Patent Publication Number: US-2023158590-A1

Title: Method of manufacturing a part of an aircraft engine

Description:
TECHNICAL FIELD 
     The disclosure relates generally to aircraft engines, such as gas turbine engines, and, more particularly, to systems and methods used for manufacturing parts of such aircraft engines by machining. 
     BACKGROUND 
     Aircraft engines include a plurality of components that may be manufactured by machining. As an example, turbine discs are typically engaged to a shaft via a spline coupling. Such spline couplings include mating splines in both the shaft and turbine disc. The splines include teeth and grooves, which may be machined with a rotating tool that has a shape corresponding to a profile of the teeth. During the machining process, however, variances between an expected position of the rotating tool in relationship to the part being machined and its actual position can sometimes occur. This may result in manufacturing discrepancies that are undesired. Improvements are therefore sought. 
     SUMMARY 
     In one aspect, there is provided a method of manufacturing a feature in a part of an aircraft engine with a cutting tool, comprising: machining a semi-finished shape of the feature in a stock material of the part by moving the cutting tool relative to the stock material; determining an actual position of at least one target point on a surface of the semi-finished shape of the feature, the surface to be machined to achieve a final shape of the feature; computing a difference between the determined position of the at least one target point and a nominal position of the at least one target point on a digitized model of the part having the semi-finished shape of the feature; as a function of the difference, determining a correction to a position of the cutting tool on a nominal tool path to achieve the final shape of the feature from the semi-finished shape, and using the correction to define a corrected tool path; and machining the finished shape of the feature with the cutting tool by moving the cutting tool along the corrected tool path. 
     The method may also include one or more of the following features/steps, in whole or in part, and in any combination. 
     In some embodiments, the determining of the correction includes determining the correction from a compensation table listing correction values to apply to the position of the cutting tool associated with difference values between actual and nominal positions of the at least one target point. 
     In some embodiments, for each of the at least one target point, the method comprises generating the compensation table by: determining a vector normal to the surface of the semi-finished shape of the feature at the at least one target point from the digitized model of the part having the semi-finished shape of the feature; and for each of the difference values taken along the vector normal to the surface, determining the correction values as a function of a projection of the vector onto each directions of movement of the cutting tool. 
     In some embodiments, the determining of the correction includes determining the correction by interpolation from the compensation table. 
     In some embodiments, the determining of the actual position of the at least one target point includes determining the actual position of the at least one target point with a probe. 
     In some embodiments, the probe is substituted for the cutting tool in a tool holder of a cutting machine. 
     In some embodiments, the feature is a groove in a member of a spline connection, the machining of the semi-finished of the feature includes moving the cutting tool in a radial direction relative to a longitudinal axis of the member of the spline connection. 
     In some embodiments, the determining of the correction of the position of the cutting tool includes determining the correction of a movement of the cutting tool along the radial direction as a function of the difference between the determined position of the at least one target point and the nominal position of the at least one target point. 
     In some embodiments, the determining of the correction includes determining the correction as a function of a distance between the determined position of the at least one target point and the nominal position of the at least one target point along a vector normal to the surface of the semi-finished shape at the at least one target point and as a function of an angle between the vector and the radial direction. 
     In some embodiments, the machining of the finished shape includes moving the cutting tool in the radial direction along a corrected depth in the stock material, the corrected depth corresponding to a nominal depth corrected by the correction. 
