模具钢的单点金刚石切削技术

1、chong fung fungchong fung fung(10902795r)(10902795r) ho hoi chauho hoi chau(10664322g)(10664322g) xiao gao boxiao gao bo(11900474r)(11900474r) zhang guo qingzhang guo qing(11901723r)(11901723r) problem definition and objectives strategy and methodology project significance conclusion main business o

2、f our companymain business of our company injection molded plastic optics hot pressed glass optics nickel-plated injection molds hardened steel molds nickel plated injection molds have long been used for the injection molding of plastic optics. established process for nickel-plated steel molds:estab

3、lished process for nickel-plated steel molds: high speed machining diamond cutting nickel plating i.high speed machining of the steel mold shape. ii.electroless nickel coating process. iii.diamond cutting of the nickel layer. disadvantages of nickel-plated molds: p nickel plating is very time and co

4、st consuming p low hardness and thus short life time p low temperature stability p can not be used for hot pressing of glass therefore, many optics need to be replicated by hardened steel molds. established process for manufacturing hardened steel molds: i. sculpturing of the steel mold by end milli

5、ng / grinding / edm ii. polishing to mirror surface disadvantages of this process: p low efficiency and high cost p polishing cause surface shape deterioration p complex surface structure can not be produced why not use single point diamond turning to replace these stupid processes ? the affinity be

6、tween the carbon (diamond) and the iron (work piece) leads to excessive tool wear and decreased surface quality in conventional diamond cutting of steel. therefore, diamond machining is conventionally limited to nonferrous materials. in order to overcome this problem, extensive research has been con

7、ducted in the past 30 years. methods proposed to reduce tool wear during diamond cutting of steel: u cut in carbon saturated atmosphere u cryogenic cutting u ultrasonic vibration assisted cutting u intermittent cutting u thermal-chemical modification of surface layer tool wear can be reduced by up t

8、o two orders of magnitude. diamond machining of steel is ready for industry application. high alloyed tool steel molds (1200hv) turned by one diamond tool the objectives of this project: to introduce the technology of diamond machining of steel into our manufacturing process to build up correspondin

9、g quality control system to ensure quality to reduce manufacturing cost and improve product quality problem definition and objectives strategy and methodology project significance conclusion three approaches with high feasibility for industry application: u cut in carbon saturated atmosphere u cryog

10、enic cutting ultrasonic vibration assisted cutting intermittent cutting thermal-chemical modification of surface layer elliptical vibration cutting the friction between the chip and the tool rake face is drastically reduced.the friction between the chip and the tool rake face is drastically reduced.

11、 cutting force and the cutting energy are reduced significantly. cutting force and the cutting energy are reduced significantly. intermittent cutting is effective in preventing tool wear and adhesion. intermittent cutting is effective in preventing tool wear and adhesion. hardened steel parts machin

12、ed by ultrasonic vibration cutting when a diamond tool is actuated in a plane by two sinusoidal waves x(t), y(t), x (t) = a cos (2ft) y (t) = b cos (2ft+) it will moves in an elliptical path. schematic illustration of the elliptical vibration cutting. the vibrator is resonated elliptically at ultras

13、onic frequency by exciting the two piezoelectric plates with some phase shift. one type of structure: ultrasonic elliptical vibration tool. three organizations have succeeded in developing ultrasonic vibration cutting devices. kobe university (japan) fraunhofer ipt (aachen, germany) simtech (singapo

14、re) both devices from simtech and fraunhofer ipt are used by industry. equipments for ultrasonic vibration cuttingequipments for ultrasonic vibration cutting son-xson-x is a spin-off company of fraunhofer ipt fraunhofer ipt and specializes in producing the ultrasonic vibration tooling system. the ut

15、s one can be integrated into any commercially available ultra precision machine. frequency: 80 khz. simtechsimtech has developed a compact ultrasonic vibration module able to cut steel (hardness hrc 55) to mirror surface finish (ra8nm). machining setup performance steel workpiece with diameter great

16、er than 40mm in diameter can be machined. mirror finish of better than 8nm ra can be obtained. profile accuracy of 0.15m can be achieved for 10mm diameter samples. diamond cut hardened steel inserts intermittent cutting - raster millingintermittent cutting - raster milling ultra precision raster mil

17、ling raster milling is another process that can suppress tool wear during diamond cutting of steel. 5-axis setup of the machine toolraster milling of freeform surface the diamond tool is rotated around the spindle axis while the workpiece is fixed. schematic illustration of raster milling process in

