Product Name: Powder-Pressed Graphite Molds

Product Features: Made from high-purity graphite powder with low ash content and excellent thermal stability. The product features uniform density, high strength, good dimensional consistency, and stable electrical resistance.

Applications: CBN synthesis, sintering of PCBN composite inserts, sintering of diamond composite inserts, PCBN sintering, and PCD sintering

Technical Specifications: Density: 2.2–2.3 g/cm³.

Product Specifications: Custom-made tubular molds and honeycomb molds with various hole patterns (available with or without a base). Hole patterns, outer diameter, height, depth, and other specifications can be customized according to requirements.

Historical Background

Initially, graphite molds for superhard materials were machined from large blocks of synthetic graphite after coring. Particularly for molds with irregularly shaped holes, the process involved gradual machining with a broach, resulting in very low production efficiency and difficulty in ensuring precision. Traditionally, these machined graphite molds generated significant dust on the production floor, had low processing efficiency, and made it difficult to ensure product consistency. Since large blocks of synthetic graphite vary from batch to batch—and even within the same block—different locations may have different properties, leading to fluctuations in the resistance of the graphite molds. This product breaks with traditional manufacturing methods by adopting powder compaction technology, making product quality easier to control and better suited for high-volume production.

Product Advantages

Uniform density. Density directly affects the product’s resistance and strength. Higher density results in relatively lower resistance and increased strength. Density uniformity significantly impacts resistance; this product employs a custom mold frame combined with multi-layer synchronized pressing technology, resulting in minimal density variation. During heating, heat distribution is consistent throughout the product, preventing localized overheating and burnout. Most comparable products use unidirectional or bidirectional pressing, which leads to significant density variations. This causes inconsistent heat distribution during use and is prone to localized overheating.

High strength. In addition to appropriate density, strength is ensured by a suitable binder. This product uses a high-temperature-resistant, high-strength binder that has excellent affinity with graphite, firmly bonding the graphite particles together. The binder can withstand temperatures up to 2000°C and does not emit gases at high temperatures, ensuring a safe and reliable synthesis process.

Good resistance uniformity and stability. Resistance characteristics are a key property of this product, directly affecting heating power and heating stability. Uniformity and stability are influenced by factors such as mixing uniformity, dimensional accuracy, and density uniformity. This product employs a multi-dimensional, high-dispersion mixing method, ensuring thorough contact and encapsulation between the binder and graphite powder, thereby guaranteeing that each graphite particle is uniformly coated with a layer of binder.

High dimensional accuracy and excellent consistency. The product is manufactured using a high-precision hydraulic press with a specially designed die set. A servo system controls the precise synchronized movement of each layer of dies, complemented by highly wear-resistant cemented carbide dies. This results in minimal weight variation in the pressed products, high dimensional accuracy, and excellent batch-to-batch consistency.

Application Advantages

Stable curves with minimal fluctuations; uniform heat generation ensures even sintering of the product without temperature variations. The absence of volatile gases prevents product erosion, and the ultra-high-pressure synthesis process is safer.

Actual synthesis curves from CBN customers: Each curve exhibits excellent repeatability; the synthesis rods show no erosion; the temperature distribution within the synthesis chamber is uniform, with no obvious over-sintered areas.

Actual synthesis curves from PCBN customers: Perfectly repeatable synthesis curves are a prerequisite for stable product quality; the uniform temperature distribution ensures consistent sintering performance of the products.