Introduction
Release Rules will determine how the Manufacturing Order’s are released for scheduling based on the Manufacturing Order’s release date. APS can be configured to release Manufacturing Order’s to be scheduled based on a number of methodologies and scheduling techniques. Each technique has strengths and weaknesses and will better suit some manufacturer’s needs than other Release Rules. APS currently provides three methods of releasing Manufacturing Order’s for production: Regular Release, Drum-Buffer-Rope, and JIT (Just-In-Time) scheduling.
Key Concepts
Regular Release Rules: The Regular Release Rule is dictated by the Manufacturing Order’s Release Date, which is frequently an imported value, or if the Job was created manually, the Release Date is a manually entered value. This value is the earliest that the Manufacturing Order can be scheduled to Resources.
Drum-Buffer-Rope: This is the Theory of Constraints method for scheduling and managing operations that have a consistent internal constraint or capacity-constrained resource. Here the “Drum” is the consistent constraint that sets the pace of the rest of the non-constrained Resources. The “Buffer” is a work backlog that is purposely maintained before a Drum Resource to avoid starving the Drum, which is undesirable since it sets the pace for the rest of the non-constrained Resources. The “Rope” is the information flow from the Drum to the front of the line material release, which regulates the release of materials to match the flow through the constraint.
The “Rope” is calculated automatically for each Manufacturing Order so that it is released at the right time to reach the Drum buffer-time before it needs to be there for on time delivery.
Using Drum-Buffer-Rope will direct APS to schedule according to this method.
JIT Release Rules: JIT scheduling is a methodology that is central to many Lean manufacturers that aims to cut down on inventory drastically by having the exact quantity of materials released at precisely the right time to finish production of an item or items at as close to exactly the need date as possible. JIT release rules will use the later of either the Resource’s HeadStartSpan or the JIT Slack Days to determine how early a Job can be released for scheduling.