The Bare Engine has high requirements for size accuracy, shape accuracy and position accuracy, but poor rigidity and easy deformation.

The main processing surfaces of the MG Roewe Maxus Engine include large and small head holes, two end faces, connecting surfaces of the connecting rod cap and the connecting rod body, and bolts.

The secondary surfaces include oil holes, lock grooves, etc. There are also processes such as weighing, inspection, cleaning, and burr removal.

The connecting rod is a die forging, and the hole processing allowance is large, and residual stress is easy to generate during cutting. Therefore, when arranging the process, the coarse and fine processing of the main surface should be separated.

In this way, the deformation caused by coarse and fine processing can be corrected in semi-fine processing. The deformation caused by semi-fine processing should be corrected first.

1) Rough processing stage The rough processing stage is also the processing stage of the MG Roewe maxus engine: it is mainly the processing of the reference surface, including the processing of the auxiliary reference surface, and the processing of the Bare Engine, such as milling and grinding of the two mating surfaces.

2) Semi-finishing stage The semi-finishing stage is also the processing of the Bare Engine, such as fine grinding of two planes, semi-finishing building of the big head hole, chamfering of the hole mouth, etc. In short, this is a stage for preparing for fine machining of large and small holes.

3) The fine machining stage is mainly to ensure that the large and small holes on the main surface of the Bare Engine meet the requirements of the drawing, such as honing large holes, fine boring small head bearing holes, etc.