The project is plastic machine with the cutting of composite material (on)

What is plastic? By what does it become minute of composition? Plastic be give priority to body with colophony, join filling (also call intensifier) with additive, heating the high polymer that makes below pressurization organic material. In modern industry, plastic replacing the data such as material of rolled steel, copper, aluminous material widely increasingly, will make the fittings such as electric equipment, machine tool, appearance, bearing, pipe fittings, car, spaceflight. The spare parts with one part not tall precision, do not need to machine. But quite one part part, to achieve treatment precision and exterior quality requirement, must use the method of machining. Plastic be by colophony, filling and additive 3 parts are comprised. Colophony is plastic main ingredient, stick since receive effect, occupy the 100 ％ of 40 ％ ～ of all composition. Filling is to be used at improving plastic physics the main component of mechanical function. Filling has farinaceous filling (wooden pink, micaceous pink, French chalk) , fiber shape filling (fibre glass, flax, line) , piece shape filling (the) such as cloth of cotton cloth, flax, glass. What make filling with fiber is plastic, have high strength. Although additive is in plastic in the proportion that hold is not large, but indispensable. Additive basically has solidify agent, plasticizer, lubricant and colorant. Plastic 2.

Plastic cent which a few kinds? What characteristic do each have? (1) is plastic divide by colophony property: Can divide for thermoplastic plastic originally with heat the gender is plastic two kinds big. ① is thermoplastic plastic. This kind plastic encounter heat to fuse or bate, refrigeration hind hardens again, this process can relapse for many times. Thermoplastic plastic have polyvinyl chloride, polypropylene, polyethylene, polystyrene and ABS of its copolymerization body, nylon, polyformaldehyde, get together carbonic acid fat, chloridize gets together ether, get together benzene aether and get together sulphone. They have certain physics mechanical function. If fluorine is plastic,return some breed, get together acyl inferior amine, have first-rate corrosion resistance, good insulating properties and inferior coefficient of friction. Thermoplastic plastic hear resistance and tigidity are inferior. Sex of ② hot solid is plastic. Below constant temperature, this kind of plastic course heats for some time, rejoin solidify agent, can solidify. Of solidify plastic, quality of a material is solid, in agent of not deliquescent Yu Rong, heat to also do not make its bate, have plasticity no longer. If temperature is exorbitant,it also can be decomposed. Hot solid sex is plastic oxygen of not phenolic aldehyde, saturated polyester, amino, annulus, furan, organic silicon cultivates ester and PDAP to wait. This kind of plastic hear resistance is better, not easy press press is out of shape. (2) is plastic the methodological cent that presses figuration: Can divide for compression moulding makings and layer compression moulding expect. ① pressing is plastic. Call glue normally (report) wood, it is with thermoplastic the pulverous shape that colophony or colophony of hot solid sex and filling configure for the foundation or fiber shape semi-manufactured goods, use the method of compression moulding by use factory again, make all sorts of spare partses or profile. ② lamination is plastic. It is the filling of a shape, wait like cloth of paper, cotton cloth, glass, after complex colophony macerate, with lamination law suppress is become plastic. Makings of layer compression moulding has glue chipboard, adhesive plaster board, glass adhesive plaster board and tubal material, great ability. This kind plastic after passing machining, use extensively make all sorts of parts. Plastic 3.

