Figure 8.1 212
The chapter describes the facilities provided for the regional milling of a sculptured surface. The primary means of tool control is a space curve. Since a sculptured surface contains an infinite number of space curves, a surface is used to represent the large family of consecutive paths required in a regional milling process. In general, this tool path control surface is a different surface from the surface being machined. In the special case, where the tool path is to be developed using the natural flow lines of a mesh structured sculptured surface, then the surface being machined can also be used as the tool path control surface. This approach gives the programmer considerable control over the choice of tool path when carrying out regional milling. Multi-axis control is available during regional milling but only a 'spherical' cutter is currently implemented.
The basic regional milling algorithm addresses the tool to surface relationship in the following manner, 'Given a tool with its end at TE, its axis at a vector TA and a direction of projection TD, calculate the distance the tool must move in the direction TD in order to contact the surface S.' This is illustrated in Figure 8.1. 213
Figure 8.2 Figure 8.3 214
The user must understand the difference between the tool axis vector, TA and the tool projection vector, TD, in order to use the regional milling facilities successfully. In the conventional Arelem, the tool is constrained to be in contact with three surfaces, part, drive and check surfaces, but the tool axis orientation can be defined independent of these surfaces, similarly in regional milling, the tool is constrained to be in contact with the part surface, its position being defined by a control point and tool projection vector, but the tool axis orientation may be defined independently. There are two ways in which the tool to surface contact can be controlled by a point and tool projection vector, 'ON' and 'AT'. If 'ON' is specified the tool end is constrained to lie on the line generated by the current control point and tool projection vector, with the tool envelope touching the surface and the tool axis at the prescribed orientation. Figure 8.2 illustrates this type of tool drive control. If 'AT' is specified then the tool is positioned so that the tool envelope contacts the surface at the point where the tool projection vector from the control point pierces the surface, with the tool axis at the prescribed orientation, as shown in Figure 8.3. 215
Figure 8.4 216
The concept of tool control by a point and tool projection vector described in the previous section can be extended to give tool path control by using a synthetic curve to represent a continuous path of space points and vectors. Figure 8.4 shows an 'ON' type tool path, where the drive control curve, DC1 was defined in the following manner, P1 = POINT/12,-40,30 P2 = POINT/20,-28,30 P3 = POINT/40,-20,30 P4 = POINT/68,-40,30 C1 = SCURV/CURSEG,P1,P2,P3 C2 = SCURV/CURSEG,P3,P4 DC1 = SCURV/COMBIN,C1,C2 and the tool projection vector was an explicitly defined vector, TPV = VECTOR/0,0,-1 and the tool axis orientation was defined by the vector, TA = VECTOR/0,0,1 Note, that the drive curve can have slope discontinuity at an arc junction, such as shown at node 1 of this example. 217
Figure 8.5 Figure 8.6 218
The continuous sheet of cross vectors which can be attached to a synthetic curve, by applying CRSSPL constraints at each arc junction, (see Chapter 2, Section 2.2.2 of this Volume) can be used as tool projection vectors and/or for tool axis control. For example, if we apply, CRSSPL constraints to C1 and C2 in our previous example, in the following manner, TPV0 = VECTOR/0.3,-0.3,-0.8 TPV1 = VECTOR/0,-0.2,-0.8 TPV2 = VECTOR/-0.1,-0.1,-0.8 C1 = SCURV/CURSEG,P1,CRSSPL,TPV0,P2,P3,CRSSPL,TPV1 C2 = SCURV/CURSEG,P3,CRSSPL,TPV1,P4,CRSSPL,TPV2 Then Figure 8.5 shows the tool path generated if the resultant sheet of cross vectors is used to define the tool projection vectors, whilst maintaining the fixed tool axis vector, TA. Whereas, Figure 8.6 shows the resultant tool path and tool orientations, if the cross vectors are used to give variable tool axis control and the tool projection vector is kept fixed. The synthetic curve used for drive control can either be explicitly defined as in these examples or can be implicitly defined as a TANSPL or CRSSPL curve of a sculptured surface with a mesh structure. In which case, the surface normal vectors may be used for tool axis and tool projection vector control. Mesh structured sculptured surfaces include those defined by SMESH, GENCUR, REVOLV, RULED and 'cross product' formats. The use of a synthetic curve as the drive control, means that no check surface is required, because the drive geometry is naturally bounded. However, the user can limit the paths by parametric values. Refer to Chapters 2 and 3 of this Volume for details of the parametric structure of curves, and Chapters 4, 5 and 6 for the parametric structure of sculptured surfaces. 219
Figure 8.7 220
A major requirement when machining sculptured surfaces is the ability to automatically generate the cutter path needed to mill a bounded region on a surface. This is done by extending the idea of tool path control by a synthetic curve and using the infinite family of curves available in a sculptured surface for drive control. In general the surface used for drive control is not the same as the surface being machined and must be a mesh structured surface. The tool path produced can be controlled by either the TANSPL or CRSSPL curves of the drive surface and can either zigzag back and forth across the surface or be unidirectional. The tool projection vectors can be either in a fixed direction or controlled by the surface normal of the drive surface, likewise the tool axis orientation. The step over from one drive curve to the next can be either calculated automatically based on cusp height requirements or be a fixed parametric step across the drive surface. Control of feedrates and tool positioning between passes is also provided. Figure 8.7 shows a zigzag tool path on a sculptured surface, where the drive surface was a rectangular planar surface with the stepover controlled by cusp height requirements.
