The cutting of difficult frit metal and pure metal is machined (below)

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Pure copper carbon fin 12.

How to undertake to pure copper cutting is machined? Cutting pure copper does not have the difficulty with special what, the key is to should have been solved stick knife and the problem that break bits. Cutting tool material can choose the hard alloy razor blade such as W18Cr4V high-speed steel and YG3, YG6, YG8. The tenacity of pure copper, plasticity is big, the heat when cutting is out of shape big. Requirement cutting tool is sharp, cutting is light, platoon bits is smooth, drop cutting temperature as far as possible. Turning pure copper often is used big before the horn after horn is mixed, ~ of general γ O=25º 35º , α O=12º ~ 15º , 3º of λ S=0º ~ . Roll bits chamfer wear is shallow and wide round arc. If be in hind grind on knife face give a few deep-slotted chip breaker, make advocate the washboard state that cutting blade becomes moire entity (place of the 10-1 that be like a graph shows) , its cut bits to submit form of rows of tiles on a roof. And, muscle of rows of tiles on a roof the tigidity that increased to cut bits curl way, the energy that wastes when curl adds, metabolize increases, brittleness rises, cut bits to break off easily (10-2) seeing a picture. Cutting pure copper can choose higher cutting rate, ~ of general ν C=120 170m/min, ap=3 ~ 15 Mm, f=0.

3 ~ 0.

6 Mm/r. Because the linear expansion coefficient of pure copper is big, should notice to control cutting temperature, finish machining should undertake after workpiece is cooling, in order to assure dimension and geometrical precision. YG kind of hard alloy it is better to grind processability, can grind a sharp point, comfortable wait for nonferrous metal at machining pure copper. But solder it is more difficult that cutting tool blade is ground, choose cutting tool of machine clip structure commonly, bit chooses but dislocation type. The groovy form of dislocation type razor blade fastens suppress and can become, all sorts of sectional changing groovy form, multistage chamfer form makes bits range very wide. When cutting pure copper, can choose the bit with bits good effect according to the cutting condition of workpiece, bei grinds from the back can use. 13.

What grinding characteristic does pure copper have? Pure copper issues hardness in normal temperature very low, have again wonderful absolutely magnetic can, apply extensively at electronic component. But when undertaking grinding to it, quench than grinding steel difficulty is gotten much. Grinding from time to tome its characteristic, easy generation cut, burn, heat is out of shape and emery wheel conglutinate wears away wait for a problem. (1) cut: The feature of pure copper cut is in workpiece apparently desultory ground presents a dent of shape of a path channel, the hand is felt have coarse feeling, general deepness is 0.

17 μ of 5 ~ M. Sort of the degree of finish that this kind of nick and emery wheel wear bead, bond is concerned, have nothing to do with the abrasive of emery wheel. It is break away from the freedom that come down to grind bits to fall into be caused by of workpiece of grinding area cut by emery wheel. The method that prevent is, the emery wheel of bond of fine granuality, black lead should be chosen when essence of life is ground, a certain quantity of saponification oil adds in cooling fluid (it is with water scale 1: 32) , can avoid cut. (2) burn and heat are out of shape: Pure copper is the data with a kind of heat stronger quick, its coefficient of thermal conductivity is 393W/(m · K) , it is 7 times of 45 steel, 1 linear expansion coefficient is 45 steel.

5 times, when grinding make workpiece surface easily calorific, produce heat to be out of shape. Be in when emery wheel in grinding after passivation, this kind of phenomenon is more serious, and can produce burn. So, when grinding pure copper, cooling fluid must first and last very enough. (The adhesiveness of 3) emery wheel wears away: The hardness of pure copper has HB35 ~ only 45, it is one kind exceeds soft metal. And the hardness that wears bead is as high as HV2000 ~ 2700, both differ a few times. Accordingly, of pure copper worry bit the space holding bit of easy built-in emery wheel, make emery wheel loses grinding ability. So conglutinate wears away is the only in pure copper grinding wear away. If use the emery wheel of 60 granuality, feed is 0.

