Numerical control lathe is a high-precision and high-efficiency active machine tool. The use of numerical control lathe can improve machining efficiency and invent more value. The emergence of numerical control lathe has freed enterprises from outdated machining technology. The machining process of numerical control lathe is similar to that of general lathes, but due to the fact that numerical control lathe is a one-time fixture, continuous active machining completes all turning processes. Therefore, attention should be paid to the following aspects. Turning the inner hole on a CNC lathe is a common machining method in production. When turning the inner hole, it is necessary to understand the tools used for inner hole machining, the process of inner hole machining, the measuring tools used for inner hole measurement, and the quality of inner hole machining.

1、 Tools for inner hole machining

According to different situations, inner hole turning tools can be divided into through hole turning tools and blind hole turning tools.

1. Through-hole turning tool

In order to reduce radial cutting force and prevent vibration, the main deviation angle of through-hole turning tools is generally 60-75 degrees, and the secondary deviation angle is 15-30 degrees. In order to prevent conflicts between the rear cutting surface and the hole wall of the inner hole turning tool, and not to grind the rear corner too large, it is generally ground into two rear corners.

2. Blind hole turning tool

Blind hole turning tools are used for turning blind holes or step holes, with a main deviation angle of 90-93 degrees. The tool tip is at the forefront of the tool holder, and the distance between the tool tip and the outer end of the tool holder is less than the radius of the inner hole.

2、 Inner hole processing technology

Turning holes are one of the commonly used hole processing methods, which can be used for rough machining or precision machining. In order to increase turning rigidity and prevent vibration, it is necessary to choose a thicker tool holder as much as possible. When clamping, the extension length of the tool holder should be as short as possible, just slightly greater than the hole depth. The tool tip should be aligned with the center of the workpiece, and the tool holder should be parallel to the axis. To ensure safety, you can use an inner hole knife to test run through the hole before entering the car. When precision machining the inner hole, the blade should be kept sharp, otherwise it may cause the hole to be tapered.

3、 Measuring tools for vehicles with inner holes

When the accuracy requirement for the aperture standard is low, steel rulers, internal calipers, or vernier calipers can be used for measurement. When the accuracy requirement is high, an inner micrometer or inner diameter gauge can be used for measurement. For standard holes, a plug gauge can also be used for measurement.

1. Vernier caliper:

When measuring the aperture standard with a vernier caliper, pay attention to the parallelism between the caliper body and the workpiece end face, and swing the movable measuring claw along the circumferential direction to find the maximum orientation.

2. Inner micrometer:

The direction of the scale line on this type of micrometer is opposite to that of the outer diameter micrometer. When the differential cylinder rotates clockwise, the movable claw moves to the right and the measurement value increases.

3. Inner diameter dial gauge:

The inner diameter dial gauge is assembled by clamping the dial gauge onto the measuring frame. Before measurement, replace the fixed measuring head based on the size of the measured workpiece aperture, and use a micrometer to align the inner diameter dial gauge with the "zero" position. The minimum value of the swing dial indicator is the practical standard for aperture.

4. Plug gauge:

Consisting of a through end and a stop end, the through end is made according to the minimum limit standard of the hole, and should be inserted into the hole during measurement. The stop end is made according to the maximum limit standard of the hole, and it is not allowed to be penetrated into the hole during measurement. When the same end can be inserted into the hole but the stop end cannot be inserted, it indicates that the hole standard is qualified.