When programming regional milling the user is able to control a single tool position, a continuous tool path or the automated clearance of a region. This flexibility means that if the automated regional milling does not satisfy the users requirements he can generate his own type of control by using the explicit lower level commands that are available. There are two types of command associated with regional milling, the first identified by the major word SCON specify the control surfaces and regional milling conditions and the second identified by the major word SMIL provide tool position and path control, generating cutter location data. These are described in detail in Sections 8.6 and 8.7. In addition, the general APT commands CUTTER, INTOL, OUTTOL, MAXDP and NUMPTS are utilized during the regional milling of sculptured surfaces. Their effect is described in Section 8.5. 221
The data and commands associated with regional milling fall into five basic groups. . Definition of surface(s) to be machined. . Definition of drive control parameters, i.e. drive control surface, tool axis vector, tool projection vector, clearance plane etc. . Specification of cutter, tolerances and limits. . Specification of the surfaces and conditions that pertain to the current regional milling operation. (SCON commands) . Selection of regional milling command(s) to generate tool path. (SMIL command) To illustrate this, the program used to produce the tool path shown in Figure 8.7 will be developed. The complete program is given in Section 8.4.2. The intention of the program is to machine a rectangular area on the sculptured surface using a zigzag path with the major direction parallel to the x axis and the stepover in the y direction to be controlled by restricting the cusp height to 0.5 mm. In this example it is assumed that the part is being machined on a three axis machine, therefore the tool axis will be fixed and parallel to the positive z axis. 222
The first step therefore is to define the sculptured surface that is to be machined, in this case the SMESH surface, PS0 defined below. P1 = POINT/0,0,20 P2 = POINT/30,-5,26.5 P3 = POINT/60,-5,26 P4 = POINT/86,0,20 P5 = POINT/-6,-30,15 P6 = POINT/28,-25,22.75 P7 = POINT/66,-25,22.5 P8 = POINT/100,-30,15 P9 = POINT/-12,-60,0 P10 = POINT/22,-55,8.75 P11 = POINT/70,-55,9.5 P12 = POINT/114,-60,0 PS0 = SSURF/SMESH,XYZ,SPLINE,P1,P2,P3,P4, $ SPLINE,P5,P6,P7,P8, $ SPLINE,P9,P10,P11,P12 The next step is to define the drive control parameters. Since the region to be machined is rectangular it cannot be defined with respect to the parametric lines lying within the surface itself, therefore a separate drive control surface is required. In this case a plane rectangular surface above the surface to be machined, parallel to the XY plane should give the required boundary and tool path control. Such a surface can be defined by taking a TRANSL type cross product of two straight lines. If the corners of the required rectangle are (30,-15,z), (70,-15,z), (30,-45,z), and (70,-45,z), then the following statements will define a suitable plane rectangular surface to be used for drive control. R1 = POINT/30,-15,50 R2 = POINT/70,-15,50 R3 = POINT/0,0,0 R4 = POINT/0,-30,0 C1 = SCURV/CURSEG,R1,R2 C2 = SCURV/CURSEG,R3,R4 DS1 = SSURF/TRANSL,C1,CROSS,C2 This surface provides an infinite number of drive curves parallel to the x axis with normal vectors parallel to the negative z axis which can be used for tool projection. 223
The tool axis vector, parallel to the positive z axis since the part is to be machined on a three axis machine, is defined explicitly, namely, TA = VECTOR/0,0,1 Note, even though no tool axis vector components are to be output on the cutter location file, a tool axis vector must be specified, otherwise an error will occur. The third step is to define the cutter, tolerances and limits to be used by the regional milling algorithms. If undefined then the standard defaults are used. Note that only a ball ended or point cutter can be accepted and that the cutter is treated as a complete sphere. For this example a 10 mm diameter ball ended cutter is used and the default values for INTOL, OUTTOL, NUMPTS and MAXDP are taken as acceptable, therefore the only statement required here, is CUTTER/10,5 If required, any conventional APT commands may be programmed to move the cutter from its initial position to a suitable position from which to approach the area to be machined, including appropriate post processor commands. The next step is to specify which surfaces and conditions apply to the following regional milling command. This is done by the SCON command which is described in Section 8.6. It is important to note that for each type of regional milling command certain groups of conditions and parameters must be defined. A table of these is given in Section 8.7.5. If a required group is omitted then error 3565 will occur and diagnostic information indicating which groups are defined and which are not will be output. See Section 8.8 for details. In addition to the SCON commands used for defining parameters etc., there is a special command for initializing the parameters and setting them in an undefined state. In order to be certain that for any regional milling command the required data has been specified, the command to initialize all the groups should be programmed first, namely. SCON/INIT,ALL Since it is intended to perform a zigzag type of regional milling over the area, it is necessary to specify the drive control parameters, the surface to be machined, the tool axis, stepover parameters and feedrate. 224
First the drive control should be ON type control, over the whole of the parametric extent of the plane rectangular surface, DS1. The tool projection vectors being normal to the drive control surface. This is defined by the following statement SCON/DS,DS1,PARAM,0,1,0,1,ON,NORMAL where DS indicates that SCON is defining the drive control parameters DS1 is the previously defined drive control surface PARAM indicates DS parametric limits follow. 0 lower ) ) extent of the u parameter 1 upper ) 0 lower ) ) extent of the v parameter 1 upper ) ON type of tool/surface contact required. See Section 8.1. NORMAL indicates that the surface normal at a point should be used as the tool projection vector. Next the surface to be machined is selected together with an indication of which side of the surface is to be cut and of any material that is to be left on for subsequent finish machining, in the following manner, SCON/PS,TO,PS0,MINUS,0 where PS indicates that SCON is defining the surface to be machined (part surface). TO indicates tool/surface relationship and has the same meaning as in conventional APT. PS0 is the previously defined sculptured surface that is to be machined. 225