When 01mm/ double journey, about 5 times emery wheel lost grinding ability, must new nap. The durability of emery wheel is very low. The size of emery wheel is smaller, hardness is taller, the organization is more close together, the working surface of emery wheel is more flowing, the durability of emery wheel is lower. Accordingly, wear away to reduce the conglutinate of emery wheel, must choose emery wheel reasonably, the chroma of cooling fluid and flow note in grinding process. Pure copper fan 14.

How to choose the emery wheel with nap grinding pure copper? (The choice of 1) emery wheel: According to the grinding characteristic of pure copper, enter sexual cut to avoid to engrave, the corundum that should choose colophony bond or black lead bond kind or the emery wheel that carborundum is abrasive. Kibble is 60 ~ with granuality the emery wheel that 80 date, hardness are K, essence of life is ground with black lead emery wheel best. Below termless circumstance, usable also corundum kind the atmosphere aperture emery wheel of bond of pottery and porcelain. Cooling lubricating fluid must filter strictly. To assure the quality that essence of life grinds, grinding mass must hold when kibble, coarsen grinds final treatment surface to must not have any drawback. (The nap of 2) emery wheel: A when decide surface roughness of surface of pure copper grinding main factor is the tall sex such as the small blade needle of emery wheel surface. The nap parameter that the nap when kibble uses general grinding is OK. When essence of life is ground, when must noticing emery wheel did not achieve complete conglutinate to wear away, must undertake nap. The tall sex such as better to obtain blade needle, use odd grain vertex angle to be 70º ~ the King Kong slate pencil of 80º , workbench goes there and back below the feed quantity that is less than 1 μ M, again idle stroke, the emery wheel after such nap can grind a Ra=0 of exterior surface roughness.

05 ~ 0.

The high grade surface of 025 μ M. To reduce the grinding surface surface roughness of pure copper further, can choose finer granuality (be less than the emery wheel that is equal to W1) , raise the tall sex such as the working face after emery wheel nap. Use store, platoon function and medicinal powder the atmosphere aperture emery wheel with hot better sex, in order to raise the durability of emery wheel. Should notice the cleanness that raises cooling fluid is spent when grinding, increase pouring quantity, in order to drop grinding temperature. Pure iron 15.

What cutting does pure iron have to machine a characteristic? Pure iron calls industry pure iron again, its metallographic organization is ferrite, hardness is HB80, intensity is low and plasticity, tenacity is tall. Cutting pure iron from time to tome the following characteristic: (The percentage elongation of 1) pure iron is 50 % , be out of shape when treatment big, sclerotic and serious, cut bits easy with cutting tool felt, aggravate cutting tool wears away. (2) cuts bits to break off not easily, often twine go up in workpiece or cutting tool, affect the treatment surface quality of the success of cutting and workpiece, temperature of the cutting when cutting is higher, affect cutting tool durability. (3) joins the nickel of 1 % , manganese or silicon in pure iron, can make crystal structure produces the change of different level, mechanical function also produces change subsequently, intensity, hardness rises and plasticity, tenacity is reduced, consequently its cutting processability can get ameliorative. Pure iron Normal >16.

How to undertake to pure iron cutting is machined? Normal > cutting pure iron can choose high-speed steel and hard alloy to make cutting tool material. Hard metal of W18Cr4V high-speed steel, YG8 is used when thick car commonly, cutting tool of YT14 hard alloy can be used when fine vehicle. The hardness of pure iron is low and plasticity is big, should increase the role before cutting tool, γ O=25º ~ 30º , α O=8º ~ 10º , 8º of ~ of α ′ O=6º , Κ R=35º ~ 75º , ~ of Κ ′ R=5º 15º , 3º of λ S=0º ~ . Before the width pouring arris on knife face is desirable 0.

05 ~ 0.

15mm, roll the 15 ~ that bits chamfer width is feed 20 times, roll radius of bits chamfer circular arc but somes big, make a bits successful. The selection of cutting dosage is as follows: C=50m/min of the ν when thick car, ap=3 ~ 6mm, f=0.