18、 ultra-precision raster milling, the contact time between diamond tool and workpiece is so short that it has enough time to cool the interface. thus tool wear can be suppressed. rotating axis cutter workpiece machines for raster millingmachines for raster milling freeform 705g freeform 700a precitec

19、hprecitech designs and manufactures ultra precision machine tools for turning, milling, and grinding. their machines can produce rotationally symmetric, asymmetric, freeform and sculpted geometries. form tolerances in the sub-micron range and nanometer surface finishes can be achieved when equipped

20、with diamond tooling. moore nanotechnology systemsmoore nanotechnology systems nanotech 350fg the nanotech 350fgnanotech 350fg is able to perform raster fly cutting of freeform, linear diffractive, micro-prismatic optical structures. basic ideabasic idea: avoid chemical reactions between the carbon

21、and iron by establishing a chemical bond between the iron and another chemical element. nitridingnitriding process has been developed for the thermal mechanical modification of steel and steel alloys. c fe n cross section of a nitrided 42crmo4 steel. through nitriding the unpaired electrons in the d

22、 shell of the iron, which are responsible for the catastrophic diamond tool wear, will be bonded. effects of nitriding diamond tool wear can be reduced by more than two orders of magnitude. the surface roughness obtained in single point diamond turning of carbon steel was better than 10nm ra. two as

23、pherical hard steel molds diamond turned with one diamond tool. nitridingnitriding is a surface-hardening heat treatment that introduces nitrogen into the surface of steel. schematic diagram of plasma nitriding equipments ionitech ltd ionitech ltd provide a full series of nitriding facilities. overv

24、iew of the nitriding systemplasma generator typically a nitriding system nitriding system consists of vacuum chambervacuum chamber, plasma generatorplasma generator, vacuum system vacuum system and the control systemcontrol system. method for quality controlmethod for quality control in-situ error m

25、easurement and compensationin-situ error measurement and compensation ultracomp module for nanoform 250 in-situ measurement using air bearing lvdt metrology probe profile error analysis in-situ error compensation in-situ error measurement and error compensation for hardened steel mold insert. diamon

26、d cutting of hardened steel would make the pricing and time consuming process of nickel plating unnecessary. diamond cutting of steel nickel plated steel molds high speed machining high speed machining diamond cutting diamond cutting nickel plating costcost is a major consideration in the modern man

27、ufacturing industry. major difference in costmajor difference in cost diamond cutting of steeldiamond cutting of steel diamond cutting nickel plated steel moldsnickel plated steel molds diamond cutting nickel plating take a 30mm diameter mold for exampletake a 30mm diameter mold for example one diam

28、ond tool is able to cut two molds. the diamond tool cost hk$ 6,000. so the cost for one mold is hk$ 3000. u one diamond tool is able to cut 200 molds. so tool cost per mold is hk$ 30. u the nickel coating for a 30mm mold is about hk$ 3000. so the total cost per mold is 3000+30=hk$ 3030. whats more 0

29、 500000 1000000 1500000 2000000 2500000 3000000 3500000 nickel harden molding shoot comparison of average insert molding life in this sense, one steel mold will bring a total cost reduction of about hk$ 10,000 in the whole manufacturing process of injection molded optics. the life time of hardened s

30、teel molds is about 35 times the life time of hardened steel molds is about 35 times longer than nickel plated steel molds. longer than nickel plated steel molds. a nitriding system costs about hk$ 800,000. this means that the equipment cost will be covered after producing about 800,000/10,000 = 80

31、steel molds. a ultrasonic tooling unit costs about hk$ 700,000. the equipment cost will be covered after producing about 700,000/10,000 = 70 steel molds. equipment costequipment cost a 5-axis upm machine costs about hk$ 5,000,000. the equipment cost will be covered after producing about 5,000,000/10

32、,000 = 500 steel molds. methodmethodadvantagesadvantageslimitationslimitations nitridingnitriding very easy processes and operations. highly mature commercially available equipments. p porous in the nitrided layer affect surface quality. p surface roughness is slightly higher. ultrasonicultrasonic v

33、ibrationvibration assisted assisted cuttingcutting cheapest device. only two processing steps are needed. good surface roughness and form accuracy can be achieved. p cautions need to be taken regarding the machining parameters. p cutting speed can not be as high as conventional diamond cutting. rast

