What-if-analysis: a dream come true Path breaking what-if analysis of a complex real shop floor is now a child’s play

Shop Floor Managers’ dream come true!

Most shop floor Managers dream of having a tool to know answers to the following simple questions:

1. Given existing work load when new orders will be completed.2. No matter what betides, what is the impact on all orders in-hand.3. In case one brings about changes or sorts on the shop floor, like adding /removing a work

centre or declaring a new holiday, etc. what impact such changes would have on all orders in-hand.

Answers should be quantified in terms of predicted date/time of completion of all orders in-hand so one is in a position to compare it with the current and take informed corrective action. What is more important is to know having taken a particular corrective action, how the situation is redressed.

Read on to know more…

What-if capability in Talika PMS

Talika PMS is a real-time scheduling and planning system. At its heart is a real-time scheduling engine capable of re-scheduling everything all over again in seconds. So, at any given point-in-time it is known when each and every order in-hand will be completed no matter what the current situation is.

Power of the this high speed real-time scheduling engine is exploited for purpose of doing extensive what-if analysis with unimaginable features.

Simulator starts by requesting the existing load in the factory as a ‘snapshot file’ and then independent of the scheduling engine performs its own what-if analysis. One can have several such Simulators working independent of each other.

Let us take you on a tour of the features quickly. However, before that let us explore how result of simulation is displayed in a succinct and easily understandable manner highlighting the positive and negative impacts on completion times of all orders (existing and new) in quantified terms.

To know how completion times are affected is the ultimate final objective of any simulation exercise. Simulator directly shows you the ‘end-result’. Detailing is an option not a compulsion.

Intuitive at-a-glance display of what-if simulation result

Break up of existing and new jobs in each selected round of simulation.

List of simulation rounds made. Compare any round with another to see the impact.

Two superimposed Bar graphs (solid line for base round) give at a glance how changes have affected existing jobs completion times. Bar graphs give at a

glance how changes have affected new jobs completion times.

Detailed impact on new jobs. Highlights if deadline can be met and suggests a commitment date as well.

Detailed impact on existing jobs sorted by delayed, on-time and early finishing.

Tabs to compare resource utilisation, Gantt view, Changes made and rollback facility, Filtering affected jobs and comparing task-to-task from one session to another is also possible.

Add or remove one or more jobs

Adding / removing jobs either in the beginning or anytime later is easy and considered a very basic feature of simulator. It is also possible not to add any new jobs but also play what-if scenarios with existing jobs and work centres.

One can search list add and delete new jobs for simulation. It is also possible to simulate without having added any new jobs as well.

New jobs added for simulation

Find or suggest a completion date/time for new orders

Having added new jobs the obvious questions would be (1) to know when they would be ready given the existing loading or (2) if a cut-off date is already known then to ascertain if it can be met.

One can exercise the option of “suggest-a-date” for new jobs. Here the simulator suggests a date / time based on current job cycle time.

Alternatively one can enter a known cut-off date to ascertain if it is feasible to be achieved.

Play with jobs’ priorityDepending upon the privilege levels of the Simulator, one can (in Base level) play within only new job’s priority or (in Intermediate level) insert new jobs anywhere among existing jobs without disturbing existing jobs priorities within themselves or (in Super level) change any job priority randomly without any restriction.

All jobs listed according to current priority. So, one can compare the what’s changed with what’s current.

Move the selected job priority position up down.

Drop not-yet-started jobs

If any job is yet to start then one can drop it to know the impact. In order to make the resultant Gantt chart easy to understand all existing jobs’ tasks appear as one clubbed-on task on screen. If one desires, it is also possible to see existing job in details task-wise.

Quick help buttons that are self-explanatory

Tick left check box to show details, whereas the right check box to drop the job. Obviously, both check boxes can never be ticked together.

Halt already-started jobs

If any job is already started then one can halt it to know the impact. In order to make the resultant Gantt chart easy to understand all existing jobs’ tasks appear as one clubbed-on task on screen. If one desires, it is also possible to see existing job in details task-wise.

Quick help buttons that are self-explanatory

Tick left check box to show details, whereas the right check box to halt the job. Obviously, both check boxes can never be ticked.

Change jobs’ start time

When first activity for a job should commence is specified as job start time. Obviously, one can change it for not yet started jobs to see the impact.

Change start time / date of the selected job.

Duplicate or remove a work centreA quintessential facility to duplicate or remove (provided alternates exists) one or more work centres and see its impact is something out-of-the-world. No more guess work in identifying bottleneck/redundant work centres. Just right-click one to duplicate/remove and see the impact of doing so on all orders in-hand.

Right click to duplicate or remove one or more work centres

Change efficiency of a work centreImprovement in any work centre could also better its speed of working. It may start working faster, say, by some percentage and anyone would like to know how such efficient working affects all orders in-hand.