35 ~ 0.

4mm/r. 80m/min of ~ of C=60 of the ν when fine vehicle, ap=0.

1 ~ 0.

4mm, f=0.

1mm/r. Normal > , can use lathe tool of double blade dip (10-3) seeing a picture undertakes cutting. Be in namely advocate place of point of a knife is stood by to grind a dip of the 2nd blade on cutting blade, make cut bits to be out of shape sufficient, bits can be broken when lesser feed, and strength of point of a knife is good, cutting tool durability is tall. 17.

What cutting characteristic does pure nickel have? Pure nickel is metal of silvery white of iron a group of things with common features. Pure nickel melting point is high 1452 ℃ ) , the sex that fight corrode is strong, have particular mechanical strength and good plasticity and hear resistance, already got applied in more and more domains. The cutting processability extreme difference of pure nickel, in cutting from time to tome the following characteristic: (The coefficient of thermal conductivity of 1) pure nickel is low, cutting temperature is in in Gaojuji cutting area, aggravate cutting tool wears away. (The affinity of 2) pure nickel is very strong, the element such as the cobalt in it and cutting tool material, iron produces felt extremely easily. (Plasticity of 3) pure nickel is tall, in cutting bits difficulty is broken when successional cutting especially. (4) cutting pure nickel is unfavorable cutting tool of use hard alloy, no matter be tungsten cobalt kind, still be tungsten cobaltic titanium kind reach carbonization titanium base hard alloy, the element such as their felt photograph cobalt, nickel, molybdenum has with pure nickel extremely tall kiss and ability. With cutting of hard alloy cutting tool pure nickel often wears away because of intense felt and fail. Normal >18.

How turning pure nickel? Normal >(1) cutting tool: Because pure nickel is right the elemental affinity such as cobalt, iron, nickel is particularly strong, cutting is out of shape big, cutting area temperature is high, the cutting tool stuff with ought to choose to fight caking property can good accordingly. Should choose when low speed cutting super- hard model M42 high-speed steel. Nitrogen turns cutting tool of silicon pottery and porcelain, do not arise to be mixed in person to nickel action, can use turning pure nickel. But the bending strength as a result of pottery and porcelain is inferior, not easy blade grinds edge very tartly, tall to cutting tenacity pure nickel effect is very not ideal. The cutting tool material with best effect of cutting pure nickel is cubic nitrogen changes boron. The hear resistance that cubic nitrogen changes boron and chemical stability are wonderful, can use King Kong again stone mill annulus grinds a very sharp point, the effect of reason cutting pure nickel is very good. The experiment proves, with pure nickel of cutting of DLS-F(CBN) cutting tool, when C=100m/min of cutting speed ν , durability of its cutting tool is 50 times of M42; It is 500 times of cutting tool of YM051 hard alloy; It is 200 times of high-speed steel commonner; It is 20 times of TiN coating hard alloy. Normal >(2) cutting tool: Use cubic nitrogen to turn boracic cutting tool, 0º of γ O=-5º ~ , Κ R=90º , Κ ′ R=8º , α O=6º ; With cutting tool of M42 high-speed steel, γ O=5º ~ 10º , other parameter and turn boracic cutting tool with cubic nitrogen basic and identical. Normal >(3) cutting dosage: The coefficient of thermal conductivity of pure nickel is inferior, cutting temperature is high, appropriate chooses inferior cutting career. The cutting rate that uses cubic nitrogen to turn boracic cutting tool is controlled in 100m/min; The cutting rate that uses cutting tool of M42 high-speed steel is controlled in 20m/min. Cutting deepness and feed and cutting are general when material identical. Normal >(4) decides bits issue: Breaking bits is a difficult problem of cutting pure nickel, because cubic nitrogen changes the effect of structure of boracic cutting tool, use bits chamfer impossibly to come bits, can solve bits problem only through changing cutting parameter. Usually, when R=90º of γ O=-5º , Κ , all can break bits below all sorts of cutting dosage; When γ O=0º , left and right sides of C=60m/min of cutting speed ν can break bits; If when γ O=5º , can be only when cutting deepness and feed are bigger, just have bits effect. Magnesium alloy spare parts 19.

