Circular arc of point of a knife machines medium influence in numerical control lathe

Graph 1

Graph 2

1 foreword is in use process of numerical control lathe, be machined to reduce the surface roughness of workpiece surface, slow down cutting tool wears away, improve cutting tool life, normally form of circular arc of wear of blade of lathe tool point of a knife, circular arc radius is commonly between 0.4 ~ 1.6mm. Use radius of point of a knife compensates a function (the numerical control lathe of G41, G42) , want to press work measure process designing directly in machine program only, won’t cause machining error because of circular arc of point of a knife; And the numerical control lathe that does not have this function, can get in treatment the influence of circular arc of point of a knife, serious when, can cause workpiece out of tolerance to discard as useless. Pursue now the treatment with a spherical SR10-0.04 in showing work will discuss this issue. Analysis of 2 machining error is in the use of lathe of economy numerical control, we are used normally try cut a way to the knife, such, the knife that machine program place describes the dot is P dot (graph 2) , and what attend cutting actually is circular arc of point of a knife (radius of circular arc of here point of a knife is not P dot for 0.4 Mm) , because this P point is real nonexistent. So, the error of different level exists between the contrail that the P that machine program place describes nods and effective treatment outline. But round outside turning, inside when aperture and end panel, this error is 0. And when machining dambered surface and cone, this error is apparent. The machining error analysis with spherical SR10-0.04 sees a picture 2. In the graph, the contrail that the P that M line describes for machine program place nods, namely the theoretical size of workpiece, and the outline after be being machined actually is N line, the shadow is the hypostatic part of little cutting, namely machining error. We use CAXA electron plate medium ” elemental attribute inquires ” function, check N line is the circular arc that a paragraph of radius is 9.6mm, the biggest error is 0.17mm about, if this error is inside tolerancepublic errand limits, we are negligible it, otherwise we are about to adopt measure to eliminate it. The elimination of 3 errors method

    Method 1: When changing process designing of process designing dimension, adjust the contrail of point of a knife, make point of a knife of circular arc form actual treatment outline and ideal outline conform to. With SR10-0.04 spherical treatment is exemple, we need to make fine vehicle block following altering only when process designing can:

    Before the change After the change

    N100 G00 X0 Z50
    N105 G03 X10 Z42 R10 FO.1

    N100 G00 X0 Z50
    N105 G03 X10 Z42 R10.4 FO.1
    … method 2: It is a knife with center of circular arc of point of a knife move of dot process designing is as follows: → of scale workpiece draft is feature of contrail of center of circular arc of computation of → of contrail of motion of circular arc of basis scale point of a knife to nod → process designing with R of radius of circular arc of point of a knife and work measure. Computation of the scale in contrail of center of circular arc of the point of a knife in this process and its feature dot shows a trouble slightly, if use the coordinate that the scale function that is apart from a line and dot wait for in CAD software to inquire the function comes,complete this work, appear very convenient. Additional, when using this kind of method to machine, handlers should notice the following at 2 o’clock: Whether is the R value of the radius of circular arc of point of a knife that 1) checks an use cutting tool worth conform to with the R in the program; 2) is right when the knife, want to consider R value to go in, namely: If to the knife that the knife receives filling value is X(X axis) with Y(Z axis) , filling value is the knife that should input actually X-2r and Y-r.

4 epilogue the article basically is beyond the treatment of arc of predestined relationship protruding is exemple undertake discussion, the dambered surface of other type, cone also is put in similar problem, the article no longer give uncecessary details.

The account that numerical control lathe produces collision and avoid measure

 [summary] : The article from education set out actually, be aimed at the practice that lathe of student numerical control handles, the account that hits a car produces in summing up unit process of cargo bandling of numerical control lathe, put forward practical settlement method, integration of theory with practice, in reflecting a profession to teach, high skill talent develops the concept in the process and teaching method.

[keyword] : Numerical control lathe produces collision reason to avoid measure

Price of numerical control lathe is high, in exercitation education, if wait for a reason as a result of student process designing, operation, make machine tool happening collides, touch bad work gently, attaint cutting tool; Make a machine tool local again damage, loss of accuracy, machine tool discards as useless, send the life security that endangers handlers very, its consequence is very serious. Oneself through coming for years the practice of careful research and exercitation education sets out, induce as follows now:

One,    process designing is wrong at 0 o’clock

The person that is engaged in process designing of numerical control lathe knows, process designing 0 o’clock is measure of work of the decision in numerical control process designing

according to, if process designing appeared at 0 o’clock accident, so the possibility that numerical control lathe produces collision is very large. In the work that following graphs show 1 times:


Its program is:

N0000G54G92   Z70.0;

If write G54 by accident,be G57 or G58, according to the regulation of process designing of numerical control lathe, two in coming from same group slant buy dimension (set by G57 or G58, G92) , call finally slant buy dimension (set by G92) effective. Its program turns into:

N0000G57G92   Z70.0;

Criterion afore-mentioned results will be:


Slanted at 0 o’clock namely calorie of claw leaves only after buy3.8mm, in process designing, axial dimension wants to be less than only3.8mm, regular meeting occurrence lathe tool and card claw collide.

