This option is used to set specific formatting and conditions for multi-axis programming. Two options are available: Multi-axis Setup and Work Plane.
Multi-axis Setup
This option is only necessary for postprocessors that contain one or more ROTARY machine axes.
Field Description
Use RTCP output Specifies that the output should be for a machine controller
supporting Rotating Tool Center Point (RTCP) output. This ignores table rotation and takes care of table rotation compensation. For example, this option takes care of the distance from the tip end of a spindle to the pivot point. The use of Pivot or Face (see the Output using… options described below) depends on the controller. You defined if the distance is to the face of the spindle or to the pivot point.
Multax on by default Enables the default startup condition of the postprocessor to multi-axis postprocessing ( as if MULTAX/ON has been programmed in the APT/CL file).
Machine Menu and Options: Multi-Axis
Field Description
Lintol on by default Enables the default startup condition of the postprocessor to linear tolerance calculations for multi-axis postprocessing (as if
LINTOL/value has been programmed in the APT/CL file).
Output using... Defines how to track the cutter. Select one:
Pivot (point of rotation on the head) Face
Center Tip
MSpost gives you the option of tracking the tool a number of ways.
Depending upon what you select in the “Output using” area, the postprocessor will make its calculations based upon the tool data passed within the APT/CL file.
The postprocessor normally gets its tool data from the LOADTL and CUTTER statements. The tool length is defined with LOADTL and the cutter diameter (or radius) is in the associated CUTTER
statement. This tool data updates these IMS system variables:
SYSTEM.TOOL_LENGTH Tool length
SYSTEM.CUTTER_RAD Cutter radius
SYSTEM.CUTTER_DIAM Cutter diameter
Within IMSpost, there is a CUT statement that instructs the system as to what is being cut (PART) and how it is being cut (TOOL...). For example, depending on what was selected in the “Output using” area;
the following four CUT statements could be generated:
CUT(PART,TOOL.RTCP) Cut part based upon tools pivot point
(Machine References)
CUT(PART,TOOL.ORIGIN Cut part with spindle face
CUT(PART,TOOL.CENTER) Cut part with tools center
CUT(PART,TOOL.TIP) Cut part with tools endpoint
Solution Condition Indicates the solution chosen by the postprocessor. As a general rule, IMSpost chooses the solution that represents the shortest movement of the tool. You can enter a conditional expression in the Solution Condition box to control the solution chosen by the postprocessor.
In multi-axis programming, depending on machine axis limits and orientations, it is quite often possible to have more than one correct output solution for any input point/vector value. When the Solution Condition is true, the postprocessor will output the alternate position.
If a valid expression is entered, the postprocessor will make this check for every 5-axis motion.
The system variable that contains this expression is:
SYSTEM.FORCE_WAY " expression "
For example:
SYSTEM.FORCE_WAY = "MACHINE.C > 45.0"
This example delete current solution expression:
SYSTEM.FORCE_WAY = ""
TIP: Use MACHINE type variables in the conditional expression, rather than REGISTER variables. MACHINE variables are checked
Machine Menu and Options: Multi-Axis
Field Description
during the calculation of the solution, whereas REGISTER variables are not set until after the solution calculation has been completed.
For example, use:
MACHINE.C > 45.0 rather than:
REGISTER.C.VALUE > 45.0) Enable read ahead to
choose best solution
Activates the routine that determines the best initial tool start-up orientation.
For 5-axis machines; this routine instructs IMSpost to look ahead through a specified area of the part file and determine the best way to initially position the tool. With this option selected, it could eliminate or reduce the need for tool retractions and tool re-orientations. For example; one start up tool orientation could be:
Nxxx X..Y..Z.. A45.0 C0.
and the alternate could be:
Nxxx X..Y..Z..A-45.0 C180.0
The global variable that controls this checkbox is:
GLOBAL.RAPID_BEST_SOLUTION
MULTAX/ON must be in effect here. If it is OFF, no SOLUTION will be returned. MULTAX/ON could be set as a default condition in this dialog.
Refer also to More Details About Best Solution, below.
Enable auto retract/-reorient for rotary axes
Activates the retract/reorient feature and the options below. (Refer to the Enable Auto Retract option for Machine > Motion.)
Automatic retract and reorient is an optional feature of multi-axis postprocessing using IMSpost. The retract/reorient condition occurs when a rotary axis sees a new tool axis vector that exceeds the angle specified in the “Auto retract angle” display area (described below), or it reaches a machine travel limit while in the process of a cutting move, and must retract the tool, unwind the rotary axis, move back to the last position, and finish the cutting move.
With this feature enabled, IMSpost performs each of these moves automatically when the condition occurs during postprocessing of a multi-axis file. This motion can be modified within the
AUTO_RETRACT macro.
Auto retract angle Defines the delta angle that activates the auto retract feature. For example, if you enter 30 and the postprocessor encounters a rotary motion of at least 30 degrees (for any rotary axis), the auto retract feature is activated. This delta angle represents the angle the
postprocessor will have to move in order to maintain the programmed tool (IJK) vector.
