PCD is made of specially treated diamond sintered with a small amount of binder under high temperature and ultra-high pressure. The disorderly arrangement of diamond grains gives PCD a uniform, extremely high hardness and wear resistance. PCD can be used for cutting tools, grinding wheel dressing, geological drilling, gauging probes, wire drawing feelers, sandblasting feelers, etc. However, the high hardness and high wear resistance of PCD also pose great difficulties for its processing.

Scholars at home and abroad have conducted a lot of researches and tests on the processing problems caused by the high hardness and high wear resistance of PCD materials, including EDM, ultrasonic processing, electrochemical processing, laser processing, etc., and have achieved certain results. However, a comprehensive analysis shows that these machining techniques are mostly applicable to the rough machining of PCD materials at present. In order to obtain good quality of PCD cutting edge, the most ideal processing method is still grinding or lapping with diamond grinding wheels.

PCD grinding process is mainly the result of a mixture of mechanical and thermochemical effects. The mechanical effect is through the diamond wheel grinding grain on the PCD material of the continuous impact and the formation of diamond micro-breakage, wear, shedding or deconstruction; Thermochemical effect is the diamond wheel grinding PCD formed by high temperature to oxidation or graphitization of diamond. The mixture of the two results in the removal of PCD material. The grinding process is mainly characterized by the following

  (1) Grinding force is very high

  Diamond is the hardest known mineral material, and a variety of metal, non-metallic material pair friction wear amount is only 1/50 ~ 1/800 of carbide; PCD hardness (HV) for 80 ~ 120KN/mm2, second only to single crystal diamond, much higher than carbide. When using diamond grinding wheel to grind PCD, the starting cutting strength is very high, about 10 times higher than that of cemented carbide (0.4MPa); the specific grinding energy reaches 1.2×104~1.4×105J/mm3; Therefore, the grinding force is much higher than that of cemented carbide.

  (2) Small grinding ratio

  نظرًا للصلابة العالية ومقاومة التآكل لـ PCD (مقاومة التآكل النسبية من 16 إلى 199 مرة من كربيد الأسمنت) ، فإن نسبة الطحن لـ PCD هي فقط 0.005 إلى 0.033 ، أي حوالي 1/1000 إلى 1/100000 من ذلك من كربيد الأسمنت كفاءة الطحن هي فقط 0.4 إلى 4.8 مم 3 / دقيقة. لذلك ، فإن وقت الطحن طويل جدًا وكفاءة المعالجة منخفضة جدًا من أجل ضمان جودة حافة أداة القطع ومقدار الإزالة ، وكفاءة المعالجة منخفضة جدًا. بالإضافة إلى ذلك ، عندما تختلف الصلابة والمحتوى وحجم الجسيمات لـ PCD ، فإن وقت الطحن يختلف أيضًا بشكل كبير.

(3) حجم الحبوب له تأثير كبير

تنقسم مادة PCD المستخدمة في أدوات القطع إلى ثلاث فئات وفقًا لحجم الجسيمات: خشن (20-50 ميكرون) ومتوسط ​​(10 ميكرومتر) ودقيق (حوالي 5 ميكرومتر) ، والفرق في قوة الطحن ونسبة الطحن عدة مرات إلى عشرات المرات . تتميز PCD ذات الحبيبات الخشنة بأعلى نسبة طحن وهي الأكثر صعوبة في الطحن ، ولها حواف خشنة وأسوأ جودة بعد الطحن ، ولكنها أقوى مقاومة للتآكل.