High accuracy changes a sold CNC Turning to treatment

2GPa and 55HRC, belong to material of high strenth, tall hardness; (Demand of 2) treatment precision is high, in two paragraphs of intermediate go up treatment of bearing pin precision asks to be F33.

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013mm is in 5 ～ between 6 class precision; (Ask turning completes treatment on 2) production, do not add grinding working procedure. Accordingly, to satisfy afore-mentioned treatment requirements, we took certain step on tool, equipment and craft, and through relapsing CNC Turning experiment reached a practical treatment program, realized the treatment of CNC Turning of high accuracy batch of this spare parts successfully. Graph 2 beforehand 2 technology program, tool and facility work are in sketch map of turning treatment tool F33.

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The on round face treatment precision demand outside the two parts of 013 is higher, be in 5 ～ between 6 class precision, treatment is relatively difficult, in F40n6(at the same time this station notes: + 0.

033+0.

017) , F33.

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This station notes 013mm, F32t6(: + 0.

064+0.

The coaxial on the 4 circumgyrate face such as 048)mm spends a requirement for 0.

02mm. Apparent, be spent to assure coaxial and achieve precision requirement, must use outfit clip to complete turning treatment. For this, spare parts left end takes dambered surface inside Kong Bi must complete treatment before finish machining. A paragraph when the device that if the graph is shown 2 times,we use finishs diameter of the Kongji inside Zun Duan to be F39mm on numerical control lathe outside of round face beforehand turning treatment. Next, two end use workpiece to the tip locates and undertake with clamp of hydraulic pressure chuck turning of essence of life is machined (graph 3) . Because hit the inevitably meeting when heart aperture,create central hole prejudicial, because this is,make sure workpiece clamp is reliable, use motivation of special hydraulic pressure to compensate chuck. The every card claw of this kind of chuck is apart from in the shift when clamp workpiece need not equal, and even ground brings to bear on to every card claw clamping force, can make sure work center aperture has consequently prejudicial when clamp is reliable. 1.

Card is ungual 2.

Workpiece 3.

Work of rear push frame is top 4.

Dead tip 5.

Chuck of hydraulic pressure compensation pursues speed of turning of sketch map of clamp of fixed position of 3 essence turning (M/min) feed (Mm/r) penetration of a cutting tool is measured (120 0 of Mm) thick car.

35 3.

160 0 of 0 half thick car.

20 0.

160 0 of 3 fine vehicle.

12 0.

05 graphs 4 F33.

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Distributinging graph of the error on face of the circle outside 013mm is achieve F33.

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The treatment precision of round face outside two place of 013mm, the fixed position precision of numerical control lathe and repeat fixed position precision to must be in respectively ± 0.

01mm and ± 0.

003mm is the following, the intensity as a result of workpiece and hardness are taller at the same time, cutting power is greater, what cause a machine tool easily is oscillatory in turning, affect turning precision thereby, to make sure the stability when turning is reached to workpiece larger clamping force and top of rear push frame tighten force, need the numerical control lathe that chooses bigger norms. We chose the lathe of PU-MA12-LB numerical control that Korea big house is versed in the company is produced again, its are main technical parameter is: Lathe bed is the biggest circumgyrate diameter F570mm; Main shaft electromotor most high-power 26kW; Rotate speed limits 20 ～ 2500r/min; Fixed position precision, x direction ± 0.

01mm, z direction ± 0.

02mm; Repeat fixed position precision, x direction ± 0.

002mm, z direction ± 0.

003mm. Turning process distributes thick car, half fine vehicle and car of essence of life. Turning uses Sandik bit with bit: Thick car uses DNMG150608-PM 4025, half fine vehicle uses VNMG160402-PF 4015, fine vehicle uses TNMG160408-PF 5015. If turning parameter expresses place to show. The 3 crucial step that make sure the spare parts machines precision we discover in turning demand of precision of the treatment on the spare parts is higher the dimension wave motion of two place is bigger, out of tolerance is relatively serious, batch of unwarrantable high accuracy is machined. For this, we took the following step: (1) every time before formal turning, make machine tool air runs half hours or so, after hot balance is being achieved in machine tool whole, the workpiece that 3 ～ discard as useless 4 times tries reoccupy cutting a few, make the temperature field of point of a knife also achieves the temperature field when formal cutting approximately. The airborne travel of the machine tool is OK come true through weaving program of an empty loop comes. (After 2) begins turning formally, turning process should successive, center a batch of workpiece to undertake turning. Because, of turning process interrupt, although maintain machine tool sky to run, the temperature field of turning point of a knife also can produce change, because the heat of point of a knife bilges cold shrink effect and influence turning precision. Our turning carries out a proof, this kind of effect answers F33.

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The effect of the turning precision of the two place such as 013mm is very distinct. (In 3) turning process, should detect continuously turning is over the precision of workpiece, according to the trend that the dimension after workpiece turning is over changes, timely amend, the compensation of cutting tool of corresponding fine vehicle in adjusting compensating parameter of cutting tool of numerical control system is numeric. Adopt above technology program, tool, equipment and cutting tool and relevant measure, the precision that we realized successfully to the CNC Turning of high accuracy batch of this spare parts is machined and achieve blueprint to set asks. In turning process, the influence of only minority spare parts as a result of accidental element, its machined precision to exceed the requirement of blueprint. Like the graph 4 are shown is a batch of spare partses after turning is machined, f33 is in a diameter.

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The on round face error outside 013mm distributings graph, be restricted what dotted line expresses a diameter to be worth up and down among them. Can see from inside the graph, it is better that the error of dimension distributings. Adopt plan of this kind of treatment, in make sure batch of high accuracy of this spare parts is machined while, decreased to machine working procedure, rose to machine efficiency, and the investment that still saved cylindrical grinder, reduced the finished cost of the spare parts consequently. CNC Milling