MINUS indicates that the tool should be on the side of the surface opposite to the surface NORMAL (cross product of TANSPL and CRSSPL vectors). O indicates that for this case no material is to be left on, that is this is a final cut. The tool axis is defined as being fixed and in the direction of the vector TA by the SCON statement, SCON/AXIS,TA The stepover parameters needed to calculate the parametric step across the drive control surface and a lift off required between passes are specified next. For this example the requirement is for the maximum cusp height between adjacent passes to be 0.5 mm, in addition the physical stepover should not exceed 5 mm. and the tool may remain in contact with the surface between adjacent passes so no lift off is required. The SCON statement to set up these parameters is SCON/STEPOV,0.5,5,0,0 where 0.5 maximum cusp height 5 maximum physical stepover 0 lift off between passes 0 not used Finally, it is necessary to specify the feedrates which will be automatically transferred to the CLFILE as FEDRAT records during the automatic generation of the zigzag tool path, this is done as follows, SCON/FEED,100,200,50,3000 where 100 feedrate for passes in the major direction. 200 feedrate for side stepping between major passes. 50 feedrate for plunging into the material when this is required. 3000 feedrate for rapid withdrawal to and traverse across a clearance plane when required. 226
Note that the regional milling algorithm does not insert a feedrate record on the CLFILE before the first path as will be seen on the CLFILE listing in Section 8.4.4. It is therefore the responsibility of the programmer to ensure that the initial feedrate is suitable, by explicitly programming a FEDRAT command before the regional milling command. It may be advantageous to include an additional regional milling command to specify the initial move bringing the tool into contact with the job at an even lower feedrate. Having defined all the surfaces and conditions required for the regional milling operation, all that remains is to invoke the regional milling tool path generation by programming the SMIL command, thus, SMIL/ZIGZAG,DS,PARAM,0,0,TANSPL,PLUS,STEPOV,PLUS,0 where ZIGZAG indicates that a zigzag path across the surface is required. DS indicates that the surface specified in the preceding SCON/DS command is to be used for drive control. PARAM,0,0 u and v parameters of the start point on the drive surface, i.e., the zigzag path will start at the point (u=0,v=0). TANSPL indicates that the major passes are to be along TANSPL parametric curves. PLUS indicates that the first pass will be in the positive direction along the curve (i.e. from v=0 to u=1). STEPOV,PLUS indicates that the stepover direction should be in the positive, CRSSPL direction in this case, (i.e. from v=0 to v=1). O this scalar indicates that the first cut vector is required. 227
The following is the regional milling program which generated the tool path illustrated in Figure 8.7. ISN 1. PARTNO/'FIG8.7 REGIONAL TOOL CONTROL' 2. REMARK/'FIXED TOOL PROJECTION VECTOR' 3. REMARK/'TOOL AXIS CONTROLLED BY SURFACE NORMAL' 4. PRINT/SSPRT,OFF 5. UNITS/MM 6. CLPRNT 7. NOPOST 8. $$ 9. $$ DEFINE SCULPTURED SURFACE TO BE MACHINED (PART SURFACE) 10. $$ 11. P1=POINT/0,0,20 12. P2=POINT/30,-5,26.5 13. P3=POINT/60,-5,26 14. P4=POINT/86,0,20 15. P5=POINT/-6,-30,15 16. P6=POINT/28,-25,22.75 17. P7=POINT/66,-25,22.5 18. P8=POINT/100,-30,15 1z), and (70,-45,z), then the following statements will define a suitable plane rectangular surface to be used for drive cINE,P1,P2,P3,P4 $ 23. SPLINE,P5,P6,P7,P8, $ 23. SPLINE,P9,P10,P11,P12 24. $ 25. $$ DEFINE DRIVE CONTROL PARAMETERS 26. $$ 27. R1=POINT/30,-15,50 28. R2=POINT/70,-15,50 29. R3=POINT/0,0,0 30. R4=POINT/0,-30,0 31. C1=SCURV/CURSEG,R1,R2 32. C2=SCURV/CURSEG,R3,R4 33. DS1=SSURF/TRANSL,C1,CROSS,C2 $$ DRIVE CONTROL SURFACE 34. $$ 35. TA=VECTOR/0,0,1 $$ TOOL AXIS VECTOR 36. $$ 37. $$ CUTTER, TOLERANCES AND LIMITS 38. $$ 39. CUTTER/10,5 $$ 10 MM DIA. BALL ENDED CUTTER 40. $$ 41. FROM/(STPT=POINT/50,-60,50) 42. $$ 43. $$ SET REGIONAL MILLING CONDITIONS 44. $$ 228
45. SCON/INIT,ALL $$ INITIALIZE ALL CONDITIONS 46. SCON/DS,DS1,PARAM,0,1,0,1,ON,NORMAL $$ DRIVE CONTROL SPECIFICATION 47. SCON/PS,TO,PS0,MINUS,0 $$ PART SURFACE SELECTION 48. SCON/AXIS,TA $$ TOOL AXIS 49. SCON/STEPOV,0.5,5,0,0 $$ STEPOVER PARAMETERS 50. SCON/FEED,100,200,50,3000 $$ FEEDRATES 51. $$ 52. $$ GENERATE ZIGZAG TOOL PATH 53. $$ 54. SMIL/ZIGZAG,DS,PARAM,0,0,TANSPL,PLUS,STEPOV,PLUS,0 55. $$ 56. FINI
During the execution phase, informative data is printed on the verification listing for each SMIL command programmed. This consists of a record of the statement number of the SMIL command PATH = statement number followed by a summary of principal curvatures encountered during the generation of each path which is listed in tabular form under the following headings. NO path number. ERRNO A non-zero value indicates that an error has occurred during the generation of the current path. The value is the number which is added to 3550 to indicate the execution phase error number. See Section 8.8.4 for details. CLCT number of cutter location points generated for current path. PATH LEN. length of current path. RADIUS/SURF minimum principal radius of curvature where the tool side of the surface is concave. PATCH patch number ) of point on part surface U - SRF u parameter ) at which the above 229
V - SRF v parameter ) minimum occurred. U - DRV u parameter ) of associated drive control V - DRV v parameter ) surface point. RADIUS/SURF minimum principal radius of curvature where the tool side of the surface is convex PATCH patch number ) of point on part surface U - SRF u parameter ) at which the above V - SRF v parameter ) minimum occurred
The regional milling command, SMIL, operates like the POCKET command, and generates a POCKET header command on the CLFILE followed by one or more GOTO records defining the cutter locations and tool orientations (if required). FEDRAT records are automatically inserted between paths during regional clearance control, as shown in the following extract from the CLPRNT generated by the example program given in Section 8.4.2. 1 PARTNO FIG 8.7 REGIONAL TOOL CONTROL 5 UNITS/MM 39 CUTTER/ 10.0000, 5.0000 41 FROM / STPT ( 0) 41 X Y Z 50.0000000 -60.0000000 50.0000000 54 POCKET 54 GOTO 54 29.9999408 -15.0001049 25.2813358 32.9617996 -15.0001077 25.5262947 35.3968353 -15.0001087 25.7287387 40.0002441 -15.0001087 25.8567237 43.7345619 -15.0001077 25.9056396 47.5529518 -15.0001058 25.8720970 51.3971214 -15.0001029 25.7544670 55.2055816 -15.0000982 25.5532073 58.0020980 -15.0000114 25.3487453 60.7147293 -14.9999732 25.1007022 64.1570053 -15.0000877 24.7075939 67.0785446 -15.0000743 24.3260345 230
70.0000915 -15.0000686 23.9134235 54 FEDRAT/ 200.0000 54 GOTO 54 70.0004119 -17.4781227 23.6054039 70.0003051 -19.6447601 23.2782897 70.0003662 -20.7345848 23.0930557 54 FEDRAT/ 100.0000 54 GOTO 54 65.7345275 -20.7347278 23.6098308 62.2279968 -20.7346401 23.9676532 58.4820823 -20.7347431 24.2668819 54.5071678 -20.7347488 24.5004215 50.3947906 -20.7347526 24.6577339 46.2183952 -20.7347545 24.7328739 42.0598335 -20.7347564 24.7225208 37.9910316 -20.7347545 24.6263351 35.0479660 -20.7346839 24.4997100 32.5242156 -20.7340621 24.3496341 29.9999179 -20.7339820 24.1572742 54 FEDRAT/ 200.0000 54 GOTO 54 29.9997920 -23.1114540 23.5984230 29.9999504 -25.8220119 22.8930854 29.9999637 -26.6968173 22.6479644 54 FEDRAT/ 100.0000 54 GOTO 54 33.4448585 -26.6967735 22.8658714 37.4729843 -26.6967773 23.0388813 41.8025741 -26.6967773 23.1399250 46.3555526 -26.6967773 23.1608638 51.0141754 -26.6967754 23.0963783 55.6367301 -26.6967716 22.9457893 58.9883232 -26.6969947 22.7792015 62.1941757 -26.6970825 22.5701599 65.2242813 -26.6971015 22.3222560 67.6121292 -26.6968212 22.0885715 69.9985733 -26.6976222 21.8253040 Note that no FEDRAT record has been inserted before the first 231
path by SMIL. It is the responsibility of the programmer to ensure that a FEDRAT statement has been defined before the SMIL command otherwise the post processor will use its default value for feedrate if no value has been previously programmed.
