CN105930589A - Data processing method of multi-axis linked electric discharge machining feeding speed postprocessor based on spatial mapping - Google Patents

Abstract

The invention relates to the data processing method of a multi-axis linked electric discharge machining feeding speed postprocessor based on spatial mapping. With respect to electric discharge machining participated by a rotation axis, a control object is a relative distance between an electrode and a workpiece. According to the method, through start from a model of the electrode and the workpiece, displacements of each line of G codes under a machine tool coordinate system and a workpiece coordinate system are solved through spatial mapping; the ratio of the displacements is solved; the ratio is multiplied by an originally planned feeding speed of each line of G codes; and a machining program is updated. According to the method, speed fluctuation resulting from spatial transformation can be greatly reduced; the discharge state of movement participated by the rotation axis is protected from instability; occurrence of open circuit and short circuit states can be reduced; and the electric discharge machining efficiency can be improved.

Description

Data processing method based on the multi-shaft interlocked spark machined feeding speed preprocessor that space maps

Technical field

The present invention relates to electric spark process control, belong to technical field, specifically one is reflected based on space The data processing method of the multi-shaft interlocked spark machined feeding speed preprocessor penetrated.

Background technology

Modern numerical control machining comprises CAD (computer-aided design), CAM (computer aided manufacturing), after Process, the several typical link of digital control processing, as shown in Figure 1.By CAD, processing workpiece is designed, CAM Simulating cutting process generates machining locus information, and last handling process is to machining code for equipment or technical process Being optimized generation processing G code file, digital-control processing system is processed in accordance with G code, it is thus achieved that preferably process Effect.

Spark machined is to utilize a series of spark discharges between workpiece and electrode, is removed workpiece material A kind of process.Spark machined is commonly used for the fields such as mould, Aero-Space, medical apparatus and instruments.Spark machined Compared with tradition Milling Process, there is the most different places.Such as spark machined is noncontact procession, multiaxis Linkage spark machined can process extremely complex die cavity, and the surface configuration of machining tool electrode is copied to work On part.Such as enclosed blisk uses six-axis linkage electric spark machine tool to be as shown in Figure 2 processed, and utilizes Three linear axis X, Y, Z and three rotary shafts A, the resultant motions of B, C, can be by machining tool electrode feeding Inside enclosed blisk, copy to the surface configuration of electrode, on enclosed blisk, complete the processing of leaf dish, As shown in Figure 3.In the case of multi-shaft interlocked, on electrode, point of discharge is relative to relatively transporting between corresponding point on workpiece Momentum is the result of resultant motion, in spark-erosion machine tool digital control system, uses the mode of extension displacement of the lines to straight line Axial velocity and rotary shaft angular velocity synthesize, and the respective velocity amplitude of N number of axle will carry out orthogonal synthesis.Due to Linear velocity and the difference of angular velocity dimension, the most do not consider that the synthesis of rotary shaft radius of turn will certainly cause speed Do not mate, thus have influence on processing effect.In spark machined, enter with the fixed speed of basis in Milling Process Give difference, be according to the interpolar Determines machine direction measured: forward or backward, and according to working as pre-test Voltage across poles and set the difference of servo voltage and determine speed forward or backward, put according between electrode and workpiece The difference of electricity condition, can be divided into four kinds of states such as open circuit, regular picture, short circuit and electric arc.Servo-control system Discharge condition, the most rule of thumb feed speed of formula determining electrode is estimated by gathering the information such as voltage, electric current. In empirical equation, feed speed refers to the relative velocity relative to the point of discharge on workpiece of the point of discharge on electrode. In the multi-shaft interlocked SERVO CONTROL having rotary shaft to participate in, digital control system is sat at lathe according to the displacement of each coordinate axes Mark system space is extended displacement of the lines composite calulation displacement, and the workpiece coordinate system of this displacement and electrode opposite piece Space displacement concept is different, and this has resulted in the gap between the amount of feeding required by the actual amount of feeding and empirical equation. In this case, same increment of coordinate, the actual amount of feeding under workpiece comparative electrode different positions and pose is different.

The multiple linkage spark machined participated in due to rotary shaft is that complex-shaped surface mould processing must use, this situation Under, the correct resultant motion processing rotary shaft participation is necessary.Owing to workpiece and electrode machining being face and face Contact, so should reference point on first Rational choice electrode and workpiece.There is the positional information of reference point, just may be used To carry out post processing planning.

Summary of the invention

For overcoming above-mentioned the deficiencies in the prior art, the present invention locates after providing the feed speed of a kind of spark machined that links Reason device method for designing, the method can be greatly decreased space and map the velocity perturbation caused, it is to avoid rotary shaft participates in Motion discharge condition is unstable, reduces the generation of open circuit and short-circuit condition, promotes the efficiency of spark machined.

