Working Principle of CNC Lathe Triggered Measurement System

- Dec 13, 2019-

On-line active measurement of processed workpieces on CNC machine tools is an effective method to improve the degree of automatic processing of CNC machine tools and ensure the accuracy of workpiece processing. Therefore, the online active measurement system of CNC machine tool workpieces is one of the important characteristics of the skill of CNC machine tools Has become an essential basic option for the purchase of CNC machine tools.


Adopting the online active measurement system, it can assist the operator to hold the workpiece to the correct position before processing, and actively implement the setting of the workpiece coordinate system, which can simplify the tooling fixture, save the fixture cost, reduce the auxiliary time, and improve the processing efficiency After the neutralization process, the workpiece size can be actively measured online, and deviation compensation data can be actively generated according to the measurement results and fed back to the CNC system to ensure the dimensional accuracy of the workpiece and the uniformity of the size of the batch of workpieces;


The in-machine online measurement can also prevent the secondary deviation caused by moving the workpiece to the measuring machine, which can improve the processing accuracy and accuracy retention. After a single cutting, qualified products can be obtained, which greatly strengthens the intelligence of CNC machine tools. .


The active measuring system for workpieces used in CNC lathes is generally a triggering probe measuring system.

Generally, the trigger probe can be assumed to be installed as a tool on a certain tool position of the tool holder to measure the workpiece size. When the tool post is moved, the touch probe triggers the CNC system to record the probe position when it touches the workpiece, and the CNC system calculates the workpiece size through the corresponding measurement software.

On CNC lathes, the trigger measurement system can measure the outer diameter, inner diameter, length, and slot width of rotating parts.

Triggered probe measurement system is usually formed by trigger probe, signal transmission and receiver, restraint interface device connected to CNC system, coordinate position data collection, processing and measurement deviation compensation system, measurement effect active feedback compensation system, etc. .


The touch-trigger probe is a normally-closed contact-type integral unit probe, and the inside of the touch-trigger probe is three sets of equally-divided series contact trigger mechanisms.

In the profession, the probe can be installed as a tool on a certain tool position of the turret tool post. When the tool post is moved and the probe touches the workpiece, a slight deviation occurs in the probe, making one of the three-point contacts. Or two contacts are disconnected, a series circuit formed by three contacts is broken and a step signal is established in Russia. 


This signal passes the signal transmitter by wire (connection) or wireless (electromagnetic coupling, infrared radiation). 

It is transmitted to the restrainer interface. The restrainer interface transmits the signal with irregular oscillations established during the triggering to the CNC system after shaping. 

The CNC system issues a stop signal after receiving the trigger signal. The machine stops moving and records the probe at this time. Position coordinates, the CNC system actively sends the data to the corresponding parameter unit, and performs arithmetic processing as a variable. 


At this time, the CNC system calculates the size of the workpiece through the data processing software and measurement deviation processing software, and immediately feeds back to the CNC system to hold the tool initiative. Compensation or workpiece coordinate adjustment to ensure the CNC machining accuracy of the workpiece.


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