《模具钢的单点金刚石切削技术课件》由会员分享，可在线阅读，更多相关《模具钢的单点金刚石切削技术课件（48页珍藏版）》请在金锄头文库上搜索。
1、Diamond Cutting of Hardened Steel Molds,Chong Fung Fung (10902795R) Ho Hoi Chau (10664322G) Xiao Gao Bo (11900474R)Zhang Guo Qing (11901723R),Problem definition and objectives Strategy and methodology Project significance Conclusion,Outline,Main business of our company,Injection molded plastic optic
2、s,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:,High speed machining of the steel mold shape. Electroless nickel coating proc
3、ess. Diamond cutting of the nickel layer.,Disadvantages of nickel-plated molds:nickel plating is very time and cost consuminglow hardness and thus short life timelow temperature stability can not be used for hot pressing of glass Therefore, Many optics need to be replicated by hardened steel molds.,
4、Established process for manufacturing hardened steel molds:sculpturing of the steel mold by end milling / grinding / EDMpolishing to mirror surfaceDisadvantages of this process:low efficiency and high costpolishing cause surface shape deteriorationcomplex surface structure can not be produced,Why no
5、t use single point diamond turning to replace these stupid processes ?,The affinity between 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 no
6、nferrous materials.,In order to overcome this problem, extensive research has been conducted in the past 30 years.Methods proposed to reduce tool wear during diamond cutting of steel:cut in carbon saturated atmospherecryogenic cuttingultrasonic vibration assisted cuttingintermittent cuttingthermal-c
7、hemical modification of surface layer,Tool wear can be reduced by up to 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 machi
8、ning of steel into our manufacturing processto build up corresponding quality control system to ensure qualityto reduce manufacturing cost and improve product quality,Problem definition and objectives Strategy and methodology Project significance Conclusion,Outline,Three approaches with high feasibi
9、lity for industry application:cut in carbon saturated atmospherecryogenic cuttingultrasonic vibration assisted cuttingintermittent cuttingthermal-chemical modification of surface layer,Elliptical vibration cutting,The friction between the chip and the tool rake face is drastically reduced.Cutting fo
10、rce and the cutting energy are reduced significantly.Intermittent cutting is effective in preventing tool wear and adhesion.,Hardened steel parts machined 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 (2
11、ft+) it will moves in an elliptical path.,Schematic illustration of the elliptical vibration cutting.,The vibrator is resonated elliptically at ultrasonic frequency by exciting the two piezoelectric plates with some phase shift.,One type of structure: ultrasonic elliptical vibration tool.,Three orga
12、nizations have succeeded in developing ultrasonic vibration cutting devices.Kobe University (Japan) Fraunhofer IPT (Aachen, Germany)SIMTech (Singapore) Both devices from SIMTech and Fraunhofer IPT are used by industry.,Equipments for ultrasonic vibration cutting,Son-X is a spin-off company of Fraunh
13、ofer IPT and specializes in producing the ultrasonic vibration tooling system.,The UTS one can be integrated into any commercially available ultra precision machine. Frequency: 80 KHz.,SIMTech has developed a compact ultrasonic vibration module able to cut steel (hardness HRC 55) to mirror surface f
14、inish (Ra8nm).,Machining setup,Performance Steel workpiece with diameter greater 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 -
15、raster milling,Ultra precision raster milling is another process that can suppress tool wear during diamond cutting of steel.,5-axis setup of the machine tool,Raster milling of freeform surface,The diamond tool is rotated around the spindle axis while the workpiece is fixed.,Schematic illustration o
16、f raster milling process,In 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.,Machines for raster milling,Freeform 705G,Freeform 700A,Precitech 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 with diamond tooling.,
