While there are many types of assembly line systems, some common variations include the classic, automated, intermittent and lean manufacturing models. These systems are often used for making different types of products. Classic assembly lines can be used to create complex items such as cars, which are more or less the same over thousands of products. Intermittent assembly lines, by contrast, are often used to make a small amount of a product based on specific, custom orders. Despite the differences in design, many of these assembly lines have some shared characteristics.
In a classic assembly line, complex products are often assembled using various stations and many automated processes. The goals of many of these systems are to reduce the amount of workers required and to alleviate the need to manually move work pieces. Workers and tools are often spaced along an assembly line, performing one task before allowing the piece to go to the next station. A worker might only perform one small task, such as tightening a series of bolts. One of the benefits of the classic assembly line system is that unskilled or semi-skilled workers are sufficient to complete many of the manufacturing or fabricating tasks.
An automated assembly line is generally one that requires little human input to operate. These can include large-scale, mass-production systems using computer-controlled machines. This type of assembly line reduces some of the dangers associated with assembly line work, which makes it especially helpful when chemicals or heat would make human intervention difficult. Automated systems are often combined with other systems, depending on the product.
Intermittent assembly line systems can include the same elements as many other systems, but work pieces are often customized to specific orders. Workers and machines must adapt to the changes, which often increases the final production cost. Guitar manufacturing, for instance, requires a similar process every time, even though each guitar might be different based on consumer demand and material properties.
Lean manufacturing uses teams of workers on an assembly line to create products. The primary difference of this assembly line system is that workers often change jobs and may split the workload in novel ways, depending on the work pieces. In some ways, this kind of system can help to alleviate many of the hazards associated with classic assembly lines, including boredom and repetitive motion injuries.