Pretreatment of CNC Machining information

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One, the coding of CNC machining information handles user machine program for the unit with block, the information form that becomes the interpreter such as speed of among them outline information, treatment and auxiliary function information facilitating computer processing, distinguish its of geometry, the data of craft and switch function, deposit in designation memory. In CNC system, user program reads in memory to deposit first commonly. The position that the program deposits can be buffer of part program memery block, part program or clavier is inputted (MDI) buffer. Translation program undertakes coding to the user program in memory. Encounter functional code (wait for) like G, M, the data after its (2 digit are after G, M) changeover is piled up for the feature, deposit the formulary unit at correspondence. If dimension code (wait for) like X, Y, will ever since several string changeover is a binary system to count, deposit the formulary district at correspondence (like) of X area, Y area, until read LF character till, translate a paragraph of program namely. Syntactic examination has in coding process, encounter a mistake to call the police. Read the character beyond the regulation for example, the digit of several string and numerical value allow a value to wait more than, attribute program mistake. 2, cutting tool compensates computation 1.

Compensation of length of cutting tool of compensation of cutting tool length is mixed in numerical control lathe there is application in CNC Milling, machining center. Be like to numerical control lathe, machine the spare parts of same outline dimension when the cutting tool that adopts different measure, or because the cutting tool of same name dimension changes knife readjustments, wear away when causing dimension to change, go to the lavatory for process designing and do not change the course that already had woven, the cutting tool position that uses numerical control system compensates a function, need to be worth variation of cutting tool size system of numerical control losing a person only, numerical control system can change to cutting tool dimension automatically undertake compensating. CNC Milling and CNC Machining center, cutting tool length compensates axial of only corresponding main shaft a coordinate undertakes compensating. 2.

Compensation of cutting tool radius basically is applied at CNC Milling and CNC Machining center. Compensation of cutting tool radius resolved the contradiction between process designing contrail and contrail of cutting tool center. Control to outline especially, through the data that gets after coding, still cannot use at interpolation control directly, want to compensate computation through radius, the data ability that changes data of process designing outline into contrail of cutting tool center is used at interpolation. According to ISO standard, it is when contrail of cutting tool center when the right of direction of advancement of process designing contrail, call right knife to fill, express with G42; Conversely, call Zun Dao to fill, express with G41; When cancelling cutting tool radius to compensate, express with G40. What need points out is, computation of compensation of cutting tool radius is not finished by to program personnel normally, to program personnel just presses the program of treatment outline work out of the spare parts, in the program demonstrate where undertakes cutting tool radius is compensated, finish cutting tool radius to compensate computation automatically by CNC system next. Compensatory of cutting tool radius carries out process cent to be 3 paces: The knife fills build, the knife fills undertake, knife filling cancel. The knife fills to be in only 2 dimension coordinate (planar) inside undertake. 3.

Radius of C function cutting tool compensates: 1) compensation method 2) between the program turn receive 3) compensation example 3, feed speed is handled 1.

Feed speed computation is in open loop system, the feed pulse frequency that enters electromotor through commanding a stage will realize the speed that reference axis moves. The speedometer of open loop system is the F value according to process designing to decide the pace enters frequency of electromotor feed pulse. The pace takes electromotor make a move, corresponding reference axis is mobile a corresponding distance δ (call pulse equivalent) . 1) processing of speed of means of pulse increment interpolation because: F of δ of F = 60 so: F = F/ (60 δ ) F: The feed speed when process designing, unit: Mm/min; δ : Pulse equivalent, unit: Mm; F: The frequency of clock, unit: Hz. 2) speed of means of data sampling interpolation handles Δ L = KFTs / (60 × 1000) Δ L: The feed displacement with an interpolation corresponding cycle, unit: Mm; K: Speed fold; F: The corresponding feed rate when process designing, unit: Mm/min; Ts: Interpolation cycle Ms. 2.

Add / decelerate control is in CNC system, pound to make sure the machine tool does not arise when start or stopping, lose a condition, exceed Cheng or oscillation, must undertake to sending the feed pulse of servo actuating device frequency or voltage decelerate is controlled adding. Start quickly in the machine tool namely when, make sure the feed pulse frequency that is increased on drive electromotor or voltage increase gradually; When machine tool decelerate stops, assure to be added in the frequency of the pulse that take a form on drive electromotor or voltage to be reduced gradually. Add before 1) decelerate control is added to make up instruction of instruction speed F to undertake controlling to Cheng only before decelerate is being added after decelerate is mixed, its advantage is the positional precision that won't affect actual interpolation to output. Its defect is to need to forecast decelerate drop, and the computational amount that forecasts decelerate drop is larger. Decelerate is being added to control after is right each axis undertakes decelerate is controlled adding respectively, do not need to forecast decelerate drop. Because undertake controlling respectively to each axis, actual the synthetic position of each reference axis forbids possibly truly, but this kind of influence just is adding the ability in decelerate process to exist, enter divide evenly this kind of influence when fast condition was done not have. The kind that 2) imposes decelerate character curve to add decelerate to come true has linear to add decelerate (divide evenly adds decelerate) , the index adds decelerate and Sin curve (S) adds decelerate, following plan institute show 3 kinds of characteristic curves that add decelerate. CNC Milling CNC Machining