What Are The Advantages of Turning And Milling Compound

Viii. Turning and Milling Compound

Modern turning and milling compound machining centers combine two technologies, allowing turning and milling operations to be completed on a single machine tool, which greatly improves the processing efficiency and accuracy of complex parts and reduces the number of clamping operations. But it is still crucial to understand their respective fundamental principles.

Turning and milling Compound Machining integrates the core functions of turning and milling, achieving the collaborative processing of "rotating workpiece + rotating tool" on the same equipment, perfectly combining the advantages of both. The core logic is: to handle rotational symmetry features with the high efficiency of turning, to handle complex contours with the flexibility of milling, and at the same time eliminate multi-process errors through "one-time clamping". The following is the specific combination method and advantage analysis:

1. Core integration mechanism: Integration of equipment and functions

Turning and milling compound machine tools are usually upgraded based on the CNC lathe platform. By adding a Powered Tool Turret (powered tool Turret), c-axis (workpiece indexing function) and milling spindle, the compound processing capability of "turning + milling" is achieved. Key hardware support includes:

Power tool turret: Equipped with turning tools (for turning outer circles/end faces) and milling cutters (for milling grooves/holes/profiles), it is a milling power head that supports independent rotation.

C-axis function: The workpiece can be divided on the basis of turning (such as 1° per revolution), and in combination with a milling cutter, it can achieve circular milling or helical interpolation.

Multi-axis linkage: The X/Z axes for turning are linked with the A/C axes (rotary axes) for milling to process complex curved surfaces or irregular features.

2. Specific combination points of advantages

The processes are highly concentrated to reduce clamping errors

Traditional mode: To process an shaft part with an outer circle, end face, keyway, thread and hole, it needs to go through:

Lathe (turning outer circle → turning end face → turning thread) → milling machine (milling keyway → drilling) → drilling machine (tapping), at least 3-4 clamping times.

Turning and milling compound mode

After the workpiece is clamped once, the following procedures are completed in sequence: turning the outer circle → turning the end face → turning the thread → milling the keyway with a power tool → drilling with a power tool → tapping with a power tool.

Advantages

It avoids positioning errors caused by multiple clamping (the cumulative error of traditional clamping can reach 0.02-0.05mm, while that of turning and milling compound can be controlled within 0.01mm), and is especially suitable for high-precision parts (such as aerospace shafts and medical implants).

3. Balance efficiency and flexibility

The efficiency of turning

For rotationally symmetrical outer circles, end faces, threads and other features, the continuous cutting efficiency of turning is much higher than that of milling (the feed rate of turning can reach 0.2-0.5mm/r, while that of milling is usually 0.05-0.2mm/tooth). The turning and milling compound retains the batch processing efficiency of turning.

The flexibility of milling

For asymmetric features (such as keyways, polygonal contours, inclined holes, and curved surfaces), the milling function of the power tool turret can directly process them without the need for additional equipment. For example:

After turning the outer circle, use a milling cutter to mill a groove that forms a 30° Angle with the axis.

When turning the end face, simultaneously use a milling cutter to process the center hole or chamfer.

Using C-axis indexing, six evenly distributed threaded holes are milled around the circumference (replacing the indexing of traditional drilling machines).

4. Shorten the production cycle and reduce costs

Time cost: Reduce the time for clamping, handling and alignment (the proportion of clamping in the traditional mode is about 30%, and it can be reduced to 5% with the combination of turning and milling).

Equipment cost: One turning and milling compound machine tool replaces multiple machines such as "lathe + milling machine + drilling machine", saving space and maintenance costs.

Labor cost: Reduce the number of operators (traditionally, 2-3 people are needed to operate multiple machines, while for turning and milling, only 1 person is required).

5. Enhance the consistency of surface quality

The roughness of the axial surface (such as the outer circle) turned itself can reach Ra 0.8-1.6μm;

During milling, due to the synchronicity of the workpiece rotation and the tool rotation, there are fewer tool marks on the radial surface (such as the milling groove), and the roughness can be stably maintained within Ra 3.2μm.

The surface quality of each feature of the entire part is more uniform, reducing the subsequent polishing process.

6. Typical application scenarios

Turning and milling compound processing is particularly suitable for the following types of parts:

Shaft parts with complex features: such as drive shafts with keyways, threads, helical grooves, and planar markings;

Disc-shaped parts: such as flange discs (end faces need to be turned + bolt holes need to be milled + center holes need to be drilled);

Small irregular-shaped parts: such as medical orthopedic implants (requiring turning of the outer contour + milling of the bone contact surface);

High-precision batch parts: such as automotive transmission gear shafts (requiring turning the outer circle + milling grooves + tapping + inspection).

Summary: The essence of turning and milling compound

Turning and milling compound processing integrates the core advantages of both (the high efficiency of turning and the flexibility of milling) into one through the mode of "turning to handle the rotating body + milling to handle the local complex features", and at the same time resolves the contradiction between precision and efficiency in traditional multi-process processing through "one-time clamping". It is a typical representative of the development of modern numerical control processing towards high precision, high efficiency and high flexibility.