Organizing the operation of radial machine sequencers for multiple PCB types

With a great variation of products, and small product lot sizes, PCB assembling machines must be reconfigured frequently, and their configuration must account for multiple product types. The tradeoff between reconfiguring between product types, or using a single (albeit locally less efficient) configuration for all product types, depends on product lot sizes, and of course, on the cost of machine reconfiguration. In this paper we consider PCB assembly machines of the radial type, which are used in manufacturing robust electronics devices. In this machine type, the components are brought to the assembly point by the means of a single component tape. The component tape is constructed on-line by a separate feeder unit (which is the sequencer), composed of a set of slots storing component reels of various types. Insertion of certain component types (slow components) causes a delay in the movement of the component tape. We study the problem of assigning component reels to the sequencer in such a way that the delay caused by the tape construction is minimized for multiple PCB types. We assume that all the necessary components fit in the sequencer and therefore, its reconfiguration between PCB types can be avoided. We also give an integer programming formulation for the problem, and present a heuristic optimization algorithm to reduce the component insertion time caused by slow components.

► We study the problem of minimizing costs of electronics assembly.
► The topic of the study are so called radial placement machines.
► These machines are used in manufacturing robust electronics devices (e.g. TV sets).
► This paper extends our earlier study from one product to multiple products.
► Minimum set cover heuristic turns out to be an effective method for this problem.