What the choice of clamping apparatus, cutting tool reachs cutting dosage is affirmatory

One, what outfit of the choice of clamping apparatus, workpiece places a method is affirmatory 1. The choice 　 CNC Machining of clamping apparatus basically has two gist to beg to clamping apparatus: It is clamping apparatus should have enough precision and stiffness; 2 it is clamping apparatus due and reliable fixed position is standard. When choosing clamping apparatus, consider the following normally: 1) choose as far as possible can adjust clamping apparatus, built up fixture and other general clamping apparatus, avoid to use special fixture, produce preparative time in order to shorten. 2) just consider to use special fixture when be produced group by group, and structure of do one's best is simple. 3) assemble and unassemble workpiece should go to the lavatory quickly, in order to reduce the machine down time of the machine tool. 4) clamping apparatus wants in the installation on the machine tool accurate and reliable, in order to make sure workpiece is in correct machine locally. 2. The clamping apparatus on the lathe of type numerical control of clamping apparatus basically has two kinds: One kind is used at dish kind or short axis kind spare parts, clip of outfit of work semifinished product is being taken adjustable the chuck that blocks claw (3 claw, 4 claw) in, rotate by chuck drive; Another kind is used at the axis kind spare parts, semifinished product outfit is between main shaft tip and tip of rear push frame, workpiece go up by main shaft batch move chuck drive to rotate. The clamping apparatus on CNC Milling, general installation is on workbench, its form basis is machined the characteristic of workpiece but varied. Be like: Revolving stage of graduation of general table vice, numerical control. 3. The installs the part on numerical control machine tool installation method of the spare parts and general accuracy machine tool are same, want reasonable alternative fixed position is standard with clamp plan, the attention is the following at 2 o'clock: 1) design of do one's best, craft and process designing calculative are fiducial and unified, the handy sex that is helpful for estimation of process designing duration calculating so and accuracy. 2) reduce the number that hold clip as far as possible, install clip hind in fixed position as far as possible, treatment gives entire work surface. 2, the choice of cutting tool and the setting to the knife dot, dot that change a knife 1. The choice of cutting tool and photograph of method of treatment of general accuracy machine tool are compared, CNC Machining raised taller requirement to cutting tool, need tigidity not only good, precision is tall, and requirement measure is stable, durability is tall, it is good to judge bits and platoon bits performance; At the same time requirement installation is adjusted convenient, such coming that satisfy the requirement with numerical control efficient machine tool. The cutting tool that chooses on numerical control machine tool often uses the cutting tool data that gets used to high speed cutting (like high-speed steel, exceed fine granuality hard alloy) use but dislocation razor blade. (1) turning reachs his to choose the lathe tool with commonly used CNC Turning to divide sharp contrast commonly with cutting tool lathe tool of lathe tool, circular arc form and shape lathe tool 3 kinds. 1) lathe tool of form of point of a knife of sharp contrast car is with straight the lathe tool that cutting blade is a feature. The point of a knife of this kind of lathe tool by straight advocate deputy cutting blade is formed, if 90 ° inside and outside is round lathe tool of lathe tool, or so end panel, grooving (cut off) lathe tool and point of a knife pour arris very small all sorts of outside circle and inside aperture lathe tool. Parameter of geometry of sharp contrast lathe tool (basically be geometrical angle) when choosing method and common turning basic and identical, but the characteristic that should combine CNC Machining (if machine interference of course, treatment to wait) have comprehensive consideration, answer the intensity of itself of point of a knife of give attention to two or morethings. 2) lathe tool of form of circular arc of lathe tool of circular arc form is spend an error with one circularity or line outline the lathe tool that blade of very small cutting of circular arc form is a feature. Blade of circular arc of this lathe tool is the point of a knife of lathe tool of circular arc form each bits, should this, knife the dot is not on circular arc, and go up in the centre of a circle of this circular arc. Lathe tool of circular arc form can be used at surface of turning inside and outside, special agree with turning all sorts of smooth join (sunken form) shape face. Lv of the take an examination when choosing radius of lathe tool circular arc at 2 o'clock: The radius of the smallest curvature that the circular arc radius that is blade of lathe tool cutting should is less than or is equal to outline of spare parts sunken form to go up, lest produce treatment interference; 2 it is this radius unfavorable choice is too little, otherwise not only production difficulty, because intensity of point of a knife is too weak,still meet or cutter hub comes loose to heat energy force is differred and bring about lathe tool to damage. 3) shape lathe tool shapes lathe tool also calls example lathe tool, the outline form that its process a spare parts is mixed completely by the appearance of lathe tool edge dimension decision. In CNC Turning treatment, shape commonly lathe tool has lathe tool of circular arc of smaller part diameter, blame rectangular recessing knife and whorl knife. In CNC Machining, should be used less as far as possible or need not shape lathe tool. (2) milling reachs his to choose CNC Machining with cutting tool in, outline of inside and outside of milling plane part and milling plane are commonly used flat bottom establishs milling cutter, this cutting tool is as follows about the experience data of parameter: 1) the Rmin of radius of the smallest curvature that RD of milling cutter radius should be less than face of the outline inside the spare parts, take RD=(0 commonly.