The following APT commands are used during the regional milling of sculptured surfaces. If omitted the system default values for the parameters are used. CUTTER/d,r The APT cutter parameters are used during regional milling. However, at present, only point and ball ended cutters are acceptable and the cutter is treated as a complete sphere. An unacceptable cutter definition will result in error number 3566 - 'GENERAL APT ARELEM CONDITIONS FOR REGIONAL MILLING ARE INVALID (PROBABLY UNACCEPTABLE CUTTER TYPE)', when processing a SMIL command. INTOL/... The inner and outer tolerances are used for the part surface. If the drive control is OUTTOL/.. provided by a synthetic curve, then since a space curve has no 'side', the outer drive surface tolerance is used to construct a tolerance 'tube' around the drive curve. If the drive control is provided by a sculptured surface then again the OUTTOL/ setting for for drive surface is used for drive surface control. MAXDP/a,b Sets limits for cut vectors and tool paths. For regional milling, variable a, which specifies the maximum length of a cut vector during continuous path motion, is used primarily to override problems that may occur as a result of stepout calculations based on - curvature. If a satisfactory stepout has not been achieved after 20 iterations then error number 3552 - 'THE CUTTER COULD NOT MAKE A PROPER STEPOUT FROM THE CURRENT LOCATION' will be output. 232
Variable b, specifies the maximum length of a tool path generated by SMIL. Note that regional control generates more than one path and this limit is applied to each path separately. Error number 3554 - 'THE TOTAL LENGTH OF THE CURRENT CUTTER PATH EXCEEDED MAXDP SETTING' will occur if a path length exceeds this maximum. NUMPTS/n Maximum number of points in a single tool path. For regional control this applies to each of the multiple paths that may be generated. Error number 3553 - 'MORE CL POINTS WERE GENERATED IN A SINGLE PATH THAN PERMITTED BY NUMPTS SETTING', will result if this value is exceeded. The normal default values for these parameters are: OR IF UNITS/MM PROGRAMMED INTOL 0 0 mm OUTTOL 0.0005 0.0127 mm Max. cut vector length 10 25.4 mm Max. tool path length 200 5080 mm Max. number of points/path 400
The parameters which specify the surfaces and conditions that are to apply to subsequent regional milling operations can be divided into six groups: . Part surface parameters . Drive control parameters . Tool axis orientation . Feedrate selection . Step over control . Clearance plane specification. Each group is specified by a single SCON command and are discussed in detail in the following subsections. In addition, there is provision for cancelling the effect of any or all of these sets of parameters, see Section 8.6.7. 233
Figure 8.8 Figure 8.9 234
The groups specifying part surface, drive control and tool axis orientation are mandatory for all types of regional milling tool control. In addition, the feedrate and step over groups are required for both types of regional clearance tool path generation and the clearance plane must also be specified for the pick feed type of control. See Section 8.7.5 for further details.
The following information is required about the part surface (surface to be machined) during regional milling: . surface canonical form data . tool to surface relationship . side of surface to be machined . amount of material to be left on or removed from the surface The part surface can be any slope continuous sculptured surface. If the surface has a mesh structure it may also be used for drive control. The SCON command which specifies the part surface parameters takes the form SCON/PS, TO, surface, PLUS ,thick ON MINUS where PS indicates part surface parameters TO specifies that the tool is to be offset from the part surface, in the same sense as for conventional APT (TLOFPS), see Figure 8.8. ON specifies that the tool tip must be ON the part surface, like TLONPS in conventional APT. This may cause gouging, see Figure 8.9. surface is the symbolic name of the part surface, which must be previously defined. PLUS indicates that the tool side of the surface is determined by the cross product,SN, of the TANSPL vector with the CRSSPL vector, see Figure 8.9. 235
MINUS indicates that the tool is on the opposite side of the surface, see Figure 8.9. thick is a scalar quantity representing the thickness of material to be left on or removed from the surface. A positive quantity will be left on and a negative quantity removed. In the event of the surface referenced by the SCON/PS statement being incorrectly defined, error number 3522 - 'A MINOR WORD OR CANONICAL FORM IN THE INPUT STREAM IS IN THE WRONG POSITION OR INVALID' will occur.
Drive control can be with respect to either a synthetic curve or a sculptured surface. The parameters required for regional milling are basically the same for both types of control, namely, . curve or surface canonical form data . bounds of the drive geometry . type of drive control, 'ON' or 'AT' . tool projection vector(s) The only limitation on the drive control geometry is that when a sculptured surface is used for drive control, it must have a mesh structure, e.g. SMESH, GENCUR, REVOLV, RULED and 'cross product' type surfaces. A drive control curve can have slope discontinuity, be closed, repeat or cross itself. An incorrectly defined surface will result in error number 3522 - 'AN INPUT CANONICAL FORM HAS NOT BEEN DEFINED PROPERLY' There are two forms of the SCON command for specifying drive control parameters, one for control by a synthetic curve and the other by a sculptured surface. 236
For synthetic curve drive control: SCON/DS,curve,PARAM,ulow,uhigh, AT, vector ON CRSSPL where DS indicates drive control parameters. curve symbolic name of a previously defined synthetic curve. PARAM indicates that drive control parametric limits follow, i.e. bounds of the drive geometry. ulow lower extent of drive curve. uhigh upper extent of drive curve. If ulow exceeds uhigh then error number 3523 - 'AN INPUT CANONICAL FORM IS NOT SUITABLE FOR THIS APPLICATION' will occur. AT 'AT' type drive control, tool contacts the part surface at the point where the tool projection vector from a control point pierces the surface. See Figure 8.3. ON 'ON' type drive control, tool tip is constrained to be ON the tool projection vector from a control point. See Figure 8.2. vector fixed tool projection vector from the curve to the part surface, may be the symbolic name of a previously defined vector or a nested definition. CRSSPL indicates that the synthetic curve posseses a complete fence of CRSSPL vectors which are to be used as variable tool projection vectors. 237
For drive control by a mesh structured sculptured surface: SCON/DS,surface,PARAM,ulow,uhigh,vlow,vhigh, AT, vector ON NORMAL where DS indicates drive control parameters. surface symbolic name of a previously defined mesh structured sculptured surface. PARAM indicates that drive control parametric limits follow,i.e. bounds of the drive surface. ulow lower extent in the TANSPL direction. uhigh upper extent in the TANSPL direction. vlow lower extent in the CRSSPL direction. vhigh upper extent in the CRSSPL direction. AT 'AT' type drive control, see Figure 8.3. ON 'ON' type drive control, see Figure 8.2. vector fixed vectorial direction of tool projection. NORMAL the surface normal at a point on the drive surface will be used as the tool projection vector. If ulow exceeds uhigh or vlow exceeds vhigh then error number 3523 - 'AN INPUT CANONICAL FORM IS NOT SUITABLE FOR THIS APPLICATION' will occur. Note, tool projection vectors or their inverse must intersect the part surface otherwise error number 3551 - 'THE CUTTER COULD NOT CONTACT THE PART SURFACE FROM THE PRESENT POSITION' will ocur whilst processing subsequent SMIL commands. 238
