Dd capacity scheduling

All material and © copyright Demand Driven Institute 2013, all rights reserved

Demand Driven Capacity Scheduling and Execution

Chad SmithPartner, Demand Driven InstituteCo-Author Orlicky’s Material Requirement Planning 3/ECo-Author Demand Driven Performance – Using Smart Metrics


Planning and Scheduling is Harder Than Ever

• The Manufacturing and Supply Chain landscape is more volatile than ever – the bullwhip is alive and well in today’s environment

• Customer Tolerance Times have decreased substantially relative to the time it takes to procure, manufacture and distribute items

• Product variety, options and complexity has put tremendous pressure on planning and scheduling systems

• FLOW is the critical link between service, asset utilization and ROI


The Demand Driven Operating Method

• The protection of FLOW is paramount• ROI is directly proportionate to the speed of flow

of relevant materials and information• Demand Driven operating methods seek to

protect the flow of both relevant information and materials


DDMRP and Capacity Scheduling

• DDMRP has Implications for Capacity Scheduling• Advanced Session Webinars• Download the paper on DDMRP Master Scheduling for

more information

DDMRP Scheduling Basics

DDMRP uses buffered “Decoupling Points” to establish independent planned and scheduled horizons.

DDMRP creates resupply signals based on the “available stock” status of each buffer. This gives prioritized sequence based on actual need.

On-the-floor priority is then determined by the real time buffer status of the decoupling points that the open orders are feeding.


When Will we Need More Scheduling Capability?

• When the use of better shop floor scheduling will compress lead times and reduce variability so that make item stock buffers can be reduced.

• When no decoupling point can be inserted before the shipping point. (Make or Configure to Order)

• Mixed-mode operation

Advanced Topics Webinar 3


An Mixed-Mode Example

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Supplier

Supplier

Purchased Components

Suppliers

In this case better scheduling and execution is required to synchronize and prioritize the make to stock and make to order business.

Better lead time and less variability within the plant will reduce the end item buffer.

All material copyright 2013 Constraints Management Group, LLC

Extending the Demand Driven Method

• The extension of Demand Driven methods to shop floor scheduling and execution can be seen in the new book Demand Driven Performance –Using Smart Metrics

• A series of articles in Strategic Finance Magazine previews the book – the articles are available for free download


Introducing Control Points

• Places to transfer, impose, and amplify control through a system.

• The 14th edition of the APICS Dictionary defines control points as “Strategic locations in the logical product structure for a product or family that simplify the planning, scheduling, and control functions. Control points include gating operations, convergent points, divergent points, constraints, and shipping points. Detailed scheduling instructions are planned, implemented, and monitored at these locations.”(p. 33)

C


Placing Control Points

Placed between decoupling points with the objective of better controlling the lead‐time zones between those points. A shorter and less variable lead time results in less stock required at the decoupling point (a working capital reduction).

C


Placing Control Points

Placed between decoupling points and a customer when decoupling the end item is not possible or in a mixed mode operation.

Customer

Customer

Customer

C

Make/Configure to Order


Determining Control Points

1. Points of Scarce Capacity determine the total system output potential. The slowest resource‐‐the most loaded resource—limits or defines the system total capacity.2. Exit and Entry Points are the boundaries of your effective control. Carefully controlling that entry and exit determines whether delays and gains are generated inside or outside your system.3. Common Points are points where product structures or manufacturing routings either come together (converge) or deviate (diverge). One place controls many things. 4. Points that Have Notorious Process Instability are good candidates because being a control point provides focus and visibility to the resource and forces the organization to bring it under control or plan for, manage, and block the effect of its variability from being passed forward.


Placing a Control Point

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Supplier

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Suppliers

In this case we have a resource is both the slowest pace resource as well a major integration point in the routings

C →

→

→ →


Scheduling a Control Point

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→

→

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Replenishment orders

Sale

s O

rder

Dem

and

1 2 3 4 5 6 7 8 9 10 11 12

Capacity

The control point is finitely scheduled with both MTS and MTO orders

Sales orders→

Loading is important to see for lead time quotation


Synchronizing Material Release

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Supplier

Supplier


Suppliers

→

→

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Schedule material release to the control point schedule

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Work orders

Work orders

Work orders

Late release will jeopardize the control point scheduleEarly release raises WIP levels unnecessarily


Control Point Schedules

30 Customer

Supplier

Supplier


Suppliers

→

→

→

C

We now have five schedules – all synchronized around a resource Control Point schedule (Drum)

→

DRUM


Protecting the Schedule

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C

We must insulate the schedules against the accumulated variability that occurs in the sequences preceding the schedule – delays are passed on, gains are not

→

How can we make sure that the schedules are maintained (not rescheduled)?

Note: the purchased part stock buffers protect the material release schedules against supplier variability


Time Buffers

Scheduled Start at Control Point

▼

Scheduled Entry to Buffer

▼

Early Late

WO 1595

WO 1781

WO 1601

WO 3279

WO 2001

WO 1626

C→

Upstream Processes

BUFFERGreen Yellow Red

Example: 9 hour buffer


Buffers Inserted

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Supplier

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The 10 Zone Buffer BoardScheduled Start at

Control Point

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Scheduled Entry to Buffer

▼

Early LateBUFFERGreen Yellow Red

Example: 9 hour buffer


Yet to be Received

Received

WO 1626

WO 1626

Green

Yellow

Red

OK

Investigate

ACT


How a Buffer Board works

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Yet to Be Received

48709-01

Early

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Green Yellow

Yellow Red

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9 Hours of BufferTime scheduled

on Drum(Wed 7:00 pm)

48801-01

Note: 16 hour work day

Current Day and Time: Monday, 7:00 am



48709-01

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Green Yellow

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Current Day and Time: Wednesday, 10:00 am

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Yellow Red

Red

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48801-01

Current Day and Time: Wednesday, 1:00 pm

Received

Yet to Be Received




48709-01

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Yet to Be Received




48709-01

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Forced Reason CodeReceived

Yet to Be Received


49322-0149527-03



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Early

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Green Yellow

Yellow Red

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48801-01


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Received

Yet to Be Received



Reason Code Analysis


Analyzing Buffers Over Time


Dd capacity scheduling

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