High precision machining of the hottest large part

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High precision machining of large parts

when machining marine engines, GMW, a large parts manufacturing expert, trusts the machine tools from Chemnitz Union. GMW pays great attention to machining accuracy, availability and service quality

Mr. Erich Brinkmann, general manager of GMW, a special service provider from Burg, and Mr. Sohn Norbert, the founder of the company, emphasized that "our main concern is the processing quality and precise control of parts and components. This is also a point of great concern to the employer." GMW's main business areas are the processing of large parts in the aerospace industry, wind turbines, power stations, cutting tools, fixtures, machine tools and special equipment manufacturing industry

Mr. Erich Brinkmann said, "our first customer came from the automotive industry, and then we established a good cooperative relationship with the steam turbine industry. At present, we have gone deep into the field of large-scale equipment processing." The most famous project of the company is to undertake the processing of parts for ariana-5 carrier rocket. In addition, the company can also process tank related parts. They even process high-altitude wings for Airbus A380. Mr Brinkmann said, "our daily business mainly focuses on the precision machining of parts in the field of heavy equipment manufacturing. Usually, we obtain these parts in the form of large parts or welded structures."

union CNC horizontal boring machine PCR 150, longitudinal feed grab station, steering/conversion platform

when processing marine diesel engines, Mr. Brinkmann came into contact with machine tools from Chemnitz Union. In the field of marine diesel engine, GMW company has undertaken the complete processing business of crankcase. It includes in-line and V-type engines with power ranging from 7000 kW to 50000 kW. GMW company completely adopts mechanical processing for the purchased large parts, cooperates with the sealing inspection, and submits the inspection report at the time of delivery

Mr Brinkmann said, "not long ago, we needed to order a high-power machine tool from union company, and the supply period was very short. Union company gave great help, and the machine tool was soon produced, debugged immediately after assembly, and quickly put into mass production."

gmw company has a 4-shift production organization, which produces 360 days a year according to the 22 hour working system. For machine tool manufacturers, reliability, machine tool starting rate and service quality are very important. Mr. Brinkmann said, "the performance of union company in these aspects is commendable. Once we mistakenly placed the spindle on the table, causing the spindle to be completely scrapped. Within 24 hours, union company provided a new spindle for us to replace and use, making our machine bed put into use again in a very short time. This left a very deep impression on us." Such operation further expands the service idea of union company and makes its modular system more value for money. Union is constantly developing modular systems. Every time GMW places an order, it will benefit a lot from good service. Therefore, at the end of 2008, GMW company added two horizontal boring machines PCR 160plus of union company to its newly completed marine engine large parts processing workshop

Thomas Ulrich, general sales manager of union company, said, "the reason why we can help GMW company so quickly is mainly because our machine tool adopts a modular structure. That is to say, we can temporarily borrow a module from the semi-finished machine tool that is still in assembly. We have high flexibility, can make decisions quickly, and do not see any bureaucratic color."

Figure 2: the blank part of the cylinder block of a marine V-type diesel engine

when the crankshaft of a marine diesel engine is produced, the loading speed valve should be manually controlled to control the rising speed of the piston (the speed and safety valve are one-piece) box, except for the crankshaft bearing surface and two camshafts, all the surfaces, apertures and threads to be machined (Figure 3) are machined by the machine tool of union company. In other words, 80% of the processing tasks of an engine cylinder block can be completed by union machine tools. GMW company also purchased the CNC horizontal boring machine PCR 150 of union company in December, 2005 (picture). In addition to the engine block, GMW's Union machine tools are also used to process wind turbine parts such as hubs and frames

Figure 3: Union's CNC horizontal boring machine PCR 150 can solve 80% of the plane processing volume on the crankcase

the horizontal boring machine can ensure the accuracy of the crankcase

GB 11945 ⑴ 999

the first step in machining the crankcase is to scribe on the measuring machine. The first rough machining can be started after the casting is marked and clamped successfully. In order to reduce the stress generated during rough machining, the workpiece needs to be loosened halfway and re clamped after waiting for a period of time. In the next rough machining step, the hole diameter to which it belongs needs to be machined. In the third step, the workpiece needs to be machined to 0.5mm allowance, and other surfaces need to be machined. Then start thread machining. The workpiece needs to be loosened again before the polishing step. Finish machining can be started only when the workpiece is assembled in place and the clamping is completed. In most cases, the stopper needs to be extended to avoid lateral sliding

brinkmann said, "generally speaking, we can mill 7 to 8 planes with high accuracy. Only in terms of precision in mass production, we can reach it5, and some can even reach it4. Within the length range of 14 meters, we can ensure the flatness and parallelism of 0.02 mm."