     In another aspect, there is provided a cutting machine comprising: a tool holder holding a cutting tool; and a controller having a processing unit and a computer readable medium having instructions stored thereon executable by the processing unit for: machining a semi-finished shape of a feature in a stock material of a part by moving the cutting tool relative to the stock material; determining an actual position of at least one target point on a surface of the semi-finished shape of the feature, the surface to be machined to achieve a final shape of the feature; computing a difference between the determined position of the at least one target point and a nominal position of the at least one target point on a digitized model of the part having the semi-finished shape of the feature; as a function of the difference, determining a correction to a position of the cutting tool on a nominal tool path to achieve the final shape of the feature from the semi-finished shape, and using the correction to define a corrected tool path; and machining the finished shape of the feature with the cutting tool by moving the cutting tool along the corrected tool path. 
     The cutting machine may also include one or more of the following features, in whole or in part, and in any combination. 
     In some embodiments, the determining of the correction includes determining the correction from a compensation table listing correction values to apply to the position of the cutting tool associated with difference values between actual and nominal positions of the at least one target point. 
     In some embodiments, for each of the at least one target point, the compensation table is generated by: determining a vector normal to the surface of the semi-finished shape of the feature at the at least one target point from the digitized model of the part having the semi-finished shape of the feature; and for each of the difference values taken along the vector normal to the surface, determining the correction values as a function of a projection of the vector onto each directions of movement of the cutting tool. 
     In some embodiments, the determining of the correction includes determining the correction by interpolation from the compensation table. 
     In some embodiments, the determining of the actual position of the at least one target point includes determining the actual position of the at least one target point with a probe. 
     In some embodiments, the probe is substituted for the cutting tool in a tool holder of the cutting machine. 
     In some embodiments, the feature is a groove in a member of a spline connection, the machining of the semi-finished of the feature includes moving the cutting tool in a radial direction relative to a central axis of the member of the spline connection. 
     In some embodiments, the determining of the correction of the position of the cutting tool includes determining the correction of a movement of the cutting tool along the radial direction as a function of the difference between the determined position of the at least one target point and the nominal position of the at least one target point. 
     In some embodiments, the determining of the correction includes determining the correction as a function of a distance between the determined position of the at least one target point and the nominal position of the at least one target point along a vector normal to the surface of the semi-finished shape at the at least one target point and as a function of an angle between the vector and the radial direction. 
     In some embodiments, the machining of the finished shape includes moving the cutting tool in the radial direction along a corrected depth in the stock material, the corrected depth corresponding to a nominal depth corrected by the correction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference is now made to the accompanying figures in which: 
         FIG.  1    is a schematic cross-sectional view of an aircraft engine depicted as a gas turbine engine in accordance with one embodiment; 
         FIG.  2    is a schematic representation of a cutting machine; 
         FIG.  3    is a flow chart illustrating steps of a method of manufacturing a feature in a part of the aircraft engine of  FIG.  1    to be executed by the cutting machine of  FIG.  2   ; 
         FIG.  4    is a schematic view illustrating the part with a cutting tool movable along a tool path to manufacture the feature and illustrating semi-finished and finished shapes of the feature; 
         FIG.  5    is an enlarged view of a portion of  FIG.  4   ; 
         FIG.  6    is a three dimensional view of a spline connection in accordance with one embodiment to be used to connect two components of the aircraft engine of  FIG.  1   ; 
         FIG.  7    is a cross-sectional view of a male member of the spline connection of  FIG.  6    with a cutting tool used to manufacture grooves in the male member; and 
         FIG.  8    is a cross-sectional view of a portion of the male member illustrating semi-finished and finished shapes of an outer groove of the male member of the spline connection. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    illustrates an aircraft engine depicted as a gas turbine engine  10  of a type preferably provided for use in subsonic flight, generally comprising in serial flow communication a fan  12  through which ambient air is propelled, a compressor section  14  for pressurizing the air, a combustor  16  in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases, and a turbine section  18  for extracting energy from the combustion gases. The fan  12 , the compressor section  14 , and the turbine section  18  are rotatable about a central axis  11  of the gas turbine engine  10 . 
