大連機械加工的零件在加工和裝配過程中所使用的基準，稱為工藝基準。工藝基準按用途不同，又分為定位基準、測量基準和裝配基準。

1）定位基準：加工時使工件在機床或夾具中占據正確位置所用的基準，稱為定位基準。按定位元件的不同，最常用的有以下兩類：

自動定心定位：如三爪卡盤定位。

定位套定位：將定位元件做成定位套，如止口盤定位。

其他有在V形架中定位，在半圓孔中定位等。

2）測量基準：零件檢驗時，用以測量已加工表面尺寸及位置的基準，稱為測量基準。

3）裝配基準：裝配時用以確定零件在部件或產品中位置的基準，稱為裝配基準。

The reference used in the machining and assembly process of parts processed by Dalian Machinery is called the process reference. Process standards are divided into positioning standards, measurement standards, and assembly standards according to different purposes.

1) Positioning reference: The reference used to ensure that the workpiece occupies the correct position in the machine tool or fixture during processing, known as the positioning reference. According to the different positioning components, the most commonly used ones are the following two types:

Automatic centering positioning: such as three jaw chuck positioning.

Positioning sleeve positioning: Make the positioning element into a positioning sleeve, such as a stop plate positioning.

Others include positioning in the V-shaped frame and positioning in the semi-circular hole.

2) Measurement benchmark: The benchmark used to measure the size and position of the machined surface during part inspection is called the measurement benchmark.

3) Assembly reference: A reference used during assembly to determine the position of a part in a component or product, known as an assembly reference.