PRS

Model of orgnaization of machine tool of the PRS-XY numerical control that mix couplet this orgnaization (if the graph is shown 1 times) by shunt-wound orgnaization and series connection orgnaization two parts are formed. On its half are the PRS that a 3 freedom spend shunt-wound orgnaization, include to secure platform and use platform, fixed platform and move pole of 3 fixed length is carried between platform join, each lever catenary includes shift deputy, rotational deputy and spherical deputy. Mobile deputy level 120 ° distributing to go up in the pillar of fixed platform equably, and by linear electromotor drive. Of this orgnaization move platform to have freedom of a translation to spend (Z axis) rotate to be spent freely with 2 () of axis of A, B. Its are X-Y workbench below half times, have 2 translation freedom to spend () of axis of X, Y. This orgnaization that mix couplet machines a machine tool for 5 axes linkage, used what series connection drive and shunt-wound drive use to mix couplet drive principle, hold the advantage of shunt-wound machine tool and traditional machine tool concurrently, overcame the weakness with little space of work of shunt-wound machine tool, applicable Yu Fu is miscellaneous model the treatment of face spare parts [1] . Graph layout of orgnaization of 1 　 PRS-XY 2.

Filling principle of knife of 3D of machine tool of the PRS-XY numerical control that mix couplet 2.

Machine tool of the PRS-XY of 1 hardware support numerical control that mix couplet controls a system to use framework of controller of motion of PC+ much axis, controller of much axis motion uses the TurboPMAC that American DeltaTau company produces. It can carry out memory alone already the program at controller interior, program of executable also exercise and PLC program, OK and automatic first to the task step undertakes differentiate, undertake real time much task is handled thereby. To mixing coupling compose machine tool, more important is it offerred powerful movement to control a function not only, wait for mode like linear interpolation, circular arc interpolation, batten curve interpolation and PVT interpolation, still offerred kinematic and go against kinematic computation ability, and radius of 3D cutting tool compensates a function, and can support function of G code process designing well. 2.

2 goes against what coordinate of machine tool of kinematic analysis PRS-XY numerical control fastens to if the graph is shown 1 times,be built, the point of ball bore with a reamer that moves platform distributings to move platform to go up in what be radius with R equably. Rotational deputy connection is used between connecting rod, slide block, , the unit direction vector that is line of 3 rotational layshaft. The plane on X-Y workbench and extension line of 3 upend slippery rail are handed in at, distributinged to go up in the circle that is radius with R equably this at 3 o'clock. Fixed coordinate is (world coordinate system) O-XYZ builds the geometrical center in equilateral, for Y axis, z axis upend up. Solid moves even what go up at using platform coordinate to fasten origin to be located in equilateral geometrical center, place, axial edge direction, on axial perpendicular at using platform. Set connecting rod to grow to all be L, turn pair of distance with plane it is respectively, cutting tool length is. Referenced coordinate department is built on X-Y workbench, its are initiative the position and world coordinate system (or fixed coordinate is fastened) O-XYZ complete coincide. Its go against kinematic analysis is position of foregone point of a knife and parameter of cutter shaft attitude, beg. Foregone condition is for position of point of a knife, position of point of a knife is in in be (, ) , the directional vector of cutter shaft. Graph concern of space of axis of 2 cutting tool analyses a model 2.

3 3D cutting tool compensates a principle 2.

3.

Compensation amount class decides 1 cutting tool to want to define class of amount of cutting tool compensatory above all to realize this function really, the graph is shown 3 times for model of section plane of cutting tool of commonly used and common milling cutter, TR is knife handle radius, CCR is radius of round horn of point of a knife. Model of class of amount of compensation of cutting tool of graph 3 3D 2.

3.