34、erraster millingmilling only two processing steps are needed. complex surface structures can be machined. p low machining efficiency. p performance in reducing tool wear is not as good. p 5-axis freeform upm machines are very expensive. advantages and limitations of each approachadvantages and limit

35、ations of each approach recommendationrecommendation ultrasonic vibration assisted cutting ultrasonic vibration assisted cutting has the best performance. best surface roughness and surface quality achieved. excellent performance in reducing tool wear. cheapest cost for equipments. therefore, theref

36、ore, ultrasonic vibration assisted cutting ultrasonic vibration assisted cutting is is recommended for adoption in our manufacturing recommended for adoption in our manufacturing process. process. problem definition and objectives strategy and methodology project significance conclusion advantages o

37、f hardened steel molds: advantages of hardened steel molds: manufacturing period can be reduced to 1 day from 2 to 4 weeks. the frequently caused damages by nickel plating within the mould die can be avoided. higher scratch resistance; no peeling off; no chipping/cracking on sharp edges. life time i

38、s 35 times longer. higher temperature stability. molds can be repaired efficiently and without external coating steps. lower manufacturing cost. advantages of diamond cutting over conventional processes (grinding advantages of diamond cutting over conventional processes (grinding and finishing) for

39、producing hardened steel moldsand finishing) for producing hardened steel molds: higher form accuracy. hardened steel molds with more complex surface structures and small radii cavities can be produced. higher efficiency and lower cost. in summary, with the higher efficiency , lower in summary, with

40、 the higher efficiency , lower cost and greater capability brought by the new cost and greater capability brought by the new technology, the competence of our company technology, the competence of our company will be greatly improved.will be greatly improved. problem definition and objectives strate

41、gy and methodology project significance conclusion three approaches for enabling the diamond machining of hardened steel molds are introduced and ultrasonic vibration assisted cutting is recommended for adoption. the adoption of this technology will bring higher manufacturing efficiency, lower manuf

42、acturing cost and greater manufacturing capability. in conclusion, the adoption of this new technology will give us a decisive lead over our competitors. 1 b. larisch, u. brusky and h. j. spies, plasma nitriding of stainless steels at low temperatures, surf. coat. technol., vol. 116/119, pp. 7, 1999

43、. 2 e. brinksmeier and r. glbe, advances in precision machining of steel, cirp ann. manuf. technol., vol. 50, pp. 385-388, 2001. 3 e. brinksmeier, r. glbe and j. osmer, ultra-precision diamond cutting of steel molds, cirp ann. manuf. technol., vol. 55, pp. 551-554, 2006. 4 e. brinksmeier and r. glbe

44、, basic studies on the wear behaviour of modified and coated diamond tools for precision machining of ferrous materials, in initiatives of precision engineering at the beginning of a millennium, i. inasaki, ed. springer us, 2002, pp. 174-178. 5 m. a. davies, c. j. evans, r. r. vohra, b. c. bergner a

45、nd s. r. patterson, application of precision diamond machining to the manufacture of microphotonics components, in 2003, pp. 94-108. 6 e. brinksmeier, precision machining of steel with ultrasonically driven chilled diamond tools, proceedings of the 17th annual aspe meeting, pp. 275-278, 2002. 7 e. b

46、rinksmeier, elliptical vibration cutting of steel with diamond tools, proceedings of the 14th annual aspe meeting, pp. 163-166, 1999. 8 h. kim, s. kim, k. lee, d. lee, y. bang and k. lee, development of a programmable vibration cutting tool for diamond turning of hardened mold steels, the internatio

47、nal journal of advanced manufacturing technology, vol. 40, pp. 26-40, 2009. 9 f. kimura, k. horio, e. brinksmeier, o. riemer and r. glbe, merging technologies for optics, in towards synthesis of micro-/nano- systemsanonymous springer london, 2007, pp. 1-9. 10 norikazu suzuki, ultraprecision sculptur

48、ing of hardened steel by applying elliptical vibration cutting, . 11 j. osmer, r. glabe, o. riemer, e. brinksmeier, s. butepage and f. hoffmann, diamond milling of nitrided steels for optical mold making, in 2009, pp. 1238-1240. 12 p. schellekens, n. rosielle, h. vermeulen, m. vermeulen, s. wetzels and w. pril, design for precision: current status and trends, cirp annals, vol. 47, pp. 30, 1998. 13 p. schellekens, n. rosielle, h. vermeulen, m. vermeulen, s. wetzels