8 ～ 0.

9)Rmin2) the ≤ of treatment height H of the spare parts (1/4-1/6) RD, in order to make sure the knife has enough stiffness. 3) when the outline inside rough machining, milling cutter is the biggest diametical D can press type calculates (refer to a graph 1) : The D1 in type, the radius of the smallest sunken round part of outline; Δ , the finish machining surplus on bisectrix of included angle of edge of round horn adjacent; Δ 1, finish machining surplus; J, round horn the smallest included angle of two adjacent edge. Nextpage4) when establishing department of the bottom land inside milling cutter milling with flat bottom, because bottom land walks along a knife twice to need to build,receive, and the radius Re=R-r with effective blade of cutting tool bottom, if the graph is shown 2 times, namely the diameter is D=2 Re=2 (R-r) , cutting tool radius is taken to be Re=0 when process designing.

95 (R-r) . To a few establish bodily form face and change the treatment of appearance of bevel angle outline, commonly used and globose milling cutter, annular milling cutter, bosomy form milling cutter, cone-shaped milling cutter He Panxi knife. If pursue,3 are shown. (3) standardization cutting tool is current, cutting tool of seriation, standardization is used mostly on numerical control machine tool, right but the knife handle that wait and knife head have lathe tool of the circle outside dislocation machine clip, end panel lathe tool national level and seriation model; Reach to machining center have the machine tool that trades knife unit automatically, the knife handle of cutting tool already had the regulation of seriation and standardization, the standard code name of system of cutting tool of the power that be like awl is TSG, JT, the standard code name of system of straight power cutting tool is DSG, JZ. In addition, to chooses cutting tool, need to undertake strict measurement to cutting tool dimension before use in order to obtain accurate data, and by handlers these data data-in systems, classics program is called and complete treatment process, process the work that gives qualification thereby. 2. After to the setting of the knife dot, dot that change a knife workpiece outfit places means to decide in the machine tool, decided through deciding workpiece origin comes workpiece coordinate is fastened, the code of each movement rod in machine program controls cutting tool to make opposite displacement. For example: Some program begins the first block to be N0010 G90 G00 X100 Z20, it is to show cutting tool moves to play X=100mm Z=20mm part to workpiece coordinate quickly. After all from what position does cutting tool begin to move afore-mentioned positions? Carry out in the program so at the beginning, must decide cutting tool fastens next positions that begin campaign in workpiece coordinate, the start that photograph of the cutting tool when this one position is carried out for the program namely moves to workpiece, say the order is bit more initial so or have knife place. This is bit more initiative decide through coming to the knife commonly, so, say at this o'clock to be nodded to the knife again. When work out program, want to choose the place that chooses to the knife correctly. To the knife place setting principle is: 1) facilitating numerical value is handled and simplify to program. 2) search to facilitating in machining a process easily examination. 3) the machining error that cause is small. To the knife the dot can be installed go up in treatment spare parts, also can install go up in clamping apparatus or on the machine tool, to raise the treatment precision of the spare parts, to the knife the dot should install the design in the spare parts as far as possible fiducial or craft is fiducial on. Exemple: Circle or aperture decide a part beyond, the node of the center of the circle outside can be being taken or aperture and end panel regards pair of knives as the dot. When operating a machine tool actually, the sword that can carry handiwork to operate a cutting tool to the knife the dot puts pair of knives to nod, namely " knife dot " with " nod to the knife " coincide. Alleged " knife dot " it is the fixed position datum mark that points to cutting tool, the knife of lathe