The high speed of sunken model machines the bumper before be based on NX CAM car

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  • source:AYOR CNC Machining
Demand of complex, precision mixes curved surface of mould of the bumper before the article is aimed at a car high the technical difficult point with the high hardness after quenching, be based on NX CAM system, designed corresponding high speed to machine strategy, use machining center of milling of Mi Kelang HSM-600 high speed, assure constant cutting load as far as possible, use blame is even justifiable B batten (NURBS) interpolation method, basis mould material chose appropriate cutting tool and technology of high speed treatment, make handling time is shortened by 120 hours finally, the entire constitution that improved comprehensive treatment efficiency and work is measured. The foreword development as computer technology, CAM technology (Computer Aided Manufacturing, CAM) got ceaseless promotion in domain of industrial manufacturing industry, each country rolled out the subdesign software that is used at CAM in succession, NX is to apply a most extensive kind among them. Product from the design, build a model to the analysis, till shape,revise, generate treatment code to all can be finished through NX. Among them NX CAM module has taller process designing efficiency, facilitating user edits quickly, debug a program; Have had prevented automatically cut and knife handle interference checks a function; Can optimize the treatment strategy with cutting tool method and special implementation; Have curve of direct output batten (NURBS) interpolation function, OK and quick treatment gives complex and extremely slick curved surface. High rate and high accuracy are current sunlight of CNC Machining industry direction of two great progress, be based on the CAM software such as NX, use high speed to machine (High Speed Machining, HSM) technology, but computer of have the aid of machines all sorts of complex industry component accurately, expediently, efficiently. Auto industry is one of industries of pillar of our country manufacturing industry, as the constant change of the market, on one hand, the appearance of the car and function also are developing ceaselessly, on the other hand the demand of car and its fittings also increases ceaselessly. Whether the development that machined the car fittings that produces all sorts of high quality to affect auto industry directly quickly. Car bumper can be absorbed when car happening collides alleviate external wallop, maintain the safety of car, its appearance is modelling of complex three-dimensional curved surface. Because be located in a car ahead, the position is marked, because this has precision of over all dimension the characteristic with strict quality of tall, surface. Car bumper mould uses synthetic resin normally or fibre glass increases plastic etc material classics mould is pouring and into. Because the actor bad of this mould affects the quality to finished product directly. The manufacturing treatment of car bumper mould puts in the following difficulty: 1) design of curved surface part is complex. Demand of the precision in process of treatment of 2) high speed is high. Demand of the hardness after 3) mould quenchs is higher. Be aimed at above difficulty, the article with NX 6.

0 develop platform for 2, the high speed of mould of the bumper before introducing a car in detail machines production strategy. 1 before if the graph is shown 1 times,the high speed of bumper sunken model machines strategy is antrum of sunken model of mould of the bumper before some car. Use technology of high speed cutting to machine the mould rolled steel of this spare parts to expect directly, can acquire higher exterior quality, and dimension and form precision. Accordingly, the electric spark that can omit groovy mould is machined is machined and repair by hand in great quantities grind wait for working procedure, shortened technological process, raised treatment to manufacture efficiency greatly. The graph protects speech of bar bar sunken model before 1 car 1.

1 those who assure cutting load is constant and light the cutting load that keeps constant in process of high speed cutting is very important. To make cutter track contrail smooth, the following should notice in machining a process: 1) uses small step pitch and shallow cutting deepness (the 10 % of cutting tool diameter are controlled) undertake machining; 2) uses circular arc or corkscrewed yarn means realizes cutting tool of advance and retreat; 3) is used in great quantities etc tall statified treatment replaces copying; 4) excision rate maintains as far as possible for constant; 5) is when rough machining, not only requirement cutting tool enters workpiece data with circular arc or corkscrewed yarn means, and ought to make of feed rate and machine tool rotate speed more optimal than achieving, the cutting tool motion that avoids sharp change thereby and direct on appearance outline feed and retreat a knife. If the graph is shown 2 times,machine cutter track light to arrange sketch map for bumper mould high speed. In process of high speed treatment, general requirement cutting tool is cut smoothly with cut a work, pass slow adjustment to be able to carry successive cutting load, achieve the goal that protects cutting tool. Use feed of corkscrewed yarn means commonly when cutting work, when cutting little work, make direction of circular arc of cutting tool edge is cut. Graph suitable sketch map of light of cutter track of treatment of 2 high speed is additional, have flowing contrail taking a knife to assure to be in in corner, cutting tool method can use round part or circular arc takes a knife, corresponding ground reduces feed rate, such past turning point can achieve smooth cutting tool orbit, the tall feed rate that keeps successive and the smooth stability that machine a process. Now NX CAM software in " horn and feed rate are controlled " in the dialog box " round horn " option was not decided for " ALL Passes " come smooth corner and step pitch, maintain stability of cutting tool bear thereby. Nextpage 1.

2 use blame are even justifiable B batten (the use that NURBS) interpolation machines equipment as high speed cutting, a kind of CNC interpolation controller that is based on NURBS theory also appears subsequently, this makes CNC system had the treatment region that can undertake NURBS format is defined automatically to build capacity. 3 parameter come to vector of worth of NURBS curve use reference point, power, node convey free curve. NURBS interpolation regards NC as the one part of the instruction these 3 parameter namely, be calculated by CNC system interior and generate NURBS curve, move according to axis of feed of machine tool of NURBS curve drive, treatment gives NURBS curve appearance. Choose NURBS format to undertake interpolation not only the error is small, precision is tall, and can simplify NC code program (the 1/10 ~ 1/100) that program length has linear interpolation code only, can control a machine tool to be calculated while edge NURBS curve moves already so the curvature of NURBS curve changes, can undertake machining with the oldest rate inside the range that machine tool acceleration permits again, realize the high rate that the mould machines and high accuracy thereby. 2 before bumper is sunken the high speed that feel is machined 2.

