Fir of rotor of turbine of pump of 1000MW water supply annulus groove machines cutting tool to consider

Summary: ? The branny?000MW that treat Juan gives ü  core fir of rotor of water pump turbine model annulus structural feature of groove and treatment difficulty, mature cutting tool life and precision, to fir model annulus groovy milling cutter undertook proper improvement is mixed optimize, and already obtained very good application in producing practice. The overview develops as the high speed of economy of our country countryman, show the sign of rapid growth to the demand of electric power. In last few years, growth of demand of our country power amounts to 15 ～ every year 20% the left and right sides. Accordingly, pressure of construction of our country power station is very great, and the stand-alone capacity of power station aircrew also designs the technology that make as equipment of large fire phone rise, incline to is large change. The stand-alone capacity of power plant of our country large fire arrives from 300MW inferior critical 600MW grade, be in at present Xiang Chao is critical large turbogenerator group develops 1000MW social estate. Will count henceforth inside year, group of 1000MW large turbogenerator is sure to become the brunt unit of power plant of our country large fire. And boiler feed pump is the main subsidiary engine in system of heating power of whole turbogenerator group, the safety that will affect firepower generation set directly to the on the safe side of water pump turbine, efficient move. To get used to the tendency that group of electric machinery of our country fire develops, drive of boiler feed pump of form a complete set of set of large fire electric machinery employs grade of 1000MW of company development development industrial turbine. Turbine is main by rotor and quiet style two parts are comprised. Rotor is the core component of turbine, in the vapour medium of high temperature high pressure, bearing to leave the action of mental efforts, curved quadrature and torque, working requirement is very abominable, accordingly, turbine rotor machines the stand or fall of quality to will affect the performance of whole turbine directly, the treatment of round of chamfer is the most most crucial, difficult treatment in rotor treatment. Turbine of pump of 1 million water supply annulus what groovy structure uses is fir model annulus groove, round of chamfer of this kind of structure increased Xie Gen and annulus osculatory area of groove, make load distributings more even, but demand of its dimension precision is high, treatment creates difficulty. This brought a lot of issues with respect to the design that gives round of chamfer milling cutter, need writtens guarantee in cutting tool material, cutting tool the respect such as detail of compose, design and cutting tool film has thorough research. Pursue molded lines of 1 chamfer of Xie Gen annulus pursues (A) mill V chamfer (molded lines of ministry of B) milling head (C) rough machining (D) finish machining pursues rotor of turbine of pump of water supply of 1000MW of analysis of 1 treatment difficulty uses the milling process with general chamfer of 2 fir Xie Gen, material uses steel of nickel of 10325GP-VA(chromic molybdenum, hardness 250HB) , its if round of groove molded lines pursues show 1 times. Rotor has 6 in all class annulus chamfer, the molded lines of chamfer of root of each class leaf is like a graph basically 1 is shown, but its dimension, precision, width and groovy number different, specific if express,1 is shown. The outline of code name of molded lines of size of level of geometrical parameter table that expresses chamfer of 1 leaf root spends dark point of view of chamfer of error of span of face of tolerancepublic errand primary and secondary 1 - SR - 8P0.

100.

01341.

1970 ° 2 - SR - 4P0.

100.

01324.

8000 ° 3 - SR - 4P0.

100.

01324.

8000 ° 4 - SR - 8PBFP0.

070.

009146.

83425 ° 5 - SR - 11PBFP0.

070.

009135.

63218 ° 6 - SR - 11PBFP0.

070.

009135.

