大连机械加工的零件在加工和装配历程中所使用的基准，称为工艺基准
。工艺基准按用途差别，又分为定位基准、丈量基准和装配基准
。

1）定位基准：加工时使工件在机床或夹具中占据正确位置所用的基准，称为定位基准
。按定位元件的差别，最常用的有以下两类：

自动定心定位：如三爪卡盘定位
。

定位套定位：将定位元件做成定位套，如止口盘定位
。

其他有在V形架中定位，在半圆孔中定位等
。

2）丈量基准：零件检验时，用以丈量已加工外貌尺寸及位置的基准，称为丈量基准
。

3）装配基准：装配时用以确定零件在部件或产品中位置的基准，称为装配基准
。

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.