Stock Control Options

The Merlin system is a database-driven product which enables you to create jobs for the production of assemblies (products) which have been defined in Design, using the BoMs (kit lists) maintained in Assembly Library / BoM Editor in conjunction with the Resources File; to progress them through the shop floor, generating Pick Lists, allocate and issue materials (including subassemblies) to the jobs from your stock.

These tasks are simply accomplished by a click of the appropriate button in Manufacturing / Shop Floor Control, but in order for the materials to be physically available for issue clearly some form of Stock Control Strategy must be in place.  Merlin provides a comprehensive selection of tools for this purpose, and you will probably want to use more than one of them within your strategy.

It is important therefore that you take time to develop your strategy for using Merlin in such a way that materials are available when you need them, and to do this you need an understanding of how the Merlin purchasing routines operate.  The purpose of this section is to familiarise you with the options available, and how you should make use of them within your strategy.

Simple Stock Control

The simplest form of flat-level stock control is achieved by use of the Minimum and Maximum Stock Level settings on your Resource Record Cards, in conjunction with the Propose Main Buy and Run Main Buy buttons in Buying.  When you select one of these options (the former to produce a listing for approval, the latter to generate the Purchase Orders for your suppliers, once you are happy with the proposed figures), Merlin will scan the stock file for all items with a Free Stock level (physical on-shelf stock if any, minus materials allocated to running jobs) below the Minimum Stock Level and calculate a purchase figure for each item to return the on-shelf figure (after all allocated materials are issued) to the Maximum Stock Level.

Using this option as frequently as is appropriate  to your operation and to your min/max stock levels (daily, weekly, or whatever) will enable you to ensure you do not run out of materials controlled in this way.  Items for which both Minimum Stock and Maximum Stock are set to zero, will be purchased only in the quantities from time to time required, i.e. when these materials have been allocated to jobs.

In this way, buffer stock can be maintained for items which are inexpensive and/or of which it would be unthinkable to run-out.

You can, optionally, create Delivery Schedules for the Purchase Orders.

However, because this is a flat-level system it is suitable for overall materials control, but not for multi-level jobs analysis.  In fact, Propose Main Buy will alert you to any subassembly shortages, but Run Main Buy will not raise Works Orders for any of these House Items.  To do this job, you need a deep-analysis tool.

Enter the  Merlin MRP Engine!

Merlin MRP Engine

In order for the above routine to be effective in providing all materials for all jobs, you would need to have manually created jobs for not just the top-level (parent) products, but also for any required subassemblies (children) [and subassemblies within subassemblies, and so on], which can be extremely complex to track.  This is where the immensely powerful Merlin MRP Engine comes into its own.

The Merlin MRP Engine can be utilised on any of three levels: it will scan through (optionally) a single job (Manufacturing  / Shop Floor Control), a nominated Job Series, or all unprocessed active top-level jobs looking for aggregated materials shortages.
It does this in two stages:-

Stage 1 identifies and aggregates the subassembly requirement to an infinite number of levels deep, checks these against the stock on-hand, and generates Works Orders to meet all the shortages.*  Don't worry, you are always offered a list of proposals for checking before the action is committed.

Merlin will then offer to create and schedule all of the jobs necessary to produce the required stock of subassemblies for all of the parent jobs and parent subassemblies.

This done, Stage 2 will then scan the entire list of jobs looking for aggregated materials shortages, and will propose and offer to generate purchase orders to procure all of these materials, and will write Delivery Schedules (re-writing any existing schedules which conflict) for your suppliers to follow (where they are checked on the Supplier Record Card and the materials are checked on the Resource Record Card as supporting scheduled deliveries).

* When you use the MRP Engine on a job-by-job level, you can elect to procure the full kit, rather than just the shortages.  See below.

Job by Job or Kit by Kit?

Less sweeping than either of the above methods of materials procurement is the option to
Run MRP for each or any top-level job independently (Shop Floor Controller), or, where no job yet exists, for any assembly, in BoM Designer.  In the latter case, you can Buy Kit for assemblies whether they are top-level or not, but the BoM will still be drilled down for subassemblies within subassemblies.

You can elect to purchase the full kit (where batch or lot considerations may be important), or just make good any shortages.

When Run MRP is launched from within Shop Floor Commander, it is invoked in Single Job mode.

Shopping List

The methods of Stock Control described above all get Merlin to do the work for you.  Your part of the exercise is to perform a sanity check on the proposal listings generated, ensuring that the figures generated are not based on incorrect data (such as incorrect maximum stock level settings, or incorrect job run quantities or BoM items). 

Merlin additionally offers do-it-yourself (or pick-your-own) purchasing via the Shopping List button in Buying.

Is is not anticipated that this module will be used for routine stock control, even less for MRP purposes, but rather for ad-hoc purchasing that might from time to time be required for any special reasons of your own, and for items which do not appear in any of the BoMs and are therefore not controlled by Merlin's shop floor routines.

Here you can manually create or edit your Shopping List, going in and out as you please, view the proposed list at any time, and, when you are ready, instruct Merlin to generate the Purchase Orders to buy all of the items on the Shopping List (Merlin will then clear the list).

Conclusion

By far the toughest part of the learning curve associated with Merlin MRP Factory is gaining an understanding of the information on this page, and from here devising your own Stock Control Strategy making use of these tools. 

You can mix and match these resources to your heart's delight, resource by resource,  according to how you want each stock item to be handled

Exactly how you end up using the system is something you can decide only for yourself after absorbing the above information and applying it to your needs.  There is no right or wrong solution in the grand sense - the correct way is the one that suits you best.

The various purchasing resources outlined in this section are each documented in the appropriate sections of this User Guide.

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