Because 63210 ° are to use form of whole forge rotor, the need when treatment is very careful, once among them treatment has round of chamfer by accident, the loss that cause will be very big, the problem that because this is before treatment,the difficulty to treatment and likelihood pose should undertake adequately analysis. Machine the option issue of method and cutting tool. As a result of fir leaf form of root annulus chamfer is complex and precision demand is high, use normally shape law treatment, main method includes figuration broaching and figuration milling two kinds. Annulus groovy broaching efficiency is taller, but need to be finished in equipment of professional broaching machine, suit the treatment of dish of shape impeller, and annulus groovy broach price is high, make reach long cross to spend bigger. To making forge rotor, still do not have the craft condition of round of groove broaching and capacity at present. Use figuration milling treatment, it is current the most commonly used treatment method inside the industry. The size of basis annulus chamfer and appearance use 3 knives or the treatment method of 4 knives commonly (if the graph is shown 2 times,be method of 4 knives milling, include among them: Open molded lines of molded lines of ministry of groove, thick milling head, thick mill and mill of essence of life, molded lines of ministry of thick milling head basically is to be aimed at the head to compare round of big groove) . Its are main as a result of,the reason is annulus groove is the narrowest department measure is lesser, place of milling cutter correspondence contains the restriction of the structural dimension such as bits chamfer because of cutting tool, the structural intensity of cutting tool and look bits ability are restricted, if be used directly,shape thick mill undertakes rough machining, because cutting amount is large, because cutting resists force, vibration,pass easily to reach the block that cut bits to bring about cutting tool to rupture greatly. Accordingly, produce manufacturer to much, to ensure safety uses 3 knives or the treatment method of 4 knives mostly. But, afore-mentioned treatment methods, no matter be cutting tool cost or finished cost opposite taller, produce cycle especially longer, do not suit my company to produce periodic demand, need is sought can shorten already handling time, reduce operating costs, can ensure again the method that machines quality. Accordingly, use 2 knives to machine directly -- shape the method of thick, finish machining made inevitable choice, the key is the problem breaking a knife when how preventing rough machining reliably. Cutting tool life and precision problem. From the watch 1 in can discover, the outline of foliaceous root chamfer spends tolerancepublic errand limits to be in 0.

07 ～ 0.

10, advocate, second the span error limits between working surface is in 0.

0091 ～ 0.

013, product precision demand is very high, to figuration milling treatment, outside placing precision except equipment and outfit, cutting tool precision is the main influencing factor that machines precision. When be being operated actually, in ensure cutting tool precision while still hope cutting tool has the cutting that grows as far as possible life and repair more wear a number, in order to reduce cutting tool cost. Generally speaking, the factor that affects cutting tool service life basically includes the following fields: The setting that cutting tool public errand takes. To finish machining cutting tool, in the consideration cutting tool installs the premise that places jumpy element, cutting tool public errand takes a setting to should make cutting tool is had as far as possible big outline, grind surplus with making cutting tool has more repairing, increase thereby long wear a number, reduce cost. Choose reasonable cutting tool to shovel back quantity. Although the larger amount that shovel a back is ameliorable cutting function, but, because belt of product public errand is narrower, larger shovel backside part makes trim size of the cutting tool when grinding change is opposite bigger, bring about cutting tool to repair those who wear a number to decrease. And too small shovel backside part, can make cutting tool and workpiece are machined exterior friction aggravate, accelerate cutting tool to wear away thereby, the quality that creates treatment appearance and cutting tool life drop. The function of cutting tool material and exterior film reachs treatment quality to also have bigger effect to the life of cutting tool. Cutting tool vibration also is met to cutting tool life and treatment precision the influence with larger generation. The factor that affects cutting tool vibration is very much, parameter of the geometrical point of view that includes clamping apparatus and tigidity of tigidity of machine tool main shaft, whole machining complex, cutting tool, cutting. Accordingly, want to undertake sufficient experiment and analysis when certain treatment method and parameter of cutting tool cutting. The treatment that 1000MW gives water pump turbine rotor annulus slot is a new challenge for the company to me, also be a kind of new test to technical personnel and operation personnel. The treatment difficulty problem that the structural feature of rotor annulus chamfer and place analyse article basis, be opposite the improvement with undertake certain designs round of groove milling cutter. Graph parameter of 2 milling cutter expresses induce sweat of graph of belt of 3 public errand molded lines code name is thick / blade of cutting of essence of life is the biggest R of diameter of diametical main aspects - 4P is thick 17.

