# [CNC Mill Concept: Deferred & Future Work](https://blog.hirnschall.net/cnc-mill-concept/deferred-and-future-work/)

author: [Sebastian Hirnschall](https://blog.hirnschall.net/about/)

meta description: Out of scope for the current CNC mill build: closed-loop servos, glass scales, custom drives, 4th and 5th axis, thermal compensation, and manufacturing docs.

meta title: CNC Mill Concept — Deferred & Future Work

date published: 25.03.2026 (DD.MM.YYYY format)
date last modified: 19.05.2026 (DD.MM.YYYY format)

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Introduction
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This post is part of the [CNC Mill Concept hub](https://blog.hirnschall.net/cnc-mill-concept/). It explicitly documents features and concepts that are **not part of the current build**, to prevent scope creep and preserve design intent for later development phases.

Motion and Feedback Upgrades
----------------------------

* Closed-loop servo drives on linear axes
* Dual-loop control using external feedback
* Glass scale integration for linear axes
* Replacement of stepper-based motion system

Drive Electronics
-----------------

* Custom servo inverter development
* Evaluation of GaN, SiC, or IGBT-based power stages
* Unified drive hardware for multiple machine projects

Additional Axes
---------------

* 4th axis integration
* 5th axis integration
* Simultaneous multi-axis machining capability

Advanced Compensation Strategies
--------------------------------

* Thermal compensation of machine structure
* Advanced force-based compensation
* Higher-order compliance models
* Integration of additional observers

Manufacturing and Implementation
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* Detailed CAD models
* Manufacturing drawings
* Assembly procedures
* Calibration procedures
* Validation and acceptance testing

Documentation Expansion
-----------------------

* Implementation-level documentation
* Firmware and software architecture documentation
* Maintenance documentation
* Operating procedures