To　establish　a　reference　for　developing　an　automated　insertion　strategy　based　on　axial　force,　as　well　as　an　active　axial　force　control　strategy　during　the　insertion　stage　for　robot　friction　stir　welding.　This　research　specifically　focuses　on　the　insertion　phase　of　stationary　shoulder　friction　stir　welding　using　the　6061-T6　aluminum　alloy.　It　investigates　the　effects　of　various　parameters,　including　spindle　rotation　speed,　insertion　depth　of　the　stirring　pin,　insertion　speed,　and　spindle　insertion　angle,　on　the　axial　force　experienced　during　the　insertion　phase.　The　experiments　were　conducted　using　a　ZK3000-500-A　industrial　robot　equipped　with　a　static　shoulder　friction　stir　welding　spindle　system.　The　axial　force　was　measured　using　a　force　transducer　and　data　acquisition　system,　recording　real-time　force　signals　throughout　the　welding　process.　The　methodology　involves　varying　the　insertion　depth　from　7　to　11 mm,　spindle　rotation　speed　from　1000　to　3000 rpm,　insertion　speed　from　10　to　50 mm/min,　and　spindle　insertion　angles　of　0°,　2.5°,　and　5°.　The　welding　process　parameters　were　systematically　varied　while　keeping　other　conditions　constant　to　isolate　the　effect　of　each　parameter.　The　results　indicate　that　the　robotic　friction　stir　welding　insertion　process　can　be　divided　into　four　distinct　stages:　initial　rise,　transition,　secondary　rise,　and　stabilization.　Furthermore,　the　change　in　the　axial　force　value　exhibits　an　approximately　linear　relationship　with　the　insertion　depth.　It　was　observed　that　the　axial　force　increased　linearly　with　increasing　insertion　depth　during　the　stable　stage.　Higher　spindle　speed　results　in　an　earlier　initiation　and　termination　of　the　transition　stage.　Among　the　investigated　parameters,　the　insertion　speed　has　the　most　significant　impact　on　the　trend　of　the　axial　force　change.　A　higher　spindle　speed　not　only　facilitated　a　quicker　insertion　but　also　resulted　in　a　more　rapid　initial　force　increase.　Specifically,　a　higher　insertion　speed　leads　to　an　increased　rate　of　force　increase,　a　decreased　stabilized　value,　and　a　shorter　transition　time.　On　the　other　hand,　the　spindle　insertion　angle　does　not　exert　a　significant　influence　on　the　trend　of　the　force　change.　This　study　establishes　a　basis　for　future　enhancements　in　force　control　strategies.　©　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　London　Ltd.,　part　of　Springer　Nature　2025.