For this, must understand to slanted at 0 o’clock the detailed meaning that buy dictates, had used correctly slanted at 0 o’clock buy statement, prevent to produce phenomenon of collision of numerical control lathe.

2,    there is the data that surmounts dimension blocking claw in the program

Above pursues 1 for exemple, process designing was to dimension of end panel blocking claw at 0 o’clock50mm, if axial dimension is apart from right

End panel distance exceeds50mm, if be 51, criterion lathe tool and card claw collide1mm. After to program ends reason, do not be eager to machine, want scrutiny whether does the numerical value of Z of all axial dimension exceed50mm.

3,    when machine tool air runs, did not stretch calorie of claw, make tool carrier is far from chuck and tailstock

When the machine tool undertakes automatic loop air runs, if did not stretch calorie of claw, make tool carrier is far from chuck and tailstock, be like occurrence motion interference, produce collision extremely likely to block the phenomenon of claw or tailstock. If stretch calorie of claw, examine the coordinate cost of the program in time, or to having the numerical control lathe of function of imitate of cutting tool contrail, move tool carrier to tailstock and chuck between, below the premise that assures safety of tool carrier dislocation, lock up dead machine tool, reentry moves automatically for nothing all right, also can judge lathe tool to whether reach workpiece collision with the machine tool roughly, after having a problem certainly, fangke undertakes cutting is machined trying.

4,    process designing is undeserved, generation collides

Because workpiece is special appearance, when requirement process designing into, retreat a knife to must be odd coordinate means, following

The graph shows work 3 times in:


Boring cutter machines Kong Shi, if use G00 to dictate mobile cutting tool is nodded to the target directly, process designing is as follows:

N0050Z of   of G00   X19.0 – 25;

Such, if solid line place is shown,will naturally collide with workpiece happening in that way;

If odd coordinate divides a pace to move to eye punctuation, such process designing:

N0050G00   Z2.0;

X19.0 of   of   of N0055     ;

Z of   of   of N0060     – 25;

If dotted line place is shown, avoided effectively to collide.

Pursue for instance again 4 in showing work, when the turning of the grooving that finish, need quick return to come

Ф100mmReach right from workpiece end panel100mmPlace, be like such process designing:

N0080  Z100.0 of G00   X100.0;


Because take oblique line,grooving knife is met and collide with spare parts step, although be in system of most numerical control, after executive G00 dictates, the actual contrail that cutting tool walks along is broken line, because G00 is fast,choose location again, lathe tool with the machine tool the rapiddest rate moves to be nodded to the target, the actual contrail of lathe tool shows dotted line share 5 times for the graph, it is a broken line namely, also should collide with workpiece happening.

Its accurate process designing method is as follows:

N0080G00   X100.0;

N0085      Z100.0;

Following plan institute show the athletic contrail of cutting tool:


Quit grooving knife radial work first namely, next again axial shift comes end panel100mmPlace, can avoid effectively to collide.

5,    mistake of process designing data or do not accord with a requirement, and caused collision

Lathe of some numerical control is decimally process designing, or already installed for decimally process designing, in next graphs 6 are shown

Below the circumstance:


Its program is:

X62.0 Z-35.0; of   of N0100   G00

Although cutting tool takes broken line, also won’t collide with workpiece. But as a result of carelessness or other reason, write the program into following programs by accident:

Z of   of X62 of   of N0100   G00 – 35;


Z of   of   of X62 of   of N0100   G00 – 35;

Numerical control system is met a coordinate word after 62 reach – 35 except with 1000 will handle, become namely:

N 0100G00   X0.062 Z-35.0;


N0100  Z of G00   X0.062 – 0.035;

Very apparent, grooving knife should collide with the circle outside workpiece or photograph of right end panel.

Collide to avoid this to plant, best method is emulated more namely, much examination, careful, fine young, find out in time apparently wrong or the data that does not accord with a requirement, amend in time.

