normal style="MARGIN: 0cm 0cm 0pt">The cutting tool choice and the cutting specifications determination is in the numerical control processing craft important content, it not only influence numerical control engine bed processing efficiency, moreover affects the processing quality directly. CAD/The CAM technology development, enables in the numerical control processing to become directly using the CAD design data possibly, specially the microcomputer and the numerical control engine bed joint, causes the design, the craft plan and the programming entire process completes completely on the computer, does not need to output the special technological document generally.
normal style="MARGIN: 0cm 0cm 0pt">Now, many CAD/The CAM software package all provides the automatic programming function, these software are generally prompt the craft plan in the programming contact surface the related question, for instance, cutting tool choice, processing way plan, cutting specifications hypothesis and so on, programmers so long as have established the related parameter, may automatically produce completes the processing the NC procedure and the transmission to the numerical control engine bed. Therefore, in the numerical control processing cutting tool choice and the cutting specifications determination is completes under the man-machine interactive condition, this forms the sharp contrast with the ordinary engine bed processing, at the same time also requests the programmers to have to grasp the cutting tool choice and the cutting specifications determination basic principle, when programming full consideration numerical control processing characteristic. This article the cutting tool choice and the cutting specifications which must face to the numerical control programming in determined the question has carried on the discussion, has produced certain principles and the suggestion, and to the question which should pay attention has carried on the discussion.
normal style="MARGIN: 0cm 0cm 0pt">First, numerical control processing commonly used cutting tool type and characteristic
normal style="MARGIN: 0cm 0cm 0pt">The numerical control processing cutting tool must adapt the numerical control engine bed high speed, is highly effective and the automatic high characteristic, should include the general cutting
normal style="MARGIN: 0cm 0cm 0pt">tool, the general connection hilt and the few special-purpose hilts generally. The hilt must join the cutting tool and install on the engine bed power head, therefore already gradual standardization and seriation. The numerical control cutting tool classification has the many kinds of methods. May pide into according to the cutting tool structure: (1) Integral type; (2) The mosaic, uses the welding or machine clamps the type connection, machine clamps the type to be possible to pide into does not index and may index two kinds; (3) Special pattern, like compound expression cutting tool, absorption of shock type cutting tool and so on. According to makes the material
normal style="MARGIN: 0cm 0cm 0pt">which the cutting tool uses to be possible to pide into: (1) High-speed steel cutting tool; (2) Hard alloy tools; (3) Diamond cutting tool; (4) Other material cutting tools, like cubic boron nitride cutting tool, ceramic cutting tool and so on. May pide into from the cutting craft: (1) The turning cutting tool, pides the outer annulus, in the hole, the thread, cuts the cutting tool many kinds of and so on; (2) Drills truncates the cutting tool, including drill bit, reamer, screw tap and so on; (3) Boring cutting tool; (4) Milling cutting tool and so on. In order to adapt the numerical control engine bed durably to the cutting tool, is stable, easy change, may trade and so on the request, in recent years machine clamps the type to be possible to index the cutting tool to obtain the widespread application, reaches higher authorities in the quantity to the entire numerical control cutting tool 30% ~ 40%, the metal excision quantity accounts for the total 80% ~ 90%.
normal style="MARGIN: 0cm 0cm 0pt">On the numerical control cutting tool and the ordinary engine bed uses the cutting tool compares below, some many different requests, mainly have the characteristic:
normal style="MARGIN: 0cm 0cm 0pt 24pt; TEXT-INDENT: -18pt; mso-list: l0 level1 lfo1; tab-stops: list 24.0pt">(1) Rigidity good (in particular rough machining cutting tool), precision high, the vibration-proof and the thermal deformation are small;
normal style="MARGIN: 0cm 0cm 0pt 24pt; TEXT-INDENT: -18pt; mso-list: l0 level1 lfo1; tab-stops: list 24.0pt">(2) Inter changeability is good, is advantageous for fast trades the knife;
normal style="MARGIN: 0cm 0cm 0pt 24pt; TEXT-INDENT: -18pt; mso-list: l0 level1 lfo1; tab-stops: list 24.0pt">(3) Life high, the cutting value stable, is reliable;
normal style="MARGIN: 0cm 0cm 0pt 24pt; TEXT-INDENT: -18pt; mso-list: l0 level1 lfo1; tab-stops: list 24.0pt">(4) Cutting tool size is advantageous for the adjustment, by reduces trades the knife time
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 10.5pt; mso-char-indent-count: 1.0">(5)Cutting tool ought to be able reliably to break the filings or the volume filings, by favors the scrap removing;
normal style="MARGIN: 0cm 0cm 0pt 6pt">(6) Seriation, the standardization, by favors the programming and the cutting tool management.
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">Second, the numerical control processes the cutting tool the choice
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">The cutting tool choice is carries on in under the numerical control programming man-machine interactive condition. Should according to the engine bed processing ability, the work piece material performance, the processing working procedure, the cutting specifications as well as other correlation factors correctly selecs the cutting tool and the hilt. The cutting tool choice always principle is: Installment adjustment convenient, rigidity good, the abrasive resistance and the precision are high. In satisfies the processing request under the premise, chooses the short hilt as far as possible, by enhances the rigidity which the cutting tool processes.
