Our ultra-fine filtration systems can be configured for a wide range of applications such as grinding, lapping or honing of hard metals, steels, glass and ceramics. Oils, emulsions and aqueous solutions can be filtered. They work largely without filter aids, eliminating the need for costly disposal of these. The environment is sustainably protected. A remarkable filter fineness of up to approx. 2 µm also opens up numerous new possibilities. An optimally cleaned cooling lubricant keeps the machine clean, clean workpiece surfaces and optimum cutting performance are thus made possible.
Thanks to an optionally available automatic cleaning of the filter elements, the machining processes do not have to be interrupted. The systems also operate quietly, energy-efficiently and in the smallest possible space - a 400 l system, for example, requires only the footprint of a Euro pallet.
Functionality of a 5-stage ultra-fine filter system
Often in manufacturing, we find the application of cooling lubricants like for example grinding oils. Their main task is of course to cool down the workpiece and the tooling, and to lead away the removed material. The alleged helper in production can show quite the nasty face, if the load it carries doesn’t get filtered. The result is an abrasive liquid that diminishes the quality of your product. A problem for high-precision manufacturing – and a call for the filtration experts at LEHMANN-UMT.
Our first example is about grinding glass, glass ceramics and high-performance ceramics in the factories of the Berlin based optics specialist Berliner Glas. Their typical products include customer-specific chucks, precision-made structural components, reference mirrors as well as stage and optics modules used in complex systems for the manufacturing of computer chips. The required tolerances are below 10nm; their latest devices can work with accuracies of even under 5 to 3nm. High-performance (glass) ceramics are the material of choice – they excel by their exceptionally low expansion coefficients, the high homogeneity of the material, their long-term stability and their consistent mechanical properties. The downside is that these ceramics are extremely hard, what proves to be challenging during their machining processes. Specialized CNC-machines grind, lap and polish a ceramic blank into its desired form with cut functional edges or light-weight structures in the demanded final quality. For this purpose, Berliner Glas uses diamond-coated abrasive pencils and grinding discs in a great variety of configurations and cools them internally and externally using high-performance grinding oil, e.g. by oelheld. At the same time, the low-viscosity grinding oil carries away the removed glass or ceramic material from the workpiece. In order to keep using this grinding oil, the material must be extracted from the medium. Berliner Glas carried out a number of trials in house, but could not achieve neither a process suitable for their clean production environment nor the required filter quality, much less a real closed circuit for their oil.
The solution was found in collaboration with the experts of LEHMANN-UMT: Challenging tasks in the field of ultrafine filtration in high-performance production processes are the main business of our Saxony-based company. After thorough studies in our technical laboratory with a great variety of testing applications and filtration trials with different levels of filtration and combinations of filtering technologies, LEHMANN-UMT found a solution for a stable, valid and consistent filtration process on an ultrafine level. The result of our efforts is an ultrafine filtration system that achieves the required filter fineness of 2–3 μm in full-flow filtration without the use of any kind of auxiliary material during the process. The 3-stage system receives, filters and returns to the CNC-machine 100 to 400 litres of grinding oil per minute in a closed circuit. Mr. Pisch – process engineer of the technical department of Berliner Glas – states that combining the CNC-machines with the filter system led to a convergence in the production process and helped to increase significantly the productivity of the plant. The LEHMANN-UMT ultrafine filtration system made it possible to run the CNC-machines continuously, what then resulted in a much higher output of Berliner Glas without any loss in quality – especially regarding the repeatability and accuracy in the production process. Furthermore, Berliner Glas saw an increase in the service life of their machines.
Accuracy is also what the tool-grinding centre Erzgebirge WSZE was looking for in their manufacturing and re-sharpening processes for drills and milling tools made of solid carbide or metal for industrial purposes. The company is especially renowned for producing and sharpening mini and micro tools with diameters of one, three or five millimetres. Naturally, working with tools in these sizes requires the application of grinding oil in the CNC-machines used in WSZE for cooling and for removing the metallic micro-particles or the particles of the coatings. To maintain the necessary accuracy, the grinding oil is kept a temperature that must not deviate by more than 0.5° K from the set value. So, the speed, the cutting steps and the feed-in movement of the CNC-machines are adjusted to these values to achieve the required dimensions in the finished product.
And besides regulating the temperature at a precise level, the cutting oil must constantly be cleaned from the particles in order to maintain the same high level of quality in the products. Our new filter systems installed at WSZE have proved that the grinding oil used in the company has a projected service life of more than 5 years.
The general result is that it pays off to study the application of grinding oil and its ultrafine filtration. Both companies mentioned here attested that the LEHMANN-UMT filtration systems not only deliver results of ultrafine filtration within the expected range, but that they even help reducing additional costs: The filtered grinding oil is used for longer periods, maintains its properties and prolongs the service life of tools and machines. The costs of investing in an ultrafine filtration system amortize through the savings and the perfect product quality in no time at all.
Development, production and service for ultra-fine filtration systems
All filter systems from Lehmann have a modular structure so that individual solutions can be developed for many problems. In this way, the fine oil filter system can also be combined with other systems, e.g. magnetic separators and / or scraper tank systems.
For additional information about the filter technology, please refer to our brochure or contact us in person. You can use the following contact possibilities for this. We look forward to presenting you with our offer.