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Vacuum Heat Treatment Furnace

Vacuum Sintering Furnace

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High-Quality Vacuum Debinding and Sintering furnace

MIM (Metal Injection Molding) is a near-net-shape technology suitable for mass production of complex-shaped products. The materials suitable for MIM technology mainly include cemented carbide, stainless steel, and sinterable oxide ceramic powder. It is derived from mature plastic injection molding technology and is suitable for fine metal and ceramic powders.

MIM technology first mixes metal powder and binder, generates feed material and then injects it into the forming cavity to obtain a forming blank (raw material), which can be used for the production of highly repeatable complex-shaped parts. The binder in the parison can be removed by chemical methods such as adding catalysts, solvents and water, or by heat treatment. The formed blank is debonded and then sintered and densified to obtain the final product. Depending on the powder material, the sintering process can pass through an oxidizing, inert or reducing atmosphere. Due to differences in the amount of powder, material and final density of the sintered parts, shrinkage of 15-22% may occur during the sintering process. During the debinding and sintering processes, temperature and atmosphere must be precisely controlled to avoid component deformation, cracks, and bubbles.

The MIM process combines the design flexibility of injection molding with the high strength and integrity of precision metal to achieve low-cost solutions for extremely complex geometric parts.

The MIM process is divided into four unique processing steps (mixing, molding, degreasing and vacuum sintering) to achieve the production of parts, and whether surface treatment is required based on product characteristics is determined.

The MIM manufacturing process generally includes: mixing and granulation, injection molding, degreasing, sintering and secondary processing.

Vacuum degreasing and sintering

Vacuum sintering is one of the unsung heroes of industrial metallurgy. In this crucial process, materials are heated close to their melting point in a vacuum environment. After heating, the material becomes denser and acquires completely different new properties.

Vacuum sintering involves two important aspects: vacuum furnace and metal powder. If a vacuum furnace is used correctly and metal powders are mixed in the right proportions, a variety of desired properties can be achieved.

For example, some metal compounds produced by sintering can reduce the failure of machine or automobile parts. It can also create components that require high porosity, such as piping components and system components involving ball bearings. So if you need to strengthen a product, or improve its porosity, sintering is often the best option.

However, it must be remembered that sintering must not precede another important process: debinding. Both processes should be considered together when developing equipment purchasing plans.

Debinding is the preparation of materials or components for vacuum sintering. Degreasing must be sufficient. All parts contain impurities, usually from the injection molding process. If these impurities remain on the surface of the component, it will easily affect the degreasing effect.

Degreasing is the removal of “binders” deposited during the production process. Insufficient degreasing can result in surface peeling or holes that cannot be eliminated by sintering.

Therefore, it is very important to perform degreasing correctly. The degreasing process system depends entirely on the type of binder. Regardless of whether special solvents are used in the binder, decomposition of organic binders almost always occurs when heat treated at temperatures typically between 150°C – 600°C (300°F – 1,110°F). In order to ensure that all the binder is completely removed, multiple treatments in the furnace are often required. Care must be taken when handling as even trace amounts of residue can contaminate the sintering process.

At this time, there is an important question that must be considered: Can the same vacuum furnace be used for degreasing and sintering? This issue is critical because it affects the cost and likelihood of success of the process. So, this issue definitely deserves careful consideration.