6, the usage that not familiar process designing dictates, cause lathe tool and workpiece collision

In system of FANUC   0I, g71 (G73) the multiple and compound fixed loop of outline of work of vehicle of as thick as G70, fine, especially when G73 instruction and G70 are combined, if the graph shows 7 times:


When ending as a result of the loop, the ground of initial site selection that the return trip chooses is improper (see what A dot shows, on the low side) , cause the phenomenon that collides with work look when cutting tool returns to happen thereby. To prevent this kind of circumstance happening, the initial drop that should make the return trip is nodded only is proper drive up is nodded to B can.

7, what the dot that change a knife appoints is improper, produce collision

The dot that change a knife is chosen too close from workpiece or the other position that leave tailstock too close or leaves a machine tool is too nearly, tool carrier

Workpiece of incidental when dislocation collision or machine tool. Want to avoid this kind of circumstance happening, have to abide by those who change knife spot to choose a principle, change knife dot to must be between workpiece and tailstock namely, approach work as far as possible, and any place that tool carrier must not meet workpiece, tailstock and machine tool when dislocation.

8, answer reference point means to choose a mistake, cause collision

When some students are winding reference point, when choosing working way, do not see operation face plate, the operation square

Formula switch is chosen move in the hand (JOG) means, is not a reference point (REF) means, do not watch video screen again, not be to cause exceed Cheng to call the police, when be like farewell to consult, of reference axis early or late order is incorrect, cause collision tailstock phenomenon extremely easily to happen. To avoid this kind of circumstance happening, as long as the student is not serious, careful, careless, operate a machine tool by the regulation can.

9, did not answer reference point to cause collision happening

The coder of numerical control lathe has opposite coder and absolutely coder two kinds, install opposite encode to adding

Implement numerical control lathe is become machine tool electrify or after cutting off the power new and electrified or the memory that pair of reference point can lose after trouble removal restoration, right now, if do not undertake winding the operation of reference point, have pair of knives or automatic treatment, certainly will causes data to read clerical error by accident, cause lathe tool and workpiece or machine tool collision then.

Happen to prevent the collision of this kind of circumstance, want to wind reference point first by the regulation only, operate related reentry travel can.

Anyhow, the reason that numerical control lathe produces collision is very much, still have other condition besides, here

no longer one one give uncecessary details. To avoid collision happening effectively, when process designing and operation, requirement student is familiar with numerical control to machine craft, understand an instruction, hep machine tool handles a regulation, close process designing, microscope, operate a machine tool by formulary safety, must not boldly act.


Reference book book:

1, ” numerical control lathe grooms ” Yuan Feng  Machinist trade publishing house

2, ” process designing of numerical control machine tool and operation ” (fascicule of numerical control lathe)

Labor and organization of office of teaching material of social security ministry write press of Chinese labor social security

3, ” numerical control lathe operates an elementary course ” press of science and technology of Cheng Meiling Anhui

4, ” numerical control uses crucial technology ” press of industry of Lou Rui electron

5, ” turning of numerical control machine tool processes technique of direct process designing ” press of industry of Sun Demao machinery

Characteristic of numerical control lathe reachs composition

The appearance of numerical control lathe and bed of general be open to traffic are similar, press the part such as refrigeration and system, lubricant system to comprise by system of box of lathe bed, main shaft, tool carrier, feed namely. The feed system of numerical control lathe and bed of general be open to traffic have qualitative distinction, traditional and common lathe has feed box and commutative gear to wear, and numerical control lathe is to use servo electric machinery to sneak away through drive of ball guide screw directly board with tool carrier implementation feed moves, consequently the structure of feed system simplifies greatly.

Accuse the classification of lathe

Breed of numerical control lathe is various, norms is differ, can undertake classified by following methods.

1.Press position of lathe main shaft to classify

Lathe of numerical control of horizontal of lathe of 1) horizontal numerical control divides amount to to accuse horizontal slideway center lathe and numerical control to tilt again slideway center lathe. Its tilt slideway structure can make lathe has bigger tigidity, eliminate to cut bits easily.

Lathe of horizontal numerical control

Abbreviation of lathe of numerical control of vertical of lathe of 2) vertical numerical control establishs a car for numerical control, its lathe main shaft is perpendicular at horizontal, the circular workbench with a very big diameter, use the work that hold clip. This kind of machine tool basically is used at machining radial dimension the large and complex part with relatively minor dimension of big, axial.

Lathe of vertical numerical control

2.Press classification of tool carrier amount

Lathe of numerical control of lathe of numerical control of 1) single tool carrier is configured commonly have multiform single tool carrier, like 4 labour lie move dislocation tool carrier or multitask turn tower type is automatic dislocation tool carrier.

Short-hilted broadsword wears numerical control lathe

The double tool carrier of this kind of lathe configures lathe of numerical control of 2) double tool carrier parallel distributings, also can be mutual and perpendicular distributing.