For regional milling, the tool axis can be either fixed or variable. If the tool axis vectors are required on the CLFILE then MULTAX must be programmed as for conventional APT. The tool axis orientation must be specified even if it fixed parallel to the positive z axis. For a fixed tool axis, the SCON command is: SCON/AXIS,vector in which case the tool axis will be orientated parallel to the specified vector, and its component will be output to the CLFILE if MULTAX has been programmed. For a variable tool axis, the command takes the form: SCON/AXIS,NORMDS, PLUS MINUS for drive control by a curve the attached fence of CRSSPL vectors will be used for tool axis orientation and for control by a sculptured surface, the surface normal will be used. In either case, the modifier, PLUS will take the orientation of the variable vector for the tool axis whereas MINUS will reverse it. 239
The different feedrates that are required for automatic selection during the generation of a tool path to mill a region, are specified by the command: SCON/FEED,f1,f2,f3,f4 where f1 feedrate for passes in the major direction while regional milling. f2 feedrate for side stepping between major passes. f3 feedrate for plunging into material, when this is required. f4 feedrate for rapid withdrawl to and traverse across a clearance plane. All four values must be input, but a zero value will be ignored during regional clearance processing. If not error number 3524 - 'TOO MANY OR FEW PARAMETERS HAVE BEEN INPUT' will occur. Note that the feedrate for the first pass of a regional clearance sequence must be explicitly programmed (FEDRAT/f) before the SMIL command. Also, this command will not select feedrates for the positioning and single path forms of the SMIL command, again they should be explicitly programmed. 240
The stepover between passes during regional clearance tool path generation can be controlled by either a fixed parametric step across the drive surface or maximum cusp height requirements further limited by either physical or parametric step size. In addition, it may be desirable to lift the tool off from the surface whilst moving from one pass to the next. The stepover conditions are specified by the command: SCON/STEPOV,s1,s2,s3,s4 where s1 = 0 fixed parametric step required. > 0 maximum allowable cusp height between consecutive passes. s2 > 0 maximum physical stepover distance. < 0 if s1 = 0 parametric stepover across the drive surface. s1 > 0 maximum parametric step. s3 additional thickness to be added to part surface while stepping over. Equivalent to lift off and plunge between passes. s4 not used, but must be entered other- wise error number 3524 - 'TOO MANY OR FEW PARAMETERS HAVE BEEN INPUT' will occur. 241
The clearance plane for rapid withdrawal and traverse during the SMIL/PICKFD type of regional clearance is defined by the SCON command, SCON/FEED,plane where plane is an APT plane.
Provision is made to globably or selectively cancel regional milling conditions. All regional milling conditions are cancelled by the command: SCON/INIT,ALL This is the state of all regional milling conditions at the start of a program. If an SMIL command requires a set of conditions that have not been specified, that is one in the cancelled state, error no. 3565 will be output and no tool path produced. Diagnostic information is supplied to identify which set or sets of data have not been specified, see Section 8.8. Sets of data can be selectively cancelled by using the command SCON/INIT,PS,DS,etc ....... 242
There are four regional milling tool control commands available, one for tool positioning, one for generating a single tool path and two for area clearance. They are: SMIL/POSN,..... tool positioning SMIL/PATH,..... single tool path SMIL/ZIGZAG,... zigzag area clearance SMIL/PICKFD,... pick feed area clearance. Each command is described in detail in the following subsections. As pointed out in the previous section, certain conditions must be specified in order that a regional milling command can be processed satisfactorily. These are indicated in each subsection, in addition a summary of these prerequisites is given in Section 8.7.5. For all regional milling tool control commands MULTAX can be ON or OFF as required. As for SCON, all surfaces referenced must have been correctly defined otherwise error number 3562 - 'AN INPUT CANONICAL FORM HAS NOT BEEN DEFINED PROPERLY' will result. Likewise if invalid vocabulary or parameter types are used error number 3561 - 'A MINOR WORD OR CANONICAL FORM IN THE INPUT STREAM IS IN THE WRONG POSITION OR INVALID' will be output. If a part of drive surface cannot be loaded into memory whilst processing on SMIL command, either because it has been incorrectly defined or there is insufficient space for the surface canonical form, error number 3567 - 'PART OR DRIVE GEOMETRY COULD NOT BE FETCHED BECAUSE OF DEFINITION ERROR OR SPACE LIMITATION' will occur. 243
Figure 8.10 Figure 8.11 Figure 8.12 244
The positioning command is used to produce a single tool position, providing the programmer with convenient and flexible tool control when required. Unlike conventional APT motion commands, the PATH and area clearance commands do not depend on a successful positioning command to bring the tool into contact with the surface. The command format is, scalar SMIL/POSN,DS,PARAM,u,v,INCR,vector plane where u,v are the parameters of the drive control point and tool projection vector, within the range specified for the drive control geometry in the preceding SCON/DS, which are to control the tool position. u or v outside this range will result in error number 3563 - 'AN INPUT CANONICAL FORM IS NOT SUITABLE FOR THIS APPLICATION'. If the drive geometry is a curve, the v parameter must be included but is ignored. scalar INCR,vector indicates how the tool is to be backed plane off from the part surface. This couplet must be programmed even if no back off is required, in which case INCR,0 should be used. scalar causes the final tool position to be back along the tool projection direction by this scalar amount. See Figure 8.10. vector causes the final tool position to be the result of moving the tool from the surface contact point in the direction and by the magnitude of the vector, as shown in Figure 8.11. plane causes the tool end to be retraced the plane by the shortest distance from the surface contact point. Figure 8.12. 245
Figure 8.13 246
