An e-coat line includes a frame supporting a process track configured to extend along a process direction, a workpiece rack moveably supported on the frame, and a plurality of electrodes supported on an electrode rack. The rack includes support members configured to hold a plurality of hollow workpieces in a predetermined arrangement, and the workpiece rack is moveable relative to the frame between a raised position and a lowered position. The plurality of electrodes are supported on the electrode rack in a predetermined arrangement complementary to the predetermined arrangement of the plurality of hollow workpieces on the support members. The electrode rack is moveable relative to the workpiece rack in a direction crossing the process direction between a first position, in which the plurality of electrodes are extended along and overlapping with the support members to fit within the plurality of hollow workpieces, and a second position, in which the plurality of electrodes are retracted away from the support members to be removed from the plurality of hollow workpieces.

A surface treatment system includes a surface treatment tank, a first guide rail and a second guide rail that extend at a position offset from a position over the upper opening of the surface treatment tank, and a plurality of transfer jigs that respectively hold a workpiece and are supported by the first guide rail and the second guide rail. The transfer jig includes a horizontal arm section, a first guide target section that is guided by the first guide rail, a second guide target section that is guided by the second guide rail, and a vertical arm section that is suspended from the horizontal arm section at a position between the first guide target section and the second guide target section, and holds the workpiece.

A surface treatment system includes a surface treatment tank, a first guide rail and a second guide rail that extend at a position offset from a position over the upper opening of the surface treatment tank, and a plurality of transfer jigs that respectively hold a workpiece and are supported by the first guide rail and the second guide rail. The transfer jig includes a horizontal arm section, a first guide target section that is guided by the first guide rail, a second guide target section that is guided by the second guide rail, and a vertical arm section that is suspended from the horizontal arm section at a position between the first guide target section and the second guide target section, and holds the workpiece.