Lathe of numerical control of double tool carrier

3.Press functional classification

Lathe of 1) economy numerical control

Use a pace to present electromotor and sheet piece opportunity is right what after the feed system of common lathe undertakes transforming, form is simple and easy model numerical control lathe, cost is inferior, but automation degree and function are poorer, turning treatment precision is not tall also, apply to the circumgyrate with not high demand kind the turning treatment of the spare parts.

Lathe of economy numerical control

Lathe of 2) ordinary numerical control machines a requirement to undertake the numerical control lathe that be designed technically and provide system of general numerical control and forms on the structure according to turning, function of numerical control system is strong, automation degree and treatment precision are taller also, apply to general circumgyrate kind the turning treatment of the spare parts. Lathe of this kind of numerical control can control two reference axis at the same time, namely X axis and Z axis.

Lathe of ordinary numerical control

3) turning machining center is on the foundation of lathe of ordinary numerical control, raised C axis and head, more advanced numerical control lathe contains knife library, controallable X, Z and C3 reference axis, linkage control axis can be (X, Z) , (X, C) or (Z, C) . Because raised C axis and milling head, the treatment function of lathe of this kind of numerical control increases greatly, it is OK to divide outside undertaking general turning, can undertake line of radial and axial milling, curved surface milling, center is absent the Konghe of spare parts centre of turning circle is radial of aperture auger cut wait for treatment.

Sketch map of interior of turning machining center

Dyad accuses the structural characteristic of lathe

Compare with traditional lathe photograph, the structure of numerical control lathe has the following characteristic:

1) parts as a result of the two direction motion of tool carrier of numerical control lathe by drive of two servo electromotor, its transmission cable length is so short. Need not use hang annulus, the drive disk assembly such as feed rod, drive tool carrier to move with guide screw coupling directly with servo electromotor. Synchronous leather belt also can be used between servo electromotor guide screw deputy or gear deputy coupling.

2) is muti_function numerical control lathe is to use dc or unit of control of communication main shaft to come drive main shaft, by control the instruction makes infinitely variable speeds, multistage gear need not be used between main shaft deputy will have speed change. To enlarge gearshift limits, pass one class gear even commonly now deputy, in order to implement section stepless speed regulation, although such, the structure inside headstock is gotten simplier than traditional lathe already much. The another structure characteristic of numerical control lathe is stiffness big, this is to match with the high accuracy control that controls a system, so that get used to the treatment of high accuracy.

The characteristic of the 3rd structure of lathe of 3) numerical control is to procrastinate gently move. Tool carrier shift uses ball guide screw commonly deputy. Ball guide screw deputy one of crucial and mechanical components that are numerical control lathe, the scroll bearing that two end install ball guide screw is special uranium bear, its pressure angle compares commonly used afferent thrust ball bear should get greatly much. Conjugate of this kind of special bearing is installed, it is to choose match, when fortunately bearing leaves factory, be didymous most.

4) is moved to procrastinate light, of numerical control lathe lubricant more sufficient, use oily mist to lubricate automatically for the most part.

5) because the price of numerical control machine tool the taller, life that dominates a system is longer, so the sliding slideway of numerical control lathe also asks wearability is good. Numerical control lathe uses the guide that set steel commonly, retentive time grows such machine tool precision quite, its service life also can be lengthened a lot of.

Lathe of 6) numerical control still has treatment cooling and sufficient, defend relatively the characteristic such as rigor, whole sealing is in commonly when voluntary movement or close partly condition.

Lathe of 7) numerical control still deserves to have unit of automatic platoon bit commonly.

The three distribution that control lathe

The rigid structure system of lathe of typical numerical control is comprised, include main shaft main transfer machinery, feed main transfer machinery, tool carrier, lathe bed, auxiliary unit (cutting tool is exchanged automatically orgnaization, lubricant with spacing of bits of cutting fluid device, platoon, overload) wait for a part.

The relative position of slideway of lathe bed of numerical control lathe and horizontal is like place of graph 1 – 2 to show, it has form of 4 kinds of layout: Graph 1-2 (a) makes the same score lathe bed, graph 1-2(b) inclined lathe bed, graph 1-2(c) makes the same score lathe bed inclined slide, graph 1-2(d) is establish lathe bed.

