CNC Milling | T Command | Tool Preparation and Change

T Code Introduction

The tool selection takes place when the T word is programmed. Whether this is a tool change or only a preselection, is defined in the machine data:

  • The tool change (tool call) is performed either directly using the T word or
  • The change takes place after the preselection with the T word by an additional instruction M6

Note: If a certain tool is activated, it remains stored as an active tool even beyond the end of the program and after turning off/turning on the control system.

If you change a tool manually, input the change in the control system so that the control system knows the correct tool. For example, you can start a block with the new T word in MDI mode.

T Code Format

T… ; Tool number: 1 … 32; T0 – no tool, use to prepare next tool for change

Usage of T Code

M06 T…. ; Tool change

T Code Example

Tool Change without M6

N10 T1 ; Tool 1
N70 T588 ; Tool 588

Tool Change with M6

N10 T14 ; Preselect tool 14
N15 M6 ; Perform tool change; thereafter, T14 is active

Note: Tool preparation and change commands can be change due machine tool manufacturer.