For box parts, generally speaking, the main
hole is used as the rough reference to produce and process the plane, and then
the plane is used as the fine reference to produce and process the hole system;
for shaft parts, the outer circle is generally used as the rough reference to
process the center hole, and then the
The center hole is used to process other surfaces such as the outer
circle and the end face of the precision reference. If there are several fine datums, the
processing of the base surface and the main surface should be arranged
according to the order of datum conversion and the principle of further
improving the machining accuracy.
The
specific working principles of non-standard parts processing can be divided
into four levels:
The
main surface of a part is generally a surface with relatively high processing
accuracy or surface quality requirements. The quality of their production and
processing products has a great influence on the product quality of a whole
part, and there are often many processing procedures, so it should be Arrange the processing of the main surface
first, and then arrange the processing of other surfaces appropriately to
intersect among them. Usually, the
assembly base surface, working surface, etc. are regarded as the main surface,
and the keyway, light hole and screw hole for fastening are regarded as the
secondary surface.
