Hello all, I'd like to start a conversation around adding finite-capacity planning support to the OFBiz MRP engine.
The MRP engine currently plans with an infinite-capacity assumption. When it back-schedules a proposed production run from its required-by date, at best it checks the machine's working calendar — which weekdays the machine is open and for how many hours. It never checks how much of that time is already taken, either by existing production runs on the shop floor or by other orders proposed within the same MRP run. As a result, every proposed order sees every machine as completely free. Two runs each needing 6 hours on a machine (based on routing task level setup/cycle time) with an 8-hour day are both planned onto the same day — 12 hours of work into an 8-hour window — with no warning or flagging. The plan looks feasible on paper but is impossible to execute as the resultant requirements get overlapping start dates that overcommit the same machine, and planners must find and resolve these overloads manually.. I reckon, MRP should offer an option to trigger a *Constrained* run with finite-capacity planning i.e., treat each machine's daily capacity the way MRP already treats material — as a limited resource that each planned order consumes — so that later orders only get what remains, demand is prioritized by date (the same principle used for material netting), and orders that cannot fit are visibly delayed or reduced (flagged Late/Short on the Requirement) rather than silently overbooked. Not to mention, the *default (Unconstrained)* behaviour would remain untouched, so existing users see zero change unless they opt in for Constrained run. Before taking this up further — would love to know if anyone already addressed it via a fork, a custom component, an old JIRA or mailing list thread I might have missed? Capacity planning (CRP-style) feels like a natural complement to the existing MRP and manufacturing components. If there's interest, I would be looking forward to hear any early thoughts or concerns on the need/approach for it. Kind Regards, Swapnil Shah VP, Consulting http://www.hotwaxsystems.com
