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Version

0.21 (Development)

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Issue description

On-Machine Inspection

Background

In commercial manufacturing using CNC, the part is inspected to ensure that the resulting part matches the required tolerance. Tool wear, backlash, and other environmental factors can affect machining accuracy.

Traditionally the part is removed from the machine after completion and placed and a Coordinate Measuring Machine (CMM) which probes the part and compares to the probe results to the required specifications. The problem with this approach is that the placement of the part is lost when it is removed from the machine. If re-work is necessary, the setup time to reestablish accurate placement can be very high.

On-machine Inspection uses a touch probe in the CNC machine to replace the CMM. The part is left in place and a toolpath is executed.

In manual mode, the machine probes the part and indicates to the operator if a probe point is out of tolerance.

In automatic mode, the probe points are gathered and saved to an inspection report

The CAM workbench in FreeCAD (Path) lacks any capability for generating an On Machine Inspection toolpath.

Details

1. Understand the basic workflow for creating a Path Job and generating tool paths for CNC machining operatoins. Understand the two main workflows for On-machine Inspection.
2. Propose a Path operation and workflow for generating a toolpath, storing and displaying inspection results.
3. Design the operation, task panels, and core logic.
4. Implement unit tests for the core logic
5. Implement the feature and demonstrate practical application
6. Create a wiki page describing how on-machine inspection is used

Expected Outcome

1. Mergable code for an OMI feature
2. Unit tests for the core logic
3. A Wiki page describing the procedure for the user to create tests and the developer to create new comparators

Future Possibilities

There are numerous other places in the CAM workflow where Integration of touch probes and other sensing equipment would reduce errors and increase cycle time. These are valuable features to implement. They make FreeCAD more attractive to commercial use.

Project Properties

Skills

• Programming language mainly Python. Familiarity with or willingness to learn G-code.
• Familiarity or willingness to learn basic CNC / machining concepts

Difficulty

Medium

Project size

175h

Additional Information

Anything else?

https://qbhmetal.com/on-machine-inspection-improve-the-machining-process/

Code of Conduct

• I agree to follow this project's Code of Conduct