Law of surface of workpiece of 1) of direction of compensatory of radius of 2 3D cutting tool is measured to arrow. This vector direction is perpendicular the surface that needs to process work at place, point to cutting tool by the surface, express in athletic program with NX, NY, NZ. Because its sheer quantity is decided by CCR, it is to use the pose that shows place machines workpiece surface, the Yu Xian of included angle of the X in can using direction of workpiece surface normal and department of machine tool coordinate so, Y, Z will decide, namely and cosine of these 3 direction can be defined at the same time only, cannot define 1 among them only or 2, such meetings bring about cutting tool radius to compensate direction to make mistake, produce the mistake that cannot expect. Till in numerical control program this definition can maintain another direction vector to be defined all the time, need the directional vector of the treatment face with new redefine before treatment surface changes so. 2) Xiang Shi is measured. Machine tool of the PRS-XY numerical control that mix couplet can realize the commutation of cutting tool attitude, vector of cutting tool direction is passed to have a description to the attitude of cutting tool with respect to need in having process of compensatory of 3D cutting tool, does vector of cutting tool direction define means to be: ? ?2.

3.

3 3D knife fills executive process is in effective treatment, once 3D knife fills to be dictated " CC3 " activation, cutting tool never joins cutting tool compensatory till the dot begins to had joined compensatory of radius of 3D cutting tool to nod, want to divide a phase to undertake cutting tool compensates motion. Above all, compensation of the first deflection has the way that along workpiece surface law Xiang Shi measures a definition campaign, the numerical value of correspondence of place of CCR of machine tool general takes the place of to have consideration in going against kinematic formula, the way that defines to vector place along workpiece surface law controls servo electromotor to drive cutting tool to undertake moving accordingly, achieve the goal that compensates CCR thereby, if pursue,4 are shown. Implementation method is: , compensation of the 2nd deflection will be inside as same as motion of the first deflection plane, provide directional vector along perpendicular Yu Dao and point to the direction of cutting tool center to undertake, deflection is apart from the L=TR-CCR that it is Δ , same ground goes against the machine tool kinematic to deflection the quantity has consideration, in the cutting tool after final recount gives corresponding compensation located finally the position, control cutting tool to undertake compensating motion thereby. Athletic program is particular carry out as follows: If the graph is shown 4 times,deflection executes direction. In the graph, ; of position of center of the cutting tool after PP nods;CP to be compensation for process designing is;CCR of vector of cutting tool direction to be arbor radius for;TR of radius of round horn of point of a knife to vector; for workpiece surface law. 3.

Treatment test test uses arbor radius to establish milling cutter for the straight handle of 3mm, reason CCR=0, TR=3mm, workpiece water paper-cover is placed in workbench, your cutting tool circles X axis to arrange hour hand deflexion 20 ° , according to right hand formula namely A=-20 ° , if pursue,5a place is shown. Nod O to be coordinate origin among them, point of a knife did not compensate the position to be PP(0, 0, 5) , position of the point of a knife after dot CP is compensation sees graph 5b. After cutting tool center moves to nod PP, executive compensation statement: CTX0TZ(cos(20)) of 　 of TY(cos(70)) of 　 of NZ1 of 　 of NY0 of 　 of NX0 of 　 of CCR0 of 　 of C3 　 TR3, carry out again finally " Z5 " athletic statement, apparently the machine tool does not move, but actually the machine tool is met according to before narrate a principle to control cutting tool to undertake compensating motion, namely cutting tool center moves to nod CP by dot PP, buy of v/arc be on the throne of place of the point of a knife after CP is compensation (0, - 2.

8191, 6.

0226) . Graph 5b is a machine tool center of actual cutting tool is real positional sketch map, and with geometry computation is analysed agree, achieve compensation goal. Test and verify of filling experiment of knife of graph 5 3D 4.

The article passes conclusion to go against radius of the kinematic cutting tool that reach 3D to compensate the analysis of the principle and experiment to machine tool of the PRS-XY numerical control that mix couplet, the new-style 3D cutting tool that offerred a kind of application in can machining a process actually compensates a method, machine experimental test and verify through process designing what this compensates a method is practical. CNC Milling