     In the embodiment shown, the gas turbine engine  10  comprises a high-pressure spool having a high-pressure shaft  20  drivingly engaging a high-pressure turbine  18 A of the turbine section  18  to a high-pressure compressor  14 A of the compressor section  14 , and a low-pressure spool having a low-pressure shaft  21  drivingly engaging a low-pressure turbine  18 B of the turbine section to a low-pressure compressor  14 B of the compressor section  14  and drivingly engaged to the fan  12 . It will be understood that the contents of the present disclosure may be applicable to any suitable engines, such as turboprops and turboshafts, and reciprocating engines, such as piston and rotary engines without departing from the scope of the present disclosure. In the embodiment shown, an accessory  22 , which may be a generator, is drivingly engaged to the low-pressure shaft  21  via a gearbox  30 . 
     Different parts of the gas turbine engine  10  may be manufactured following a machining process. However, some shapes may be complicated to machine. The machining precision of specific form, such as spline profile, gear shaping may be challenging. In some cases, manufacturing tolerances, offset between the actual and expected positions of a cutting tool, and so on may create discrepancies between the desired shape of the part and the actual shape of the part obtained after machining. Because of the complexity of the calculation, there may be no direct calculation of profile characteristics using probing devices inside the manufacturing center while the part is clamped. The measurement data may need to be processed externally to compute these characteristics. This may be time consuming. The precision of the obtained surface after machining using the cutting tool may be affected by two major sources. First, the cutter shape form defect. This may be improved using cutter grinder or cutter production process to have cutter with acceptable shape. Second, is the cutter position. This related to the process such as setup and tool positioning. This can be corrected during the process by adjusting the position of the cutter relative to the part. 
     Referring now to  FIG.  2   , a cutting machine is shown at  100 . The cutting machine  100  includes a controller  200  for controlling movements of a cutting tool C held by a tool holder  102  of the cutting machine  100 . The tool holder  102  is also operable to hold a probe R for probing a surface being machined by the cutting tool C as will be explained further below. The controller  200  comprises a processing unit  202  and a memory  204  which has stored therein computer-executable instructions  206 . 
     Referring now to  FIGS.  3 - 4   , a method of manufacturing a feature F in a part B of the gas turbine engine  10  with the cutting machine  100  equipped with the cutting tool C is shown generally at  300 . The feature F may be any shapes such as, for instance, an airfoil profile, the teeth/grooves of the spline coupling, and so on. The processing unit  202  of the controller  200  may comprise any suitable devices configured to implement the method  300  such that instructions  206 , when executed by the controller  200  or other programmable apparatus, may cause the functions/acts/steps performed as part of the method  300  as described herein to be executed. 
     The method  300  comprises machining a semi-finished shape of the feature F in a stock material of the part B by moving the cutting tool C relative to the stock material at  302 . This step of machining the semi-finished shape may comprise machining a shape that is similar to the finished shape, but that is offset from the finished shape. For instance, in the embodiment shown, this may be done by performing a first pass with the cutting tool C following a first tool path T 0  at a first depth that is less than a final depth to be achieved to obtain the finished shape of the feature. The expression “depth” refers herein to a thickness of material being removed by the cutting tool C. In  FIG.  4   , the cutting tool C may be programmed to remove a given thickness of material along the first tool path T 0  to create a surface S 1  that defines a semi-finished shape of the feature F. In the context of the present disclosure, the expression “finished” in finished shape does not necessarily imply that no more manufacturing is carried on the part P. For instance, the finished shape may still undergo further processing such as, for instance, surface treatment, polishing, coating and so non. The expression “finished” denotes that the manufacturing step using the cutting tool C may be completed. But, subsequent steps using another cutting tool may follow. 
