Page 12 - 《橡塑技术与装备》英文版2025年12月

HINA R&P TECHNOLOGY AND EQUIPMENT

machining process. The quality of barrel machining is related machining process exceptionally difficult. Especially when
to the service life of the overall equipment, which in turn intermittent cutting is required, tool wear intensifies, and the
determines the success or failure of the unit and ultimately surface of the workpiece is prone to cold work hardening,
affects the quality of raw material mixing and plasticization. further increasing the difficulty of machining. In addition,
It restricts the healthy and rapid development of China's a layer of oxide layer will form on the surface of the barrel
petrochemical and coal chemical industries, endangering after quenching and tempering treatment. This oxide layer
national economic security. The quality and efficiency of barrel not only affects the cutting performance of the tool but may
machining severely restrict the construction period of large also lead to the generation of more heat and cutting force
extrusion granulation units. It is imperative to solve and break during machining, thereby affecting machining accuracy and
through this technical bottleneck. workpiece quality.

Figure2 Barrel

Currently, the double-hole machining of the barrel utilizes
Figure 1 Assembly diagram of co-rotating granulation grinding processes. Despite employing equipment with a CNC
unit barrels in series
vertical lathe for clamping and grinding heads, the analysis of
1 Process issues and cause analysis post-processing data reveals that the straightness of the barrel's
In the process of machining machine barrels, double- inner hole grinding still fails to meet the drawing requirements.
hole machining is a crucial step, especially when these two This machining process indeed presents a series of significant
holes need to intersect at a specific angle to form the so-called difficulties and challenges.
"figure-eight hole". This hole type not only requires the hole
itself to meet standard dimensions and shape accuracy, but
also necessitates ensuring the straightness of the hole and its
perpendicularity to the barrel's end face, both of which must
be controlled within 0.03 mm. For a set of machine units,
typically 8 to 11 such machine barrels are assembled in series,
which requires that the double-hole machining of each barrel
must meet the same high-precision standards to ensure smooth
coordination of the entire unit during operation, reduce friction
and wear, and enhance the overall performance and lifespan of
the equipment. Figure3 CNC vertical lathe grinding machine cylinder
bore
The material of the barrel is 38CrMoAlA, which is a
kind of alloy steel that has undergone special quenching and
Firstly, the grinding method of CNC vertical lathes
tempering, exhibiting excellent wear resistance, corrosion
primarily relies on spindle feed grinding (see Figure 3).
resistance, and high-temperature performance. However, the
However, when machining double holes, the spindle extends
high hardness and toughness of this material also make the
a long distance, leading to a significant reduction in spindle

·6· Vol.51，No.12