87822R - 4P essence 18.

66522R - 8P is thick 29.

41635R - 8P essence 30.

40635R - 8PBFP is thick 31.

41435R - 8PBFP essence 32.

36235R - 11PBFP is thick 23.

5632R - 11PBFP essence 24.

Because choice of 308322 cutting tool and design use 2 knives treatment, to avoid the problem breaking a knife when rough machining, reach the service life that improves cutting tool and precision, undertook to milling cutter of thick, essence a few improve. The means of settlement that break a knife. The problem that break a knife basically appears in rough machining process, because of form of blade of the wave after this was used to thick milling cutter, can make cut bits to become filament state so, make cutting force reduces 30%~40% thereby, it is easy also to cut bits at the same time in cutting fluid erode below by eduction, because cut bits to jam,prevent to cause cutting tool to rupture. It is certain to was designed at the same time before horn and helix angle, make cutting tool sharper, cutting process is smoother, because cutting force, vibration is caused greatly too,can prevent cutting tool rupture. Tolerancepublic errand takes a setting. The outline of foliaceous root chamfer spends tolerancepublic errand limits to be in 0.

07 ～ 0.

10mm, machine tool radial is jumpy 0.

005mm, cutting tool is jumpy 0.

005mm, won't cause work measure out of tolerance to ensure machine tool and cutting tool are jumpy, the smallest maximum that cutting tool safety abundant spends is set for 0.

01mm, cutting tool public errand is set for 0.

01, make dimension of cutting tool outline as far as possible big, if pursue 3, can be in so assure round of chamfer to machine precision while, improve cutting tool life. The shovel carries a quantity on the back to be decided really. Improve cutting tool life to make sure workpiece surface quality is mixed, the shovel carries the size of the quantity on the back to be ground in order to repair 3 times, always repair grind a quantity to arrive 0.

45mm ～ 0.