tool the dot is point of a knife or center of circular arc of point of a knife; Making the same score a bottom to establish milling cutter is the node of cutting tool axes and cutting tool underside; Ball head milling cutter is the ball heart of ball head, broach is to get a needle to wait. Move pair of knife operations with the hand, inferior to knife precision, and efficiency is low. And some factories use optics to be opposite Dao Jing, right wait Dao Yi, automatically to knife device, in order to reduce pair of knife time, raise pair of knife precision. When the need in machining a process changes a knife, should provide the point that change a knife. Alleged " the dot that change a knife " it is the position when showing tool carrier roll changes a knife, what the dot that change a knife should set in workpiece or clamping apparatus is exterior, workpiece and other component are not touched in order to change to be when the knife accurate. 3, when the process designing of affirmatory numerical control of cutting dosage, process designing personnel must determine the cutting dosage of every working procedure, write into the program with the form of the instruction. Cutting dosage includes quantity of penetration of a cutting tool of main shaft rotate speed, back and feed speed to wait. To different treatment method, need chooses different cutting dosage. The choice principle of cutting dosage is: Make sure the spare parts machines precision and exterior surface roughness, develop property of cutting tool cutting adequately, assure reasonable cutting tool durability; Develop the property of the machine tool adequately, utmost improves productivity, reduce cost. 1. The rotate speed of affirmatory main shaft of main shaft rotate speed should be mixed according to the cutting rate that permit workpiece (or cutting tool) the diameter will choose. Its computation formula is: The V in type of N=1000v/ π D, cutting speed, the unit is M/min, by the durability decision of cutting tool; N, main shaft rotate speed, the unit is R/min; D, workpiece diameter or cutting tool diameter, the unit is Mm. N of rotate speed of calculative main shaft should choose machine tool some or more adjacent rotate speed according to machine tool manual finally. 2. The affirmatory feed speed of feed speed is the important parameter in dosage of cutting of numerical control machine tool, the material property of the treatment precision of the spare parts and requirement of exterior surface roughness and cutting tool, workpiece chooses main ground. Speed of the biggest feed accepts the function restriction of machine tool stiffness and feed system. Decide the principle of feed speed: 1) when the quality when workpiece asks to be able to get assuring, manufacture efficiency to rise, can choose higher feed rate. Choose inside limits of 100 ～ 200mm/min commonly. 2) in cut off, when machining deep Kong Huo with high-speed steel cutting tool, appropriate chooses inferior feed career, choose inside 20 ～ 50mm/min limits commonly. 3) should machine precision, when demand of exterior surface roughness is high, feed speed should choose a little bit small, choose inside 20 ～ 50mm/min limits commonly. 4) when cutting tool idle stroke, especially remote " time 0 " when, can set the highest feed speed of set of system of numerical control of this machine tool. 3. Quantity of back penetration of a cutting tool carries penetration of a cutting tool on the back to measure the stiffness according to machine tool, workpiece and cutting tool to decide certainly, below the condition that allows in stiffness, answer to make carry penetration of a cutting tool on the back to measure the mental allowance that is equal to workpiece as far as possible, can reduce knife number so, improve manufacturing efficiency. To assure to machine exterior quality, can leave a few finish machining surplus, general 0.

2 ～ 0.

5mm. Anyhow, the particular numerical value of cutting dosage should combine practical experience to decide with analogy method according to machine tool function, relevant manual. In the meantime, make deepness of main shaft rotate speed, cutting reachs feed rate 3 person can suit each other, in order to form optimal cutting dosage. CNC Milling