Purpose　A　three-dimensional　(3D)　printing　error　simulation　approach　is　proposed　to　analyze　the　influence　of　tilted　vertical　beams　on　the　3D　printing　accuracy.　The　purpose　of　this　study　is　to　analyze　the　influence　of　such　errors　on　printing　accuracy　and　printing　quality　for　delta-robot　3D　printer.　Design/methodology/approach　First,　the　kinematic　model　of　a　delta-robot　3D　printer　with　an　ideal　geometric　structure　is　proposed　by　using　vector　analysis.　Then,　the　normal　kinematic　model　of　a　nonideal　delta-robot　3D　robot　with　tilted　vertical　beams　is　derived　based　on　the　above　ideal　kinematic　model.　Finally,　a　3D　printing　error　simulation　approach　is　proposed　to　analyze　the　influence　of　tilted　vertical　beams　on　the　3D　printing　accuracy.　Findings　The　results　show　that　tilted　vertical　beams　can　indeed　cause　3D　printing　errors　and　further　influence　the　3D　printing　quality　of　the　final　products　and　that　the　3D　printing　errors　of　tilted　vertical　beams　are　related　to　the　rotation　angles　of　the　tilted　vertical　beams.　The　larger　the　rotation　angles　of　the　tilted　vertical　beams　are,　the　greater　the　geometric　deformations　of　the　printed　structures.　Originality/value　Three　vertical　beams　and　six　horizontal　beams　constitute　the　supporting　parts　of　the　frame　of　a　delta-robot　3D　printer.　In　this　paper,　the　orientations　of　tilted　vertical　beams　are　shown　to　have　a　significant　influence　on　3D　printing　accuracy.　However,　the　effect　of　tilted　vertical　beams　on　3D　printing　accuracy　is　difficult　to　capture　by　instruments.　To　reveal　the　3D　printing　error　mechanisms　under　the　condition　of　tilted　vertical　beams,　the　error　generation　mechanism　and　the　quantitative　influence　of　tilted　vertical　beams　on　3D　printing　accuracy　are　studied　by　simulating　the　parallel　motion　mechanism　of　a　delta-robot　3D　printer　with　tilted　vertical　beams.