The technical solution of the present invention is as follows:

The data processing method of a kind of multi-shaft interlocked spark machined feeding speed preprocessor mapped based on space, should Method comprises the steps of

Step one: choosing of machining tool electrode and work piece reference point, witness mark is relative to the rotation of center of rotation Turn the positional informationes such as radius；

Step 2: open G code file, reads the first row G code；

Step 3: read next line G code, if absolute magnitude pattern, the coordinate of one's own profession G code is deducted The coordinate of a line G code obtains the displacement increment of coordinate axes；If incremental mode, read the seat of one's own profession G code Mark increment

Step 4: calculate lathe coordinate space extension displacement of the lines amount Δ s, as a example by 6 axle lathes；

$\mathrm{\Δ}s=\sqrt{{\mathrm{\Δx}}^2+{\mathrm{\Δy}}^2+{\mathrm{\Δz}}^2+{\mathrm{\Δa}}^2+{\mathrm{\Δb}}^2+{\mathrm{\Δc}}^2}.$

Step 5: on calculating workpiece coordinate system space electrode, reference point is relative to reference point displacement δ s on workpieceIts three durection component δ x, δ y, δ z can be mapped by space and obtain.

Step 6: the feed speed that this row G code was originally planned is multiplied by Δ s/ δ s, and replaces original feeding speed Degree；

Step 7: determine whether next line G code, if there being entrance step 3, without entering step 8.

Step 8: having changed the G code after feed speed and preserved and pass to digital control system, digital control system is according to more G code after changing is processed such that it is able to reducing the motion discharge condition instability that rotary shaft participates in, minimizing is opened Road and the generation of short-circuit condition, promote effective discharge rate.

The principle of the invention is as follows:

For having the multi-shaft interlocked spark machined that rotary shaft participates in, control to as if between electrode and workpiece Relative distance.It is the side of employing extension displacement of the lines in the lathe coordinate system of multidimensional owing to the coordinate axes of lathe moves Rectilinear axis speed and rotary shaft angular velocity are synthesized by formula, will the respective velocity amplitude of N number of axle just join Become.Feed speed in digital control system is no longer equal to the feed speed of electrode opposite piece in workpiece coordinate system.

For solving this problem, need to obtain the extension displacement of the lines corresponding to a line G code respectively relative with actual electrode Displacement in workpiece.Participating in as a example by the six-axis linkage of motion by three rotary shafts of three linear axis, three linear axis are fixed Justice is X, Y, Z axis, and three rotary shafts are defined as A, B, C axle.

The reference point of machining tool electrode and workpiece selects to be cad models based on them.In general, participate in The part of electric discharge is easiest to produce the position that electric discharge concentrates and is chosen as reference point, so on machining tool electrode and workpiece Reference point is elected as along the point corresponding to the maximum radius of turn of this kinematic axis.

In definition the first row G code, the displacement of each coordinate axes is Δ x, Δ y, Δ z, Δ a, Δ b, Δ c, then machine coordinates Spatial spread displacement of the lines amount Δ s is:

$\mathrm{\Δ}s=\sqrt{{\mathrm{\Δx}}^2+{\mathrm{\Δy}}^2+{\mathrm{\Δz}}^2+{\mathrm{\Δa}}^2+{\mathrm{\Δb}}^2+{\mathrm{\Δc}}^2}$

And reference point is relative to a displacement δ s in the actual displacement of reference point is theorem in Euclid space on workpiece on electrode, Being defined as δ x, δ y, δ z at three-dimensional three direction projection components of theorem in Euclid space, this can be asked by spatial alternation Go out.δ x, δ y, δ z is the spatial alternation of this coordinate figure corresponding to row G code and increment of coordinate, and g represents empty Between transforming function transformation function.

(δ x, δ y, δ z)=g (Δ x, Δ y, Δ z, Δ a, Δ b, Δ c, x, y, z, a, b, c)

After obtaining δ x, δ y, δ z, δ s can be obtained by equation below.

$\mathrm{\δ}s=\sqrt{{\mathrm{\δx}}^2+{\mathrm{\δy}}^2+{\mathrm{\δz}}^2}$

If this row G code feed speed of original planning is f, then on electrode to be realized, reference point is relative to workpiece Upper reference point feed speed f, digital control system need feed speed F that sets according to lathe coordinate system as:

$F=\frac{f\mathrm{\Δ}s}{\mathrm{\δ}s}$

After obtaining this amended feed speed of row G code, preserve and pass to digital control system, after amendment G code carry out spark discharge processing.

Compared with prior art, untreated machining code has bigger velocity perturbation, in this case, nothing Method keeps continual and steady spark discharge processing.Likely because the complexity of resultant motion, cause the single cycle The amount of feeding excessive or too small, cause frequently short circuit and arcing, not only reduce working (machining) efficiency, also can produce The short circuit bad processing consequence that causes of arcing, such as ablated surface, metal-modified.By use the present invention based on sky Between map multi-shaft interlocked spark machined feed speed preprocessor, carry out according to the actual displacement of workpiece coordinate system Speed planning, can substantially eliminate velocity perturbation, it is achieved more stable spark machined state, reduction short circuit, The bad machining state probability such as open circuit, arcing, promote spark machined efficiency.

Accompanying drawing explanation

Fig. 1 is enforcement system digital control processing of the prior art several typical link schematic diagram.

