Multi-zone atmosphere control metal injection molding vacuum sintering furnace

Abstract

The invention discloses a multi-area atmosphere control metal injection molding vacuum sintering furnace which comprises a material box, at least two layers of material plates, air inlet valves, at least two division holes, a convergence groove and an air outlet pipe. The material box is provided with air inlets which communicate with the air inlet valves. The material box is internally provided the material plates. To-be-machined products are stored on the material plates. Each side plate of the material box is provided with at least two sets of division grooves which divide the material box into a plurality of areas. Each set of division grooves corresponds to one air inlet. The bottom of the material box communicates with the convergence groove through the division holes. The convergence groove communicates with the air outlet pipe. According to the multi-area atmosphere control metal injection molding vacuum sintering furnace, through multi-area division and width direction air inflow, the atmosphere uniformity in the material box is ensured, and the size deviation of the products in the areas is adjusted and controlled by adjusting the airflow in all the areas.

Description

technical field [0001] The invention relates to the technical field of powder metallurgy, in particular to a vacuum sintering furnace for metal injection molding with multi-zone atmosphere control. Background technique [0002] The metal injection molding process has a history of more than 30 years. After continuous efforts, many problems have been solved, but despite this, various problems still exist in the daily process of powder making, mixing, injection, degreasing, sintering, etc. appears in . [0003] If the size of the product after being fired exceeds the tolerance range, that is, the size of the product is unstable, and there is a large deviation in the size of the product sintered from the same furnace, which has become an issue in the industry. The main reasons for the unstable product size are as follows: [0004] 1. The influence of temperature distribution uniformity in the furnace on product size. The current graphite thermal field metal injection molding ...

AI Technical Summary

Problems solved by technology

The air intake from the upper and lower intake valves cannot effectively distribute the air flow evenly to each layer of the material board. Such an air intake method often results in most of the air entering the lower air intake valve being directly sucked away without flowing through the material board. The airflow from the upper air intake valve flows through the material board very irregularly. There may be some corners where the airflow does not flow through. The size deviation of each part of the product on a material board is relatively large, and the product yield cannot be controlled;

[0006] 3. The air flow through the material plate has a long stroke and the impact of turbulence on the product size

This type of air intake method makes the air flow through each layer of material plates, but because the air flow through the material plates has a long stroke, there will be deviations in the air flow on one material plate, the air flow flows between the material plates, and the air flow passes through There will be turbulent flow after a straight line L, and the air outlet pipe plays a throttling role, so the carbon potential distribution in the area near the outlet pipe mouth is relatively serious, and the carbon content of the product will increase after sintering, affecting the size and performance of the product

[0007] In addition, due to the airflow trend, there will be some corners where the airflow cannot pass through. The larger the furnace shape, the more obvious the size deviation

At the same time, there are leakage points in the graphite material box, such as the gap between the plate and the plate, and the gap between the door panels. Many equipment material boxes are fed by the intake valve, and the intake valve needs a certain pressure difference to open. Before the air valve is opened, the internal and external pressure difference generated by the material box forces the air flow to enter from the leakage point. The leakage point is irregular, and the air flow into each layer of the material board is also different, which will also affect the stability of the product size.

Moreover, in the debinding process, due to the area with low air flow rate, the product binder will not be completely released. After entering the sintering process, the residual binder in the product will be blackened due to carbon deposition at high temperature, and the size will also exceed the tolerance range by a lot.

Images