Integral Logistics Management — Operations Management and Supply Chain Management Within and Across Companies

6.2.1b Cyclic Planning and “Heijunka” — Lead Time Reduction through Setup Time Reduction and Batch Size Reduction

Intended learning outcomes: Present in detail cyclic production planning and leveling of the production (“heijunka”).

Continuation from previous subsection (6.2.1).

2. Cyclic planning:

Cyclic planning attempts to sequence the products to be manufactured by a machine in such a way as to keep total setup time at a minimum.[note 607].

Cyclic planning is an example of sequencing, the planning of optimum sequences. Cyclic planning yields a basic cycle, as Figure shows.

Fig.        Cyclic production planning.

In a cyclic manner, batches of parts A, B, E, D, and C are manufactured. It is simple to introduce variations in order quantities; additional batches are planned for a part at the same point that has been planned for that part in the basic cycle. Varying the quantity according to current requirements could also result in a cycle of A, E, E, D, and again A.

Exercise: Try to find a sequence of parts A, B, C and D with a minimum setup time. For creating a sequence, drag parts to the empty circles. The result is called a basic cycle.

Reducing the setup time allows for reducing the lot size. Therefore, instead of producing a big lot of each product (e.g., 1000 A, 4000 E), several cycles of smaller lots can be produced (e.g., 4 * 250 A, 4 * 1000 E). This leads to the principle of leveling of the production.

Leveling of the production (Japanese “heijunka”) is an approach to level highly discontinu­ous production orders throughout the supply chain to match the planned rate of more continuous customer demand. It is an important tool for reducing “mura.”

“Ideally,” a product should be produced on the day it will be shipped.

Continuation in next subsection (6.2.1c).

Course section 6.2: Subsections and their intended learning outcomes