May 2012.
Advice and Assistance for Manufacturers.
I’ve been around long enough to remember the days when it took many hours to complete an MRP regeneration – sometimes 20 hours or more. In those circumstances, MRP could only be run once per week, on the weekend, and hopefully would complete successfully because there wouldn’t be another chance until the next weekend.
When faster and more affordable computing power brought that calculation time down to a few hours or less, companies began running MRP every night. This can be a great benefit in a dynamic environment where new orders are received every day, new priorities are developed and conditions are changing constantly. But the planning staff, who previously had a full week to work through the recommendations and actions that resulted from the MRP run, now got a whole new plan every day. For most, it was impossible to keep up with the deluge of changes and action messages. Many companies reverted to regular weekly runs with occasional updates in between when big changes hit, or daily “net change” runs and weekly regenerations.
A similar pattern became evident with Advanced Planning Systems (APS). In addition to speed, APS plans material and capacity at the same time, overcoming one of the perceived limits of traditional MRP. A typical APS can regenerate the plan in seconds, so many companies recreated the plan any time a new order or a noticeable change became evident. But the constantly changing plan was a nightmare on the plant floor. Efficiency nosedived when schedules and priorities were constantly in flux. Once again, the tool was most beneficial when its full capabilities were scaled back, with most companies regenerating the plan and schedule daily and only updating it during the work day when a significant change made it valuable to do so.
New technology and tools can be great competitive weapons when properly applied and where they help to enhance performance. But not all tools are of benefit in all situations. Lots of folks get excited about drum-buffer-rope, lean and kanban and other ideas and techniques but these, too, must be applied appropriately in order to deliver the expected improvements.
