1a.School of Mechanical Engineering， 1b.School of Materials Science and Engineering， University of Jinan， Jinan 250022， China；

2. Institute of Process Engineering， Chinese Academy of Sciences， Beijing 100190， China

Abstract

Significance In recent years， powder forming， a pivotal technique in near-net-shape manufacturing， has developed rapidly， impacting fields such as powder metallurgy， pharmaceuticals， and ceramic materials. This technique simplifies complex component processing， reduces material and energy consumption， and facilitates recycling of metallic wastes. In powder forming， the uniform distribution and loose density of powder during die filling are crucial to achieving a homogeneous microstructure in the final product. Any flaws such as the uneven distribution or inconsistencies in the powder cannot be corrected in later compression steps. Thus， optimizing die filling processes and exploring their mechanisms have become a research focus to enhance product quality， reduce costs， advance material systems， accelerate green manufacturing， and broaden technological applications.Progress Given the diverse properties of powder materials and production requirements， die filling methods have become highly versatile. Selecting the appropriate die filling method （categorized as linear， suction， rotary， and forced feeding） is crucial for cost control， quality enhancement， and efficiency improvement. Each method offers unique strengths. Linear die filling is simple， cost-effective， and space-efficient. Suction die filling ensures superior uniformity and efficiency， especially for complex molds and powders of low-fluidity， minimizing the impact of material properties. Rotary die filling is well-suited for batch and continuous layered structures. Forced feeding die filling， with precise control， enhances powder fluidity and mixing. Material properties significantly influence uniformity and loose density in linear and rotary methods， while suction and forced feeding alleviate these constraints by improving powder fluidity. Additionally， environmental factors， including air， humidity， and static electricity， also exert complex effects on the filling process. However， the mechanisms underlying are yet to be fully explored， highlighting the need for rigorous environmental monitoring during operations.

Conclusions and Prospects Linear die filling， as a traditional and widely used method， is well-suited for single-filling molding requirements of powder materials such as ceramics and cemented carbides， although its uniformity is constrained by multiple factors， limiting its application in high-precision scenarios. Suction die filling， with optimized aspiration components， effectively reduces the interference of air resistance， thereby significantly enhancing filling efficiency， loose density， and uniformity. Although it allows for varying process parameters， further coordination and control among these parameters are still required to address the challenges posed by diverse powder material properties. Rotary die filling is effective in continuous operations， particularly for small molds in medium-to-low-speed tablet presses， but its dependence on powder fluidity hinders its broader applicability. Forced feeding die filling， with optimized structure and paddle rotation， demonstrates immense potential in achieving high efficiency and uniformity， but at a higher cost. The following aspects need to be further studied： 1） Leveraging forced feeding to enhance the uniformity of die filling， combining with suction mechanisms to improve filling density， and developing low-cost， high-precision， and widely applicable die filling processes. 2） Introducing innovative applications of rotary and suction die filling methods into powder metallurgy， and developing a new suction-rotary die filling method to achieve uniform powder distribution， high densification， and high efficiency. These approaches are instrumental in improving the process and equipment standards of China's powder metallurgy industry. 3） Conducting a comprehensive and in-depth systematic investigation of key factors affecting die filling， especially the influences of environmental factors， such as air， humidity， and static electricity， as these factors vary with powder material characteristics. 4） Based on the comprehensive analysis of die filling uniformity and density， combined with the commonalities between die filling and powder laying processes， providing a more scientific reference and improvement strategies for the optimization of powder laying process in additive manufacturing.

Keywords： die filling； powder metallurgy； uniformity； density； research progress

Get Citation:ZHONG Wenzhen， LI Runzi， WU Xiaochen， et al. Research progress on die filling methods［J］. China Powder Science and Technology， 2025， 31（6）： 1-15.

Received: 2024-09-06 .Revised: 2024-11-01 ,Online: 2025-05-27

Funding Project:国家自然科学基金项目， 编号： 51605192。

First Author:钟文镇（1981—），男，副教授，博士，硕士生导师，研究方向为粉体工程与装备。E-mail：me_zhongwz@ujn.edu.cn。

Corresponding Author:段广彬（1983—），男，教授，博士，硕士生导师，研究方向为新能源材料及工程、气固两相流。E-mail：mse_duangb@ujn.edu.cn。

DOI：10.13732/j.issn.1008-5548.2025.06.008

CLC No: TB44              Type Code: A

Serial No:1008-5548（2025）06-0001-15