One can decrease (by 50%) or increase (up to 100%) selected work centres efficiency.

It is also necessary to specify the period over which this change in efficiency is applicable.

Change cut-in cost of a work centreWorking on overtime may incur an additional cost that could vary with work centre. These costs are defined in the factory dB and could be changed. Simulator not just calculates impact on the schedule in time terms but also the cost of executing a job that could change if cost of working on overtime changes.

First - Select a work centre

Specify the new hourly cut-in cost here.

Second - select the Holiday for which one wishes to change the cut-in cost.

Increase work centre capacity to handle tasksHow many tasks a work centre can handle concurrently is decided by its capacity. Say, a buyer can handle 5 purchase requisitions concurrently. What if he could manage 10 instead? What is the impact on all orders in-hand? Duplicating a work centre and doubling its capacity may sound synonymous though they do not exactly mean the same thing. Duplicating term is used for work centres that can handle a single task at a time.

Select a work centre

Specify the new capacity multiplier and since when

Moving a work centreMoving work centre is a common practice. Movement could even be across plants. It takes a while to move the work centre during which it cannot be used and later becomes available in some other place. Obviously, that will affect orders in-hand, how? Get to know right away by faking actual movement.

On dropping over the selected to cluster a pop-up opens for one

to specify the movement duration

Select a work centre to move and drag it over to an appropriate cluster (new place) on the right hand pane

Change work centre resource requirementIf a work centre is already defined as requiring resource to become active then one can change the amount of resource the work centre could partake. Resources are of two kinds (absolute) like power, space that must be available in prescribed quantity, whereas (relative) like manpower typically could be in multiples of some minimum.

Only if a work centre is defined to require resources will this

kind of change screen opens up

Select a work centre to change its resource requirement.

Modify Holidays

Holidays or off-periods are called Non-scheduling Time Zones (NSTZ) in Talika PMS. Meaning no new task is scheduled during these periods unless user specifically overrides a holiday by allowing a 100% cut-in.

However, an already running task can cut-into an NSTZ. We recognise this as working on overtime. Now this working could be planned or forced as the task in question couldn’t finish on-time.

NSTZ could be one-time (e.g. Independence Day) marked by a specific start and end time or could be periodic (e.g. weekly off) that occur weekly at the same time.

Simulator allows one to add / remove a one-time or periodic holiday or modify an existing one that includes redefining its applicability on different work centres.

Please note in Talika PMS one could define holidays at individual work centre level as well.

The next two slides shows how one could modify a one-time and then a periodic holiday. Just simulate to know impact on all orders in-hand.

Modify Holidays - OnetimeRemove a one-time holiday.

Add a one-time holiday.

Select a one-time holiday.

Start and end time.

Right click on selected Plant, Cluster or work

centre to allocate

Right click on selected Plant, Cluster or work centre to de-

allocate

Modify Holidays - Periodic

Right click on selected Plant, Cluster or work centre to de-

allocate

Right click on selected Plant, Cluster or work

centre to allocate

Modify various periodicity parameters that are self-explanatory.

Select a periodic holiday.

Change material movement - type and time

Material movement is a done thing in any real factory. Work-in-progress made at one place must be moved to another and that requires time and it affects the schedule. In Talika PMS one can define two types of material movements:

(1) Fixed movement – here the movement time is reasonably short, fixed and 100% guaranteed to happen. Like moving material within a department. Obviously, there is no need to track and notify such movement as ‘done’. One can assume it will take place.(2) Variable movement – here the movement time is not short nor fixed. One may know the average movement time, but not how much each movement would require. So, all variable material movements must be notified as ‘done’.

There is a concept of clusters that houses one or more work centres. Movement time within work centres of a cluster by definition is fixed and short. However, inter-cluster movement could be any type – fixed or variable. It is user’s prerogative to define what work centres form a cluster and how many cluster one can have. System places no restriction on number of work centres in a cluster or number of clusters. Movement type and average time between clusters too is user defined and can be changed.

Change material movement - type and time

Define the new movement type and duration.

Select a “From” cluster

Select a “To” cluster

Change in resource availability

We talked about changing resource requirement by a particular work centre. However, total quantum of resource available to a plant in a factory itself could vary. Say, one has two 1200 KVA generators powering a factory. However, if one generator is closed down for maintenance for a specified duration what could be the impact on work centres that require power and in turn on all orders in-hand.

Manpower available (number of persons) too could be considered a resource and this number available could vary. So what is the impact?

The next slide shows how nominal value of a resource could be changed.

Change in resource availability

Identify a resource

Modify its nominal value as well as period when the modified value must be used.

Many more changes possible!

Until now we had concentrated on changes that could be brought about globally by clicking the ‘change’ icon on the toll bar. Instead click on the ‘status’ button on the tool bar to open the Gantt chart. Use the left hand filter pane to view Gantt chart for particular selection and click the ‘show’ button below.

