Technology of grinding of frame of aluminium alloy top studies

7g/cm3, 35% what be steel only, have the characteristic with function stability, better plasticity, heat treatment quenchs and after ageing treatment but aggrandizement interior is organized, raise intensity and wearability. The part of construction of accurate top frame that makes with aluminium alloy material, apply extensively in the product of spaceflight aviation domain. In traditional treatment method, the fixed position datum plane of the spare parts basically relies on benchwork to repair shovel and abrade finish, efficiency is inferior and be out of shape easily, make sure dimension asks very hard. The author adopts treatment practice, summary gives the planar grinding technology of spare parts of frame of aluminium alloy top, solved its effectively to machine difficult problem. 1.

Grinding machines the grinding of frame of top of difficulty aluminium alloy to machine difficulty to be: Material of ① aluminium alloy organizes easy generation fission below high temperature. Aluminium alloy material has melting point the characteristic with low, can big activation, after temperature is elevatory, plasticity greatens, below high temperature high pressure, easy generation sticks knife phenomenon when grinding, form the tumour that accumulate bits. ② spare parts is changeful form. Thin, tigidity differs wall of frame of aluminium alloy top, because stress is released,every time grinding is machined, cause workpiece to be out of shape, the dimension precision that affects top frame part and form tolerancepublic errand. ③ emery wheel grinds loss effect. When material of grinding aluminium alloy, except stick receive diffuse besides, aluminium alloy material and emery wheel are ground chemical reaction has between bead, accelerated the wear process of emery wheel. Material of ④ aluminium alloy because hardness is low, material resists plasticity is out of shape or the ability of nick is differred, when grinding is machined easy cut and surface of the workpiece that touch an injury. When ⑤ grinding changeful form. When grinding of aluminium alloy material cannot adsorptive, the kind that can take impaction only undertakes grinding, because wall of top frame spare parts is thin, appear below the action of thrust be out of shape, when grinding treatment is finished, the spare parts regains flexibility, cause out of tolerance of spare parts dimension to discard as useless. 2.

The chooses grinding material option of grinding material is as follows: ① abrasive uses brittleness is big and sharp black carborundum emery wheel, reduce grinding to stick receive, improve grinding efficiency. ② makes appliance has relatively the bond of pottery and porcelain of high strenth, and oil resistant, acid-proof, alkali resistance and anti-corrosive, raise the constituent intensity of emery wheel and durability thereby, reduce number of emery wheel nap, increase the stability that machines dimension. ③ uses thick date emery wheel below the circumstance of contented requirement, reduce grinding heat, those who control a part be out of shape, prevent emery wheel to jam, improve grinding surface quality. ④ should choose inferior emery wheel hardness, make emery wheel keeps good from acute sex. Choose hardness of class of H ～ J commonly. ⑤ should use more loose organization to accommodate worry bit, so that make grinding fluid enters grinding area, enhance cooling result, drop grinding area temperature. Optional appliance has the atmosphere aperture emery wheel of loose organization, have better grinding effect. ⑥ uses good emulsification oil to taste make grinding juice, in order to prevent grinding area temperature exorbitant cause spare parts burn. 3.

If attached drawing place is shown,machine frame of top of example aluminium alloy, the fiducial A of spare parts of aluminium alloy 2A12-T4 and parallelism 0.

005mm needs grinding treatment to achieve dimension precision requirement. The aluminium alloy data that embarrassed grinding processes data of top frame hardware, the precision to the spare parts reachs force of grinding temperature, grinding, emery wheel and grinding rate be out of shape have very big effect. It is fixed position face with A face, the end panel on impaction spare parts, use planar grinding machine, first the plane on grinding leaves surplus 0.

1mm, in above plane fixed position grinding of face of will fiducial A arrives dimension, will go up with the A side fixed position with good grinding again planar grinding arrives dimension, make sure parallelism asks. Parameter of the emery wheel that grinding chooses, grinding and grinding fluid introduction are as follows. Frame of aluminium alloy top pursues (1) the choice of emery wheel parameter is shown 1 times like the watch. (2) the choice of grinding dosage is shown 2 times like the watch. (3) grinding fluid. When grinding aluminium alloy, grinding fluid has refrigeration, lubricate and rinse action, use 30% ～ the oily juice that with 30% ～ the engine oil of 70% mixes configuration regards the kerosene of 50% as refrigeration and lubricating fluid, prevent and reduce emery wheel to jam the spare parts burn that cause and cut. (4) other note. Speed of the feed in ① grinding process wants even, especially transverse feed speed wants even. The emery wheel in the grinding process of ② aluminium jams very easily, passivation, so treatment surface appears very easily emery wheel nick and burn trace, the need when surface of reason emery wheel is machined is lubricant, lubricating fluid of the besmear outside can increasing appropriately, oily, cream. Can choose to be above emery wheel Tu Chai is oily, but dirtier; Still can be above emery wheel candle of besmear candle, industry, lubricant and lubricant cream etc, decrease thereby jam the burn that cause, cut. The aluminous bits that sticks above ③ emery wheel, can use oilstone to perhaps use a kind of sharp razor blade to be blown. ④ emery wheel must seasonable nap, nap is gotten some coarser, but must sharp, with preventing to jam. Horn of edge of ⑤ emery wheel can use emery wheel knife flat horn, with the seasonable eduction of benefit aluminous bits. 4.

This planar grinding craft uses epilogue dosage of fluid of correct emery wheel parameter, grinding, grinding and method of low stress grinding, abrasive of logical choice emery wheel, granuality, hardness reachs the parameter such as bond, adjust parameter of grinding force, grinding, improved the exterior grinding quality of the spare parts. Pass much batch to machine, make spare parts percent of pass by original 80% rise 98% the left and right sides. Bibliographical reference: [Association of technology of cutting of 1] Shanghai metal.

Metallic cutting manual [M] .

Shanghai: Press of Shanghai science and technology, 2000.

Author: Zhang Lijun Shen Wei CNC Milling