How to Calibrate CNC Milling Machine

CNC milling machines are commonly used in today’s producing process. When people need to use CNC milling machine, they need to learn how to calibrate CNC milling machine primarily. Calibration is undoubtedly one of the most important steps when using CNC milling machines. Today, this article will introduce calibrate to you, and we will tell you the reasons for periodic calibration, also we will teach you how to calibrate CNC milling machine.

List: 1. Introduction of Calibration

         2. Reasons For Periodic Calibration of CNC Milling Machine

         3. How to Calibrate CNC Milling Machine

Introduction of Calibration

Calibration means a set of operations to determine the indication error of a metering device under specified conditions. It is a set of operations for determining the relationship between the indication of a meter or measurement system, or the value represented by a physical gauge or a reference material, and the corresponding measured known value, under specified conditions. Calibration results can be used to assess the indication error of a meter, measurement system, or physical gauge, or to assign a marker to any scale. Machine calibration is a process of measuring, diagnosing and correcting manufacturing errors in machine tools or CNC machines.

Reasons For Periodic Calibration of CNC Milling Machine

Most large machine tools come directly from the manufacturer and have a set of tolerances. With the passage of time, the errors of machine tools will increase when parts (drilling, milling, lathe) are manufactured. The volume or centering accuracy of the machine may be the reason why your parts are not within tolerance range. When the quality problem of the electric spindle needs to be strictly considered, the cycle time is directly affected by calibration and compensation. A machine tool with a range of accuracy can work at high speed while maintaining machining accuracy. Calibration allows on-line inspection of the workpiece, saving time in moving the workpiece back and forth between the machine and the CMM. In addition, periodic calibration can also be used to predict whether the machine is about to deviate from the accuracy specification.

Why we need periodic calibration? There are five reasons:

1. Reducing the Reprocessing of Parts

2. Reduce machine wear and tear

3. Standardization

4. Increase output

5. Increase the normal running time of the machine

How to Calibrate CNC Milling Machine

First check the accuracy of the level on the inspection platform, as the key to determine the level of adjustment. The method is to test a certain fixed position on the platform, generally placing a corner. After the bubble of the level is stabilized, flip it 180 degrees to see if the level is consistent. Consistent can proceed to the next step, inconsistent, please adjust the level with experienced people. Previously, laser calibration instruments required professional metrologist. The machine cover needs to be opened so that the optics can be adjusted on the table, the spindle and the independent tripod. The process of spatial calibration takes several days, depending on the size of the machine. Therefore, when the workpiece is measured within the tolerance range by the CMM, spatial calibration is not necessary. With the advancement of technology, the cost of laser calibration equipment is greatly reduced, and professional metering personnel and external services are not required, and machine downtime is greatly reduced. A mechanic trained in laser calibration for one day was able to complete a space measurement of a 1 cubic meter machine in half a day. The software can automatically write out the compensation table and upload it to the controller of the machine. For many years, the body diagonal displacement method (BDDM) defined in the ASMEB 5.54 or ISO 230-6 standard has provided a method for quickly detecting spatial errors for many manufacturers. The BDDM measures the four diagonals of the machine's workspace and produces four sets of data including all errors.

From all the information given above, we believe you have already learned the meaning of calibration and how to calibrate CNC milling machines. In addition, you know why periodic calibration is necessary. We hope this article can help you solve your problems.