How to ensure the stability of part fixation during machining on CNC machine tools?

During the machining process of CNC machine tools, the stability of part fixation is crucial to machining accuracy and surface quality. Even the most advanced CNC machine tools may cause part displacement, vibration or shape error if the parts are not firmly fixed during machining, thus affecting the final machining effect. Therefore, how to ensure the stable fixation of parts on CNC machine tools is the key to improving machining accuracy and reducing errors.

Basic requirements for part fixation
The fixation of parts must ensure that the parts will not be displaced, tilted or vibrated during the entire machining process. In this way, the relative position between the tool and the workpiece can be kept consistent, thus avoiding machining errors. To ensure stability, the fixing method needs to consider the following factors:

Weight and size of parts
Large or heavy parts may require a more robust fixing method, while small parts can use lighter fixtures. Ensuring that the fixing method matches the size, weight and shape of the part is the basis for ensuring stability.

Vibration during machining
During the cutting process, the parts may be subject to a certain degree of vibration due to the high-speed rotating tool and feed speed. In order to avoid the influence of vibration on machining accuracy, appropriate fixing measures need to be taken to reduce the error caused by vibration.

Common fixing methods
In the process of CNC machine tool processing, the commonly used methods for fixing parts are mainly the following:

Mechanical clamps
Mechanical clamps are the most common fixing method. It fixes the parts firmly on the workbench by clamping different parts of the parts. Common mechanical clamps include:

Plane clamps: suitable for flat parts, and the parts are pressed on the workbench by the clamps.

Three-jaw chuck: suitable for round parts, the chuck fixes the parts tightly with three clamping jaws to prevent the parts from moving during processing.
Screw clamping: The clamp is fixed by rotating the screw, which is suitable for small or irregularly shaped parts.
Vacuum clamps
Vacuum clamps adsorb parts to the workbench by generating negative pressure. This method is particularly suitable for thin plates, precision parts or irregularly shaped parts. Vacuum clamps can evenly distribute pressure to avoid unnecessary deformation of the part surface.

Magnetic clamps
Magnetic clamps use strong magnetic fields to adsorb metal parts and are suitable for parts processing of magnetic materials. Its advantages are quick installation and disassembly, and the ability to fix the workpiece in a short time, reducing the clamping time.

Hydraulic clamps
Hydraulic clamps provide strong clamping force through the hydraulic system, which is suitable for parts that require high clamping force during processing. Hydraulic clamps can fix large parts or parts with complex shapes very stably, especially in high-precision processing.

Locating pins and fixing pins
Locating pins are important tools to ensure that the part is fixed in position in the fixture. It aligns with the matching holes of the part to ensure that the position of the part does not change, and is usually used in conjunction with the fixture.

How to reduce errors in part fixing
In addition to choosing a suitable fixing method, a series of measures need to be taken to reduce the errors that may occur during the fixing process:

Part pretreatment
Before installing the part on the CNC machine, ensure that the surface of the part is clean and flat to prevent dust or oil from affecting the contact surface of the fixture, thereby affecting the fixing effect. Precisely measure the machined surface of the part to ensure that it is perfectly docked with the fixture to reduce errors.

Apply force evenly
When fixing parts, ensure that the force applied by the fixture is evenly distributed to avoid excessive or insufficient force on the parts, which may cause deformation or loosening. Especially during processing, the distribution of pressure will affect the stability of the parts.

Avoid excessive fixing
When fixing parts, avoid excessive fixing force. Excessive clamping force may cause deformation or damage to the parts. Reasonably select the fixing force of the fixture to ensure that the parts will not deform and remain stable during processing.

Check the fixing status regularly
During processing, check the fixing status of the parts regularly to ensure that the parts are not loose or displaced. During long-term or high-load processing, parts may loosen due to mechanical vibration or long-term pressure, so they need to be checked frequently and adjusted in time.