Plastic what character and cutting characteristic are there? (1) is plastic had characteristic ① is opposite density is small. Its opposite density has steely 1/8 ～ 1/4 only, it is aluminous 1/2 left and right sides. This one character, the industry such as light to weight requirement spaceflight, aviation, shipping, car has particularly important sense. The insulating property with good ② . Almost all plastic admirable electric insulation is reached be able to bear or endure electric arc is characteristic. It can wait for insulating material photograph to compare the United States with pottery and porcelain, balata, use extensively in electron, electric machinery and electric equipment industry. The chemistry with good ③ is inert. It is pair of acid, alkaline wait for chemical material to have fight goodly corrode ability. This refuses cankerous facility to chemical industry, it is good stuff. The coefficient of thermal conductivity with extremely low ④ . Plastic coefficient of thermal conductivity has the L/175 ～ 1/450 of steel only, can use heat-insulating material. ⑤ is taller than intensity. If press weight to calculate intensity, criterion some is plastic (makings of layer compression moulding, glass reinforced plastics) it is contemporary material is highest. What fibre glass is base material is 5 times taller than Q235 steel than intensity, 2 times taller than high strenth aluminium. ⑥ is decreased admirably grind, wear-resisting function. Have a lot of plastic coefficient of friction very small, can use the slideway of production machine tool, bearing, seal ring that do not have oil, gear to wait. Be in especially the condition that grinds bead, impurity falls, this performance is more superior. The suction with admirable ⑦ shake and noise elimination function. Plastic this one character, make it OK be used to the spare parts such as the bearing that production high speed rotates, gear, in order to reduce noise. (The characteristic when 2) plastic cutting: The plastic spare parts that precision asks taller plastic spare parts and batch are small, use machining commonly, in cutting from time to tome the following characteristic: Small, thermal conductivity and hear resistance need ① cutting power. Plastic hardness and intensity are low, cutting force is smaller than cutting metal 6 ～ 7 times. Because its coefficient of thermal conductivity is small, hear resistance has 100 ℃ ～ only 250 ℃ , because this cannot use higher cutting rate, in order to prevent bate, stick a knife and affect workpiece surface quality. ② organization, hardness, intensity is inhomogenous, resilience is stubborn, dimension precision is controlled not easily. Plastic comprise by a variety of composition, the organization is extremely inhomogenous, especially stuff of layer compression moulding is more serious. So, when cutting cutting tool point wants sharp, wear-resisting. ③ cutting tool wears away serious, when cutting easy brittleness craze. A lot of plastic, be like phenolic aldehyde plastic, glass reinforced plastics, when cutting, vitreous fabric filling be hard to cutting, cutting tool is worn away very quickly, and lose cutting ability. Grind with cutting tool below cutting strength effect blunt hind, extruding effect is big, cut cut source easy happening craze and collapse edge. ④ heats up coefficient of expansion big. The 3 ～ that its hot coefficient of expansion is general metal 4 times, affect the stability of dimension, to cutting treatment brings certain difficulty. ⑤ breaks bits difficulty. Mix in turning auger cut thermoplastic plastic when, cut bits to show banding, easy twine go up in workpiece or cutting tool, squash sometimes strong group, affect working success, destroy already machined exterior quality. Plastic 4.

Plastic the place that what inadequacy there is on function? (The hear resistance with plastic 1) is low: Below general situation, plastic can be in only 80 ℃ ～ works below 120 ℃ temperature. Should suffer when power is greater, can be in only 80 ℃ of 60 ℃ ～ work below or so condition. What have a few only is plastic, if fluorine is plastic, get together benzene aether, get together sulphone, get together acyl inferior amine, can work in 150 ℃ above. Some plastic spare partses still can be below 270 ℃ of 260 ℃ ～ long-term job. Afore-mentioned characteristic influences use range plasticly. (2) heats up coefficient of expansion big: The 3 ～ that plastic coefficient of expansion is general metal 4 times, such making that the spare parts is in use and change of the dimension in cutting process is bigger, affect the stability of dimension. When using calm dimension cutting tool especially, should consider its heat to bilge cold the metabolic rule that shrink. (3) thermal conductivity is poor: Because thermal conductivity is poor, cutting area quantity of heat comes out not easily, cause cutting temperature to lift, aggravate cutting tool wears away, make machine material bate. Certain and plastic because cutting temperature is high and create half fused position, form what treatment surface fuses one layer partly to be cut material, destroy already machined exterior quality. (4) squirm is metamorphic: When plastic spare parts is working, bear plasticity of generation of the meeting after load is out of shape. (5) ageing phenomenon: Plastic and long-term fall in the action of solar, air, mechanical stress or certain medium, meeting generation oxidation, become angry, phenomenon of the demote below craze and mechanical intensity. This is the blemish that the plastic part that uses for a long time should notice. Thermoplastic plastic 5.

How is turning thermoplastic plastic? In turning pvc, polystyrene, nylon, fluorine plastic, organic glass, polyethylene, colophony thermoplastic plastic when, want to ask according to their respective characteristic and treatment, will choose cutting condition. (Material of 1) cutting tool: Because the hardness of this kind of material is low, cutting force is small, should pick the cutting tool material that can grind a sharp cutting tool point, if quench,the steel of carbolic element tool after, alloy tool steel, high-speed steel is mixed tungsten is cobaltic kind of fine grained hard alloy. When nicety is machined optional diamond lathe tool. (Parameter of geometry of 2) cutting tool: Its choice wants the characteristic with plastic and respective basis, usually, before ～ of horny γ O=15º 25º , hard alloy cutting tool takes small cost. As a result of thermoplastic plastic stretch model amount is small, flexibility restores big, should choose bigger hind horn, γ O=10º ～ 14º , ～ of R=45º of Κ of tool cutting edge angle 90º , 5º of ～ of S=3º of blade dip λ , 2mm of ～ of =1 of ε of R of radius of circular arc of point of a knife, of figuration knife before horny γ O=0º . The surface roughness Ra of each knife face should is less than 0.

