目前主流熔丝增材制造技术主要采用的热源包括激光、电子束、电弧及等离子弧等，它们有着各自独特的优势，但也存在能量利用率低，设备成本高，热输出量大等不足。为降低增材制造能耗及成本，提高成形质量，本文以焦耳热为热源，搭建了熔滴式及滑压式熔丝增材制造实验平台，进行了设备结构优化并开展了相关工艺实验，打印了表面及内部质量良好的单道成形层。

基于焦耳-楞次原理，利用电流流经金属丝材时在最大电阻处（丝材尖端与基板接触位置）产生的焦耳热，定量熔化丝材。通过对气氛保护、导电嘴及丝材感应加热等关键部件的设计，搭建了熔滴式焦耳热增材制造实验平台。通过理论分析及实验方法确定了成形304不锈钢丝材的影响因素，研究了电流、送丝速度及平台移动速度对单道成形层形貌及截面尺寸的影响，设计了田口实验研究工艺参数对成形结果的影响权重并进行工艺参数优化。结果表明：宽高比、稀释率随电流和平台移动速度的增加而增大，随送丝速度的增加而减小。对宽高比影响权重依次为电流、平台移动速度、送丝速度；对稀释率影响权重依次为电流、送丝速度、平台移动速度；通过工艺参数优化优化得到了最佳单道成形层，但表面质量较传统增材制造工艺提高不明显。

提出了滑压式焦耳热增材制造方法，电流流经滚轮-丝材-基板形成的回路，在滚轮与丝材接触位置产生最大焦耳热，界面熔化丝材，避免熔滴过渡不稳定对成形质量的影响。设计搭建真空系统，进行铜质滚轮、压力传感及丝材预热等关键部件设计，搭建了实验平台。通过工艺实验研究了电流、压力及接触长度对单道成形形貌和截面尺寸的影响，设计田口实验分析工艺参数影响权重并进行工艺参数优化。结果表明：随着电流增加，宽高比和稀释率增加；压力和接触长度增加，宽高比和稀释比率降低。压力对宽高比和稀释比的影响最大，其次是电流和接触长度；通过工艺参数优化得到最佳单道成形层，丝材和基板可实现完全冶金结合，内部无气孔、裂纹等缺陷，成形质量良好。

本文验证了焦耳热熔丝增材制造作为一种高质量、低成本小型金属零部件快速成形方法的可行性，为后续该技术的发展提供了技术参考，为低能耗、高质量的绿色增材制造发展提供了新的方向。

Currently, the main heat sources used in mainstream fusion additive manufacturing technology include laser, electron beam, arc and plasma arc, etc. They have unique advantages but also shortcomings, such as low energy utilization rate, high equipment cost, large heat output, etc. To reduce the energy consumption and cost of additive manufacturing and improve the forming quality, the experimental platform of Molten-Droplet and Sliding-Pressure wire additive manufacturing was set up with Joule heat as the heat source. The equipment structure was optimized, and related process experiments were carried out. The single-track forming layer with good surface and internal quality was printed.

Based on the Joule-Lenz principle, the wire is quantitatively melted using the Joule heat generated at the maximum resistance (the point where the wire tip contacts the substrate) when the current flows through the wire. The experimental platform for Joule Heat of Molten-Droplet Additive Manufacturing was built by designing key components such as atmosphere protection, conductive nozzle, and wire induction heating. The influencing factors of forming 304 stainless steel wire were determined by theoretical analysis and experimental methods. The influences of current, wire feed speed, and platform moving speed on the morphology and cross-section size of a single pass forming layer were studied. Taguchi experiment was designed to study the influence weights of process parameters on forming results and optimizing process parameters. The results showed that the aspect ratio and dilution rate increase with the increase of current and platform moving speed but decrease with the increase of wire feeding speed. In order, the influence weights on aspect ratio are current, platform moving speed, and wire feed speed. The influence weights on dilution rate are current, wire feed speed, and platform moving speed. The process parameter optimization obtained the optimum single-track forming layer, but the surface quality was not improved significantly compared with the traditional additive manufacturing process.

A Sliding-Pressure Joule heat additive manufacturing method is proposed. The current flows through the loop formed by the roller, wire, and substrate, and the maximum Joule heat is generated at the contact position of the roller and wire. The wire is melted at the interface to avoid the influence of droplet transition instability on the forming quality. The vacuum system was designed and built, the key components such as copper roller, pressure sensor, and wire preheating were designed, and the experimental platform was built. The influence of current, pressure, and contact length on a single pass's shape and section size was studied through process experiments. Taguchi experiment was designed to analyze the influence weight of process parameters and optimize process parameters. The results showed that the aspect ratio and dilution rate increase with the current increase. The pressure and contact length increase and the aspect and dilution ratios decrease. Pressure has the greatest influence on aspect and dilution ratios, followed by current and contact length. The optimum single-track layer was obtained by optimizing the process parameters. The wire and substrate could be bonded completely with no pores, cracks, and other defects inside, and the forming quality was good.

This paper verified the feasibility of Joule hot fuse additive manufacturing as a high-quality and low-cost rapid-forming method for small metal parts, provided a technical reference for the subsequent development of this technology, and provided a new direction for developing low-energy consumption and high-quality green additive manufacturing.