Only the final cutter offset position is output to the cutter location file. Before SMIL/POSN can be successfully processed, the part surface, drive control parameters and tool axis orientation must have been satisfactorily defined. A typical use of this command would be to bring the tool safely into contact with the surface to be machined, as shown in Figure 8.13, by first positioning the tool above the initial position at rapid traverse rate, then plunging into the part to the initial position at a suitable feedrate. e.g. V1 = VECTOR/0,0,2 RAPID SMIL/POSN,DS,PARAM,0,0,INCR,V1 FEDRAT/2 SMIL/POSN,DS,PARAM,0,0,INCR,0 which would result in the following records being written to the cutter location file. RAPID POCKET GOTO 2.2376111 0.0000000 3.9474828 FEDRAT 2.0000 POCKET GOTO 2.2376111 0.0000000 1.9474828
The SMIL/PATH,... command is used to program a single tool path. The drive control geometry for the path can be either an explicitly defined synthetic curve or one of the infinite number of implicit curves contained within a sculptured surface. 247
The command format is, SMIL/PATH,DS,PARAM,ust,vst, TANSPL , PLUS ›,1! CRSSPL MINUS - where ust,vst are the parameters of the initial point on the drive control surface. If the drive geometry is a synthetic curve, the vst parameter must still be included but is ignored. The point must be within the bounds of the drive geometry region as defined in the preceding SCON/DS statement, otherwise error number 3563 - 'AN INPUT CANONICAL FORM IS NOT SUITABLE FOR THIS APPLICATION' will occur. TANSPL indicates that the TANSPL curve through the point selected by ust and vst is to be used for tool path control. CRSSPL indicates that the CRSSPL curve through point ust,vst is to be used for path control. Note: Only TANSPL has any meaning if the drive control geometry is a synthetic curve. PLUS indicates that the drive control curve is to be traversed in the direction of increasing parametric values. MINUS indicates that the direction of traverse is to be that of decreasing parametric value. 1 the final optional parameter, if set to 1 will cause the first cut vector of the tool path to be omitted from the cutter location file. If this parameter is omitted or set to zero, then the first cut vector will be produced. The tool path generated will start at the initial position selected by ust,vst and extent to the boundary of the drive geometry specified in the preceding SCON/DS statement, in the indicated direction. 248
No feedrate commands are generated by the SMIL/PATH command, only cutter location data. It is the responsibility of the programmer to insert FEDRAT commands where required. The optional feature to omit the first cut vector may be required to prevent dwell marks caused by repetition of cutter location, or to permit flexible feedrate selection. For example, if the tool is brought into contact with the surface at a reduced feed by a SMIL/POSN command, then the feed can be increased for the SMIL/PATH command and the omission of the first cut vector will prevent a dwell mark occurring, in the following manner, FEDRAT/2 SMIL/POSN,DS,PARAM,0,0,INCR,0 FEDRAT/4 SMIL/PATH,DS,PARAM,0,0,TANSPL,PLUS,1 which would result in the following records being written to the cutter location file. FEDRAT/ 2.0000 POCKET GOTO 2.2376111 0.0000000 1.9474828 FEDRAT/ 4.0000 POCKET GOTO 2.2376112 1.0000000 1.9474827 2.2376112 2.0000000 1.9474827 Before SMIL/PATH can be successfully processed the part surface, drive control parameters and tool axis orientation must have been satisfactorily defined by preceding SCON statements. 249
The ZIGZAG type of area clearance will produce a sequence of tool paths zigzaging back and forth across the sculptured surface. The user can select the major and minor directions, the initial major motion direction and the direction of stepover between passes. The boundaries of the region to be machined are defined by the preceding SCON/DS statement. The drive control geometry must be a mesh structured sculptured surface. The command format is, SMIL/ZIGZAG,DS,PARAM,ust,vst,TANSPL ,PLUS ,STEPOV,PLUS ›,1! CRSSPL MINUS MINUS where ust,vst are the parameters of the drive conrol point at which the zigzag path is to begin. TANSPL indicates that the major tool path is to be in the tangent spline direction of the drive control surface. CRSSPL indicates that the major tool path is to be in the cross spline direction of the drive control surface. PLUS indicates that the initial motion direction is to be in the direction of increasing parametric value. MINUS indicates that the initial motion direction is to be in the direction of decreasing parametric value. STEPOV,PLUS indicates that the stepover is to be MINUS in the direction of increasing parameter (PLUS) or decreasing parameter (MINUS), along the alternate spline direction to that selected for the major tool path. 1 the final optional parameter, if set to the scalar value 1 will cause the first cut vector to be omitted, as for for SMIL/PATH. 251
Figure 8.14 252
Although feedrates are automatically selected between paths according to the values specified in the preceding SCON/FEED statement, no feedrate is generated for the first path. It is the users responsibility to insert a FEDRAT command before the SMIL/ZIGZAG command for the first path. Stepover is controlled by the parameters set in the preceding SCON/STEPOV statement. The basic zigzag area clearance path, shown in Figure 8.14 is a path along the first curve in the initial major direction, followed by a lift off, as specified in SCON/STEPOV, then a side step to the next major path at the feedrate selected for side stepping, on a parallel offset surface, followed by a plunge at the appropriate feed back to the surface before moving off back along the next curve in the major direction at the specified feed. The following is an extract from the cutter location file, showing the insertion of feedrates, lift off, stepover and plunge between passes. 57 POCKET 57 GOTO 57 33.9618015 -15.0001075 25.5262944 36.3968337 -15.0001086 25.7287396 40.0002435 -15.0001087 25.8567235 43.7345622 -15.0001078 25.9056393 47.5529528 -15.0001059 25.8720966 51.3971227 -15.0001028 25.7544671 55.2055816 -15.0000984 25.5532068 58.0020993 -15.0000113 25.3487458 60.7147297 -14.9999734 25.1007017 64.1570027 -15.0000877 24.7075939 67.0785479 -15.0000747 24.3260350 70.0000920 -15.0000688 23.9134241 57 FEDRAT/ 200.0000 57 GOTO 57 70.0000253 -15.0002272 28.9957739 70.0000868 -17.2750440 28.7257518 70.0000815 -20.1944494 28.2976792 70.0002576 -20.7347035 28.2082598 57 FEDRAT/ 57 GOTO 57 70.0000790 -20.7347249 23.0930685 253
Figure 8.15 254
57 FEDRAT/ 100.0000 57 GOTO 57 65.7345272 -20.7347280 23.6098304 62.2279969 -20.7346400 23.9676527 58.4820805 -20.7347431 24.2668810 54.5071686 -20.7347467 24.5004211 50.3947909 -20.7347528 24.6577347 46.2183950 -20.7347552 24.7328730 42.0598344 -20.7347560 24.7225200 37.9910331 -20.7347551 24.6263355 35.0479674 -20.7346842 24.4997095 32.5242139 -20.7340728 24.3496347 29.9999189 -20.7339826 24.1572735 The final tool position of a ZIGZAG area clearance sequence is at the end of the last path in the major direction, in contact with the surface. If a zero lift off is requested the lift off and plunge records will be omitted and a path similar to that shown in Figure 8.15 will result. The cutter location file for which is listed in Section 8.4.4. In order that SMIL/ZIGZAG can be successfully processed, the part surface, drive control parameters, tool axis orientation, feedrates and stepover parameters must have been satisfactorily defined by preceding SCON statements.
