## 1 Introduction  
Polycrystalline diamond (PCD) manufactured by high-pressure synthesis is a high-performance synthetic super-hard material with high compressive strength, high wear resistance, good thermal conductivity, low thermal expansion coefficient, and favorable chemical stability [1]. PCD has greater fracture toughness than single-crystal diamond and ceramic materials; therefore, it can be used in cutting tools to obtain excellent machining accuracy and efficiency [2, 3]. PCD tools are mainly used for non-ferrous metal processing and high-wear processing, and have been widely used in the aerospace, automotive, and wood industries [4, 5]. In recent years, the use of carbon fiber/glass fiber composite materials in the aerospace and automotive industries has continued to expand; these materials are mostly processed using PCD tools. The Global Market Analysis Agency (GII) has estimated the global aerospace composite materials market to reach US $41.4 billion by 2025 [6], which will increase the demand for processing tools for PCD blanks. Owing to the excellent properties of PCD materials, such as high hardness and high strength, PCD tools are more difficult to process and shape, and are not suitable for production by traditional milling or turning processing methods [7]; therefore, the development of PCD processing technology is necessary. At present, in the manufacturing of PCD tools, wire electrical discharge machining (WEDM) is commonly used to cut the PCD material into a tool blank, which is then welded to the tool-holder and then polished and finished using a diamond grinding wheel [8]. Electrical discharge machining is a non-contact machining process, which is not affected by the strength and hardness of the material during processing. However, wire electrical discharge machining produces a surface damage layer, which affects the quality of the cut edge [7], and the discharge efficiency is affected by the diamond grain size [9]. The discharge pulse will also cause surface pits on the cut surface, which will reduce the strength of the material. Hence, it needs to be polished with a diamond wheel during post-treatment. [PERSON] et al. [7] mentioned that the processing of a PCD material by wire electrical discharge machining is limited by the fact that diamond cannot conduct electricity, and it is necessary to induce electrical discharge to remove the material through a cobalt binder. The study explored the effects of processing parameters such as pulse time, pulse interval, and servo voltage on the PCD surface morphology after processing. After the optimization experiments, the best surface roughness (Ra = 0.684 \(\upmu\)m) was obtained with pulse time of 0.4 \(\upmu\)s, pulse interval of 20 \(\upmu\)s, and servo voltage of 80 V. However, the results showed that when the PCD was processed by wire cutting, the surface of the PCD was contaminated and damaged due to sputtering of the spark during discharge, resulting in obvious damage layers and pits on the surface of the PCD. [PERSON] and [PERSON] [10] discussed the difference in the quality of PCD tools obtained by electrical discharge machining and grinding. Applying diamond-wheel grinding to the PCD workpiece ensures better surface quality. However, the processing efficiency of grinding is poor, and the tool to be ground must have sufficient material strength to support the cutting force generated during processing. Hence, it is not suitable for processing tools with complex geometric shapes. The study also revealed that because the surface quality after PCD cutting is better with fewer surface defects, the impact resistance and fatigue damage resistance of the cutting edge would be improved. It can also reduce the cutting heat caused by friction between the tool and workpiece. Therefore, diamond grinding wheel finishing is widely used in the finishing process of PCD tools. However, it has problems such as high processing cost, low processing efficiency, and unsuitability for both complex geometry tools and micro tool processing [10; 11; 12; 13; 14].