Over and over again I hear people saying, “MRP doesn’t work”. They’ll complain it can’t plan the right parts or it can’t plan the right quantities, or even that it can’t plan the correct start and completion dates.
As if the computer software has a personality!!!
MRP is basic math gang. Its pluses and minuses and basic multiplication and division. If you’ve got 5 pieces of a product on hand, and the demand is for 9, MRP WILL come back and tell you you’re short 4 pieces. And if the 4 pieces are needed on day 315 and the lead time to acquire the pieces is 5 days, MRP WILL tell you to get it in on day 315 and start the order on day 310. Math is math. If the computer can’t do basic math we have other problems and better be seeing if our paycheck is being calculated properly. If there’s a fundamental flaw in the math, we’ll see the problem everywhere in the software. I have only once in 28 years seen a computer program do fundamental math wrong and that’s because the software provider tried to convert another competitors software into their code automatically and it messed up the code. It just doesn’t happen today.
Now if you tell me you can’t manage the process effectively or there’s problems with the data we’re working with and therefore can’t use MRP as a planning tool, that I’ll buy. Managing MRP as a tool is where we get into trouble. The typical culprits we should look at if our planning fails are the following:
Bad on hand quantities
Poor transaction timing or accuracy or lack of
Bad Bills of Materials
Bad due dates on orders
Uninformed workarounds because we don’t understand Operations and organizations in an integrated manner
Bad planning data