Factory Information System

Finite capacity planning

What does the Finite Capacity Planning module do?

The Finite Capacity Planning module helps you allocate works order operations to machines in such a way that you meet customer delivery dates. It is a tool to help you plan; it makes no claim to produce optimized schedules. Despite this it has some powerful features.

Key features

  • Automatically generates a rough plan by scheduling works orders in due date order.
  • Allows you to move operations between machines by dragging and dropping with the mouse.
  • Automatically changes the selected route during dragging and dropping.
  • Shows which works orders will be delivered late.
  • Allows you to introduce overtime and see what effect it will have on your plan.
  • Ensures that an operation cannot start until all its raw materials are available.
  • Calculates the number of setters and operators required to implement the plan.
  • Identifies works orders for stock.
  • Updates open operations from the Machine Monitoring and Works Order Processing modules.
  • Highlights situations when resources are not available to execute the plan.
  • Uses the Tool Management module to calculate variable setting times.

Is it suitable for my business?

If you use the Works Order Processing module, then the Finite Capacity Planner will be suitable for your business.

The Rhombus finite capacity planner is relatively simple as computerised schedulers go, and you may decide that you need something more sophisticated. It does not attempt to produce optimal schedules, do critical path analysis, identify bottlenecks, or use any other scheme to do the planning for you. It simply allows you to see the effects of changes which you make to your plan.

In its favour is the ability to get instant feedback from the shop-floor from the Machine Monitoring and Works Order Processing modules. A realistic and up-to-date plan may be much more valuable than an optimized but out-of-date plan.

Its simplicity means that it is actually usable in a real business environment.

Finite Capacity Planner

The Finite Capacity Planner displays your machines and sub-contractors down the left hand side, and time across the top. The time scale is infinitely variable from hours to days. The plan extends 180 days (6 months) into the future.

Works orders created by the Works Order Processing module are loaded automatically to their preferred route in due date order.

Each operation of a works order is represented by a bar whose length represents the expected duration of the operation. Queueing operations are shown in white. Operations which are in production are shown in green. Operations for which there are no raw materials available are shown in pink. If you click on an operation, it and all other operations on the same works order are highlighted in blue. The panel at the right of the screen shows details of the highlighted operation in the plan. If a works order will be delivered late, there is a red bar along the top of all operations of that works order. The number of days late or early is shown in the right hand panel. If a works order is for stock, there is a blue bar along the top of all operations of that works order.

You can right-click on an operation and display a list of all operations from the same works order with details of planned start and finish dates for each one.

You can click on a machine at the left hand side of the screen to display a work-to list for that machine.

You can click on a list of all the parts in the plan to highlight all works orders which make the same part number. This is useful for grouping works orders to minimise changeover time.

You can drag operations between machines, and see immediately what effect this will have on your plan. If there are alternative routes for a works order, you can drag an operation to a machine in a different work centre. The planner changes the route automatically and recalculates the duration of each operation, possibly with different cycle times for the new route. The planner will only allow you to load an operation to the machines you have specified in the manufacturing process layout.

Material availability

The planner checks the availability of all the raw materials required for an operation. If raw materials are available, the operation cannot start until the date when the latest material becomes available. If raw materials are not available the operation is coloured pink.

Raw materials are allocated dynamically to the operations which need them. If you change the order of two operations which use the same raw material, you do not have to worry about reallocating raw materials to the operations; this is handled automatically.

Set earliest possible start date

If you know, for example, that tooling will not be available before a certain date, you can set an earliest possible start date for an operation. The planner will not then allow you to start this operation before the specified date.

Setting time

You can specify a planned setting time for each operation in the Manufacturing Information module. The planner looks at adjacent pairs of operations on the same machine, and introduces setting time between them if the two operations are not for the same part. The setting time is coloured red on the planner screen.

If you use the Tool Management module, you can specify set up and breakdown times for all the tools in a tool schedule for an operation. The planner will use this information to work out how much time it will take to break down the operation just finished, and how much time is needed to set the operation just started. Thus the planner will show variable setting times depending on the two adjacent operations. This facility identifies long setting times, and helps you avoid two major set ups which could have been avoided by changing the order of operations. See Chapter 12: Tool Management on page 55 for more information.

Machine capacity

You set the capacity of a machine by specifying which shift pattern it will work. You can use the shift pattern to reduce capacity for Bank Holidays and annual shutdown. You can specify potential overtime shifts in your shift pattern for a machine. When you display the time scale of the planner as shifts, you can see working shifts as green blocks, and overtime shifts as red bars. You can click on an overtime shift to indicate that you want to work during that shift. The planner will immediately show you the effect of this increased capacity on the due dates of the works orders. In this way you can experiment to see if working overtime will enable you to meet customer due dates. You can adjust the overtime independently for each machine.

Notes

You can attach a note to any operation in the plan. This can be printed when you print the plan, or displayed to the machine operators at a screen on the shop-floor.

Keeping the plan accurate

As operations are started and finished on the shop-floor, the planner is updated by the Works Order Processing module. If you have the Machine Monitoring module, the planner is updated as often as you wish from actual parts counts and cycle times of machines. If a machine runs more slowly than planned the expected duration of the operation will increase, and the planner will show its effect on subsequent operations on that machine immediately. Similarly the effects of a long period of machine downtime will show in the plan.

Resources

You can specify the resources available for each shift, such as the number of operators, and the number of setters. The planner will show you when your plan is impossible to implement because it requires more resources than are available.

Work-to list

The result of the planning process is a work-to list for each machine and work centre. This is distributed to anyone who needs it by the Works Order Processing module. The system can print a production plan for a specified period into the future.

©2011 Rhombus Systems Limited, Sumpter House, 8 Station Road, Histon, Cambridge CB24 9LQ