     As shown in  FIG.  4   , differences are present between the surface S 1  of the semi-finished shape of the feature and an expected or nominal surface S 0  of the semi-finished shape of the feature. This nominal surface S 0  represents the shape of the surface that was supposed to be obtained and as planned using a digitized simulation of the first pass of the cutting tool C along the first tool path T 0 . These differences may be caused by the position of the cutting tool C being different than expected, movements of the cutting tool C being offset from what was originally planed, manufacturing tolerances of the cutting tool, wear and tear on cutting edges of the cutting tool, and so on. Data about the nominal surface S 0  may be obtained from a digitized model of the part B having the semi-finished shape of the feature F. 
     The method  300  may then comprise determining an actual position of at least one target point, three target points P 1 , P 2 , P 3  in the embodiment shown, but more or less may be used, on the actual surface S 1  of the semi-finished shape of the feature F that was machined by the cutting tool C along the first tool path T 0  at  304 . The actual surface S 1  that defines the target points P 1 , P 2 , P 3  is to be further machined by the cutting tool C to achieve the finished shape of the feature F, which is denoted in  FIG.  3    by the finished surface S 2 . 
     The method  300  includes computing differences between the determined positions of the target points P 1 , P 2 , P 3  and nominal positions of nominal target points P 01 , P 02 , P 03  on the digitized model of the part B having the semi-finished shape of the feature F at  306 . The nominal target points P 01 , P 02 , P 03  corresponds to the target points on the digitized model. These differences may correspond to distances along vectors V 1 , V 2 , V 3  being normal to the actual surface S 1  of the semi-finished shape of the feature and at the target points P 1 , P 2 , P 3 . These vectors V 1 , V 2 , V 3  may extend from the target points P 1 , P 2 , P 3  on the actual surface S 1  of the semi-finished shape of the feature F to the nominal target points P 01 , P 02 , P 03  on the nominal surface S 0  of the semi-finished shape of the feature from the digitized model. 
     The method  300  then includes, as a function of the differences, determining corrections to positions of the cutting tool C on a nominal tool path to achieve the final shape of the feature F from the semi-finished shape, and using the corrections to define a corrected tool path for the cutting tool C at  308 . For instance, the nominal tool path may require the cutting tool C to remove material from the stock material of the part B up to a certain nominal depth for each of the target points P 1 , P 2 , P 3 . However, maybe too much or too little material was removed by the first pass of the cutting tool C along the first tool path T 0 . This implies that locations where too much material was removed, the cutting tool C needs to remove less material, and where too little material was removed, the cutting tool C needs to remove more material to obtain the final shape of the feature F. The corrected tool path therefore includes data about movements of the cutting tool C to follow to machine the surface S 1  of the semi-finished feature F to obtain the finished surface S 2  of the feature. 
     At which point, the method  300  includes machining the final shape of the feature F with the cutting tool C by moving the cutting tool C along the corrected tool path at  310 . The cutting tool C may be moved along the corrected tool path to remove corrected amount of material from the stock material of the part B. For instance, too much material was removed at a first target point P 1  of the target points P 1 , P 2 , P 3  since the position of the first target point P 1  is closer to the finished surface S 2  of the finished shape of the feature F than a first nominal target point P 01  of the nominal target points P 01 , P 02 , P 03 . The corrected tool path may therefore require the cutting tool C to be inserted in the stock material at a corrected depth that may be less than a nominal depth. 
     For better understanding, we assume that the cutting tool C is movable along axes X and Y. The corrected tool path includes a corrected movement of the cutting tool C to remove less material as was originally planed at, for instance, a second target point P 2  of the target points P 1 , P 2 , P 3 . This correction therefore includes both a correction along the X axis and a correction along the Y axis. 
     In the embodiment shown, the determining of the corrections at  308  may include determining the correction from a compensation table that lists correction values to apply to the position of the cutting tool associated with difference values between the actual and nominal positions of the target points P 1 , P 2 , P 3 , P 01 , P 02 , P 03 . An example of the compensation table is shown below. It will be appreciated that the compensation table may instead be a compensation graph. 
     
