Core Tip : In recent years , with the rapid development of the aerospace , large ships and ship manufacturing, mining and new energy industries , the demand for large and very large workpieces increasing. Machine tool industry as a manufacturing base , in order to meet the processing needs of such parts , and also continue efforts to develop a number of new machine tools .
A few years ago when the Chinese machine tool market for large machine tools demand, Chinese machine tool companies to develop a number of bridge or gantry CNC milling machine and CNC milling machining centers and other large , heavy machine tools. Where there is a relatively large size Qiqihar plant, Plant stand vehicles , Plant boring bar diameter 320mm heavy duty CNC boring and milling centers and CNC lathes , Shanghai Machine Tool Plant tie roll grinders , Wuhan Heavy Duty Machine Tool Plant early 16 m vertical lathe etc. , the demand of the market, promote and accelerate the development of China's big , heavy machine tools , development with remarkable results .

Known, the characteristics of the workpiece is large and very large large size ranging from several meters to tens of meters ; heavy weight , the weight of several tons from dozens to hundreds of tons tons , which requires the machine has sufficient stiffness and load bearing ability to have enough space to accommodate the workpiece , but also have enough drive and cutting power , cutting tools must have the appropriate cutting ability and longevity. Therefore, we must overcome this set of equipment and processing technology to complete these tasks large, very large parts.

Abroad in the outcome of research and development for the processing of large and very large parts of the equipment are more progress faster than us , more specialty tools , a higher level of technology. Here , from the German "WB" magazine reported the relevant information , there are a few European companies to selectively Profile machining representative large and very large piece of equipment and processing methods , the only reference of the industry .

Processing large size of the transmission housing

In large-scale processing equipment for the manufacture of ship gear unit housing applications such as wind power equipment provided by the company's good reputation in Germany Renk . They made ​​weighing 100 tons , up to 350 kNm torque transmission standard series of drives. Since the drive gear is a core component of each actuator , Renk company's own production gear . The transmission housing , the housing consisting of two parts , the housing itself weighs 20 tons , and also his housing manufacturing .

 
Under weighing 20 tons of gear casing sample processing company Renk

For this task , Renk company with the size of the workpiece can be processed for two 9m × 3.8m × 2m large machining centers , milling both assume plane , but also the pre- processing of the bearing bore , from roughing to finishing and all sizes the hole machining . In this way , Renk save a lot of time to prepare. Processing time is an important factor , so to take full advantage of the machine 's production capacity. Each large processing center in the last 7 years, the average time had 4,700 h. Processing a gear upper and lower case takes 30-50 hours , so can save is worth every minute .

To improve the efficiency of machining large parts of the machine itself, in addition to good performance outside , good cutting tool is important. 20 years , Renk Company has applied the high mountains (SECO) tool company tool . In the mainframe application of SECO 's bed Double Octomill face mill , this has 16 blades face milling , ranging in diameter from 63mm to provide 500mm. Power indexable inserts suitable for large parts of different materials for roughing and finishing process . Considering the application flexibility , in the middle of high speed steel (HSS) and the clamping bore formed in the guide bar to ensure a large amount of feed , the indexable insert 16 can be positioned very precisely , each blade shows costs are low. Double Octomill face milling can be carried out at high speed machining, but also reduces tooling costs .

Contrast with this the actual cutting tool in the cast iron box conducted tests proved that the effect of the processing of large pieces of cast iron box well . Blade coating material has good abrasion resistance , suitable for high-speed machining . Cutting speed up to 350m/min , the power instruction sheet is always in the green zone . From the vibration and noise of view, this tool can achieve higher cutting speeds , as a comparison , here 's the cutting speed is 215m/min.

Test records show that engages the time the blade and the workpiece is reduced by more than half , from 25.86min reduced to 11.78min., While cutting the amount increased from 1,209 cm3/min to 2,268 cm3/min. For users, the direct benefits of improved cutting efficiency or improved processing speed is significantly lower processing costs.

Another test is to compare the results with previous tooling , each blade can only process half of the workpiece , but with SECO 's Double Octomill face milling cutter, knife processed 5 per piece . Obviously, tool life increased by 10 times . Thus , Renk company is equipped with their large machine SECO 's Double Octomill face milling machining program is successful.

Up to 8,000 mm diameter circular parts processing

Strong growth of the energy industry in recent years, especially in the wind power plant applications requiring annular parts ; flange connection pyramid structures need also need a diameter of 8,000 mm circular parts ; Similarly, the cable car hanging box and rotor blades required for optimal positioning the large rotary coupling mechanism and ultimately, a large circular pieces . But looking for a high- productivity machining of large parts of the ring dedicated machine is not easy. As the actual market size is not large, people tend to only use some of the existing vertical lathe or milling center vertical gantry structure to process . The Spanish Ibarmia company proposed a set of machining large parts of the ring special solutions . Because many users need to include a full set of processing solutions drilling, milling and turning , such as processing large circular pieces . Here's a brief account of their programs .

