Skipped lines with G43 H1 and G98 in my CNC program (Stepcraft - Fusion 360)

Subject: Skipped lines with G43 H1 and G98 in my CNC program (Stepcraft - Fusion 360)

Hi everyone,

I'm facing a strange issue with my CNC program, generated using the Stepcraft post-processor for Fusion 360 on a Q408 machine (2024 model). When running the program in continuous mode, the machine skips certain lines, especially those with G43 H1. I also suspect that G98 might be involved.

Context:

• I use a Z probe to measure tool lengths, which are supposed to be recorded in the tool table.
• Here’s an example of commands causing issues:
  gcode

   

  G98 G73 X142.5 Y1009.4 Z-10.5 R5 Q1 F1000 
  G43 H1 Z10

   

  

• In step-by-step mode, the program runs perfectly. However, in continuous mode, random line skips occur (e.g., jumping from line 7 to 137).

Symptoms:

• When the machine skips lines, it starts behaving erratically:
  • It moves diagonally without following the program's intended path.
  • It stops reading the G-code entirely, requiring a reset.
• The issue seems related to the interaction between G98 (used for returning after a drilling cycle) and G43 H1 (used for tool length compensation).
• I’m using the Stepcraft post-processor, so there might be compatibility issues with certain specific commands.

Checks already performed:

1. The tool table is configured, but the offset associated with H1 might be set to zero.
2. A minimal program with just G43 H1 works without issues.
3. The combination of G98 and G43 H1 seems to cause the skipping in continuous mode.

Questions:

1. Could the Stepcraft post-processor for Fusion 360 mismanage certain commands like G98 or G43 H1?
2. Could an H1 offset of zero explain this behavior?
3. Why would the machine behave erratically (diagonal moves, ignoring G-code) after skipping lines?
4. Should I manually adjust some commands or avoid specific combinations to work around this issue?

Thanks in advance for your help and advice! 😊