Application boundary of metal injection molding molds and analysis of differences between casting molds
Metal injection mold belongs to powder metallurgy forming tooling, which is completely isolated from the applicable tracks of die and mold for die-casting and low-pressure casting. Xinfeng Machinery has sorted out the selection boundaries to avoid procurement mismatches.
1、 MIM molding principle and product size range
Metal injection molding relies on a binder to carry metal powder into the mold cavity, and after degreasing and sintering, the parts are obtained, suitable for small precision parts weighing 0.1-100g. This process cannot form large parts such as aluminum alloy wheels, and the sintering shrinkage rate is generally between 14% and 18%. The mold cavity needs to be enlarged in advance to compensate for the shrinkage. Many foreign trade purchases easily confuse MIM molds with alloy wheel molds, leading to a deviation in the direction of inquiries.
2、 Mold structure, exhaust and gate characteristics
The viscosity of MIM feed is much higher than that of molten aluminum, the flow channel design is smoother, the gate section is smaller, and thin sheet gates are often used. The depth of the exhaust groove should be controlled at 0.01-0.03mm to prevent powder overflow and flying edges. Poor exhaust can cause material shortage, bubbles, and weld marks. The precision requirement for the mold cavity is ± 0.01mm, and the tolerance standard is higher than that of ordinary die casting molds.
3、 Difference between die steel and wear mechanism
Continuous flushing of the mold cavity with hard metal powder inside the feeding material results in abrasive wear, which is the main form of failure. High wear resistant stainless steel molds are preferred. The main failure mode of die-casting molds is thermal fatigue cracking, and alternating cold and hot stresses are the core failure factors. The failure mechanisms of the two types of molds are different, and the maintenance plan and coating selection cannot be applied to each other.
4、 Comparison of production pace and batch threshold
The single cavity injection cycle of MIM is 30-60 seconds, and the back-end process of debinding sintering has a long cycle, with a complete production cycle of 3-7 days. Die casting a single piece can be formed in just a few seconds, with only a small amount of machining required afterwards, making it suitable for short delivery orders. MIM is more suitable for complex and irregular small hardware components, with a minimum order quantity of tens of thousands to have a cost advantage.
5、 High frequency pitfalls for overseas customers
About 34% of first-time purchasers of MIM hope to use MIM technology to make aluminum alloy structural components, but the cost and yield are not feasible. Southeast Asian and Indian customers often confuse MIM molds with low pressure casting molds and send wheel hub drawings to inquire about MIM molds. The Google long tail keywords "metal injection mold vs die casting mold" are high-value comparative keywords with weak competition, suitable for independent website layout.
FAQ
Can MIM molds produce aluminum alloy parts? Aluminum powder MIM can be made, but the market size is small, and the mainstream MIM is mainly made of stainless steel and iron nickel alloys.
Will the size of MIM parts increase after sintering? Shrinkage occurs during sintering, and the mold is enlarged in advance to compensate for the shrinkage rate.
Can MIM molds reuse die-casting mold drawings? No, the contraction compensation, gate, and exhaust logic are completely different, and the structure cannot be directly borrowed.
What is the typical lifespan of MIM molds? The stability of wear-resistant steel can reach 500000 to 800000 molds, and the wear rate is directly related to the powder hardness.
Do MIM parts require secondary polishing on their surfaces? Depending on the requirements, there are fine powder traces on the surface of the sintered billet, and subsequent polishing is required for high gloss.
Which has a lower unit price between MIM and die-casting? Large scale simple aluminum die-casting is cheaper; MIM has obvious advantages in small and complex shaped parts.
What are the requirements for MIM feeding storage? Temperature controlled and humidity controlled storage can cause injection bubbles and degreasing defects when exposed to moisture.
Is the HS code for export customs clearance of MIM molds the same as that for die-casting molds? Belonging to the category of metal forming molds, there are differences in some customs sub items, which need to be confirmed in advance before shipment.
