Feed for large-size part metal powder injection molding and preparing method thereof

Abstract

The invention discloses feed for large-size part metal powder injection molding. The feed is composed of a bonding agent and gas atomization metal powder; the mass ratio of the bonding agent to the metal powder ranges from 96:4 to 92:8. Powder used in feed is gas atomization spherical powder, the high vibration density is achieved, the metal powder size proportion is high, after feed injection forming green blank sintering, the shrinkage rate is small, and the sintering size of a large-size part can be precisely controlled. Feed fluidity is good, low injection pressure and injection speed canbe used for forming the large-size part, the internal stress of the injection green blank is reduced, the phenomenon that the injection green blank is not full and flow lines exist is avoided, and thestable shrinkage rate after injection green blank degreasing and sintering can be kept; raw materials of components are cheap and easy to obtain, the adding amount is flexibly adjusted according to equipment, part molds and product quality, the mixing process is simple and easy to operate, and batch stability and high production efficiency of the feed can be ensured.

Description

Technical field [0001] The invention belongs to the technical field of powder metallurgy, and specifically designs a feeding material for metal powder injection molding of large-size parts and a preparation method thereof. Background technique [0002] Metal injection molding (MIM), as a near-net-shape technology for manufacturing high-quality precision parts, has advantages that conventional powder metallurgy and machining methods cannot match: it can manufacture many parts with complex shape features, such as various external cuts, External threads, tapered outer surfaces, blind cross holes, recesses and key pins, stiffener plates, surface knurling, etc., parts with the above characteristics cannot be obtained by conventional powder metallurgy methods. Since MIM can form parts with a high degree of complex shape at one time, the manufactured parts hardly need to be machined, which greatly reduces the consumption of materials, so it can produce high-performance mechanical parts ...

AI Technical Summary

Problems solved by technology

For some large-sized complex parts (thickness above 20-30mm and weight above 50g) that are urgently needed in the market, there is still no stable feeding option

Since a large amount of binder is added to the metal injection molding feed, the injection molding green body will shrink by about 40% during the sintering process, so the dimensional accuracy of the parts is not easy to control

In addition, the stability of the MIM process is difficult to accurately control, which affects the dimensional tolerance of parts in mass production, and it is difficult to remedy parts with complex shapes such as finishing or machining

For large-sized parts, large shrinkage and deformation after sintering of the green body and poor dimensional accuracy have always been difficulties in the MIM industry