Overlap and Special Sequences of Manufacturing Operations

The Overlap and special sequences of manufacturing operations functionality allow:

1. Overlapping consecutive production operations in batch production.
2. Configuring special (non-linear) operation sequences, e.g., parallel chains of operations, in a single Routing,

This function can be enabled at Settings -> System settings -> Professional functions ->  Overlap and special sequences of manufacturing operations. 

When this function is enabled:

• The Overlap column becomes available in the Routing Details with a checkbox (Yes/No) on every operations line. The overlap quantity, which is how many products must be finished in the previous operation before starting, can be defined if selected.
• The Sequence columns are added to the Routing Details page, where each operation's preceding operations can be defined.

Jump to:

1. What is Routing?
2. What is overlapping? How to set up an overlap of operations?
3. What is a special sequence? How to set up special sequences of operations?
4. Demo video

Overlap of operations

The Overlap setting in the Routings details means that consecutive operations in the same Manufacturing Orders can overlap, i.e., the next operation could start before the previous finishes when batch processing products. For example, when 10 table assemblies are finished (of 100 total), the next operation, painting, can start.

For configuring Overlap for an operation:

1. Open the Routing of the product.
2. Tick the Overlap checkbox on the operation line, which can start before the previous operation is finished. (The overlap setting cannot be applied to the 1st operation.)
3. Enter the number of products that need to be processed in the previous step before this operation can start.

If this function is used:

• The operation is divided into (many) smaller operations, each with an "Overlap" quantity (or greater).
• For best results, it is recommended that multiplication "Cycle time" * "Overlap" = 1 minute or more, and "Overlap" equals to or is a multiple of "Quantity".
• If "Overlap" quantity * "Cycle time" < 1 minute, then the software will round this up to 1 minute, which is the minimum scheduling time unit in MRPeasy.
• For example, if "Cycle time = 0.05 min" and "Quantity = 1", then 20 units are processed in 1 minute, and if the "Overlap = 1", MRPeasy will treat each separate 0.05-minute operation as a 1-minute operation (which means it would take 20 minutes for 20 units).
  To resolve this, the parameters should be defined along the following lines:
  - "Cycle time = 1 min"
  - "Quantity = 1 / 0.05 = 20"
  - "Overlap = a multiple of "Quantity" = 20 or more"

Take note:

• In practice, this kind of overlapping is easily applicable in a balanced production line (i.e., different steps take equal amounts of time). However, overlapping scheduling is harder to apply to an unbalanced production line because it's more difficult to avoid queues or idling, which requires careful planning.
• This setting only affects the scheduling of the operations, allowing the MO to be scheduled in a more compact way if workstations are available.
• This setting does not forbid reporting the start of the next operation before the previous one is reported as finished.

Demo video: How to schedule manufacturing operations, which can overlap with each other, in a continuous flow manufacturing mode.

Special sequences of operations

The Sequence setting in the Routing details allows defining parallel and converging/diverging chains of operations. While by default the sequence of operations in routing is linear, this allows configuring a custom order of production operations. E.g., when two independent operations start in parallel, and the third operation can only start before these two have finished.

For configuring a special sequence of operations:

1. Open the Routing of a product.
2. The first operation's Sequence value must be chosen as 0.
3. Set the Sequence values for the operations which can start immediately as 0.
4. For every other operation, in the operations' Sequence choice, choose the number of operations that need to be finished before this operation can start. (Press the Ctrl or Shift key, or click-hold the left mouse button to select multiple values.)

Example:

The number in the Sequence field indicates after which operations this operation can start. The operation's ID number is displayed at the beginning of its line.

Demo video: How to configure complex sequences of operations - parallel, converging, or diverging chains of operations.