Clearance distance Defines the relative distance to retract (along the tool axis) in G0 mode before the rotary axis repositions (unwinds).
Feed in/out distance Defines the initial retraction distance in feed (G1) mode. Remaining retraction will be done in G0 mode as specified in the Clearance distance, above.
Machine Menu and Options: Multi-Axis Rotating Tool Center Point (RTCP)
Rotational Tool Center Point (RTCP) programming mode, allows tool paths (calculated from the center of a ball nose tool or the tool tip point for an end milling cutter) to be directly matched to the center of rotation of the corresponding axis. This feature eliminates the need to re-post the program for tool length changes or reestablish the zero position of the workpiece for every axis rotation.
With RTCP turned on, new X, Y, and Z values are automatically calculated at the control so that the center of the tool tip will follow the original tool path centerline. For the postprocessor in the standard case, this means the X, Y, and Z linear values are not adjusted based on the rotary axis positions, but rather this adjustment takes place at the machine controller.
The RTCP feature must be supported by the controller.
The IMSpost variable that controls this feature is:
SYSTEM.COORD_RTCP = 1 The “Enable auto retract/reorient for rotary axes” option is checked (ON).
SYSTEM.COORD.RTCP = 0 The “Enable auto retract/reorient for rotary axes” option is not checked (OFF).
When the RTCP option is off, the postprocessor will adjust for the tool length by moving the linear axes.
This system variable usually applies to table rotations only. Rotary head rotations are controlled within IMSpost with the CUT statement and are dependent upon the options selected on the Multi-axis Setup dialog. The CUT statement instructs IMSpost as to which part component will be cut and which tool components will do the actual cutting. For example:
CUT(PART,TOOL.RTCP) Cut part with tools defined pivot point (Machine References).
CUT(PART,TOOL.ORIGIN) Cut part with spindle face.
CUT(PART,TOOL.CENTER) Cut part with tools center point.
CUT(PART,TOOL.TIP) Cut part with tools tip.
IMSpost also tracks the tool based upon tool data being processed within the part file. Tool data such as tool length, cutter radius, or diameter update IMSpost variables as these LOADTL and CUTTER statements are read within the part file.
Each IMS model component contains a control point called its origin. This point is the local coordinate system of that particular component. Cutter (tool) type components have four of these local origin points:
ORIGIN tracks the spindle face (no tool length).
TIP uses the SYSTEM.TOOL_LENGTH
CENTER = SYSTEM.TOOL_LENGTH + SYSTEM.CUTTER_RAD
RTCP uses the specified pivot point (distance from spindle face to center of heads rotation).
The tool origin that will be in effect is dependent upon the options selected on the Multi-axis Setup dialog.
Support for Contact-Point Output with Corner Radius Cutters
The GOTO macro and GOTO solution statement allow output of the tool contact point in addition to the tool tip point. The tool contact point is the point where the tool actually touches the part. It may not be the tool tip, but could be some other point on the side or radius of the tool. The GOTO
Machine Menu and Options: Multi-Axis statement processing accepts three additional parameters, representing a vector from the tool radius center to the contact point. In addition, the CUTTER statement processing saves the tool information for the diameter, radius, and length of the tool in IMSpost variables that are used in calculating the contact points.
More Details About the Best Solution
In order for the Best Solution routine to work, there are a few variables necessary to define here:
SYSTEM.BEST_START_COMMAND = "APT Statement"
SYSTEM.BEST_END_COMMAND = "APT Statement"
Enter the names of the APT statements that will define the start and end of the boundary.
SYSTEM.BEST_START_REPEAT = # SYSTEM.BEST_END_REPEAT = #
This indicates how many times to locate the start and end of the boundary. Typically, the value for both of these variables is set to one. If set to a value greater than one, IMSpost would keep searching until the APT word is encountered the specified number of times.
If set properly, finding the Best Solution is a one-shot command activated within the RAPID macro (SYSTEM.BEST_SOLUTION = GLOBAL.RAPID_BEST_SOLUTION).
If activated, IMSpost will do a look-ahead through all the GOTO points located within the specified boundary in order to determine the best tool orientation at start-up.
For example, to specify boundaries:
SYSTEM.BEST_SOLUTION = 1
RAPID/ Activates Best Solution in RAPID macro
GOTO/100,150,300,0,1,0 RAPID/
GOTO/400,350,300,0.,1,0
FEDRAT/1500,MMPM Starts Best Solution Boundary
GOTO/X,Y,Z,I,J,K GOTO/X,Y,Z,I,J,K GOTO/X,Y,Z,I,J,K GOTO/X,Y,Z,I,J,K GOTO/X,Y,Z,I,J,K
RAPID/ Ends Best Solution Boundary and returns SOLUTION to
first RAPID motion
Machine Menu and Options: Multi-Axis