The specialist in Leser safety valves updated its lathes with Walter Cut

The safety valves are necessary for any application in which liquids and gases are under pressure, as it is the case of the chemical and petrochemical industries. Its objective is to protect humanity, nature and the installation. Leser GmbH & Co. kg KG is one of the most important of this type of equipment manufacturers. This company, headquartered in Hamburg, has increased its demand for a few years. The standardization measures are also contributing to the increase in the number of individual pieces. A few years ago, Leser committed itself to meet this growth by modernizing its fleet of machines at its plant in production of Hohenwestedt, a hour drive north of the Hanseatic City.

The inner workings of the safety valves consists mainly of pieces with circular symmetry such as spindles, bodies of admission, bushings, plates of spring, covers of ventilation, etc. For this reason the investment of Leser focused mostly on new lathes. This brought about a significant improvement: complete machining. Turned parts that are used to process on multiple machines and were moored and desamarradas repeatedly are now produced with a single mooring process. This saves a lot time. The company currently operates twelve centers of turning high-performance with advancement of bar and automatic handling of parts.

Once modernized machines Park, responsible for production focused on other inductors of cost. First of all recognizing that their inventory of tools needed to be optimized and initiated a project to reduce tool costs. With the level of savings that had been projected, specialists in valves had set an ambitious goal. To get to it was necessary to improve machining processes and introduce a new high-performance and more durable tools.

As most of the pieces are produced using bar, the tronzado was also included in the list of processes to examine. Every 15 seconds is a piece. To achieve maximum profitability, the material and the cutting tool geometry, material from the workpiece and cutting data must fit perfectly. In the past, the processes are often interrupted due to premature wear of tool and this was a crucial problem for a modern production plant. "We apply a system of three shifts." Only four or five employees handle our twelve lathes. "To be able to produce without wasting time, have had to rely on tools that offer the maximum reliability of process", stresses Jochen Lindemann, responsible for the project of reducing costs.

First of all carried out numerous tests using familiar tools. It was then when Jochen Lindemann discovered Walter Cut, the solution of the company Walter AG with headquarters in Tübingen. "Information on tools and calculations and cost effectiveness of the manufacturer did that we would like to know more", recalls the responsibility of the project. "That is why we decided to test these claims".

In Leser, trials with new tools and the possible conversions are carried out following a given programme. The viability assessment is followed by a phase of two-stage test which consists of rapid testing and real time to observe how the theory in practice. If both stages are passed successfully, is "organized" a "strategy to phase out" the old tools. This procedure prevents that different tools systems remain in service for a single process in any significant time.

The results of these tests of tronzado were unequivocal. Walter Cut emerged as the new reference. As the depths of Court were substantial, the company chose to blades to chop for plates of Court of a single edge of the FX line with a width of inclusion of 3 mm (see picture). Double-sided blades is shortened on one side, which allowed existing adapters could tie them. As Leser in almost all parts are made of stainless steel 1.4404 and 1.4122, those responsible for the project were reverted by a material of cutting quality WSP43 especially tough and effective in the developing countries-Tiger•tec range. "This cutting tool material is suitable for groups from ISO-P, ISO-M and ISO-S materials," explains Sven-Ole Berg, technical consultant, Walter. "Therefore, can be used in any type of application". As a result, the operator manages with a unique quality of material from court, even when different 1.4404 and 1.4122 materials are processed. Same applies to the selected geometry. Produces perfect chip in any situation, a prerequisite essential to achieve a high reliability in the process.

Since then, specialists in valves of Hohenwestedt have completely changed the system of tronzado and have opted for the system of the manufacturer of tools of Tübingen, leaving aside those blades to chop too long. For shallow cuts which do not exceed the 24 mm, production planning deposit their trust in the line GX insertions of cut double-sided with monobloc tool.

Thanks to high-performance cutting tool material Tiger•tec was possible in an increase of record data of cutting: cutting speed Vc of 120 meters per minute at 150 metres per minute; advance (f) of 0.12 to 0.15 mm. As a result, programmers had a little more work, as had to be revised around 600 programs CN. Good news, therefore, for the operators of machines: despite obtaining a higher cutting data, the service life of tools increased from 50 to 70 pieces.

In fact, in the Department of machining, the project's cost reduction has been fully rewarded, not only in terms of overall result, but also in terms of the tronzado as a single operation. According to Leser, was met with more than the original goal of saving. With approximately 20% of the overall rate, the rate for the tronzado turned out to be surprisingly high. This percentage includes the savings derived from the shortened time of production, as well as the increased useful life of the tools. The tronzado, therefore belongs to the Group of individual processes with the greatest potential for savings. Greater cost reduction was the result of the improvements introduced in drilling and drilling operations. Closely followed the process of tronzado along with the milling and the Burr by drill bit of milling. The outcome reaffirms the importance of an operation often overlooked.

The tools are only a part of the story, the other corresponds to the practical support of the workers. Walter, it also gives great importance to the winch. The availability of technical consultants is a key aspect in this philosophy. In addition, the Department of management of product in Walter has devised something quite special: a series of guides size pocket for the user containing individual processes such as the tronzado, slotted and ahuecado. "This practical guide for the user is always at hand." "Is a good source of reference provided that they have doubts about a particular aspect of the technology," confirms Carsten Trede, responsible for issuing and precalibración tools. This guide is, fundamentally, a catalog and a technical manual in one. The technical manual is designed to answer any questions that could arise to the professional. It contains a wealth of information on topics such as data from court, formation of chips, detection of wear and tear, etc. The data included are updated according to current engineering practices.

Safety valves manufactured in Germany

Leser GmbH & Co. kg KG was originally founded in 1818 as a brass foundry. Initially the company supplied general mechanical components for mounting on the final machine. In 1885, he produced his first valves for steam boilers. In the 1970s he began to specialize in this product area. The industrial demand of safety valves accelerated over time, while the products itself experienced a continuous development. Since then, Leser has become the largest manufacturer of safety valves on Europe.

With subsidiaries in Brazil, France, Poland, Singapore, Bahrain, India and USA, Leser actively operates globally and its staff is composed of more than 550 employees. The company headquarters is in Hamburg, Germany. In the town of Hohenwestedt, to the North of Hamburg, the company operates a manufacturing plant with 230 employees.

The product range currently offers 38 models of valves of safety with a diameter ranging from DN10 to DN400 or 1/2 "to 16". The annual production reaches 90,000 units.