Do you recall Spirograph, the toy? Gears were moved around other gears and the pencil created a pattern. The Epicycles Logo (top of this page) is drawn using the mathematical equivalent of Spirograph.

The general motion is epicyclic, identical to the earth around the sun, and the planetary gears in automatic gearboxes. There are some examples of compound epicyclic chucks in the British Science Museum in London.

The mathematics used to calculate how many turns of the small gear around the big gear are required before the line the pencil makes returns exactly to its starting point are simple. Find the highest common factor of the radii of the two gears - this is common high school mathematics.

The basis for the simple computer calculation to solve the puzzle was provided by Euclid in approximately 800 BC. . There are similar simple calculations to map the path the pencil would take and to predict its position.

Interestingly, the future inventory of a material, at any point in time, where the received lot size is different to the issued lot size, involves similar simple calculations, as does the frequency of deliveries to maintain a given throughput of the overall process. When discrete orders are needed they can be created and used in the calculation.

Paradoxically, with less data, just production rate and lot sizes  instead of discrete orders,  more information is available. Imagine an inventory calculation to the nearest second (if that is the requirement) as far into the future as you may wish to look without having to examine each second (Epicycles unfortunately stops at the year 9999, fortunately just a bit beyond the typical strategic planning horizon).

The discrete orders of traditional Materials Requirements Planning (MRP) solutions, with due dates and times, can only be always accurate when the order quantity equals the lot size and as far into the future as the orders exist. That can result in a lot of orders.

In the real world, something always comes along to change the plan, but (rhetorical question) guess which approach is easier to replan.

Questions like  "the supply hasn't arrived, when will we run out of raw material at the current rate of production?" become easier to answer.

The simple concepts within a drawing toy and a bit of Euclidean mathematics have been applied to Planning, Scheduling and Inventory Management within Epicycles to provide a significant part of the basis for a "Lean. Quiet. Seamless" system.

Several attempts have been made by others to bridge the gaps, for example Process Flow Scheduling,  but each of them was necessary but not sufficient to solve the problems. Unfortunately, we believe they remain collectively insufficient.

The mix of MRP/DRP/CRP also represented the legacy of manual techniques, computer programming languages and databases which were prevalent during its genesis many years ago. Three decades ago, memory, disk storage and computer processing power were exorbitantly expensive.

From a traditional MRP perspective the Process Industries continue to present the most difficult implementations. For an extreme example, a single constraining intermediate material used in all finished goods, with a very stable production rate which could not be decreased or increased easily. For finite capacity planning, we knew the rate but it had nothing to do with available hours as that was absolutely always, without exception, 24.

The presence of this very stable but unusual material, which is very difficult to model in traditional MRP systems made the limitations of contemporary MRP become glaringly obvious

The presence of such an obvious inverted  / divergent) Bill of Materials (BOM) caused speculation as to why we needed to consider the shape of BOMs at all. In fact, we believe we don't. The concept of BOM shape  is simply a legacy of the limitation which computer based tree structures placed on BOMs.

Similar questions followed.

Initially Epicycles was a series of disjointed thoughts resulting from an endless stream of "why?". Over several years it turned into disjointed partial solutions as both the production operations thinking and the computer based  system design played on one's mind. It finally emerged as a research project which took a holistic approach to rethinking the fundamentals of MRP/CRP/DRP and its implementation in a computer based system.

Credit should be given to Eliyahu Goldratt for providing his book "The Goal" at just the right time in the Epicycles journey. Within weeks it led to the relief of a production bottleneck, in a real life situation, through changes in product sales prices, to give a more productive and profitable product mix with more satisfied customers (a memorable win-win-win). The general concept of a constraint is as important to Epicycles models as it is to any process..

Goldratt's writing also reinforced the sense that Capacity and Materials, as modelled with Routings and Bills of Materials need not be separate and restrictive, generally lending some credibility to the more abstracted, simpler, more functional, network production process model which is at the core of Epicycles. Goldratt's inspirations are never far from the Epicycles design.

Having experienced the evolution of costing systems, in particular the use of "profit margin per bottleneck hour" some advances were to be made in the calculation, presentation and analysis of costs and revenues to support product mix decisions. Yet again, Goldratt has provided some valuable insights.

Object oriented programming techniques have also advanced rapidly in recent leading to a much more feature rich solution than has previously been possible. It allows the Epicycles process model to be a network, a structure made easy to implement with object oriented design and programming techniques. It also allows Resources in our hierarchical "tree" structures to have more than one parent - we always found it a little odd that the software industry was alone in believing that one parent was sufficient. Some days it seems that a whole industry in data warehouse solutions has emerged to adopt the missing parents as "dimensions".

