS brake components to large water pump parts,” . “The machine also had to be very reliable and easily maintainable as it was to form part of a lean manufacturing cell. Höckh was the natural choice as Presspart already operated two other Höckh plants, one, a large, high-volume pin wash machine and another, older basket type, Perchloroethylene degreaser.”
With the new system the parts are held in a standard perforated basket size of 660x480x300mm and are automatically fed onto a conveyor, which can buffer multiple baskets, allowing the system to run without any intervention. The basket is pneumatically placed in the vacuum–proofed chamber and the transparent glass door is closed with a knee lever lock mechanism, which is an added safety measure in case of any power failures. Once the chamber is completely under vacuum and the seal has been checked, the process begins with a spray pre–wash from tank one circulating in a circuit through the chip filters with the basket rotating or swivelling, capturing most of the contaminants with the first stage using only a small amount of solvent. After spraying the solvent is pumped directly from the cleaning chamber for recycling ready for the next load.
The chamber is then surged with solvent until fully immersed to allow the parts to be cleaned thoroughly with the support of ultrasonics. The solvent is then drained back into its respective tanks through the filters to keep the solvent free from particles with highly efficient topline filters in the last tanks.
With the double-grouped filters allowing for the automatic switch over to permit filter change over or maintenance without stopping production thus keeping the machine running 24/7.
Pure solvent vapour which is generated in a unique Höckh patented distilling system is directed into the working chamber where it condenses on the cold parts achieving a lasting finish.
With the vacuum Running at up to eight loads per hour, depending on the wash program, the Multi clean system has allowed them flexibility to degrease and clean a cocktail of contaminants from a mix of 120 different types of parts with 30 types of geometries and up to 15 different materials with a series of filtered circuits coupled with a more efficient combination of spray, rotation, immersion and ultrasonic capacity. The last tank allows for anti rust protection for certain products.
The vacuum drying process starts by lowering the pressure in the process chamber to aid the evaporation of solvent from the parts then the chamber is vented again to the ambient pressure. A Double regenerating carbon absorption system removes the last traces of solvent from the chamber prior to finishing of the cleaning cycle. For adherence to the legal regulations, the system is equipped with a concentration measuring instrument, which monitors the solvent concentration in the working chamber at regular intervals. Only after falling below the concentration value legally designated of 1g/m³ of air is opening of the transparent door possible. The double carbon adsorptions system can be regenerated automatically allowing the machine to be operated 24/7.
“The new plant in the lean manufacturing cell has revolutionised the manufacturing process at their site, as all parts are cleaned immediately after pressing rather than remaining in an oily state for long periods,” . “Keeping parts in an oily condition for an extended period leaves them susceptible to staining and they are difficult to store due to the amount of oil present on them.
Höckh brings an untouchable reputation for supplying high quality degreasing plants throughout the world for companies that value automation, high grade cleaning, sparing solvent distillation and reduced energy costs.
Only with a Höckh system is it possible to achieve such low solvent use due to the ability to distillate Perchlorethyelne with a highly efficient double distillation process of which Prespaart has benefited greatly.
The Höckh range, which features stainless steel construction allied to very high quality welding procedures, also includes fluid management facilities that can be interconnected with the SAFE-TAINER™ system provided by SAFECHEM, a subsidiary of The Dow Chemical Company.
already a user of the SAFE-TAINER™ system, and so with the need for new equipment SAFECHEM’s Service Alliance with Höckh, was able to co-ordinate early in the project to discuss the various aspects. With the large amount of oils and the varying types we decided to check potential problems by carrying out a number of oil compatibility tests on a cocktail of oils used in their processes. The results of these highlighted areas for concern and again after consultation between Höckh and the customer SAFECHEM agreed that a slight change in the stabilisation of DOWPER™ was desirable. This is now in place and no problems have materialised.
By installing a hermetically sealed solvent degreaser from Höckh in combination with the closed-loop SAFE-TAINER system, the company is benefiting from the high-quality cleaning performance of chlorinated solvents used in a safe and sustainable manner – thereby complying with legislative requirements and contributing significantly to care of the environment.
Höckh with 30 years of metal cleaning experience behind it has installed over 600 plants under the multi clean brand. Höckh have set the benchmark when it comes to innovation and quality whilst achieving various patents throughout their history notably the Vacuum Drying patent as far back as 1987. The Multi-clean range, are hermetically sealed plants and can be delivered for using Perchloroethylene, trichloroethylene or alternately halogen, flammable solvents. The Höckh system is totally sealed and works under vacuum therefore allowing solvents to work under reduced temperature and perform consistently with parts with various types of oils concentrations, complex shapes and high throughput demands. Höckh’s speciality is to build customised cleaning plants from small to large chambers all based on standardised modules.
In conclusion: “The approach from Höckh was extremely professional, starting from initial concepts and quotations through solvent compatibility testing, component trials and finally delivering, and commissioning the machine on time. Furthermore, we continue to benefit from the on-board diagnostics, together with the design and layout of the machine, which are enabling our maintenance technicians and operators to easily monitor the condition of the machine. The fact that the machine is a completely sealed system; solvent loss is virtually zero, meaning that they significantly exceed all current environmental regulations and has seen solvent consumption decrease more than tenfold in the first six months.”
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