Solutions for Overcutting and Inaccurate Centering on a CNC Machining Center



Vertical machining centers are convenient for setup, easy to operate, and allow for better visibility during machining, making program debugging simpler and widely applicable. However, due to the height limitation of the column and the tool changer, they are not suitable for machining tall workpieces. Additionally, when machining cavities or recessed surfaces, chip evacuation becomes difficult, which can severely damage the tool, ruin the machined surface, and negatively impact the machining process.

So, how should we address issues like overcutting and inaccurate centering during operation? Let’s take a closer look below.


1. Overcutting

External causes of overcutting typically include inadequate tool strength or improper tool size. Internally, it may result from improper operator procedures, incorrect cutting parameter settings, or uneven allowance settings, all of which can lead to excessive tolerances and ultimately cause overcutting and machining errors.

Solutions:
    •    When adding a corner-cleaning program, try to leave a uniform machining allowance.
    •    Use larger and more robust tools where possible.
    •    Utilize the SF (feedrate override) function of the vertical machining center to gradually fine-tune and optimize cutting performance.


2. Inaccurate Centering

Centering is the step where the machining center determines the origin point. Every operation on a machining center relies on this step. Besides human error during manual operation, factors such as burrs around the mold, non-perpendicular edges, or a magnetic centering bar can lead to inaccurate centering.

Solutions:
    •    Demagnetize the centering bar before performing centering on the mold.
    •    Double-check manual centering operations to ensure the same point and height are used consistently.
    •    Regularly use a dial indicator to check whether all four sides of the mold are perpendicular.


By addressing both external and internal causes systematically, you can greatly improve the accuracy and quality of your machining operations.