subject: Design For Automated Assembly Can Boost Production Rates [print this page] Automated assembly of products has been around long enough now for there to be a set of guidelines that can be used to assist in the design of products that will be assembled by automation. To design for automated assembly it is best to keep the product as simplistic as possible. A simple product design is one that does not have much chance of having a defective part or an automated assembly error because of poor design. The greater the number of pieces that are used to assemble a product, the greater the likelihood that there will be an assembly error when automation puts the product together. Actually there are other reasons that the design for assembly automation should be simple. The cost of assembly of a product will go up when there are more parts to put together in assembly. This is due to the fact that there will be more parts to inventory, keep track of, and manage. There would be added costs to purchase, handle, fabricate, and make these extra parts available for production. Eliminating any of the parts that are purchased from the design will reduce lead times and make the finished product more readily available.
Employees who design for automated assembly should carefully review the design of all the parts included in the product to determine if that part is actually necessary or can it be eliminated. To refine the design for automated assembly it must be determined if it is necessary for a part to be separated so that it can move. It also should be discovered if the part should be made of a different material from the other parts that are near it in the assembly. It is very important to make the design include only those parts that are absolutely necessary to complete the product assembly without detracting from the product usefulness. It should be a standard practice in design for automation that parts be made of a specified materials. Those materials should be the ones that suppliers will e able to make the parts in good supply, and will freely bid to supply. Using the reference lists from product data management and component supplier management can help to center the materials into a group that is specific for the needs of the design in question.
Design for automated assembly should be done with an emphasis on the easy of part manufacture. The limited list of materials that were selected should be able to be readily processed into the parts that are required for assembly. This is where the simplistic design of a part becomes important. It is much easier to manufacture a part that is simple in design than it is to create one that is more complex. Part features that are more complicated should be avoided. This will make manufacturing more difficult and increase tooling and other expenses.
Guidelines should be in place that will help to determine the features to include and not include in any part design. These guidelines would be developed from the assembly requirements of the products in question. A major influence should be requirements of the customer that would be dictated through their demands for the product. It is not a good idea to include steel parts in a products that customer expect to be made of aluminum. Most guidelines are of a practical nature, like avoiding features such as thin wall parts, tapers, contours, deep pockets, or holes that make machining difficult. For parts that require large volumes castings or stampings might be better than requiring machined parts. The guidelines that are used should be a result of the automated assembly requirement of a single company. These will vary from company to company.
Design for automated assembly should not create part designs that make unusually difficult demands of parts suppliers or the in-house production equipment. Very tight tolerances should be reviewed carefully to determine if there is some way to accomplish the required result without very difficult machining. Tight tolerance work usually cause more re-work that machining with lower tolerances. This will definitely add to the cost of parts, so it should be avoided. Part designs should lend themselves to assembly by automation. Parts being handled by automation equipment should readily be manipulated with causing jams and problems when they are used in assembly.
Consider the type of automated assembly that will be used to assemble the products when performing design for automated assembly. There is very little flexibility in automated as opposed to manual assembly. The two types of automated assembly each have their own set of characteristics for optimization. Robotic assembly has a tendency to be more flexible than its counterpart high speed assembly. Products that are assembled using robotics should have part designs that use standard end-effectors. Parts should have a tendency to self-locate and be handled by simple part presentation devices. High speed assembly automation should be used with standard parts that are not open or have projections to avoid nesting.