Spanish company Ibarmia a machining program of a machining diameter of 6,500 mm annular member

Ibarmia annular member mounted in the company turret machine , showing the exact process of natural horizontal position , it is easy indexing turret or corner can be a boring head carried by one horizontal hole. The company manufactures high-precision turntable , direct drive with the appropriate synchronous motor, then the need to use static or rolling bearing turntable turntable , two turntable , is through a high-quality gear and two small gear drive turntable also a direct measurement system with synchronized transmitter work through HEIDENHAIN RCN hollow shaft for precise rotary control . The past 20 years , Ibarmia company has developed a series of suitable user needs, and to meet a variety of different workpiece clamping manually or auto -centering clamping device , in which there is a fast and flexible alignment of the jaw and bracket.

Ibarmia company also integrates an advanced control system includes a monitoring and management tool . In addition to unmanned production, but also the time of diagnosis tool breakage or damage caused by machine downtime workpiece when needed .

With indexable insert boring tool , in the case of a known hole depth , also called high-pressure coolant used to cool the tool . This is not only necessary to heat , but also by means of high pressure coolant chip discharge is important to ensure the precision and quality requirements. Coolant pump with a pressure of 20 bar to 60 bar adjustable pump . To prevent the outflow of high pressure coolant and swarf wounding , processing space sealing is necessary. Chips and coolant through two purification.

Ibarmia moving column machine vertical spindle head can be standard or SVK Series SV Series vertical / horizontal spindle head automatic conversion . A large pillar sizes , moving from the outside at the side of the turntable , the diameter of the ring can be processed in different parts . The powerful spindle head placed in front of the pillars of a hole. The spindle head is automatically configured SVK programs can be vertical and horizontal hole processing , which can be done for a loaded card processing and other processing of all kinds of holes is the ideal configuration.

The machine may also be configured to two machining units, while machining the workpiece . If FVV series machine on the two vertical spindle cell configuration ; FVK series machine configured with a vertical spindle unit and can be used in a vertical / horizontal machining vertical / horizontal spindle automatic conversion unit ; while FKK series machine is used with two vertical / horizontal machining vertical / horizontal spindle automatic conversion unit . In the case of asymmetric hole machining or milling when necessary , other tools can be used with a cross slide of the control shaft to extend the function of the machine .

On the machine structure, better think gantry structure , processing almost unlimited . So they developed the P series and G series of different gantry machine . P Series gantry structure machine can process small-diameter circular pieces to large diameter. Turntable is located below the middle of the beam , the beam optional one or two movable vertical spindle machining unit , and at the same unit with two vertical spindle machining process more efficient. For horizontal machining , you can choose different angles needed boring head or horizontal spindle head . Gantry structure on G Series machine , radial positioning of the workpiece is not passed turntable , and the application of a unique linear axis gantry along the longitudinal direction of the movement , including uprights , including positioning, in addition to its great advantage is the large circular pieces can be processed , but also the processing of large flat pieces .

2011 developed a new ring piece dedicated to processing large vertical lathe series , the body is equipped with a huge bed turntable hydrostatic drive power of 350 kW, a diameter of 3,500 mm or more processed workpiece , and a variety of processing can be done on a machine .

In fact, China Machine Tool Plant and Plant Qiqihar production of large CNC vertical lathe or CNC vertical turning / milling machining center ring type parts can be processed . Wuhan Heavy Duty Machine Tool Plant early on a 16m vertical lathe production to meet the Chinese construction. Parts of this large diameter circular flat on the vertical lathe workbench , after clamping and alignment can be processed . Perhaps domestic machine tool performance and processing efficiency to be further improved and enhanced.

Class and the internal processing of large cylindrical parts cylinder class

As you know, on the lathe can be clamped with unilateral inner contour machining and boring bar diameter , in the combination of the vibration damping structure , but also to achieve effective processing of large aspect ratio (L / D) parts. Traditional processing program that, as in the inside of the large -sided pipe clamping and machining , the tool support is missing , found an important factor in this case is the aspect ratio (L / D) would restrict processing .

Germany Rottler machine tool manufacturing company with users and technology partners , according to the requirements of the processing task and prioritize user production conditions , structure and processing machine program feasibility study . 20 years, the application of new technologies to develop a variety of tools for internal processing and bushing bore cylindrical bore and pipe fittings contours and large rod material and reaming .

ABD structure of the series is a combination of hole machining machine tool diameter 2000 mm and 15000 mm long cylindrical hole in the workpiece and development. In the machine tool cutting tool and the workpiece fixed rotation . In the machine so far , stability and limited processing capacity of the hole from the center of rotation between the bed , the bed frame and the center of the coupling is unstable , the feed force of the lever transmission ratio unfavorable machining the tool into the hole can not be ignored factors. To overcome these shortcomings , Rottler the ABD series machine adds a bed body . Thus, the bed body parts can form the center frame and swing bracket structure is more compact , the outer diameter of the workpiece is also big. Increased costs can be compensated by increasing the feed rate. The new head is mounted using a new process indexable insert , in the processing of the hole, guided by a dedicated guide plate .

As the feed force can pass 300 kN and 400 kW drive power , so the chip thickness up to 70mm, and set the parameters for the indexable cutting inserts standard Road King and drilling length , so that can be done without tool change time cutting. Emulsion used as a tool and a guide plate cooling lubricants.

