Postprocessor mods for Brother machine simulation

[fredsi]

I downloaded the most recent post for Brother speedio machines to modify it for use with a Brother U500 5axis machine model. I modified the post per Autodesk instructions, removing certain code and adding snippets from the machine simulation .cps. Once complete I tested with the model; everything worked except the A and C axes did not position at all. After checking my mods again, I went into the post and checked 'Use A/C axes' in the post configuration properties. Now it works fine. 

So my question is 'why does this work?'. Unlike earlier Speedio posts from Autodesk, there is no simple "true/false" to enter to disable axis configuration in the post. Instead, the most recent Speedio post has conditionals at the start of the 'onOpen' function that interrogate properties relating to the presence of either an 'A Axis' or an 'A/C axes'. I assumed that by leaving both conditionals 'false' it was the equivalent of removing the hardcoded machine configuration from the post thus disabling the kinematics. Apparently, not so.

I'm posting this to give others who might run into it a 'heads up' and to ask if anyone at Autodesk can comment on why this works as it does. Thanks in advance for any responses.

Fred

[serge.quiblier]

Hello @fredsi 

The kinematic definition in the Fusion 360 post processors went thru several iterations.

It was driven by the capabilities of the software, the introduction of new functions, in the soft, or the post engine and so on.

One of the earliest methods had been handling a 4^th axis definition.

This was frequently implemented using a post property for selecting either the axis direction (positive/negative), or the centerline direction (around X, around Y).

This is what is used in the vanilla Brother post.

function onOpen() {
  if (getProperty("useRadius")) {
    maximumCircularSweep = toRad(90); // avoid potential center calculation errors for CNC
  }
  gRotationModal.format(69); // Default to G69 Rotation Off

  if (getProperty("hasAAxis")) { // note: setup your machine here
    var aAxis = createAxis({coordinate:0, table:true, axis:[1, 0, 0], range:[-360, 360], preference:1});
    //var cAxis = createAxis({coordinate:2, table:false, axis:[0, 0, 1], range:[-360, 360], preference:1});
    machineConfiguration = new MachineConfiguration(aAxis);

    setMachineConfiguration(machineConfiguration);
    optimizeMachineAngles2(1); // TCP mode
  }

We have here a boolean property "hasAAxis", and when set to true, we define the axis and the machine configuration in the code inside the onOpen function.

Another method, used in the Brother M140, can define multi axis kinematics.

In that example, a piece of code allows to define the axis, direction, limits, and TCP support.

We are not using properties for that. Defining all the different combinations in the list would be cumbersome, with A, B or C axis on the head or the table….

function onOpen() {
  turningAngle = getProperty("turningAngle") * -1; // turning rotation is in opposite direction of C-axis rotation
  turningAngle = turningAngle < 0 ? turningAngle + 360 : turningAngle;
  if (turningAngle < 0 || turningAngle > 360) {
    error(localize("TurningAngle must be between 0 and 360 degrees."));
  }
  saveTurningAngle = turningAngle;

  if (getProperty("useRadius")) {
    maximumCircularSweep = toRad(90); // avoid potential center calculation errors for CNC
  }
  gRotationModal.format(69); // Default to G69 Rotation Off

  showSequenceNumbers = getProperty("showSequenceNumbers");

  if (true) { // note: setup your machine here
    var aAxis = createAxis({coordinate:0, table:true, axis:[1, 0, 0], range:[-30, 120], preference:1});
    var cAxis = createAxis({coordinate:2, table:true, axis:[0, 0, 1]});
    machineConfiguration = new MachineConfiguration(aAxis, cAxis);

    setMachineConfiguration(machineConfiguration);
    optimizeMachineAngles2(1); // TCP mode disabled
  }

Inside the "if (true)" conditional statement, we are defining our axis and configuration for a multi axis machine.

We don't rely on an external post property.

You can note that it's using some of the functions previously used in the 4th axis schema.

The speedio post is a mix between these first two solutions. But it does not used the same properties, and add his own ones.

function onOpen() {
  if (getProperty("useRadius")) {
    maximumCircularSweep = toRad(90); // avoid potential center calculation errors for CNC
  }
  gRotationModal.format(69); // Default to G69 Rotation Off

  if (getProperty("useTrunnion")) {
    var aAxis = createAxis({coordinate:0, table:true, axis:[1, 0, 0], range:[-30, 120], preference:1});
    var cAxis = createAxis({coordinate:2, table:true, axis:[0, 0, 1], cyclic:true});
    machineConfiguration = new MachineConfiguration(aAxis, cAxis);

    setMachineConfiguration(machineConfiguration);
    optimizeMachineAngles2(1); // TCP mode disabled
  } else if (getProperty("hasAAxis")) { // note: setup your machine here
    var aAxis = createAxis({coordinate:0, table:true, axis:[1, 0, 0], range:[-360, 360], preference:1});
    machineConfiguration = new MachineConfiguration(aAxis);

    setMachineConfiguration(machineConfiguration);
    optimizeMachineAngles2(1); // TCP mode disabled
  }

Either the "useTrunnion" property, or the "hasAAxis" will be used.

The first one taking precedence. I am using their internal name, externally theyr are "Use AC-trunnion" and "Use A-axis"

Another solution, actually not implement in the Brother post, can be found in the Fanuc post.

It’s a mix between solution 2 and our newest method.

If a machine configuration file is associated to the wcs in Fusion, then the kinematic is provided by this file.

But we can eventually also define the kinematic in the post, using the create axis functions.

Let's start in the onOpen function:

function onOpen() {
  // define and enable machine configuration
  receivedMachineConfiguration = machineConfiguration.isReceived();
  if (typeof defineMachine == "function") {
    defineMachine(); // hardcoded machine configuration
  }
  activateMachine(); // enable the machine optimizations and settings

We check if a machine configuration had been provided, before using it, or else the kinematic can be defined in the defineMachine functions.

function defineMachine() {
  var useTCP = true;
  if (false) { // note: setup your machine here
    var aAxis = createAxis({coordinate:0, table:true, axis:[1, 0, 0], range:[-120, 120], preference:1, tcp:useTCP});
    var cAxis = createAxis({coordinate:2, table:true, axis:[0, 0, 1], range:[-360, 360], preference:0, tcp:useTCP});
    machineConfiguration = new MachineConfiguration(aAxis, cAxis);

    setMachineConfiguration(machineConfiguration);
    if (receivedMachineConfiguration) {
      warning(localize("The provided CAM machine configuration is overwritten by the postprocessor."));
      receivedMachineConfiguration = false; // CAM provided machine configuration is overwritten
    }
  }

To enable the definition from the post, the "if (false)" MUST be changed to "if (true)".

And you should not assign a machine configuration file in the wcs. (or it will be overwritten by the post)

Regards.

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