The second type of area clearance, PICKFD, produces a tool path which gives unidirectional machining passes, so that all material removal is done by either climb or conventional milling. As for ZIGZAG area clearance the user can select the major and minor directions, the direction of cut, and the direction of stepover. The boundaries of the region to be machined are defined by the preceding SCON/DS statement and the clearance plane to which the tool is retracted and across which the tool is traversed between machining passes, is defined by the preceding SCON/FEED,plane statement. 255
The command format is SMIL/PICKFD,DS,PARAM,ust,vst, TANSPL, PLUS ,STEPOV, PLUS ›,1! CRSSPL MINUS MINUS where ust,vst are the parameters of the drive control point at which the PICKFD path is to begin. TANSPL indicates that the major tool path is to be in the tangent spline direction of the drive control surface. CRSSPL indicates that the major tool path is to be in the cross spline direction of the drive control surface. PLUS indicates that the machining direction is to be in the direction of increasing parametric value. MINUS indicates that the machining direction is to be in the direction of decreasing parametric value. STEPOV,PLUS indicates that the direction of MINUS stepover is to be along the alternate spline direction to that selected for the machining passes. PLUS for increasing parameter. MINUS for decreasing parameter. 1 the final optional parameter if set to the scalar value 1 will cause the first cut vector to be omitted, as for SMIL/PATH. Feedrates are automatically selected between paths according to the values specified in the preceding SCON/FEED statement. Note that no feedrate is generated for the first path, it is the users responsibility to select this explicitly. Stepover is controlled by the parameters set in the preceding SCON/STEPOV statement. 257
Figure 8.16 258
The basic pick and feed area clearance tool path, shown in Figure 8.16, is a machining pass along the first curve in the selected major direction, from the start point to the defined extent (2), followed by a retraction to (3) and traverse back across the clearance plane, at the traverse feedrate, f4 to a position above the start of the path (4). The cutter then plunges to its initial position (5) at the plunge feed, f3, before lifting off (6) and stepping over to a point above the start of the next path (7), and the stepover feed, f2. Finally the tool plunges to the start of the next path (8) at the plunge feed ready to repeat the sequence. The final tool position of a PICKFD area clearance sequence is at the end of the last machining pass in contact with the surface. The following extract from the cutter location file, illustrates the tool path generated showing the insertion of feedrates and additional movements between each machining pass. 53 POCKET 53 GOTO 53 29.9999405 -15.0001048 25.2813363 32.9618015 -15.0001075 25.5262944 36.3968337 -15.0001086 25.7287396 40.0002435 -15.0001087 25.8567235 43.7345622 -15.0001078 25.9056393 47.5529528 -15.0001059 25.8720966 51.3971227 -15.0001028 25.7544671 55.2055816 -15.0000984 25.5532068 58.0020993 -15.0000113 25.3487458 60.7147297 -14.9999734 25.1007017 64.1570027 -15.0000877 24.7075939 67.0785479 -15.0000747 24.3260350 70.0000920 -15.0000688 23.9134241 53 FEDRAT/ 3000.0000 53 GOTO 53 70.0000920 -15.0000688 40.0000000 29.9999405 -15.0001048 40.0000000 53 FEDRAT/ 50.0000 53 GOTO 53 29.9999405 -15.0001048 25.2813363 259
53 FEDRAT/ 200.0000 53 GOTO 53 29.9999035 -15.0000595 30.3711513 29.9991972 -15.8256773 29.8765466 29.9999480 -20.7347432 29.2927104 53 FEDRAT/ 50.0000 53 GOTO 53 29.9999463 -20.7347486 24.1571047 53 FEDRAT/ 100.0000 53 GOTO 53 29.9999463 -20.7347486 24.1571047 33.2091889 -20.7347521 24.3942471 36.8984623 -20.7347546 24.5851539 40.7859712 -20.7347559 24.7018316 44.8325220 -20.7347557 24.7389869 48.9817079 -20.7347538 24.6926526 53.1592948 -20.7347502 24.5612066 57.2868282 -20.7347450 24.3458405 60.3006424 -20.7346830 24.1317031 63.2109600 -20.7346677 23.8753032 66.6054542 -20.7347317 23.5104487 70.0000809 -20.7347202 23.0930691 If zero lift off is requested the additional moves between the machining passes are fewer, as shown in Figure 8.17 namely, retraction to (3) and traverse across the clearance plane to a position above the start point of the current pass (4), plunge to the start point (5), and finally stepover in contact with the surface to the start of the next pass (6). Comparison of the following CLFILE extract with the previous one illustrates the differences in detail. 64.1570027 -15.0000877 24.7075939 67.0785479 -15.0000747 24.3260350 70.0000920 -15.0000688 23.9134241 54 FEDRAT/ 3000.0000 54 GOTO 54 70.0000920 -15.0000688 40.0000000 29.9999405 -15.0001048 40.0000000 54 FEDRAT/ 50.0000 260
Figure 8.17 261
54 GOTO 54 29.9999405 -15.0001048 25.2813363 54 FEDRAT/ 200.0000 54 GOTO 54 29.9986448 -18.0325112 24.7253928 29.9999474 -20.7347487 24.1571048 54 FEDRAT/ 100.0000 54 GOTO 54 29.9999463 -20.7347486 24.1571047 33.2091889 -20.7347521 24.3942471 36.8984623 -20.7347546 24.5851539 40.7859712 -20.7347559 24.7018316 Before SMIL/PICKFD can be successfully processed, the part surface, drive control parameters, tool axis orientation, feedrates, stepover parameters and clearance plane must have been satisfactorily defined by preceding SCON statements.
The following table summarises the SCON statements which must be satisfactorily defined before a particular type of SMIL statement can be successfully processed. ---------------------------------------------------- : : SMIL/ : ---------------------------------------------------- : SCON/ : POSN PATH ZIGZAG PICKFD : ---------------------------------------------------- : PS : * * * * : : : : : DS : * * * * : : : : : AXIS : * * * * : : : : : FEED : * * : : : : : STEPOV : * * : : : : : FEED,plane : * : ---------------------------------------------------- 262
If any of the required items have not been satisfactorily defined then ERROR 3565 will be indicated and a summary of the status of all the SCON data areas, together with the statement sequence number, error number and other internal variables (see Section 8.8) are printed on the verification listing. A positive value (121) indicates a SCON block has been satisfactorily defined and a negative value (-121) that a block is undefined. For example, DS = 121 PS = 121 FEED = -121 STOV = -121 AXIS = 121 CPLN = -121 would indicate that DS,PS and AXIS have been satisfactorily defined and FEED,STEPOV and clearance plane (CPLN) are undefined.
When an error occurs during regional milling, the error number is passed to the CLEDITOR for subsequent ouput on the verification listing and processing is restarted in the same manner as for an ARELEM error. The error numbers for regional milling are in the range 3520 to 3599, and are detailed in subsections 8.8.2 to 8.8.4. In addition for each occurrence of an error resulting from a SCON or SMIL statement during the Execution phase, a short block of information consisting of the input statement sequence number, error number and the values of some useful internal variables is printed. For both SCON and SMIL the values of the following internal variables are then printed out. ISEQ input statement sequence. NLST address in BLANK COMMON of the last internal parameter for the current input statement. NLEN number of internal parameters for the current input statement. IRR error number. ICUR address in BLANK COMMON of the internal parameter being processed when the error occurred. IRBS base number for the error messages. = 3520 for SCON errors = 3550 for SMIL errors 263
Finally in the case of SMIL a summary of the status of the SCON data areas is printed. This is particularly useful in identifying which block of SCON data is undefined when error 3565 occurs. A positive value (121) indicates that a data area has been satisfactorily defined and a negative value (-121) that it is undefined. The data areas are identified as follows, DS drive control parameters PS part surface data FEED feed rate values STOV stepover parameters AXIS tool axis orientation CPLN clearance plane.