       
         
           
               
               
               
             
               
                   
               
               
                 Differences  
                 Correction of  
                   
               
               
                 between 
                 the cutting 
                 Correction  
               
               
                 actual and  
                 tool along  
                 of the cutting 
               
               
                 nominal 
                 the X 
                 tool along the  
               
               
                 positions 
                 axis (ΔX) 
                 Y axis (ΔY) 
               
               
                   
               
             
            
               
                 −0.0020 
                 0.0019 
                 0.0017 
               
               
                 −0.0018 
                 0.0017 
                 0.0016 
               
               
                 . . . 
                 . . . 
                 . . . 
               
               
                   
               
            
           
         
       
     
     It will be appreciated that a similar table is stored for each of the target points P 1 , P 2 , P 3 . Moreover, the compensation table may further have a correction along a third axis normal to both of the X and Y axes when the cutting tool C moves in three dimensions. 
     The compensation table is used by the cutting machine  100  ( FIG.  2   ), and may be stored on the memory  204 , to correlate movements of the cutting tool C along the X and Y axes with depth variations of the cutting tool C inside the stock material of the part B; the depth variations being taken along the vectors V 1 , V 2 , V 3 . For example, if the second target point P 2  is spaced apart from the second nominal target point P 02  along the second vector V 2  by  1  mm, it implies that the movement of the cutting tool C along the nominal tool path has to corrected by AX and AY along the X and Y axes to obtain the proper depth on the finished shape of the feature F denoted by the surface S 2  on  FIG.  4   . The compensation table is therefore used because the movements of the cutting tool C are required in both the X and Y axes to remove material from the stock material of the part B along the second vector V 2 . 
     Referring now to  FIG.  5   , an enlarged view of the first actual and nominal target points P 1 , P 01  is presented. A compensation table may be generated for each of the target points P 1 , P 2 , P 3 . The compensation table may be generated using the digitized model of the part having the semi-finished shape of the feature F. For each of the target points P 1 , P 2 , P 3 , the vectors V 1 , V 2 , V 3  normal to the surface S 1  of the semi-finished shape of the feature F at the target points P 1 , P 2  P 3  is determined. Then, a range of acceptable values of differences between the nominal target points P 01 , P 02 , P 03  and the actual target points P 1 , P 2 , P 3  is discretized in a given number of intervals. For instance, if a difference from −0.002 mm to +0.002 mm is acceptable, this range may be divided in twenty values (e.g., −0.0020, −0.0018, −0.0016, . . . , +0.0018, +0.0020). If the differences is outside this range, this may be indicative of another manufacturing problem requiring further investigation. For instance, this may be indicative of the cutting tool C being broken, dull, etc. A signal may then be sent by the controller  200  to a user of the cutting machine  100  to notify the user of the problem. 
     For each of these difference values, correction values are determined as a function of a projection of the vectors V 1 , V 2 , V 3  onto each possible of directions of movements of the cutting tool C. For instance, the correction of the cutting tool C along the X axis, ΔX, is calculated by projecting the vectors V 1 , V 2 , V 3  on the X axis, and the correction of the cutting tool C along the Y axis, ΔY, is calculated by projecting the vectors V 1 , V 2 , V 3  on the Y axis. In the embodiment shown, the correction along the X axis, ΔX, may be done by multiplying the distances along the vectors V 1 , V 2 , V 3  between the actual and nominal target points P 1 , P 2 , P 3 , P 01 , P 02 , P 03  by the cosine of a first angle Al between the vectors V 1 , V 2 , V 3  and the X axis. The correction along the Y axis, ΔY, may be done by multiplying the distances along the vectors V 1 , V 2 , V 3  between the actual and nominal target points P 1 , P 2 , P 3 , P 01 , P 02 , P 03  by the cosine of a second angle A 2  between the vectors V 1 , V 2 , V 3  and the Y axis. This is done for each of the possible difference values of the intervals. Hence, the compensation table contains data about what corrections to apply to the cutting tool C along both of the X and Y axes as a function of the offset from the nominal and actual target points to obtain the final shape, denoted by the surface S 2  on  FIG.  4   , of the desired feature F. 
     Referring now to  FIGS.  2 - 5   , during the machining process, the cutting machine  100  moves the cutting tool C along the first tool path T 0  ( FIG.  4   ) to machine the semi-finished shape of the feature F; the semi-finished shape being denoted by the surface S 1  on  FIG.  3   . At which point, the cutting machine  100  may release the cutting tool T, which is held in its tool holder  102 , and grab a probe R with the tool holder  102 . The probe R may therefore be moved along the surface S 1  to probe each of the actual target points P 1 , P 2 , P 3  on the surface S 1 . At which point, data about the positions (e.g., along the X and Y axes) of the actual target points P 1 , P 2 , P 3  is stored by the controller  200  of the cutting machine  100 . The controller  200 , which may contain data about the positions (e.g., along the X and Y axis) of the nominal target points P 01 , P 02 , P 03 , computes differences between the positions of the nominal and actual target points P 01 , P 02 , P 03 , P 1 , P 2 , P 3 . For each of these computed differences, the controller  200  determines corrections values to apply to the nominal tool path of the cutting tool C to obtain the corrected tool path. These corrections may be determined by reading the compensation tables of each of the target points P 1 , P 2 , P 3  and that may be stored in the controller  200 . The cutting machine  100  may then release the probe R and grab the cutting tool C and move the cutting tool C along the corrected tool path to machine the finished shape of the feature, which is denoted by surface S 2  on  FIG.  4   . If the actual distances are not listed in the compensation tables, the corrections may be computed by interpolating (e.g., linear interpolation, polynomial interpolation, etc) the data listed in the compensation table. 
