The reference used in manufacturing and assembling parts is called the process reference. Process standards are divided into positioning standards, measurement standards, and assembly standards according to their different uses. Let's learn in detail below.

Key points of basic knowledge in machining.

(1) Machining positioning reference: The reference used to place the workpiece in the correct position of the machine tool or fixture during machining is called the positioning reference. According to different locations, the following introduction can generally be made:

Three jaw chuck positioning: such as automatic centering positioning.

Sleeve positioning: Make positioning components into positioning kits, such as fixed plate positioning.

The others are V-shaped frames and semi-circular holes, etc.

(2) The measurement benchmark for mechanical machining: The benchmark used to measure the size and position of the machining surface during part inspection is called the measurement benchmark.

(3) Mechanical machining assembly reference: The reference used to determine the position of parts or components in a product during assembly is called the assembly reference.

In the process of mechanical processing, the quality of workpiece installation not only directly affects machining accuracy, workpiece installation speed and stability, but also affects production efficiency. To ensure the relative positional accuracy between the machining surface and its design reference, the design reference of the machining surface should be positioned relative to the machine tool during workpiece installation. For example, in the precision machining process of the ring groove, to ensure the circular runout of the bottom diameter of the ring groove and the axis of the skirt seat, the workpiece should be installed in line with the axis of the machine tool spindle.

There are various installation methods for processing different types of machine tool parts. The installation methods can be summarized as right angle, positioning, and fixture installation.

(1) Through a series of experiments, the correct position that the workpiece should occupy on the machine tool can be directly found, so that this method can be used. Specifically, after the workpiece is directly installed on the machine tool, it is checked with a stylus or stylus to ensure correct positioning of the workpiece, and the workpiece is calibrated while checking until it meets the requirements of mechanical processing.

(2) The labeling method is a method of using a stylus on a machine tool to align the workpiece based on the lines drawn on the blank or semi-finished product, in order to obtain the machining position. Obviously, this method also requires a marking process. The marking itself has a certain width, and there is a marking error during marking, and there is an observation error during workpiece calibration. Therefore, this method is mostly used for small batch production, with low blank accuracy, and is not suitable for rough machining of large workpieces using fixtures.

(3) The process equipment used to clamp the workpiece and place it in the correct position using the fixture installation method is called a tool clamp. A fixture is an additional equipment of a machine tool. Before loading the workpiece, its position with the cutting tool on the machine tool is pre adjusted. Therefore, when processing a batch of workpieces, it is a very effective positioning method that does not require individual alignment and positioning, ensuring the requirements of the processing technology. It is also a very effective positioning method, widely used in large-scale mechanical processing production.