Mr. Rainer schillbach, the regional sales manager of union company, said, "GMW company ordered a PCR 150 horizontal boring and milling machining center of union company in 2005, with Siemens 840D control system. The machine tool is equipped with an automatic tool change system, and a 1000mm retractable steel beam is used to cooperate with heavy cutting. The headstock can move along the 6000mm long x axis, while carrying the cabin of the machine operator and the 4000mm long Y axis (the spindle can move longitudinally along the steel beam on the Y axis), as well as the tool magazine and automatic tool change mechanism. "

the crankcase is clamped on the rotation/conversion platform, and the maximum weight of the workpiece can reach 60000 kg (Fig. 4). Mr. schillbach said, "we can also provide greater carrying capacity on demand." The rotation/conversion platform allows four planes to be machined in one clamping. If you need to machine the fifth plane, you can use two vertical milling heads. The milling cutter head is stored in a grab station that can feed parallel and longitudinally along the X axis of the machine tool. In this way, the milling cutter head can be automatically replaced. In other words, the x-axis of the machine tool can be automatically replaced without additional extension. If the clamped workpiece interferes with the hair of the automatic milling cutter, the workpiece can move along the 1500 mm long V axis on the rotation/conversion platform and leave the interference area

Figure 4: the crankcase

gripping station clamped on the rotation/conversion workbench is also equipped with additional process devices: 2 NC screw loose heads, 1 automatically adjusted vertical milling cutter head and 1 automatically adjusted special milling cutter head

in order to process the engine block, the preset tool can be used to operate with the chain tool magazine, and the automatic tool change system can be sent to the spindle. The standard chain tool magazine can hold 80 cutters

basis of high-precision machining

ulrich stressed: "In order to ensure the high precision of machining, we have formulated effective strategies and technical preconditions. The machine tool development adopts three-dimensional design, and the stability evaluation is carried out according to the finite element method. In addition to the additional load analysis, we also investigate the vibration phenomenon to explore the potential optimization direction of the machine tool. We constantly produce the machine tool according to the power parameters agreed with the customer. Therefore, we can start the machine tool in the negotiation stage Design work. " The exchange of experience is very effective: the cooperation between the service personnel of GMW and union is exemplary. They cooperated well and selflessly contributed their valuable experience

ulrich emphasized on the "service group" of Union: "we listen carefully to the actual needs of production. We can find all potential points on the machine tool that need to be optimized on the site, and we can immediately modify the design and put it into practice. The discussion in this group can expand ideas and provide other help for our machine tool manufacturing." This is also one of the factors that can significantly affect the manufacturing accuracy

first, stick slip effect can promote manufacturing accuracy. Mr. schillbach said: "All linear spindles are equipped with modern bearings and guide rails. A series of measures have also been taken to compensate for the sag of the spindle. For example, a 700mm long working spindle is placed on the telescopic beam with a length of 1000mm, which can maximize the parallelism with the plane of the machine tool. This design is especially suitable for clamping vertical and universal rotatable milling heads, 2-axis CNC milling units, CNC plan supports, and And special tools to adapt to multi-facet and contour processing. "

in addition, the geometric accuracy of the vertical milling cutter head should be rechecked at least every 3 months. GMW also uses the loosening and clamping process to maintain and measure the machine tool to ensure the accuracy and safety of processing. The modern measuring system can record all important accuracy parameters before delivery

when fixing the finished engine block on the hydraulic base for accuracy analysis of crankshaft and camshaft, fine adjustment is required to ensure that all positions bear the same weight. The Flucht accuracy can be measured and recorded with a fast laser measuring instrument (Fig. 5). Mr Brinkmann said, "we use laser beams for measurement. Using this modern precision measuring instrument can ensure the high quality of our products."

Figure 5: use the fast laser measurement to ensure the safety meter to measure and record the accuracy of Flucht

author's profile

master engineer Peter springfeld is a columnist from Berlin

email address: d@

user information

GMW precision Lianghe Co., Ltd.

39288 Burg

: 03921 726911

Fax: 03921 726930


.Manufacturer information

union Machine Tool Co., Ltd.

09116 Chem Nitz

:0371 87410

Fax: 0371

address: (end)

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