In many system implementations we've observed the fascinating, but often fruitless, behaviour of the project team moving a problem around in circles searching for a none existent solution. The first signs of this are often when a particular function is required in one part of the system but it only exists in an altogether different part. In a few cases, as people raise their heads above the noise, we've heard statements such as "its as if we have to solve it in all places simultaneously". 

A very trivial example of this is to consider the "material" called electricity. We call it a material because it obviously isn't capacity, but in the context of the production process it can't be kept in inventory. At some point the software design decision has been whether to introduce a new type of material, if it's been considered at all. Within Epicycles the answer is self-evident because we haven't separated capacity (time, which cannot be held in inventory) from other materials. We already have the best of both worlds, or should we say a single world that should never have been divided in the first place.

During our formative years we were led to believe that the classification taxonomy of species was an absolute of nature. In later years we realised it was a human construct that nature generally  ignored. We also observed that on occasion sections of the taxonomy were revisited and revised. A very public recent revisiting of taxonomy was the de-classification of Pluto as a Planet. There is a nagging suspicion  that nothing changed on Pluto as a result of the decision.

In the context of MRP we have observed a very dense, heavy-weight,  taxonomy. We believe there is value in revisiting the taxonomy. We believe that debating whether electricity is a material or capacity changes nothing at all about the fundamentals of electricity. We therefore consider the debate to be wasteful, the root cause of the waste may be our taxonomy and computer based systems design.

Individually, the ideas within Epicycles are probably not unique or new. Collectively they work together and in that sense they are indeed both unique and new.

In this lies the essence of Epicycles. The general Epicycles approach has been an holistic one with an abstracted view, which is the antithesis of reductionist developments.

In the capital intensive process Industries, where 24x7x365 operation is common, a typical traditional MRP implementation results in "daily production orders". In this context, the lot size for MRP has become one day. It can only get noisier from there on. More data doesn't translate into more information. Epicycles just needs the daily (or any other time interval) rate. A quiet system minimises the data and maximises the information, a concept which is thoroughly embedded in Epicycles.

If you believe that because your business is not a capital intensive process industry it doesn't apply then we respectfully suggest you think again. The limitations imposed by discrete orders and a lot size of 1 day are more obvious in capital intensive  industries, not that they don't exist in all industries. For example, from our perspective it is very rare in reality that, in the planning sense, production against an order is not available until the order is complete, it is unlikely that the physical inventory suddenly jumps when the order is complete. Our research indicates that discrete manufacturing is a subset of continuous processing rather than a totally different subject. Perhaps there's some evidence in the general adoption of Lean Manufacturing  ("Lean") techniques. We believe traditional MRP is a barrier to improvement as well as the adoption of "Lean".

In our holistic world we have observed that if we put a continuous process under a microscope we can find discrete production. Similarly, if we observe a discrete manufacturing plant from a helicopter it looks remarkably like a continuous process. It's more a question of detail and emphasis, not a fundamental difference in the software requirement.

The introduction of some simple mathematical concepts leads to a number of exciting innovations, not the least of which is a true rolling horizon for planning whereby detail is progressively added as it becomes available and, without any artifical barriers between sales and operations planning (in months), scheduling (of discrete orders) and other parts of the system. The issues in differences between " Make to Stock" and " Make to Order" in the presence of an inverted BOM evaporate when such artificial barriers no longer exist. It means that, if required, sales and operations planning and scheduling can occur in parallel without having to first complete one and handover the outcome. If different people are involved in each, then they are each informed as to the impact of the other's decisions without the need for the separate feedback loop within traditional MRP.

We must be careful in this description of "Lean. Quiet. Seamless." to not convey the idea that Epicycles is bereft of the essential functionality. Quite the opposite. The design process which has been followed allows a richness of functionality to pervade the software. Because we are only ever writing functions once and making them universally available we can be thorough. We are unlikely to ever limit the design because we believe the function is of no value in a particular area. Its generally quicker to add the function than have the discussion about whether there is a business likely to use it.

You hopefully now have an insight into how we can rationally make the important claim of "Lean. Quite. Seamless." It is both an outcome of the rethink of MRP and also a design principle we have applied to all aspects of Epicycles.

There are some very simple concepts which lead to some extremely significant differences in the way in which Epicycles can be applied in both process and discrete manufacturing industries to their benefit.

We'd be pleased to discuss how Epicycles will add value to your business.