4 μ M. (3) cutting dosage: Turning is thermoplastic plastic the cutting dosage when, answer to consider from the following element: Because its bate temperature is low, of speed of the cutting when restricting cutting rise, want material only not bate, in bits is being cut to be not blocked up in aperture because of bate when bore, should choose higher cutting rate, in order to improve productivity, the size of deepness of penetration of a cutting tool basically is mixed according to tigidity of workpiece surplus, workpiece be out of shape will choose, lest affect treatment precision; The size of feed, basically suffer exterior quality, vibration and workpiece metabolic effect, to assure to machine quality, small cutting deepness and feed should choose when finish machining. Hot solid sex is plastic product 6.

How does turning heat up solid sex plastic? Oxygen of turning phenolic aldehyde, annulus, amino when sex of solid waiting for heat is plastic, because plasticity of its hear resistance specific heat is plastic tall, and some plastic intensity (of fibre glass base material plastic) adjacent at the metal, intense abrasive is formed to wear away when cutting. Hot solid sex is plastic intensity big, hardness tall, thermal conductivity is extremely low, the temperature of cutting area can amount to 600 ℃ , cutting tool durability drops apparently. (Material of 1) cutting tool: When sex of solid of heat in metal cutting is plastic, wear away as a result of cutting tool abrasive serious, except use high-speed steel and cobalt of fine grained tungsten kind outside hard alloy, should choose man-made to get together as far as possible brilliant diamond is compound cutting tool of a cutting tool, solder of drill rod of thick film of person selected diamond, still can choose hot pressing cutting tool of compound pottery and porcelain, in order to raise cutting tool durability. (Parameter of geometry of 2) cutting tool: When sex of solid of heat in metal cutting is plastic, area of surface contact of the knife before cutting bits and cutting tool is small, attrition force is small. To increase point strength, should choose lesser before horn, ～ of the general O=5º that it is γ 10º . Diamond cutting tool and ～ of O=0º of γ of cutting tool of pottery and porcelain - 5º . Horn should choose to be α O=15º ～ after 20º , in order to prevent paper of glue of cutting phenolic aldehyde, cotton cloth and fibre glass lamination plastic from time to tome cottony phenomenon. When rough machining ～ of R=45º of Κ of tool cutting edge angle 75º , ～ of R=60º of the Κ when finish machining 90º . Because heat up solid sex to cut bits plasticly to submit pulverous form, cut bits to be affected to already machining the surface not quite, blade dip chooses ～ of the S=-10º that it is λ commonly - 5º . Come loose for improvement hot condition and reduce already machined exterior surface roughness, =1 of ε of R of circular arc of point of a knife.

5 ～ 3 Mm. Graph 11-1 place shows the lathe tool that is makings of layer compression moulding. (The choice of 3) cutting dosage: The sort with hot solid plastic sex is very much, cutting function each different, material itself coefficient of thermal conductivity is low, cause cutting temperature tall, basically avoid cutting rate exorbitant and make material scorchs degenerative. When what there is farinaceous filling in treatment is plastic, should reduce feed and cutting tool tool cutting edge angle, in order to prevent the collapse edge of material. The cutting dosage with plastic sex of turning hot solid is referenced express 11-1. When using diamond cutting tool, a few times OK the land improves cutting tool durability and exterior quality. Twist drill head 7.

Auger cut plastic from time to tome is He Te nodded? How to choose the geometrical parameter of broach? Plastic applied range is increasingly wide, certain proportion is had in machining, bore holds very large proportion again in plastic treatment. Broach is calm dimension cutting tool, it is to close partly cutting, its cutting characteristic and metal are a little different, main show is in the following respects. It is to get phenomenon of daub of the generation when cutting above all. Because plastic bate temperature is low,this is, make the plastic daub cutting bits of molten already was being machined apparently, produce crackle sometimes, make machine quality to drop. It is to be gotten next when be being gotten, burr arises on workpiece. It is next again, because plastic hot coefficient of expansion is big, flexibility restores big, the hole that drills produces shrinkage cavity phenomenon. Get plastic bit, use the twist drill of broach of fried dough twist of standard high-speed steel and razor blade of the hard alloy that set solder and bit of integral hard alloy. High-speed steel broach basically is used auger cut thermoplastic plastic, hard alloy broach is used at getting to cut hot solid sex plastic. Expressing 11-2 and watch 11-3 is to get the geometrical parameter that cuts two kinds of plastic broach respectively. CNC Milling CNC Machining