Three levels of post work
- Customisation – changing how an existing post formats its output, and exposing options. The logic stays the same.
- Modification – changing what the post does: new logic, new machine functions or corrected behaviour.
- Custom development – building a post, often with a machine definition, for a machine or control where no suitable post exists.
Side-by-side
| Aspect | Customisation | Modification | Custom development |
|---|---|---|---|
| Starting point | Working post | Working post | Library base or blank |
| Typical examples | Headers, comments, number formats, safe start lines, coolant codes | Tool change logic, new cycles, rotary clamping, probing, sub-spindle transfer | New 5-axis kinematics, multi-channel, special machines, unusual controls |
| Effort | Hours to a few days | Days | Days to weeks |
| Risk | Low | Medium | Higher until proven |
| Testing | Output comparison | Comparison plus machine trials of changed features | Full test library, simulation and staged proving |
When customisation is enough
If the post already produces correct motion and the machine runs its programs, but operators edit every file for headers, comments or codes, customisation fixes that. It is the quickest and safest option. See Fusion post customisation.
When you need modification
If the post lacks a function the machine has, such as rigid tapping, rotary clamping, tool preselection or sub-spindle transfer, or it behaves wrongly in some situations, the logic must change. That is modification. See Fusion post modification.
When to build a custom post
If no library post fits your machine, if the existing post has been patched so many times that nobody trusts it, or if the machine has unusual kinematics or channels, a custom post is the cleaner answer. It costs more up front but is easier to maintain. See custom Fusion post development.
Small changes to a sound post are cheap. Many patches to a weak post are expensive.
A quick way to decide
- Does the machine run the current output correctly? If yes, and you only want it to look different, customise.
- Is a machine function missing or wrong? Modify.
- Is there no suitable post, or is the current one unreliable? Build a custom post.
Whatever you choose, test it
Every change should be tested. Output comparison catches unintended changes; machine trials prove new behaviour. See testing and validation.