     EXAMPLE 
     Splines 
     Referring back to  FIG.  1   , each of the low-pressure compressor  14 B, the high-pressure compressor  14 A, the low-pressure turbine  18 B, and the high-pressure turbine  18 A may be drivingly engaged to a corresponding one of the low-pressure shaft  21  and high-pressure shaft  20  using a spline connection. Also, a similar spline connection may be defined between the low-pressure shaft  21  and the gearbox  30  and/or between the gearbox  30  and the accessory  22 . 
     Referring now to  FIG.  6   , an exemplary spline connection is shown at  40 . The spline connection  40  includes a male member  41  and a female member  42 . The male member  41  includes a plurality of outer teeth  43  and outer grooves  44  whereas the female member  42  includes plurality of inner teeth  45  and inner grooves  46 . Each of those teeth and grooves extend longitudinally along a longitudinal axis L of the spline connection  40 . The male member  41  is slidably received inside the female member  42  until each of the outer teeth  43  is received within a respective one of the inner grooves  46  and until each of the inner teeth  45  is received within a respective one of the outer grooves  44 . 
     Referring now to  FIG.  7   , the outer teeth  43  and the outer grooves  44  may be machined with a cutting tool  50  having a shape corresponding to a negative of the outer grooves  44 . For each of the outer grooves  44 , the cutting tool  50  may be moved in relationship to the male member  41  along a direction D 1 , which may be substantially radial relative to a longitudinal axis L of the male member  41 . The outer teeth  43  and the outer grooves  44  may be machined one after the other; the male member  41  being rotated about the longitudinal axis L to machine each subsequent ones of the outer grooves  44 . 
     The machining process described above with reference to  FIGS.  2 - 5    is further described for the machining of features corresponding to the outer grooves  44  of the male member  41  of the spline connection  40 . This process may be adapted to the inner grooves  46  of the female member  42 . 
     Referring more particularly to  FIG.  8   , in the present case, the cutting tool  50  is movable solely in the direction D 1 . A semi-finished shape of the outer groove  44  is machined in a stock material of the male member  41  by moving the cutting tool  50  in the direction D 1  relative to the stock material. This creates the surface SS 1  of the semi-finished shape of the outer groove  44 . Then, the actual positions of the target points P 11 , P 12 , P 13 , P 14  on the surface SS 1  is determined. This may be done by probing the surface SS 1  as explained above. Although four target points are used in this example, any suitable number of target points may be used. For instance, one, two, three, five, etc target points may be used. The differences between the actual positions of the target points P 11 , P 12 , P 13 , P 14  and the nominal positions of the target points are determined. As explained above, the nominal positions is determined from a digitized model of the male member  41  of the spline connection  40  having the semi-finished shape of the outer groove  44 . At which point, the correction to the position of the cutting tool  50  on a nominal tool path to achieve the final shape of the outer groove  44 , which is denoted by the surface SS 2 , is determined to obtain a corrected tool path. Then, the finished shape of the outer groove  44  may be machined using the cutting tool  50  moved along the corrected tool path. 
     As previously explained, the determining of the corrections may include reading the compensation tables for each of the target points P 11 , P 12 , P 13 , P 14 . For a first target point P 11  of the target points P 11 , P 12 , P 13 , P 14 , the compensation table may include data correlating values of distances between the nominal and actual target points P 011 , P 11  along a vector V 11  normal to the surface SS 1  and at the first target point P 11  and corrections to apply to the cutting tool  50  along the direction D 1 . In other words, because the vector V 11  is not parallel to the direction D 1  of the cutting tool  50 , movements of the cutting tool  50  along the direction D 1  to achieve the desired final shape of the outer groove  44  is affected by the angle between the vector V 11  and the direction D 1 . For example, if the angle between the vector V 11  and the direction D 1  of the cutting tool is 45 degrees and if the distance between the nominal and actual positions of the first target point P 11  is 1 mm, the movement of the cutting tool  50  along the direction D 1  needs to be altered by 1 mm×cos(45 degrees). The compensation table stores corrections to apply for a plurality of possible distances between nominal and actual positions of the target points. If the actual distance is not listed in the compensation table, the correction may be computed by interpolation (e.g., linear interpolation, polynomial interpolation, etc). 