6mm undertakes deciding for the basis. Material and film choose. Cutting tool material uses CPM of pulverous high-speed steel, its tenacity, hardness, but grinding sex is good. Film is used compound and multilayer coating TiCN, it is good that its fight felt, hear resistance, wearability. Cutting tool parameter is affirmatory. Undertake an analysis to workpiece for many times in the course, if the main parameter that decides each model milling cutter finally expresses 2 to show. Graph appearance of root of 4 standards leaf piece measure means and measure choice: According to the structural feature of rotor and precision requirement, besides using the measurement technique such as dial gauge of general outside callipers, lever, still designed special gauge, like standard leaf root appearance piece, stop compasses undertake metrical. The standard leaf root that designs among them appearance piece is shown 4 times like the graph, molded lines part takes the treatment of dimension of the biggest outline in the graph by public errand of corresponding leaf root, the 1 ／ that outline spends tolerancepublic errand to spend tolerancepublic errand for foliaceous root outline 3, the 1 ／ that span public errand is public errand of foliaceous root span 2. Compasses press round of chamfer design of the largest hypostatic size, stop compasses press round of chamfer design of the smallest hypostatic size, fir annulus groove is connected stop compasses it is a kind of omnibus gauge, can make sure molded lines and public errand ask at the same time. Specific measurement means and target are as follows: A) is become after treatment finishs round of chamfer, push Xiegenyang piece, imitate leaf root is assembled, if shift is smooth, and shoulder blade plane adopts rule of a place of strategic importance certificate of proof, of contented Xiegen and foliaceous chamfer assemble clearance to ask; B) is connected compasses is OK because cutting tool wears away,detect round of groove size that cause is too small, can selective examination only a few round of chamfer; C) stops compasses is OK because cutting tool or machine tool are jumpy,detect round of groove size that cause is too large, the first chamfer that needs to be machined to place of new cutting tool only undertakes metrical. Clamping apparatus: Use FD500 graduation platform, high accuracy collet of puissant milling cutter (7: 24 BT50) . Among them FD500 graduation platform is the special fixture that in the light of graduation of the rotor when chamfer of root of milling fir leaf design makes, clamping force is larger, graduation is accurate, if pursue,5 are shown. Graph assembly of 5 graduation platform pursues 3 process are designed 3. Clip of 1 rotor outfit and search (1) installs graduation platform device on workbench; (Before 2) workpiece loads graduation platform, examine with red oil the osculatory circumstance between two bearing journal and plain bearing liner; (3) workpiece loads graduation platform and put on machine tool workbench, on the order of graduation gear installation on desired result device and rotor annulus groove arranges order to agree; (4) searchs axial center, the error must not is more than 0. 05mm, clip, pressure prison; (5) is built in place of aperture of the balance between various impeller auxiliary prop up in order to increase tigidity. 3. 2 rounds of chamfer machine round of groove treatment to change knife treatment twice to finish through milling cutter of thick, essence, the angle between photograph adjacent chamfer is covered by ministry of assembly of the dividing head of graduation platform device and cent tine assure. Annulus groovy part sketch map is shown 6 times like the graph. (1) machines inclined chamfer (or platform) before, with angle desired result piece examines the validity of contrail of cutting tool diagonal; (What if the graph shows vane wheel of 1 one S 6 times,2) is in is initiative the center makes round of chamfer label apparently, the others is various round of groovy position of rest all as identical as 1 one S; (Platform of the circle outside 3) mill, complete treatment whole rounds through graduation; (4) changes a knife, thick mill annulus groove, examine, finish round of groove rough machining whole rounds through graduation; (5) changes a knife, mill of essence of life annulus groove, examine, complete round of groove precision work whole rounds through graduation; (6) changes a knife, treatment issues one class impeller, repeat (3) one (5) measure (till all annulus groove machines) ; (7) clears, go burr. Pursue 6 rounds groovy part sketch map 3. 3 cutting parameter passes the analysis that waits to cutting tool character and hardware data, structure certainly, combine the treatment function of the machine tool at the same time, precision reachs the experience that operates personnel, if express 3 shown cutting parameter,decided finally. Express parameter of cutting of 3 milling cutter to express molded lines code name thick / rotate speed of essence of life (R/min) feed (Mm/min) is cut deep (Mm) new knife but cutting length (M) is repaired after grinding but cutting length (M)R-4P thick 400~53422~3224.

602.

51.

5R-4P essence 385~51228~4124.

82.

51.

5R-8P thick 245~32514~1940.

9972.

51.

5R-8P essence 235~31417~2541.

1972.

51.

5R-8PBFP thick 230~30413~1846.

6342.

51.

5R-8PBFP essence 220~29516~2446.

8342.

51.

5R-11PBFP thick 305~40617~2435.

4322.

51.

5R-11PBFP essence 295~39321~3135.

6322.

51.

5 3. · of law of 4 check proved recipe uses standard Xie Gen appearance piece examines, appearance of standard leaf root piece insert round of chamfer like can relaxed ground, can freely axial of edge annulus chamfer is slip, stop without card phenomenon, and clearance accords with a requirement, it is qualification. · is used stop compasses examine molded lines dimension and public errand. · the others examines with measure. Surface roughness of · dimension precision, surface and form tolerancepublic errand requirement, press a design and clinical examine. Fir of rotor of turbine of pump of water supply of 1000MW of 4 last words annulus groovy treatment, the challenge is for the company to me. Although appeared to do not have a few problems that anticipate beforehand in machining a process, if appear in cutting process,cut bits hard eduction brings about cutting tool to die, workpiece produces little vibration to wait, but fall in company technology personnel and operation personnel joint efforts, mix in ceaseless exploration, analysis each problems were solved in improving, completed rotor treatment smoothly as scheduled. Of this second treatment example finish smoothly, the to chamfer of this kind of structure annulus treatment after giving provided valuable experience and data data, also be opposite at the same time machine and improve of the technology of round of new chamfer henceforth further laid a foundation. CNC Milling