A flexible manufacturing system (FMS) is an automated mechanical manufacturing system composed of a unified information control system, a material storage and transportation system, and a set of digitally controlled processing equipment. It can adapt to changes in the processing objects.
Flexible manufacturing systems have centrally computer-controlled machine tools and transport systems, and can sometimes process several different parts simultaneously. The components of a flexible manufacturing system include:
1. Processing equipment
The main processing equipment used is machining centers and CNC lathes. The former is used to process box-shaped and plate-shaped parts, while the latter is used to process shaft-shaped and disc-shaped parts. For medium- and large-volume production with few varieties, FMS often uses machining centers with interchangeable spindle boxes to achieve higher production efficiency.
2. Storage and handling
The materials handled by the storage and handling system include blanks, workpieces, cutting tools, fixtures, gauges, and chips; the methods of storing materials include pallet warehouses with a flat layout, as well as gantry-type automated warehouses with a large storage capacity.
Raw materials are typically first loaded by workers into clamps on pallets and stored in a specific area of the automated warehouse. Then, the automated material handling system (AWDS) delivers them to designated workstations according to instructions from the material management computer. Fixed-track trolleys and conveyor rollers are suitable for FMS systems that arrange equipment according to process sequence, while the order in which automated guided trolleys transport materials is independent of the equipment's arrangement, offering greater flexibility.
Industrial robots can transport and load/unload workpieces for 1-4 machine tools within a limited range. For larger workpieces, automatic pallet exchange devices (APCs) are often used for transport. Alternatively, robots that travel on tracks can be used to simultaneously transport and unload workpieces.
Worn tools can be removed one by one from the tool magazine for replacement, or a tool magazine full of tools to be replaced can be replaced by a spare sub-tool magazine. The jaws of lathe chucks, special fixtures, and spindle boxes of dedicated machining centers can also be automatically replaced. The chip transport and handling system is essential for ensuring the continuous and normal operation of the FMS; an economical structural design is generally selected based on the shape of the chips, the amount removed, and the processing requirements.
3. Information Control
The structure of a Factory Management System (FMS) can take many forms, but it generally adopts a hierarchical system with group control. The first level consists of the computer numerical control (CNC) devices of each process equipment, which control each machining process. The second level is the group control computer, which is responsible for distributing production plans and CNC instructions from the third-level computer to the CNC devices of the relevant equipment in the first level, and at the same time reporting their operating status information to the higher-level computer. The third level is the FMS main computer (control computer), whose functions are to formulate production operation plans, manage the FMS operating status, and manage various data. The fourth level is the plant-wide management computer.
High-performance software is the foundation for realizing FMS functions. In addition to system software that supports computer operation, there are more specialized application software developed based on usage requirements and user experience. These generally include control software (controlling machine tools, material storage and transportation systems, inspection devices and monitoring systems), planning and management software (scheduling management, quality management, inventory management, tooling management, etc.), and data management software (simulation, retrieval and various databases).
