Presetting tools

Tool Presetting and Zero-Setting

Tool presetting is the activity of measuring a cutting tool mounted in its tool holder, an operation commonly referred to as zero-setting or tool setting. This process is essential when replacing a worn tool with a new one on a machine tool.

This practice allows the measuring task to be performed during machine idle time, as two complete tool holders with perfectly zero-set tools are typically prepared to the same reference height (offset). With two tool holders available, one is mounted on the machine while the other is prepared offline, ensuring that when the tool currently in use wears out, the second tool can be mounted immediately. This drastically reduces the time required to replace the worn tool and minimizes machine downtime.

The precision of tool assembly for off-machine zero-setting is determined not only by the operator's professionalism and technical training but also by the use of specialized equipment. This includes length setters (simpler devices) and dedicated tool presetting machines (or tool presetters) equipped with optical, digital, or analog magnification systems.

Presettaging plays a crucial role in reducing lead times during the installation and set-up (tooling) of a new product to be manufactured. This presetting activity is also used during the initial set-up to perform a data collection of all tool offsets used for the production of the workpiece. While the time used for data collection is substantial during the first set-up, it provides a great advantage during the replacement of worn tools and in subsequent set-ups or tooling.

The primary function of a Tool Setter (the device, often a sensor or probe mounted directly on the CNC machine) is the zeroing of the tool to a well-defined reference datum. This ensures that the exact required dimensional measure is maintained after tool replacement, guaranteeing constant quality of the workpieces from the beginning to the end of the production process.