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">When selects the cutting tool, must cause the cutting tool the size with to process the work piece the superficial dimension to adapt. In the production, the plane components peripheral outline processing, often uses the end mill; When milling plane, elected hard alloy bit milling cutter; When processes raised Taiwan, the scoop channel, chooses the high-speed steel end mill; When processing semifinished materials surface or rough machining hole, may selec inlays the hard alloy bit the corn milling cutter; And changes the drift angle outline contour to some three-dimensional profiles the processing, often uses a ball milling cutter, the ring-like milling cutter, the coned milling cutter and the disc cutter.
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">When carries on the free curved surface processing, because the ball cutting tool nose cutting speed is a zero, therefore, for the guarantee processing precision, the cutting row spacing obtains generally very can be dense, therefore ball commonly used in curved surface precision work. But the flat head cutting tool all surpasses a ball knife in the face work quality and the cutting efficiency aspect, therefore, so long as under the premise which the guarantee only cuts, regardless of is the curved surface rough machining precision work, all should first choose the flat head knife. Moreover, the cutting tool abrasive resistance and the precision and the cutting tool price relations are enormous, must bring to the attention is, in the majority situation, the cutting tool which chooses although increased the cutting tool cost, but from this the processing quality and the processing efficiency enhancement which brings, then may cause the entire processing cost to reduce greatly. In the processing center, each kind of cutting tool installs separately in the knife storehouse, according to the procedure stipulated carries on as necessary chooses the knife and trades the knife movement. Therefore must use the standard hilt, in order to makes to drill, the boring, to expand the standard cutting tool which, working procedure and so on milling uses, is rapid, accurately installs to the engine bed main axle or the knife storehouse comes up. The programmers should understand on the engine bed uses the hilt the structure size, the adjustment method as well as the adjustment scope, in order to in programming time determines the cutting tool the radial direction and the axial size. At present our countrys processing center uses the TSG tool system, its hilt has the straight handle (three kind of specifications) and the bit holder (four kind of specifications) two kinds, altogether includes 16 kinds of different uses the hilts. In economy numerical control processing, because the cutting tool sharpens, surveys and replaces many manual carries on for the man-power, takes the non-cutting time to be long, therefore, must reasonably arrange the cutting tool the order of rank. Should follow the principle below generally: (1) Reduces the cutting tool quantity as far as possible; (2) After a cutting tool attire clamps, should complete all processing spot which its can carry on; (3) The thick precision work cutting tool should separate the use, even if is the same size specification cutting tool; (4) The mill drills after first; (5) The advanced good curved surface precision work, latter carries on the two-dimensional outline precision work; (6) In the possible situation, to be supposed automatically to trade the knife function as far as possible using the numerical control engine bed, by enhances the production efficiency and so on.
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">Third, numerical control processing cutting specifications determination
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">The reasonable choice cutting specifications principle is, when rough machining, by enhances the productivity generally primarily, but also should consider the efficiency and the processing cost; When half precision work and precision work, should in under the guarantee processing quality premise, the proper attention to both cutting efficiency, the efficiency and the processing cost. The concrete value should act according to the engine bed instruction booklet, the
normal style="MARGIN: 0cm 0cm 0pt">cutting specifications handbook, and the unio experience but decides.
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">(1) Depth of cut t. In the engine bed, the work piece and in the cutting tool rigidity permission situation, t was equal to processing remainder, this is enhances the productivity a effective action. In order to guarantee the components the processing precision and the surface roughness, should keep the certain remainder generally to carry on the precision work. The numerical control engine bed precision work remainder may be smaller than slightly the ordinary engine bed.
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">(2)Cutting width L. General L and cutting tool diameter d has the direct ratio, has the inverse ratio with the depth of cut. In the economy numerical control processing, the general L value scope is: L= (0.6 ~ 0.9) d.
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">(3) Enhances v also is enhances the productivity a measure, but v and the cutting tool abrasive resistance relations quite are close. Along with v increasing, the cutting tool abrasive resistance drops suddenly, therefore v choice mainly is decided by the cutting tool abrasive resistance. Moreover, the cutting speed and the processing material also have the very big relations, for example when anther jingang 30CrNi2MoVA with the end mill milling, v may use 8m/about min; When with same end mill milling aluminum alloy, v may choose 200m/Above min.
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">(4) Main axle rotational speed n (r/Min). The main axle rotational speed general basis cuts the speed v to designate. The formula is: The in the formula, d is the cutting tool or the work piece diameter(mm). On the numerical control engine bed control panel has the main axle rotational speed to repair generally adjusts (percentage) the switch, may carry on the integral multiple adjustment in the processing process to the main axle rotational speed.
normal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0">(5) Enters for speed vF. VF should choose according to the components processing precision and the surface roughness request as well as the cutting tool and the work piece material. The vF increase also may enhance the production efficiency. When the processing surface roughness requests lowly, vF may choose big. In the processing process, vF also may repair through the engine bed control panel on transfers to a readjusts the switch the pedestrian wage adjustment entire, but enters most greatly for the speed must receive the equipment rigidity and enter for the system performance and so on the limit. Along with the numerical control engine bed in the production actual center widespread application, the numerical control programming already became one of in numerical control processing key questions. In the numerical control procedure establishment process, must choose the cutting tool and the determination cutting specifications immediately under the man-machine interactive condition. Therefore, the programmers must be familiar with the cutting tool the choice method and the cutting specifications definite principle, thus the guarantee components processing quality and the processing efficiency, fully display the numerical control engine bed the merit, enhances the enterprise the economic efficiency and the production level.
