Workpiece loading and unloading device and control method for workpiece loading and unloading device

A workpiece loading and unloading device, comprising:

• a placement portion that comprises two pallets placed thereon, each of the two pallets configured to store a plurality of workpieces arranged thereon;
• a pallet movement portion that is configured to move the pallet placed in the placement portion;
• an arm that is configured to move relative to an automatic lathe that machines the workpiece;
• a hand that is configured to hold the workpiece and transfer the workpiece between the pallet and the automatic lathe;
• and
• a controller that is configured to control the pallet movement portion, the arm, and the hand, wherein
• the placement portion comprises the two pallets of a first pallet placed in a first position and a second pallet placed in a second position adjacent to the first position, the first pallet and the second pallet being arranged side by side in a plan view,
• the controller controls the arm to move within a combined range of a first range and a second range, in the first range, the hand reaches all of the workpieces arranged on the first pallet and in the second range, the hand reaches only some of the workpieces arranged on the second pallet, which are arranged closer to the first pallet than the workpieces arranged on the first pallet, and
• the controller controls the pallet movement portion, such that the second pallet moves toward the first position while the hand holds the workpieces arranged in a position of the second pallet close to the first pallet, and the arm separates from the second pallet when all of the workpieces arranged and stored on the first pallet are stored.