     In other words, after the machining of the semi-finished shape of the outer groove  44 , which is defined by the surface SS 1 , the position of at least one target point P 11  is determined. The offset between the actual position of the at least one target point P 11  and the expected or nominal position of the at least one nominal target point P 011  is computed. As explained above, this offset may be caused by many factors such as a different position of a cutting edge of the cutting tool  50  than expected. In  FIG.  8   , the actual position of the at least one target point P 11  is deeper in the stock material than the nominal position of the at least one nominal target point P 011 . This implies that the cutting tool  50  was penetrated in the stock material deeper than originally planned. This increased in depth is therefore subtracted from the nominal tool path to obtain the corrected tool path. Hence, when machining the finished shape of the outer groove  44 , which defines the finished surface SS 2 , the cutting tool  50  is inserted in the stock material at a corrected depth that is less than a nominal depth to account for the excessive machine depth when machining the semi-finished shape. 
     The disclosed method  300  may allow the control of shaping process by probing a set of discrete points and compare them to a predefined compensation table to read the correction of the cutter position relative to the part in order the cancel the deviation of the profile in the finishing cut. This may allow a control of process without complicated measuring methods and calculation. This method  300  may be carried as a process control in closed door mode. The method  300  may: enable to control the cutting process in closed door mode using in-process measurement; enable to increase quality and productivity; enable producing complex shape using pre-computed data and measurement; enable to simplify in-process quality control for these type of machining; enable to correct the process without complex calculation; and improve process capability. 
     Controller 
     The processing unit  202  may comprise, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof. The data about the positions of the nominal target points P 01 , P 02 , P 03 , the compensation tables, the positions of the actual target points P 1 , P 2 , P 3  may be stored in the memory  204  of the controller  200 . 
     The memory  204  may comprise any suitable known or other machine-readable storage medium. The memory  204  may comprise non-transitory computer readable storage medium, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. The memory  204  may include a suitable combination of any type of computer memory that is located either internally or externally to device, for example random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like. Memory  204  may comprise any storage means (e.g., devices) suitable for retrievably storing machine-readable instructions  206  executable by processing unit  202 . 
     The methods and systems for machining a feature described herein may be implemented in a high level procedural or object oriented programming or scripting language, or a combination thereof, to communicate with or assist in the operation of a computer system, for example the controller  200 . Alternatively, the methods and systems for machining a feature may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the methods and systems for machining a feature may be stored on a storage media or a device, for example a ROM, a magnetic disk, an optical disc, a flash drive, or any other suitable storage media or device. The program code may be readable by a general or special-purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein. Embodiments of the methods and systems for machining a feature may also be considered to be implemented by way of a non-transitory computer-readable storage medium having a computer program stored thereon. The computer program may comprise computer-readable instructions which cause a computer, or more specifically the processing unit  202  of the controller  200 , to operate in a specific and predefined manner to perform the functions described herein, for example those described in the method  400 . 
     Computer-executable instructions may be in many forms, including program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Typically the functionality of the program modules may be combined or distributed as desired in various embodiments. 
     The embodiments described herein are implemented by physical computer hardware, including computing devices, servers, receivers, transmitters, processors, memory, displays, and networks. The embodiments described herein provide useful physical machines and particularly configured computer hardware arrangements. The embodiments described herein are directed to electronic machines and methods implemented by electronic machines adapted for processing and transforming electromagnetic signals which represent various types of information. The embodiments described herein pervasively and integrally relate to machines, and their uses; and the embodiments described herein have no meaning or practical applicability outside their use with computer hardware, machines, and various hardware components. Substituting the physical hardware particularly configured to implement various acts for non-physical hardware, using mental steps for example, may substantially affect the way the embodiments work. Such computer hardware limitations are clearly essential elements of the embodiments described herein, and they cannot be omitted or substituted for mental means without having a material effect on the operation and structure of the embodiments described herein. The computer hardware is essential to implement the various embodiments described herein and is not merely used to perform steps expeditiously and in an efficient manner. 
     The term “connected” or “coupled to” may include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). 
     The technical solution of embodiments may be in the form of a software product. The software product may be stored in a non-volatile or non-transitory storage medium, which can be a compact disk read-only memory (CD-ROM), a USB flash disk, or a removable hard disk. The software product includes a number of instructions that enable a computer device (personal computer, server, or network device) to execute the methods provided by the embodiments. 
     The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology. Yet further modifications could be implemented by a person of ordinary skill in the art in view of the present disclosure, which modifications would be within the scope of the present technology.