Correctly　integrating　and　planning　the　use　of　heat　source　to　provide　heat　and　mass　transfer　on　demand　is　the　key　factor　to　achieving　high　forming　efficiency　and　high　forming　accuracy　in　arc-based　directed　energy　deposition.　The　Alternating-Arc　through　Polarity-Switching　Self-Adaptive　Shunt　(PSSAS)　method　precisely　manages　current　distribution　between　wire　and　substrate,　effectively　decoupling　heat　and　mass　transfer.　This　allows　tailored　heat　input　for　each　deposition　layer　while　maintaining　high　efficiency.　Using　in-situ　measurements,　this　study　quantifies　heat　transfer　to　the　substrate　and　wire,　calculates　droplet　temperature,　and　captures　droplet　size　via　high-speed　imaging.　Results　show　that　PSSAS　transfers　anode　heat　from　the　substrate　to　the　wire　during　the　electrode　negative　(EN)　phase,　reducing　substrate　heat　transfer　by　45.9　%　to　55.7　%.　As　EN　current　increases,　substrate　heat　transfer　grows　slowly,　rising　only　41.7　%　within　70A　to　150A.　At　the　same　welding　current,　wire　heat　transfer　in　PSSAS　is　31.3　%　to　43.9　%　higher　than　in　traditional　Variable　Polarity　Plasma　Arc　(VPPA),　indicating　superior　wire　melting　efficiency.　Overall,　PSSAS　reduces　heat　transfer　to　the　substrate　by　approximately　50　%　compared　to　the　traditional　VPPA　mode,　while　increasing　heat　transfer　to　wire　by　about　35　%.　Further　analysis　reveals　that　electromagnetic　and　plasma　flow　forces　drive　droplet　transfer　in　PSSAS,　ensuring　controlled　transfer　and　good　forming　quality.　PSSAS　thus　offers　decoupled　heat　and　mass　transfer　with　controllable　droplet　transfer,　providing　a　novel　approach　for　arc-based　directed　energy　deposition.