C8 dimension capability analysis

This week we began working on a capability analysis for the hub height dimension also known as the C8 dimension. There is a hub in the center of each battery seal where eventually the nail is put through. This measurement must be in line with the customer’s parameters or the battery may not be able to function. However, due to the accuracy of the machines and the leniency in the parameters we believe that it is unnecessary for us to be measuring this dimension during each sample because the probability of the C8 dimension being out of the parameters is very small. Using the PPK from 17 different samples and Minitab we created a I-MR chart and a C8 Distribution Plot. PPK is the long term capability of a process. The I-MR chart shows the difference of PPK over each sample. The distribution plot gives us the probability of “out of speculation,” or the probability of the hub height being out of the customers parameters. We found that if the machine is operating on a 6 second cycle, meaning one shot every 6 seconds, that we would expect one rejectable C8 in 100 octillion years.

LR-3

This week we began the study of LR-3 sized batteries. Because the most efficient molding parameters are unknown we must experiment to find the most adequate parameters. We began by getting different shots, each with a different injection velocity. Then we measured the weight of each individual cavity and then the weight of each shot. This allows us to narrow down the range the injection velocity parameter can be in. For example we found that when the injection velocity was set at 0.2 the cavity and shot weights were not up to standard and therefore setting the injection velocity at 0.2 would create inadequate parts.

Next week we hope to continue working on the LR-3 battery seals.