Fig. 2 is the flow chart of the data processing method of the present invention multi-shaft interlocked spark machined feeding speed preprocessor.

Fig. 3 is platform six-axis linkage electric spark machine tool schematic diagram of the present invention.

Fig. 4 is the present invention multi-shaft interlocked feeding track schematic diagram.

Fig. 5 be embodiment of the present invention reference point choose schematic diagram, wherein, a is the reference point of electrode and b is workpiece Reference point.

Detailed description of the invention

The specific embodiment of the present invention is implemented and upper in the electrode machining enclosed blisk G code shown in Fig. 3 Carry out on HE 70 spark-erosion sinking machine that the dynamo-electric company limited of Hai Han despot produces.The reference point of the workpiece chosen is around peace The rotary shaft radius of turn of dress workpiece is 120mm, and initial position and coordinate axes Z angle are 0 degree, machining tool electrode On reference point be 27.5714mm around installing the radius of turn of rotary shaft of electrode, initial position is with coordinate axes Y's Angle is 21.75 degree.

Embodiment:

According to measurement, the reference point distance workpiece centre of gyration 120mm on the workpiece chosen, the electrode chosen is joined Examination point distance electrode centre of gyration 27.5714mm remembers), as shown in Figure 5.

Read the first row code, then start to read G code line by line from the second row, calculate the second row G code relative In the displacement of the first row at the displacement Δ x, Δ y, Δ z, Δ a, Δ b, Δ c of each kinematic axis.Calculate lathe coordinate space Extension displacement of the lines amount Δ s.On calculating workpiece coordinate system space electrode, reference point is relative to reference point displacement δ s on workpiece. The feed speed that G code of changing one's profession originally was planned is multiplied by Δ s/ δ s, and replaces original feed speed.

Original processing feed speed empirically formula is planned to f10, entering after calculating each row G code optimization Different changes is produced to speed value, in the range from: F4.775 to F320.010.(feed speed in G code)

Then with above-mentioned changed feed speed after G code pass to digital control system, carry out enclosed blisk Machining experiment, uses the code of Constant feeding rate F10 to carry out contrast experiment with whole process.The machining tool that experiment uses Electrode material is POCO EDM-C3, and enclosed blisk workpiece material is C45E4 steel.Processing conditions such as table 1 below Shown in:

Table 1-enclosed blisk machining experiment parameter

Workpiece polarity

Open-circuit voltage

Peak point current

Pulse width

Pulse spacing

Cutter lifting height

The cutter lifting cycle

Negative pole

120V

36A

80μs

8μs

1mm

5s

Each method is respectively adopted 1 machining tool electrode machining 3 times, shown in the table 2 of concrete processing result:

Two kinds of feed speed control method processing results of table 2-compare

As can be seen from Table 2, either on process time or in the loss of tool-electrode, use based on space The result that the multi-shaft interlocked electric spark feed speed control method mapped obtains all is better than Constant feeding rate.

The preferred embodiment of the present invention described in detail above.It should be apparent to a person skilled in the art that not In the case of departing from the scope of the invention, many modifications and variations can be made according to the design of the present invention.Therefore, all Technical staff is the most on the basis of existing technology by changing material or spy in the art The point available technical scheme of situation, all should be in the protection domain being defined in the patent claims.

Claims (4)

1. a data processing method for the multi-shaft interlocked spark machined feeding speed preprocessor mapped based on space, It is characterized in that, the method includes the steps of:

Step one: choosing of machining tool electrode and work piece reference point, witness mark is relative to the rotation of center of rotation Turn radial location information；

Step 2: read the first row G code；

Step 3: read next line G code, calculates the displacement increment of each coordinate axes of lathe；

Step 4: calculate lathe coordinate space extension displacement of the lines amount Δ s；

Step 5: on calculating workpiece coordinate system space electrode, reference point is relative to reference point displacement δ s on workpiece；

Step 6: the feed speed that this row G code was originally planned is multiplied by Δ s/ δ s, and replaces original feeding speed Degree；

Step 7: determine whether next line G code, if there being entrance step 3, without entering step 8.

Step 8: changed the G code after feed speed and preserved and pass to digital control system such that it is able to reduce rotation The motion discharge condition that rotating shaft participates in is unstable, reduces the generation of open circuit and short-circuit condition, promotes effective discharge rate.

The data processing method of multi-shaft interlocked spark machined feeding speed preprocessor the most as claimed in claim 1, It is characterized in that, electrode and work piece reference point described in step one are to be easiest to produce electric discharge on electrode and workpiece concentrate Position.

The data processing method of multi-shaft interlocked spark machined feeding speed preprocessor the most as claimed in claim 1, It is characterized in that, the machine coordinates spatial spread displacement of the lines amount Δ s described in step 4 is each coordinate axes displacement quadratic sum Arithmetic square root.

The data processing method of multi-shaft interlocked spark machined feeding speed preprocessor the most as claimed in claim 1, It is characterized in that, on the electrode described in step 5, reference point is European in three-dimensional relative to reference point displacement δ s on workpiece Three, space direction projection component is the spatial alternation of this coordinate figure corresponding to row G code and increment of coordinate.