What is manufacturing?
Manufacturing is the process of processing or converting materials into articles that are useful or desired by a consumer. There are many different kinds of manufacturing processes, and each has different requirements. The continuous flow processing of soft drinks is different than the assembly of mechanical wrist watches, however, all manufacturing follows the same set of steps:
• Incoming raw material
• Processing of materials
• Combining or assembly of materials
• Removal of finished goods
Let’s look at those steps in a product example, automobile engines. Many finished and unfinished parts enter the engine factory. Some are ready to assemble into the engine, and others, like the block or crank, need to be machined first. These are the raw parts that require processing. Once all of the parts are processed, some may require finishing (plating or painting) before they go into the assembly.
Next, all of the parts, including nuts and bolts, are assembled into the engine. This probably takes place in subassemblies, like the heads, manifolds, block and rotating components. The completed assembly is then tested and inspected. If it passes inspection it is packaged for shipment to the automobile plant, and moved to outbound shipping. Along the way there are additional processing, testing, inspection, and adjustment steps. Of course more than one engine type is made in the factory, and the volume mix changes based on customer demand.
In a recent presentation, made to the Congressional Robotics Caucus Advisory Committee, I discussed the costs involved in manufacturing. These include capital costs, operating costs, and overhead. Some of these costs can be significantly impacted with flexible automation, such as flexible AGVs.
There are two components which drive the cost of the facility: the building structure and its associated physical plant, and the capital equipment used for manufacturing. The size of the facility and the amount of capital equipment required is driven by the expected output of the plant, PLUS capacity required to overcome inefficiency, PLUS the capacity required to manage production variability.
Flexible AGVs (and other forms of automation) can help greatly by keeping the machinery “fed”, thereby, maximizing its utilization, and by delivering materials consistently, reducing variability (like shift surge).
Traditionally, machinery utilization has been maximized by maintaining large amounts of floor inventory near the machinery, so it is not sitting idle waiting for parts. This practice increases the cost of inventory, and the space required in the facility. This is not lean. The objective is to minimize inventory size and cost WITHOUT affecting equipment utilization…it drives the whole concept of Just-In-Time (JIT) materials flow, not Almost In Time. Achieving this with manual handling systems requires constant oversight of the handlers; robotic vehicles are always working on demand with super efficiency.
In order to reduce the cost of labor, we tend to increase the mechanization used to support labor. If the operator can move a larger load, it can be done less often. It still translates to more inventory on the plant floor; moving larger loads less often, means larger loads sitting around longer times. Think buses versus taxis. By eliminating the labor cost associated with moving the loads, (by employing technology like flexible AGVs) we can reduce the size of the loads, while transporting them more frequently.
Another advantage to smaller load handling is an increase in plant flexibility which allows manufacturers to utilize best practices in meeting customer demand. Using flexible material handling technologies means faster changeovers can be made with less inefficiency.
Optimizing manufacturing processes
There are some things that can be done to improve the operating efficiency of a manufacturing operation:
1. Maximize equipment utilization ,requires ensuring materials are always on-hand for the particular process tool
2. Minimize inventories ,move the smallest amount of material to buffer the machinery for continuous operation
3. Reduce manual handling labor ,allows more frequent, timely, smaller load handling, at lower cost
4. Reduce facility size ,by operating at peak efficiency
5. Reduce variability ,operate at consistent throughput, 24/7 avoiding designs for capacity peaks
Flexible AGVs help Optimize the Manufacturing Process
Traditionally, high-volume, low-mix manufacturing employs fixed automation to achieve efficient operation. High mix manufacturing employs a blend of fixed automation and labor. AGVs can be used to support a high mix or low mix operation by making timely deliveries. However, most installations up to now have tried to completely replace the human labor, resulting in reduced flexibility by tightly integrating the AGVs with the load/unload operations at the work cells.
Seegrid’s flexible AGVs can work WITH the people in the work cells, and the material supermarkets in the factories. Operators in the work cells can load racks or trailers with finished goods in the cell, and position the racks for pickup by a flexible AGV when it is ready. The vehicle can be any vehicle in the fleet, not one dedicated to that cell, so delivery rates are higher. The rack could be any of a number of different designs for handling different parts, with a standardized hitch. The operator could even instruct the vehicle with a different destination each time.
A similar scenario works for bringing parts to the line for operations or assembly. The flexible AGV is loaded up with materials at central stores (the supermarket) and dispatched to the appropriate work cell as required. The flexible AGV automatically delivers and unloads the rack or pallet at the work cell for ready access by the work cell operator. The flexible AGV will then pick up at the load cell, or continue to the next work cell requiring service.
By working with operators, flexibility is increased; optimized efficiencies are achieved with flexible AGVs by providing consistent delivery and service rates, and allowing greater operating best-practices.