Oct. 28, 2025
Laser pneumatic chucks are generally classified into three-jaw chucks, hydraulic chucks, soft-jaw chucks, and four-jaw linkage chucks.
1. Three-jaw chucks determine the turning center of the workpiece. Based on the circumference of the clamping part of the workpiece,
three-jaw chucks are generally chosen to complete turning, grinding, and milling operations with high clamping accuracy.
For high-precision milling parts, a universal indexing head is used, while for grinding, lathe rough turning, and parts requiring less precise positioning,
a three-jaw chuck with lower clamping accuracy is used. The principle of a three-jaw chuck clamping the workpiece is to rotate any three bevel teeth on the circumference using a chuck wrench.
Three-jaw chucks used on lathes often have small chips that frequently enter the bevel gear pair and disc-shaped chuck, causing uneven chuck tightness or even jamming,
while also increasing wear on parts and affecting normal operation. Another reason for chip insertion into the chuck is insufficient chuck flange stop height,
resulting in excessive clearance between the flange and the pressure cover behind the chuck.
2. Hydraulic chucks generally consist of three parts: the chuck, a rotary cylinder, and a hydraulic station. They are a widely used type of chuck.
Its main characteristics are high clamping accuracy, durability, strong clamping force, and very stable performance.
Therefore, precision CNC lathes manufactured worldwide are mainly equipped with hydraulic chucks.
3. Soft jaw chucks can improve positioning accuracy and save auxiliary time for workpiece installation during mass production.
To allow for adjustments to the arc diameter and shape of the jaws as needed, low-carbon steel, copper, or aluminum alloy jaws can replace the hardened jaws of a three-jaw chuck;
this improves workpiece positioning accuracy after machining. Soft jaw chucks clamp the machined surface or soft metal, but are not suitable for clamping surfaces.
For thin-walled workpieces, fan-shaped jaws can increase the contact area with the workpiece and reduce workpiece deformation.
Soft jaw chucks are suitable for semi-finish turning and finish turning of workpieces with machined surfaces, serving as a reference for positioning accuracy in mass production.
Correct adjustment and rotation of the soft jaw chuck are the primary conditions for ensuring its accuracy.
The bottom of the soft jaw and the positioning platform should slide with the jaw bottom for correct positioning. To eliminate clearance,
a cylinder or sealing ring of appropriate diameter must be installed inside or outside the jaw.
The soft jaws should be positioned according to the workpiece clamping direction. Otherwise, the positioning accuracy of the workpiece cannot be guaranteed.
When clamping the workpiece, the cylinder should be clamped inside the chuck jaws, making the surface of the chuck jaws flexible.
When tightening the workpiece, the ring should be installed outside the chuck jaws and the rotating flexible jaws.
4. The four-jaw linkage chuck is a manual four-jaw machine tool self-centering chuck. It consists of a wire, four small umbrella-shaped teeth, and a pair of jaws.
The four small umbrella-shaped teeth mesh with a disc-shaped thread. The back of the disc-shaped thread has a planar thread structure,
and the jaws are mounted equally on the planar thread. When the small umbrella-shaped teeth are pulled with a wrench, the disc-shaped thread rotates,
and the flat thread on the back of the wrench causes the jaws to simultaneously approach or retract from the center.
Because the pitch of the planar rectangular thread on the disc is equal, the four jaws move at the same distance, providing an automatic centering function.
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