The main task that CNC Machining working procedure designs is to be each working procedure to choose machine tool, clamping apparatus, cutting tool and measuring tool, dosage of dimension of order of situation of plan of clamp of firm fixed position, course taking a knife, labor, mental allowance, working procedure and its public errand, cutting and man-hour norm, had made sufficient preparation for work out machine program. (1) walks along cutter track line and labor situation order to take cutter track line certainly is cutting tool opposite in whole treatment working procedure the athletic contrail at workpiece, not only the content that included labor situation, and the order that also reflects an industry condition. Course taking a knife is one of basises that write a program. When certain route taking a knife, basically follow the following principle: The treatment precision that ① assures a spare parts and exterior surface roughness undertake machining on milling machine for example when, because the athletic contrail of cutting tool and way are different, the likelihood is arrange mill or go against mill, the quality of the spare parts surface that its different treatment course earning goes to is different. Use means of which kinds of milling after all, the specific requirement such as the processes data of requirement, workpiece characteristic that should look a part and machine tool cutting tool considers integratedly, affirmatory principle and common machining are identical. Numerical control machine tool uses transmission of ball guide screw commonly, its motion space is very little, and arrange mill advantage over go against mill, answer to use suitable mill as far as possible so. When outline of inside and outside of mill of essence of life, to improve exterior surface roughness, the line taking a knife that should introduce suitable mill machines plan. Wait for material to alloy of aluminum-magnesium alloy, titanium and heat-resisting alloy, the proposal also uses the treatment that arrange mill, this is advantageous to reducing the surface to surface roughness is worth and raise cutting tool durability. But if part semifinished product is black metal forging or cast, cuticular hard and surplus is larger, use at this moment go against mill relatively advantageous. When treatment position precision asks taller aperture is fastened, should the treatment that special attention plans opening is ordinal. If arrangement is undeserved, take the backlash of reference axis possibly, affect positional precision directly. Be like graph 4-35, boring pursues (A) place shows the hole with on the spare parts 6 same size, have two kinds of lines taking a knife. Press a plan (when B) place shows a course to machine, as a result of 5, 6 aperture and 1, 2, 3, way of 4 opening fixed position is opposite, x can make locate the error increases to backlash, affect thereby 5, the positional precision of 6 aperture and other aperture. Press a plan (when C) place shows a course to machine, many shift is apart from the upgrade after machining 4 aperture one paragraph to be nodded to P, fold next come back to be in 5, 6 aperture place undertakes locating machining, thereby, make the treatment feed direction of each aperture consistent, avoid backlash introduce, rose 5, the positional precision of 6 aperture and other aperture. (Aperture of boring of 4-35 of graph of A) (b) (c) fastens cutter track line to compare (A) part drawing (B) is poor (the line of cutter track of advance and retreat of C) good cutting tool should avoid to be in in outline as far as possible stop a knife or perpendicular cut cut a work, lest leave knife mark. ② makes cutter track line the shortest, reduce time of cutting tool idle stroke, improve treatment efficiency. Graph 4-36 place shows the case that machines a course to choose bore correctly. According to general habit, always machine first all cloth at same and circumferential after the circuit opening that attend, aperture of rework other circuit, if graph 4-36(a) place is shown, this is not best course taking a knife. the numerical control machine tool to nodding position control, ask fixed position precision is tall, fixed position process as far as possible fast. If press the feed course treatment that graph 4-36(b) place shows, can make the sum of each aperture span the smallest, light locomotive trip is the shortest, save fixed position time thereby. (Final outline of ③ of choice of course of the shortest treatment walks along 4-36 of A) (b) graph place of 4-37(a) of the graph that finish shows the knife to cut the outline inside law treatment all right to use. Add man-hour not to take dead space, decreasing every time below the situation that feed jackknife measures, course taking a knife is shorter, but stay between the starting point that takes a knife twice and terminus have leftover height, affect exterior surface roughness. Graph (B) is to use annulus to cut law treatment, exterior surface roughness is lesser, but knife computation slightly complex, course taking a knife also relatively cut a law to grow all right. Adopt a plan (the line taking a knife that C) place shows, use a treatment that cut a way first, finally again a week of edge outline cutting, make outline surface light whole. In 3 kinds of plan, graph (A) plan is the wrongest, graph (C) program is optimal. (4-37 of graph of A) (b) (c) closes inside outline machines cutter track line (A) cuts a way all right (B) annulus cuts a way (C) go ahead of the rest is cut again annulus is cut (the fixed position of the certain work of the fixed position of 2) workpiece and clamp plan is standard with clamp plan affirmatory, should abide by in front the main demand that narrates the choice principle with concerned standard fixed position and workpiece clamp. In addition, still should notice following at 3 o'clock: ① do one's best is designed craft is fiducial, fiducial as unified as process designing origin, in order to decrease fiducial not the computational workload in process designing of numerical control of coincide sum of errors. ② tries to reduce the number that hold clip, accomplish as far as possible in clip of fixed position outfit, can machine a workpiece to go up all or major work surface, in order to reduce outfit clip error, raise the mutual position precision between treatment surface, develop the efficiency of numerical control machine tool adequately. ③ avoids to use occupy machine is artificial adjust plan, lest take machine time too much, the influence machines efficiency. (The chooses CNC Machining characteristic of 3) clamping apparatus raised two basic requirements to clamping apparatus: The coordinate direction that is the