What cutting does magnesium alloy have to machine a characteristic? (Hardness of 1) magnesium alloy is very low, be less than HB80 commonly, taller cutting dosage can be chosen when cutting. What ought to notice is, the stuff with hardness, low intensity resists plasticity metabolic ability is differred, touch injury, clip easily bad, platoon bits is bad to also be met cut already machined the surface. (2) because coefficient of thermal conductivity is big, the quantity of heat that bits cuts to take away in cutting process so is much, cutting tool wears away small. Cooling lubricating fluid can be not used when cutting, can use get much cutting rate higher than steel of structure of cutting carbon element, cutting tool durability is very tall also. Coefficient of linear expansion of 3) magnesium alloy is big, thermal capacity is inferior, dimension precision is controlled not easily. (Amount of model of flexibility of 4) magnesium alloy is small, below the action of cutting force and clamping force, produce bigger flexibility easily to be out of shape, make workpiece obtains taller treatment precision not easily, also can cause the acuteness clash that the surface already machined with workpiece at the back of cutting tool. (5) magnesium alloy is when temperature of 400 ℃ above, finely bits holds easy combustion on fire, answer to keep clear of to cut bits and strengthen fire prevention measure at any time. (6) magnesium alloy is able to bear or endure corrode sex is poor, the workpiece attention that machines does not want with other metal (steel, copper, nickel) the spare parts is put together, lest produce electrochemistry,corrode. Magnesium alloy marvellous Normal >20.

How cutting magnesium alloy? Normal > magnesium alloy is better, hard alloy of YG6, YG8 and W18Cr4V high-speed steel can be used when cutting. Mix when workpiece surface quality when dimension precision demand is particularly high, also can undertake careful cutting with diamond cutting tool. Normal > uses hard alloy cutting tool, although can raise durability, but not as easy in that way as high-speed steel cutting tool blade is ground sharp. The application in production is more is W18Cr4V, especially the example knife with complex form. Normal > cutting magnesium alloy should be chosen bigger before horn, make cutting blade sharp, decrease to cutting is out of shape and cut the felt before bits and cutting tool, drop cutting force and cutting temperature, raise cutting tool durability. General ~ of O=25º of the γ when thick car 30º , ~ of O=30º of the γ when fine vehicle 35º . Hind horn also answer some more largish, the stretch model amount because of magnesium alloy is small and linear expansion coefficient is big, face of the knife after restoring what the phenomenon causes to bilge with heat by flexibility and the attrition that machine the surface are very serious also. ~ of O=10º of the α when thick car 12º , ~ of O=12º of the α when fine vehicle 15º . The other geometry parameter of cutting tool is: Κ R=45º ~ 90º , λ S=5º ~ 10º . Normal > good magnesium alloy makes its can use big feed and high speed cutting. But coefficient of because stretch model quantity is small, rigid poor, linear expansion is big, easy generation flexibility is out of shape, plasticity is out of shape and heat is out of shape. To restrict cutting force and cutting temperature, cutting dosage also cannot pass big. What temperature must restrict when fine vehicle especially is elevatory, in order to assure treatment precision and exterior quality. Normal > is choosing cutting dosage, should tigidity of mature work structure and mental allowance. Tigidity is good and when mental allowance is big, can use bigger cutting deepness and feed; Rigid difference or cutting thin wall when, should use lesser feed; Magnesium alloy is drossy and easy on fire burns, deepness of the cutting when treatment cannot is less than 0.

05 Mm. General ~ of C=300 of the ν when the circle outside thick car 500m/min, ap=3 ~ 10mm, f=0.

3 ~ 1.

0mm/r. ~ of C=600 of the ν when fine vehicle 900m/min, ap=0.

5 ~ 2mm, f=0.

1 ~ 0.

3mm/r. CNC Milling