To illustrate how the diagnostic output can be used to identify the cause of an error, consider the following erroneous coding. 9. P1 = POINT/0,0,20 . . . 45. SCON/DS,DS1,PARAM,0,1,0,1,ON,NORMAL 46. SCON/PS,TO,PS0,MINUS,0 47. SCON/AXIS,P1 48. SMIL/PICKFD,DS,PARAM,0,0,TANSPL,PLUS, STEPOV,PLUS which would give the following diagnostic output, ***** DEFINITION ERROR 3521 ISN 47 FROM SUBROUTINE SCON ***** A MINOR WORD OR CANONICAL FORM IN THE INPUT STREAM IS IN THE WRONG POSITION OR INVALID. ISEQ = 47 NLST = 49 NLEN = 9 IRR = 3521 ICUR = 45 IRBS = 3520 END = SMIL ISEQ = 48 NLST = 61 NLEN = 21 IRR = 3565 ICUR = 61 IRBS = 3550 DS = 121 PS = 121 FEED = -121 STOV = =121 AXIS = -121 CPLN = -121 ***** RESTART DIAGNOSTIC 3565 ISN 51 FROM SUBROUTINE SMIL ***** AN 'SCON' DATA AREA (DS,PS,FEED,ECT.) HAS NOT BEEN DEFINED OR HAS BEEN INCORRECTLY DEFINED. 264
The first error 3521 results because P1 is a point not a vector. In this case it is easily recognized, if not, inserting PPOPTN/INTLNG,ON before the offending statement will give a print of the internal parameters set up for the statement, as follows. 47. SCON/AXIS,P1 MOVE 3 $$TAB $ 146. MOVE 4 $$TAB $$ AXIS MOVE 5 $$TAB $ 19. REPL 3 6 $$TAB 0 P1 MOVE 2 $$TAB $ 9. CALL APT110 $$ SCON - Then by considering the values of NLST,NLEN and ICUR the offending item in the input statement can be identified. In this case, NLST = 49, NLEN = 9 and ICUR = 45, therefore the input statement parameters will start at (NLST-NLEN)=40 so the offending item is in location 5 from the start, (ICUR-start). Examining the internal language print above, it can be seen that the fifth entry in $$TAB is 19, which is the internal code for a point, and that the values defining the point are the coordinates of P1 which are transferred to the next three locations by the REPL instruction. It is not necessary for the user to know and understand all the internal codes used by the system, since in general the parameters stored in $$TAB are in pairs, the first item is the internal code and the second the character form of the input parameter, e.g. MOVE 3 $$TAB $ 146. MOVE 4 $$TAB $$ AXIS. mean that the 3rd entry in $$TAB is 146 and the 4th entry in $$TAB is AXIS. The second error 3563 indicates that an 'SCON' data area has either not been defined or was incorrectly defined. Examining the first line of internal variables, it can be seen that all the parameters in the SMIL statement have been accepted, since NLST and ICUR are both 61. Examining the second line, which gives the status of the SCON data areas, it can be seen that only DS and PS have been satisfactorily defined. FEED, STOV, AXIS and CPLN are all undefined or incorrectly defined. AXIS has obviously been incorrectly defined because of the previous error, the others however have not been defined and by referring to Section 8.7.5 it will be noted that for SMIL/PICKFD all the data areas must be defined for successful processing to occur. 265
The following error messages may occur whilst processing an SCON statement. See preceding Sections 8.8 and 8.8.1 for a detailed explanation of additional diagnostic information. 3521 A MINOR WORD OR CANONICAL FORM IN THE INPUT STREAM IS IN THE WRONG POSITION OR INVALID Ref: 8.6.1, 8.8.1 3522 AN INPUT CANNICAL FORM HAS NOT BEEN DEFINED PROPERLY Ref: 8.6.1, 8.6.2 3523 AN INPUT CANONICAL FORM IS NOT SUITABLE FOR THIS APPLICATION Ref: 8.6.2 3524 TOO MANY OR FEW PARAMETERS HAVE BEEN INPUT Ref: 8.6.4, 8.6.5
The error messages that can occur whilst processing an SMIL command fall into two categories, those which are of a semantic origin or relate to the status of required parameters and those which occur when attempting to calculate cutter positions. This last group are detected by the subroutine PATH and are detailed in the next section. The first group are detailed below. An explanation of the additional diagnostic data produced during the Execution Phase is given in the preceding Sections 8.8 and 8.8.1. 3561 A MINOR WORD OR CANONICAL FORM IN THE INPUT STREAM IS IN THE WRONG POSITION OR INVALID Ref: 8.7 3562 AN INPUT CANONICAL FORM HAS NOT BEEN DEFINED PROPERLY Ref: 8.7 3563 AN INPUT CANONICAL FORM IS NOT SUITABLE FOR THIS APPLICATION Ref: 8.7.1, 8.7.2 266
3464 TOO MANY OR FEW PARAMETERS HAVE BEEN INPUT 3565 AN SCON DATA AREA (DS,PS,FEED,ETC.) HAS NOT BEEN DEFINED OR HAS BEEN INCORRECTLY DEFINED Ref: 8.6.7, 8.7.5, 8.8.1 3566 GENERAL APT ARELEM CONDITIONS FOR REGIONAL MILLING ARE INVALID (PROBABLY UNACCEPTABLE CUTTER TYPE) Ref: 8.5 3567 PART OR DRIVE GEOMETRY COULD NOT BE FETCHED BECAUSE OF DEFINITION ERROR ON SPACE LIMITATION Ref: 8.7
The following error messages can occur whilst attempting to calculate cutter positions when processing an SMIL command. See Sections 8.8 and 8.8.1 for a detailed explanation of additional diagnostic data provided. 3551 THE CUTTER COULD NOT CONTACT THE PART SURFACE FROM THE PRESENT POSITION Ref: 8.6.2 3552 THE CUTTER COULD NOT MAKE A PROPER STEPOUT FROM THE CURRENT LOCATION Ref: 8.5 3553 MORE CL POINTS WERE GENERATED IN A SINGLE PATH THAN PERMITTED BY NUMPTS SETTING Ref: 8.5 3554 THE TOTAL LENGTH OF THE CURRENT CUTTER PATH EXCEEDED THE MAXDP SETTING Ref: 8.5 267