Slow speed of the delta 3D printer
When you command a move such as G1 Z10, you are omitting the speed at which the tool head travels. Without specifying the speed, the speed from the last command or speed setting is used. Frequently, after levelling the bed, the tool head is raised in Z direction with a low speed (movement in Z direction is always much slower than in X or Y direction), if you command a movement after raising the tool head it uses this speed. For faster movement you must include the feedrate, e.g. G1 Z10 F600, now it will accelerate from the initial feedrate (e.g. 300) to 600 during the move. If you want instant speed you set the feedrate first and then move the tool head:

G1 F600
G1 Z10