The contrapuntal buy of slideway of lathe bed of numerical control lathe and horizontal pursues

The craft sex of horizontal lathe bed is good, the treatment of facilitating slideway face. Horizontal lathe bed deserves to sail upstream the athletic precision that makes the same score the tool carrier that place to be able to raise tool carrier, can use at the layout of lathe of large numerical control or lathe of small-sized and rigid numerical control commonly. But horizontal lathe bed because bottom space is little, reason discharges bits difficulty. Look from structural dimension, tool carrier level is placed make slide transverse dimension is longer, increased the structural size of direction of machine tool width thereby. Following plan institute are shown,

Lathe bed of level of numerical control lathe

Configuration of horizontal lathe bed tilts placement slide, deploy shield of bend inclined slideway, form of this kind of layout, the respect has the characteristic with good sex of Ding Yi of horizontal lathe bed, on the other hand the dimension of direction of machine tool width relatively of horizontal configuration slide want small, and platoon bits is convenient. Horizontal lathe bed deserves to go up tilt form of layout of inclined slide of placement slide and configuration of inclined lathe bed is used generally by place of lathe of medium, small-sized numerical control. The characteristic of form of these two kinds of layout is a bits easy, hot scrap won’t pile up to go up in slideway, also facilitate installation discharges bits automatically implement; The operation is convenient, install manipulator easily, in order to implement stand-alone automation; The machine tool covers an area of an area small, the shell is simple, beautiful, easy implementation is enclosed defend.

Numerical control lathe tilts lathe bed

The angle that its slideway tilts is inclined lathe bed respectively 30 ° , 45 ° , 60 ° , 75 ° and 90 ° (call) of vertical lathe bed, if tilt angle is small, discharge bits inconvenience; If tilt point of view is old, the oriented sex of slideway is poor, condition getting power is poor also. The bulk that slideway banking angle spends still can affect the proportion of height of machine tool over all dimension and width directly. Consider the factor above integratedly, in the numerical control lathe of small norms the gradient of its lathe bed with 60 advisable.

Vertical lathe bed

Shanghai of lathe of numerical control of neck of first crankshaft main shaft comes out

    Limited company develops plant of Shanghai heavy-duty machine tool successfully recently made 2 CK61125 × lathe of numerical control of neck of 6500 crankshaft main shaft. This machine tool has the characteristic such as easy control of high speed, efficient, quality, can shorten apparently crankshaft treatment is periodic, solved domestic high-power diesel engine difficult problem of craft of special crankshaft treatment.  

    6500 crankshaft of CK61125 × lathe of numerical control of main shaft neck according to Germany company of pattern of Wo Lun shellfish designs a standard to undertake designing, use 3 slideway form, central tall 675mm, procrastinate board on 1000mm of diameter of the biggest circumgyrate, the biggest treatment grows degree of 6500mm, 10t of weight of the biggest crankshaft (2 tips) . Machine workpiece circularity 0.005mm, machine dimension precision IT6, m of μ of Ra1.6 of exterior surface roughness, the round cylinder outside fine vehicle spends 0.015/300mm.  

    Shanghai serious chance still developed a variety of special components for the machine tool, if slippage type C center is worn, can assure the bearing tigidity demand of cutting already, the convenience sex that can satisfy workpiece of outfit, discharge again asks, Φ of 150~ of bearing limits Φ 350. In addition, according to neck of crankshaft main shaft treatment nods the characteristic of thorough workpiece, develop special multitask bit body, after cooperating with tool carrier of numerical control horizontal, can satisfy main shaft neck to machine the successive treatment of the dot individually, improve treatment efficiency considerably.

5 lathe do not amount to mark to recoup a loss 140 thousand

   On November 18, pass the mediation of association of industry of Taiwan businessman of city of elder brother hill, manufactory of hardware of abundant of limited company of metals of some machinery of Wu Jiang city and city of elder brother hill harding iron reachs intercessory agreement: 5 lathe make the processing that return money entirely, remand buy payment for goods 210 thousand yuan, recoup the pecuniary loss such as cost of man-hour of manufactory of hardware of abundant harding iron, artificial cost one hundred and forty-three thousand five hundred and fifty-three yuan.
On November 5, yuan Quanjin of factory manager of mill of hardware of abundant harding iron will offspring industrial and commercial substation states Shan Zhouzhuang: This factory this year on June 15 to the stage endowment limited company of metals of some machinery of city of enterprise Wu Jiang buys Taiwan to produce ” the name is in relief ” card 15 model accurate cam lathe 5, money paid for something purchased or received for something sold every fifty-nine thousand eight hundred yuan, add up to payment for goods 299 thousand yuan, pay on the spot 210 thousand yuan are rectified. After can purchasing installation, the product after classics technology personnel is debugged cannot achieve a requirement however. Hind although agency also sends technical personnel, technician to come to a factory for many times,undertake debugging, but the error level that product precision still cannot reach manual place to set.