Machine tool of numerical control of choice of machine tool of treatment of 1 high speed uses Switzerland machining center of milling of the HSM-600 of company of Mi Ke period high speed, top rotate speed can amount to main shaft 60000r/min, speed of control axis feed can amount to 40m/min the most quickly, manage function mixes the address of high speed data when having DNC to machine " before make a present of " control technology, support NURBS interpolation form. 2.

2 moulds material and the treatment material that cutting tool chooses are 7CrSiMnMoV of steel of casting condition mould, the hardness after high temperature quenchs achieves 55 ~ 58HRC, have better strength and tenacity to cooperate. Cutting tool chooses Japanese black milling cutter of high speed of type of outstanding machine clip, bit material changes boron for cubic nitrogen (semifinishing machining model is JBN330, finish machining model is JBN245) , cutting speed can be more than 100m/min, when the tall hardness material of cutting 60HRC above, durability of its cutting tool achieves 60min above. 2.

Antrum of sunken model of the bumper before 3 high speed machine craft to plan to be like the car that the graph shows 1 times, by composition of all sorts of complex curved surface. Among them the curved surface groove that steam brake part includes a lot of stricture, and the difficulty that the clear part of groove also is treatment. 2.

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1 rough machining is in the process of rough machining, can make full use of the main shaft power of the machine tool, go up from semifinished product as far as possible efficient purify is major surplus, make surplus of follow-up precision work even. Rough machining divides a pace to undertake, use milling cutter of head of φ 30R15 ball to undertake above all statified milling, withhold 1mm surplus. Use mill of outline of fixed axis curved surface next " FIXED_CONTOUR " undertake rough machining 2 times, all sorts of knife mark that should machine means to excise rough machining cutting tool effectively to stay, machine in workpiece apparently leave evener surplus, corresponding rough machining cutter track is shown 3 times like the graph. 30 milling cutter of Φ of graph 3 sketch map of course of 2 rough machining knives because curved surface of steam brake part antrum is complex, the space is narrow, milling cutter of 30 balls head cannot undertake Φ be excised effectively, need uses smaller cutting tool to be machined technically. Milling cutter of head of Φ 10R5 ball is used in article, use follow model of antrum " ZLEVEL_FOLLOW_CORE " the method is statified cutting. If parameter of main cutting craft expresses 1 to show. Express 1 high speed to machine craft parameter to express Nextpage 2.

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Finish machining of 2 finish machining divides a part to undertake, use mill of outline of fixed axis curved surface to all curved surface above all " FIXED_CONTOUR " , the major surplus that leaves with cleared rough machining. Use milling cutter of head of ball of smaller Φ 8R4 to have precision work to steam brake part again next, if the graph is shown 4 times,its machine knife course. In finish machining process, want to machine method of politic smooth suitable cutting tool according to high speed, make cutting load keeps constant. 2.

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Because root of 3 Qing Dynasty and clear part treatment are in those who use in finish machining it is Φ the ball head milling cutter of 20, the in the spare parts hollow after finish machining is in, reach model antrum underside still has a few redundant material to had been not excised at flank boundary, the cutting tool with need smaller application undertakes clear root or clear part are handled. Use Φ respectively 10 with Φ the ball head milling cutter of 6 undertakes clear root is machined. Because the curved surface amount of the spare parts is more, when choosing cutting area very trival also, and the spare parts is or so semmetry, because this can is opposite first left half part undertakes cutter track is handled, again the mirror is generated right method of half part cutting tool. 8 milling cutter of Φ of graph 4 finish machining of steam brake part knife course sketch map among them milling cutter of 10 balls head carries out Φ clear root is machined " FLOWCUT_MULTIPLE " , NX CAM system decides cutting direction and treatment around order automatically, optimize course of knife of clear root result, make cutting tool maintains as far as possible at the same time express surface contact with the spare parts, in order to reduce time of blame cutting campaign. Method of its cutting tool is shown 5 times like the graph. 10 milling cutter of Φ of graph 5 are sunken sketch map of course of knife of treatment of clear root of modular bottom left uses Φ the ball head milling cutter of 3 undertakes to 4 of steam brake part perpendicular groove " ZLEVE_CORNER " clear part processing, the corner area that can concern before one cutting tool because of diameter and corner radius and cannot reach is excised effectively. Through 3D trends emulation imitate all cutting tool move, whether does contrail of motion of examination cutting tool appear idle stroke and cut too / owe cut wait for interference phenomenon, carry out postposition processing by NURBS format next, create CNC Machining program. Because program code is giant, use RS-232C serial interface to pass into numerical control system, executive network is online treatment, if the graph is shown 6 times,bumper sunken model machines emulation effect. Graph sunken model treatment emulates the bumper before 6 cars the effect pursues the bumper before 3 last words are based on craft of traditional electric spark to narrate a car to preamble place is sunken the model undertakes machining, need course produces the many move such as treatment of electrode, electric spark and polish, handling time needs 120 hours about. And be based on NX CAM system to undertake high speed designs treatment, whole process needs to make an appointment with 38 hours only, shortened greatly treatment is periodic. Visible, the mould with the complex to appearance, taller hardness after quenching, use NX CAM system to undertake three-dimensional model and numerical control process designing, use high speed processing technique to complete the treatment of the mould, raise treatment effectively to manufacture efficiency already, shorten the manufacturing time of the mould, can ensure again the exterior character of the mould and treatment precision, obtain favorable integrated beneficial result thereby. CNC Milling