# POM

POM is one of the more comfortable plastics to machine on compact CNC machines.\
It behaves predictably, cuts cleanly, and tends to be more forgiving of small mistakes than aluminium.

### Why POM works well 

* clean shearing → little to no smearing
* low cutting forces → forgiving on low-stiffness systems
* predictable chip formation → less heat accumulation
* dimensional stability → stays flat, doesn’t swell like nylon or warp like ABS
* no abrasive fillers (default POMs) → tool wear stays minimal

### Where POM behaves differently than aluminium

Even though it’s easier in many ways, POM is not just “softer aluminium.”

| Area            | What to expect                                                             |
| --------------- | -------------------------------------------------------------------------- |
| Chip evacuation | Chips can be long / stringy → sharp tools help chip breakage               |
| Heat            | Less heat tolerance than aluminium → keep engagement steady, avoid rubbing |
| Finish          | Excellent finishes are possible, but require *shearing*, not melting       |

{% hint style="info" %}
**Quick Notes on POM (Acetal / Delrin®)**

* **POM** is the material name.\
  Also called **Acetal**.\
  **Delrin®** is a brand name for **POM-H** (one specific type).
* There are two common types:\
  **POM-H** (homopolymer) → slightly stronger, crisp cutting\
  **POM-C** (copolymer) → more stable, less heat-sensitive
* **For dry milling on compact CNCs:**\
  POM-H and POM-C behave so similarly that you can **treat them the same in practice**.\
  If you don’t know which one you have, it’s fine — use the same workflow.
  {% endhint %}

***

### Related Pages

Where to buy / sourcing --> [Sourcing Tools & Materials](/miwicnc/sourcing-tools-and-materials.md)


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