A process for production of expanded thermoplastic elastomer beads wherein a gaseous medium surrounds thermoplastic elastomer beads, said process comprising a) an impregnating step, wherein the gaseous medium has an impregnating temperature T a, the absolute pressure of the gaseous medium is greater than ambient pressure and wherein a blowing agent is dissolved in the thermoplastic elastomer beads, b) an expanding step, wherein the thermoplastic elastomer beads are exposed to a pressure reduction at a first expanding temperature T b and expand, and c) optionally a fusing step, wherein the expanded thermoplastic elastomer beads are fused together at a fusing temperature T c to form at least one shaped part, and wherein the thermoplastic elastomer beads are constructed of amorphous thermoplastic elastomer or partly crystalline thermoplastic elastomer, or mixtures thereof, the impregnating temperature T a, the first expanding temperature T b and the fusing temperature T c depend on the nature of the thermoplastic elastomer in that i. when the thermoplastic elastomer is amorphous, the impregnating temperature T a, the first expanding temperature T b and the fusing temperature T c are higher than a first limiting temperature T G-40, wherein the first limiting temperature T G-40 is 40°C below the glass transition temperature T G, according to DIN EN ISO 11357-2:2013-09, of the nonimpregnated thermoplastic elastomer beads, ii. when the thermoplastic elastomer is partly crystalline, the impregnating temperature T a, the first expanding temperature T b and the fusing temperature T c are higher than the glass transition temperature T G, according to DIN EN ISO 11357-2:2013-09, of the nonimpregnated thermoplastic elastomer beads and lower than a second limiting temperature T S-5 which is 5°C below the melting temperature T S, according to DIN EN ISO 11357-3:2013-04, of the nonimpregnated thermoplastic elastomer beads and wherein the thermoplastic elastomer beads comprise thermoplastic polyester elastomers, thermoplastic copolyamides or thermoplastic polyurethanes, or mixtures thereof. a) an impregnating step, wherein the gaseous medium has an impregnating temperature T a, the absolute pressure of the gaseous medium is greater than ambient pressure and wherein a blowing agent is dissolved in the thermoplastic elastomer beads, b) an expanding step, wherein the thermoplastic elastomer beads are exposed to a pressure reduction at a first expanding temperature T b and expand, and c) optionally a fusing step, wherein the expanded thermoplastic elastomer beads are fused together at a fusing temperature T c to form at least one shaped part, and wherein the thermoplastic elastomer beads are constructed of amorphous thermoplastic elastomer or partly crystalline thermoplastic elastomer, or mixtures thereof, the impregnating temperature T a, the first expanding temperature T b and the fusing temperature T c depend on the nature of the thermoplastic elastomer in that i. when the thermoplastic elastomer is amorphous, the impregnating temperature T a, the first expanding temperature T b and the fusing temperature T c are higher than a first limiting temperature T G-40, wherein the first limiting temperature T G-40 is 40°C below the glass transition temperature T G, according to DIN EN ISO 11357-2:2013-09, of the nonimpregnated thermoplastic elastomer beads, ii. when the thermoplastic elastomer is partly crystalline, the impregnating temperature T a, the first expanding temperature T b and the fusing temperature T c are higher than the glass transition temperature T G, according to DIN EN ISO 11357-2:2013-09, of the nonimpregnated thermoplastic elastomer beads and lower than a second limiting temperature T S-5 which is 5°C below the melting temperature T S, according to DIN EN ISO 11357-3:2013-04, of the nonimpregnated thermoplastic elastomer beads and i. when the thermoplastic elastomer is amorphous, the impregnating temperature T a, the first expanding temperature T b and the fusing temperature T c are higher than a first limiting temperature T G-40, wherein the first limiting temperature T G-40 is 40°C below the glass transition temperature T G, according to DIN EN ISO 11357-2:2013-09, of the nonimpregnated thermoplastic elastomer beads, ii. when the thermoplastic elastomer is partly crystalline, the impregnating temperature T a, the first expanding temperature T b and the fusing temperature T c are higher than the glass transition temperature T G, according to DIN EN ISO 11357-2:2013-09, of the nonimpregnated thermoplastic elastomer beads and lower than a second limiting temperature T S-5 which is 5°C below the melting temperature T S, according to DIN EN ISO 11357-3:2013-04, of the nonimpregnated thermoplastic elastomer beads and