coordinate direction that assures clamping apparatus and machine tool is relatively fixed; 2 it is the measure that wants can harmonious spare parts and department of machine tool coordinate. Besides, the key considers the following: ① is odd when small lot is produced, preferential choose built up fixture, adjustable clamping apparatus and other and general clamping apparatus, produce preparative time and economic operating costs in order to shorten; When ② is being produced group by group, just consider to use special fixture, and structure of do one's best is simple; Of ③ spare parts assemble and unassemble should fast, convenient, reliable, in order to shorten the halt time of the machine tool, reduce auxiliary time; ④ is precision of contented CNC Machining, precision of fixed position of requirement clamping apparatus, clamp is tall; Each component should not hamper the machine tool is opposite on ⑤ clamping apparatus spare parts the treatment of each surface, namely clamping apparatus wants to open wide, its fixed position, clamping unit cannot affect treatment to take a knife mediumly (if produce the) such as collision; ⑥ is the efficiency that improves CNC Machining, the spare parts treatment with bigger batch can use pneumatic or hydraulic pressure clamping apparatus, multitask clamping apparatus. (The chooses cutting tool option of 4) cutting tool is one of serious content in CNC Machining craft, affect the treatment efficiency of the machine tool not only, and immediate impact machines quality. With conventional treatment methodological photograph is compared, the CNC Machining requirement to cutting tool, mix in tigidity especially durability respect is more strict. Should dosage of working procedure of the function of material of the process capability according to the machine tool, workpiece, treatment, cutting and other and relevant element choose cutting tool and knife handle correctly. Cutting tool chooses total principle is: Already claimed accuracy tall, intensity is big, rigid good, durability is tall, ask dimension is stable again, installation is adjusted convenient. Below the premise that asks in contented treatment, choose shorter knife handle as far as possible, in order to raise the tigidity of cutting tool. The data of metallic cutting cutting tool that uses now basically has 5 kinds: High-speed steel, hard alloy, pottery and porcelain, cubic nitrogen changes boron (CBN) , get together brilliant diamond. ① is opposite according to CNC Machining the requirement of cutting tool, the general principle that chooses cutting tool material is to choose hard alloy cutting tool as far as possible. Want to machine a circumstance to allow to choose hard alloy cutting tool only, need not high-speed steel cutting tool. Cutting tool of ② pottery and porcelain is used at treatment not only all sorts of cast-iron expect with different steel, also apply to treatment nonferrous metal and metalloid material. Razor blade of use pottery and porcelain, whatever circumstance should use the part before losing, for blade of not easy collapse, can pour point when necessary blunt. Cutting tool of pottery and porcelain uses the effect to owe beautiful below following case: The treatment of short spare parts; Pound big interrupted cutting and heavy cut; The simple substance material that wait reachs beryllium, magnesian, aluminium and titanium the treatment of its alloy (easy generation affinity, bring about cutting blade to flake or collapse blade) . ③ diamond and cubic nitrogen change boron to be belonged to exceed material of strong cutting tool, they can be used at processing the workpiece data of any hardness, have very tall cutting property, treatment precision is tall, exterior surface roughness is worth small. Can use cutting liquid commonly. Get together brilliant diamond razor blade is used at processing nonferrous metal and metalloid data only commonly. Cubic nitrogen changes boracic bit of 450HBS of ＞ of hardness of general and applicable treatment cold hard the nickel of steel of steel of structure of cast-iron, alloy, tool steel, high-speed steel, bearing and hardness ≥ 350HBS base alloy, cobalt radical alloy and spare parts of metallurgy of tall cobaltic powder. ④ uses a field from the structure of cutting tool, CNC Machining should be used as far as possible set a type engine to place but after dislocation razor blade wears away with reducing cutting tool change and preliminary adjustments time. ⑤ chooses coating cutting tool in order to raise wearability and durability. (The affirmatory cutting dosage of 5) cutting dosage includes main shaft rotate speed (cutting speed) , quantity of back penetration of a cutting tool and feed (feed speed) . The cutting rate that main shaft rotate speed should permit according to machine tool and cutting tool will decide; Back penetration of a cutting tool measures what basically suffer machine tool stiffness to restrict, below the condition that allows in machine tool stiffness, increase amount of back penetration of a cutting tool as far as possible; Feed wants surface roughness of the treatment precision according to the spare parts, surface, cutting tool and workpiece material to choose. The logical choice of cutting dosage machines immediate impact quality of precision, surface, productivity and economy, its decide principle and common treatment are similar. Specific data should according to dosage of machine tool operation instruction handbook, cutting manual, combine practical experience to try to amend affirmatory. Cutting dosage is decided really besides abide by " the choice of cutting dosage " outside concerned regulation, still should consider following factors: The difference of cutting tool quality that different manufacturer produces difference of ① cutting tool is bigger, because this cutting dosage needs a basis,actual place uses cutting tool and spot experience to try to amend. Dosage of cutting of character of ② machine tool accepts the restriction of the power of machine tool electromotor and machine tool tigidity, must choose inside the range that machine tool manual sets. Because power is insufficient,avoid and happen frowsty car, tigidity is not worth and the machine tool with large generation is out of shape or oscillatory, the influence machines precision and exterior surface roughness. The man-hour cost of the machine tool of productivity numerical control of machine tool of ③ numerical control is higher, place of charge of cutting tool loss holds proportion inferior, answer to use tall cutting dosage as far as possible, will improve the productivity of numerical control machine tool through lowering cutting tool life appropriately. CNC MillingCNC Machining