Metal injecting molding catalytic debinding method and catalytic debinding furnace

Abstract

The invention discloses a metal injecting molding catalytic debinding method. A product to be subjected to catalytic debinding is placed inside the catalytic debinding furnace, pressurized nitrogen is added in a furnace cavity, compressed air and oil air are added in a burning chamber, fire is lit to burn, a negative pressure is formed at an exhaust mouth position, air inside the furnace cavity is discharged from the furnace cavity under the pressure of the nitrogen and the negative pressure of the exhaust mouth, nitric acid is added inside the furnace cavity through a metering pump, under the catalytic effect of the nitric acid , polyformaldehyde in the product is decomposed as formaldehyde, the formaldehyde is burnt with the air inside the burning chamber to generate water and carbon dioxide, adding the nitric acid in the furnace cavity is stopped after the catalytic debinding is finished, waste air inside the furnace cavity is discharged by the nitrogen out of the furnace, the product debinding rate is monitored in real time after the acid adding catalyzing is finished, if the debinding rate is qualified, the next washing is conducted; if the debinding rate is not qualified, the acid adding catalyzing and debinding is conducted again. Through accurately controlling the debinding rate, the passing rate of the metal injecting molding product is improved, and the cost is relatively lowered.

Description

Technical field [0001] The invention belongs to the field of injection molding, and relates to a catalytic degreasing method and device, in particular to a metal injection molding catalytic degreasing method and a catalytic degreasing furnace. Background technique [0002] The raw materials for metal injection molding are made of a mixture of plastic, metal powder and polyoxymethylene. After injection molding with the above raw materials, the binder needs to be removed. The polyoxymethylene chain is a repetitive carbon-oxygen bond. Atom is very sensitive to the action of acid. When it is put in a suitable acid catalyst, a chemical reaction will occur to split the macromolecule polyformaldehyde into formaldehyde. The catalyst is gaseous nitric acid, and the polymer is directly converted from solid to gas. The small molecule formaldehyde gas can escape through the porous outer area of ​​the product workpiece, so it will not damage the powder particle accumulation structure. After h...

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Problems solved by technology

[0003] At present, the commonly used metal injection molding catalytic degreasing method and the catalytic degreasing furnace matched with the method are generally open-loop control processes, that is, it is necessary to confirm whether the degreasing rate is up to standard after the entire catalytic degreasing process is completed, even if there are substandard products , and cannot modify and modify the process method, and cannot accurately control the degreasing rate in the production process

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