Vertical pallet pools are an economical option for expanding storage and automating production on one machining center. The basic model has 6 buffer stations and one loading station. The two- and 3-level VPP accommodates 11 to 15 buffer stations without consuming any additional floor space. Horizontal pallet pools are one level, but can be expanded to two HMCs and two loading stations. HPPs have 6 to 18 buffer stations for pallet storage.