The YK-TW rethinks SCARA geometry from the ceiling down: the Y-axis arm passes beneath the X-axis, so the arm swings its orbit freely and the robot accesses the full 1000 mm diameter below it - pallets and conveyors place themselves without motion restrictions, and the whole machine stands just 392 mm tall at 27 kg.

What did the geometry change buy?

Thirty-six percent off the cycle: the 0.29 s standard motion on the YK500TW comes from optimized internal weight balance and the pass-under arm structure taking the shortest path between points. Position repeatability of plus/minus 0.01 mm on the YK350TW beats parallel-link robots at the same job, and the 5 kg payload accepts the heavier end-effectors that light SCARAs usually refuse.

Resolver or optical encoder?

Yamaha chose the resolver - the magnetic position detector used in hybrid vehicles and aircraft - because its simple structure has fewer potential failure points than optical encoders in demanding environments. Against the NXY long-stroke family for big X travels, the YK-TW owns the compact ceiling niche: a dedicated mounting frame is optional, setup skips the strength calculations, and the layout freedom of a full downward circle is the feature integrators quote back.