From the Gantt chart view two more categories of changes can be effected.(1) Right click on a work centre band and select ‘change task execution order’ whereas,(2) Right click on any task to edit its execution properties.

Changes possible from Gantt chart viewClick Status icon button to open Gantt view

Select appropriate filter by work Centre or job floating pane

Select within pane

Click Show button to see the Gantt chart

Zoom on x-axis (time)

Zoom on Y-axis (number of work centres seen)

Right click on work centre band to see ‘change task execution order’ option

Right click on a particular task band to see ‘Edit Properties’ option

Change task execution order on a work centreScheduling engine allots tasks to a work centre first ordered by job priority and then by task’s future burden within a job. User is, however, free to change this order of execution provided the task in question is matured - meaning all inputs to undertake the task are notified as available.

Scheduling engine’s order of executing tasks on this work centre

Click to add selected task in new execution order.

Edit task execution properties Right click on any selected task to open ‘Edit Properties’ and click it to open the screens below. One can change a host of execution preferences (as explained later) for a task as well as select / deselect or re-order work centres for its execution.

The task properties window has three tabs-[1] properties that specify task properties in question;[2] Attributes giving details of all attributes and its values[3] Execution Preferences that can be modified by the User while performing what-if analysis.

Execution Preferences can be changed in simulation. Each is explained later.

Click this button to open Work Centre options menu window that shows all work centres on which the task could be executed. User can select / deselect work centres as well as change its default order.

Edit task execution properties Execution preference What it means Scheduling engine usage

WIP control

Attempt to minimize work-in-progress (WIP) from being created too much in advance and thus remain unused.

If WIP is not on the critical chain and has enough time left to be produced and used then its creation is deferred thereby minimizing WIP build-up on the shop floor.

Control of task execution order

User desires to change task execution order, if necessary, at run-time.

Tasks are allotted first by order priority and then by the future burden on the task within an order. However, user may change this natural order of execution at run time.

Work center choiceIf one has a choice of work centers to perform a task then which one to choose?

Scheduler tries to honors user preference with switchover savings, if any, considered. In case the first preferred work center is unavailable it tries to allot the task on the second preferred work center and so on.

Locking OptionEnsuring a particular task is only executed within a user specified period.

Always tries to execute the said task within the specified period, as far as possible.

Edit task execution properties Execution preference What it means Scheduling engine usage

Auto-breaking option

Breaking up a task to run concurrently on more than one work center with an intention to reduce task execution time.

If the task is on the critical chain or its execution cannot be deferred any further scheduling engine will try to optimize and select the most appropriate breaking option possible.

Spanning Option

Stop and resume task execution after a holiday, recess period. Commonly referred to as a non-scheduling time zone (NSTZ) in the system.

Scheduler wisely decides to span or not to span depending on the current situation.

MCI option

It may not be necessary to wait to start the next value-adding task that uses or consumes what is produced by the current task until the current task is not over. One can overlap in time both tasks in order to expedite the order. We can say the preceding task gives a mid-course intimation (MCI) to the next task to begin.

Scheduler tries to begin the next value adding task even before the earlier one feeding into the next one is not yet over. Time to initiate the next task can be user decided or left to the scheduling engine to figure out.

Edit task execution properties Execution preference What it means Scheduling engine usage

Interleaving option

User may want some tasks (orders) to be executed only when there is free time available. Contrast this with auto-breaking where the objective was to expedite.

Scheduler ensures the task is executed whenever there is nothing urgent to be done.

MCF Option

Especially in long running tasks interim milestone reached feedback may be necessary to re-adjust expected task completion time. We call it a mid-course feedback (MCF).

MCF is used constructively to adjudge the expected completion time for long running tasks.

NSTZ cut-in option

NSTZ is an acronym for non-scheduling time zones. Periods when the scheduling engine will not schedule (allot) a fresh task. However, an already running task can either by design (or because it is delayed) cut-into an impending NSTZ. System supports five categories of NSTZ with varying importance and user can define how much a particular task can actually cut into each of them.

Scheduling engine takes appropriate decision to cut into NSTZ whenever necessary. Working during NSTZ is an additional cost and calculated accordingly.

Edit task execution properties Execution preference What it means Scheduling engine usage

Task line-up

It is possible for user to specify that in an order if some task A is executed on a particular work center then preferably task B too should be the next one followed by task C and so on. Valid reason could be substantial saving in cost and time if done so. We call it task cascading. This again could be a preferential cascading or a forced cascading when user insists that the scheduling engine waits a pre-determined period for the next cascaded task to mature for execution.

You can guess concept of cascading is different from controlling task execution order. The former is applicable within an order whereas the later could be across orders and typically is a run-time user intervention.

Thank you!

Visit www.etalika.in to know more and download a trial version for your experience and evaluation.