Hydrostatic guideways with critical damping and an auxiliary ram supported by four roller bracket on the base composition is considered outstanding stability during drilling . Since the stiffness, there is no need to support the processing power of the boring bar with a pilot hole or hit the center hole of the guide . In the processing of the eccentric hole on the stability of the stent is large , resulting in a base bracket coupled to the loose and moving on the bed through the headstock to accommodate different lengths of workpiece . Giving rise to a new heavy machine design , this series machine can process up to 5,000 mm and a length of 25,000 mm outer diameter of the workpiece .

Based on the complex contour paper machine rolls and rollers with special requirements , such as machine made ​​, Rottler has developed a portable dedicated turning unit , it can fit into the existing flat bed lathes , forming a structure Tabo series boring machine and portable processing unit , processing covering inner diameter 1,200 mm, length of 12,000 mm rolls , rollers and cylindrical workpieces can be processed according to their needs within the outline of free programming .

Botek typ entity for direct drilling 700mm diameter 43 deep-hole machining tool

And later in the series ABD structural components , based on the development of a series of deep structural TFB machine tools, machining diameter of 150 mm to 1,800 mm and lengths up to 15,000 mm of workpieces. This TFB BTA deep hole drilling machine suitable manner ( ie, make chips with high-pressure cutting fluid discharged from the hollow drill mode ) or Ejector mode ( which uses high-pressure gas to the hollow drill cuttings discharged from the way ) hole machining . TFB structure series machine with the workpiece and the tool can also be simultaneously rotating manner hole machining , hole machining will thus get as high concentricity.

Later, because he would be able cylindrical material processing 700 mm diameter in a short cylinder bore large dedicated manufacturer Hilfrich company requests , Rottler company after about 15 months of development, and manufacturing , with the world's first solid drilling method of drilling diameter 700 mm deep space machine tools in 2012 has been delivered to the user to use. After two drive units produce maximum feed force of 200 kN . Processing tasks required by the plan , the four headstock drive power 308 kW, while the two on the tool drive power is 130 kW. Deep processing tool for drilling diameter 700 mm entity as shown .

Through strong clamping spindle through four jaw machine faceplate to 132,000 Nm maximum torque transfer to the workpiece , 4 tool holder and three stents were supporting the drill pipe workpiece and the workpiece .

Supply the necessary spare parts have drilling equipment , drill pipe and drill and so on. Hole diameter corresponding to the different needs of the drill bit and drill diameter , with the rotation of the workpiece and tool fixed manner Ø700 mm hole drilling entity requires 290 kW driving power , the processing of chips per hour with 1,900 kg, while use of cutting cooling oil sprayed directly through the drill pipe and drill cutting edge to cool tools and exclude chips . Visible , processing efficiency is very high, of course, is also a great need for power tools , which solve breaking and timely exclude such a large number of chips is also not easy , so the processing difficulty is not small .

Large-size ultra-precision machine tools DIXI 210

DMG Mori Seiki ultra- precision machine tools DIXI 210

DMG Mori Seiki developed products, large-sized ultra-precision machine tools DIXI 210 comes as the world's highest unique latest specifications largest technical level of ultra-precision machine tools. It combines traditional Swiss precision machining and German engineering craftsmanship and technical personnel seriously manufacturing process. This is a high-end machine gantry structure , made ​​it perfect. In order to achieve the highest possible rigidity and stability , gantry structure using three-point support , which uses three of GGG60 block casting material support . This is to achieve the best precision and power values ​​as large as possible while milling strong foundation . Data representation , using DIXI 210 ultra-precision machine tools, as long as a little more grip , can be processed in diameter 2,500 mm, height 1,250 mm and 8,000 kg heaviest workpieces , both high-efficiency roughing , high dynamic can (0.6g ) , rapid feed (60mm/min) for fine finishing, precision volume <35μm. Spindle using different power spindle, maximum power of 114 kW. You can also choose 1,550 Nm and maximum speed of 6,300 r / min motor -driven spindle. Such a large machine tools, precision is really good skills, after only scraping by hand DIXI experienced staff more than 500 hours , in order to meet the requirements of the contact surface flatness, straightness and squareness of the precision required in all linear coordinates and the coordinates of the common precision rotary action , and ultimately to reach the minimum error on the shape and position of the workpiece .

User 's use of the process in the future without losing accuracy, one of which is to pay attention to the issue of all controlled cooling heat-generating components . In addition, after the machine is installed to measure all three dimensions , and sometimes precise adjustment , it is necessary to pay attention to local thermal expansion , but also concerned about the spatial accuracy and ambient temperature gradients.

In short , the world's leading machine tool manufacturing country , large and heavy machine many innovations , the rapid development of China Machine Tool and large , the results of heavy machine is also very prominent, not saying much . Processing equipment described above involves large and very large workpieces , China 's machine tool industry provides almost all . In recent years, strong growth and the development of China's wind power industry 's achievements in aviation, aerospace and defense industry and technology, are good examples. I think, now China 's machine tool industry is fully capable of solving problems of this part of the process