One kind eletroplate new-styly CBN grinds a matrix design

[summary] the basis is machined currently narrow deep chamfer current situation and difficult problem, introduced a kind of new-style treatment narrow deep chamfer grinds provided matrix design, use finite yuan undertook to its mode is analysed, reached the frequency that grinds a vibration. [keyword] CBN is ground; Wear a size; Natural frequency [in the graph classifies date] TG74 ＋ 9 [document label is piled up] A [article number] 1003 - 773 X (2008) 03 - 0114 - 02 foreword high accuracy is narrow the difficult problem that deep chamfer is machining all the time. Previously, of the width ＞ 2mm that goes up to average data spare parts narrow deep chamfer, it is to use cut milling cutter normally beforehand mill chamfer, via the reoccupy after heat treatment thinner colophony or grinding of emery wheel of bond of pottery and porcelain are machined. This kind of craft machines effect to lead intensity of low, emery wheel low, rigid difference, life is brief, precision of more inaccessible tall treatment. Use technology of grinding of feed of delay of common emery wheel, go out through can be being machined when the workpiece after grinding heat treatment relatively of high accuracy narrow deep chamfer. To width ＜ 2mm narrow deep chamfer, when milling is machined, cost is high, precision is low; When using grinding of feed of delay of common emery wheel, the ply of place of emery wheel work is very thin, nap amount is large, when grinding and nap extremely easy broken, finished cost is very high. In recent years, eletroplate the delay feed grinding that exceeds hard abrasive emery wheel to be used extensively at high accuracy chamfer. Abroad already was used eletroplate CBN emery wheel is in the 4340 steel of hardness HRC42 on delay feed grinding goes out wide 1.

52mm, deep 6.

35mm, contain R for 0.

Of 38mm round horn narrow deep chamfer. Home also is used eletroplate CBN emery wheel goes out in grinding of feed of the delay on common rolled steel wide 1.

Of 5mm narrow deep chamfer. A lot of aviation parts that make by difficult treatment material, have various high accuracy model groove, especially high accuracy of ministry of root of plane turbine lamina is alveolar and narrow the treatment of deep straight chamfer, it is the difficulty that domestic lamina machines all the time. The article eletroplates the introduction grinding of feed of delay of CBN emery wheel is narrow of deep chamfer grind a matrix design. The 1 radius design that grinds a matrix grinds a speed to increase, the value reduces grinding surface surface roughness, because increase emery wheel speed to be able to make,this is odd grind bead to not was out of shape, the cause that the ply that worry bit reduces. High rate grinding can raise metallic excision to lead, reduce grinding force, reduce power to use up, can improve grinding efficiency. Raise CBN to grind a speed, can make workpiece surface surface roughness is improved; Grind a speed taller, workpiece surface surface roughness is better, tangential drop to grinding force with the law, reduced so individual grind the susceptive on bead force, grind consequently wear away reduce, grinding heat can be reduced. But what the addition that grinds a speed makes wear bead is the biggest cut deep reduce, cut bits sectional area is reduced, at the same time cutting frequency and grinding heat increase, these two elements all make jam the quantity increases [1] . When according to craft the requirement grinds provided linear velocity to want 30mps above, machine tool rotate speed wants to be able to achieve 6000rpm; Bring adverse effect to prevent machine tool vibration, we choose 4000rpm commonly. At this moment, grind the Dn of π of ＝ of linear velocity V that provides the margin. D provides a diameter to grind, n is machine tool rotate speed. We choose D ＝ 200mm, computation gets V ＝ 41.

9mps, accord with the speed requirement that machines craft. The 2 ply that grind a matrix choose to grind a total ply to be 2mm, considering the ply of film and bottom nickel, the ＝ of matrix ply δ of the design 2 - 2d1 - 2d2. D1 is eletroplate abrasive bead diameter, d2 is bottom nickel ply. General, bottom nickel ply 5 μ of 3 ￣ M, take 4 μ M. The choice of abrasive granuality basically considers the requirement of grinding efficiency and workpiece surface surface roughness. Integrated we choose two elements the CBN of 120 granuality of 100 ￣ , according to GB6408 - 98 standards, relevant measure is 120 ￣ 150 μ M, desirable maximum 150 μ M, calculate ply δ ＝ 1.

692mm. But the heat that considers arenaceous bead expands, according to experience heat expands to be 5 μ M probably, because this final ply is decided,be δ ＝ 1.

687mm. 3 grind those who provide matrix to build feel and finite yuan of analysis 1) grind build model and the unit model after grinding a reseau to differentiate 2) undertake finite yuan of analysis, examine 3 rank natural frequency. FREQLOADSTEPSUBSTEPCUMULATIVE12477 of ／ of SETTImE of ＊ of ＊ of ＊ ＊ INDEXOFDATASETSONRESULTSFILE.

211127661.

812237696.

3133 (3) each rank natural frequency is ground be out of shape circumstance. Should grind with critical when rotating, grind a matrix to get stress is the greatest, strain is the greatest, arrive " critical " when condition, grind an intense vibration, bring about grind a life to drop, destroy even grind [2] . Grind a critical rotate speed and frequency relation to be: 60 × of N ＝ F. N is rotate speed (Rpm) , f is frequency (Hz) . But will grind a frequency translate into critical rotate speed, see on watch. Grind provided working rotate speed to be 4000rpm. By on the watch can see, grind provided working rotate speed far under critical rotate speed. Grind fall in these frequency, deflection is very small, won't bring about grind an attaint when working, can work normally. 4 conclusion are in assure to grind a condition of the craft that make to fall, grind by afore-mentioned designs provide pair of machine tools to damage little, grind a life tall, treatment precision also can get assuring. CNC Milling