5.2 - Personal Factory: Functional Analysis
We want to break our Personal Factory project into manageable pieces that can be individually designed. Since the factory will grow and evolve from a starter set, there is a strong time element. Thus our first division will be into phases that meet increasing levels of the total goals. Part of the growth will be how many people are in the community the project serves, so the phases also scale in amount of outputs. This keeps the equipment from being over-sized for the number of people involved. Operation on a smaller scale in the early phases should also provide some feedback for later design improvements. The Personal Factory is also intended to directly support the needs of the owner-operators. Thus where the food, shelter, and utility outputs go and how they are used is an integral part of the project. We will include these items as part of our complete system analysis.
With limited people to work on the design, we cannot examine every possible alternative at present. Therefore we will make one set of functional flow diagrams as a reference point, and leave variations for future work. We plan to follow this reference design approach through the complete design cycle. Given more time and people we can then go back and look at improvements and variations.
Figure 5.2-1 illustrates our division of the factory expansion starting with a conventional workshop, and six phases numbered 1A through 1F (you can click drawings for larger versions). Six is an arbitrary number of divisions of what is really a continuous expansion. We chose it as a reasonable compromise between number of phases to analyze and complexity of the additions in each step. The diagram is a partial functional flow type illustrating the time sequence, but it only shows some of the inputs and outputs. Conventional shop equipment and new parts and materials are inputs from outside the project.
The process starts with building the conventional workshop in the lowest box. We use construction tools and inputs of lumber, sheet metal, etc. and use those to assemble a building, then install the remainder of the workshop equipment. The completed conventional workshop is an output from the first function box. Along with additional outside parts and materials, we use the conventional shop tools to build the first Phase 1A expansion elements. These will be a set of added equipment that can process more materials, make new kinds of parts, etc. The loop marked "Phase 1A Expansion Elements" indicates as soon as a new piece of equipment is finished, it starts being used to help build more equipment. When the full set of Phase 1A elements are finished, we transition to the next function and start building Phase 1B. As equipment accumulates, we must also expand the building(s), roads, outdoor space for solar collectors, etc.
We continue building expansion phases in sequence through the final Phase 1F. During expansion, our ability to make our own parts and materials grows, but our target is 85% at the end of the expansion. Therefore all the phases still require new parts and materials from outside that we cannot make ourselves. The final box, "Operate Phase 1F Location" indicates the factory is complete according to this design, and outputs the full range of products for the owners, plus whatever replacement parts are needed for maintenance. This diagram does not show the outputs of final products, but all the expansion phases will do so, in increasing amounts over time.
Top Level Functions
To the outside world, the entire project can be treated as a single function box with inputs and outputs (see Figure 4.1-1). From within the design process, the edges of that function box are treated as the System Boundary, the logical division between the system we are designing and everything outside that we are not (see Figure 4.1-2). The inputs and outputs across that boundary can then be broken down into separate flows by type: Energy, Food, Water, Parts and Materials, etc. The question then becomes how to break up the sub-tasks internal to the boundary into smaller pieces. We choose as our first level of division the general type of activity: making things (Production), using things (Habitation) and moving things (Transport). This is not the only way you could divide up the project, but we think it is logical way to apply the rule of Functional Relatedness. This rule organizes functions that are more related to each other than to other functions into one group at the next higher level of a project. One reason for doing that is it places sequences of related tasks and the flows between them in a more compact and understandable layout. Another is optimizing groups of related functions is easier than trying to optimize everything at once. Changes to the related functions have less effect on the rest of the project, so they can be updated independently.
Lower Tier Functions
There is not sufficient information in the top three function boxes to identify what external flows link up with them, and what the flows are between them. To find that out, we begin a process of breaking down each function into smaller parts, identifying their inputs and outputs, and repeating until we reach individual items that are simple enough to design. Box and arrow type functional flow diagrams help understand how the parts of a system are connected, but they don't have room for full descriptions or technical data. We link the additional information to the diagrams by using the same names and numbers within the diagrams as reference labels on the other data.
Since the factory will grow in phases by additions to the previous phase, we don't need to create a completely new set of diagrams each time. Instead, our higher level diagrams will be based on the completed project (Phase 1F). We will make a version of the lower tier diagrams for each phase, showing what items were present in the previous phase, and what is added or changed in the current one. Therefore they represent slices in the time dimension of the project, with each slice showing the physical relationships at that time.
1. Provide Production Capacity
Production is numbered first among our three top level functions, because logically it comes before using the products for living space or transportation. In practice, though, the other two top functions will operate mostly in parallel. Figure 4.1-3 shows the bare breakdown into second-tier functions. The core of the production flow is the sequence from extracting raw materials such as ores, processing them into finished materials such as metal alloys, fabricating parts from those finished materials, and then assembling them into finished products. To these core steps, we add a control function to issue commands to the production equipment, supply power to operate them, and store inventory as needed between steps. Lastly we have growing organics as a separate item because living things perform self-production in a fundamentally different way than human designed equipment.
Again, there are other ways the Production function could be divided up, but we think this is a logical way of grouping related tasks. The numbering sequence is also arbitrary, but more or less in time order so that flow arrows will proceed from left to right. In this form the diagram is incomplete. Next, we need to describe each function in more detail and what the flows are that connect them. This defines the scope of the tasks that a given function includes. We start with descriptions:
1.1 Control Location - This function provides overall control of project operations, including habitation, transport, and external flows, as well as production. Individual elements can also have internal controls for local operation as needed. This function operates at a higher level where coordination across the entire project is important. It includes a mix of human-operated, automated, and software generated commands, issued locally or remotely, and transmitted to individual elements. The hardware elements will include computers, networking, displays, observation, measurement, and data collection equipment. Control tasks include future planning, real-time operation, and retrospective analysis.
1.2 Supply Power - This function is to supply all forms of power to the location, and converting it to the needed form, including electrical, thermal, hydraulic, stored energy, and others. It also includes providing a significant surplus as a goal. Power can be divided by demand class - residential and control power should be more reliable than some industrial tasks that can be interrupted. It can also be divided into fixed and portable power.
1.3 Extract Materials - This includes excavation and mining, water and air collection, and harvest of plants, either directly at the location or nearby, using location equipment. The goal is to obtain the majority of total materials from local supply, or recycled local or outside sources. This can be divided into extracting from project-owned land, and using extraction rights to other land. Delivery of bulk materials produced by others using their equipment is not part of this function, it is an external input.
1.4 Process Materials - This includes conversion of raw materials to finished materials inventory, ready for storage, parts making, or consumption. It can use chemical, mechanical, thermal, electrical, or other processes, and operate as a continuous flow or in separate batches. Outputs for a Personal Factory may include many of the following categories: stone and concrete, metals, ceramics, glass, wood, fibers, electronics, organic and inorganic compounds, fertilizers, and clean water.
1.5 Fabricate Parts - This takes finished materials from processing or storage, and transforms them into finished parts ready for assembly. Historically a wide variety of production machines and processes have been used for this function. We can organize fabrication tasks by the same materials categories as the previous Process Materials function. We can also list parts types such as castings, structural and mechanical parts, electrical, and electronic parts,
1.6 Store Inventory - This task includes storage for materials, parts, and completed items not currently in use. It includes temporary storage for other Production functions, and long term storage for Habitation and Transport. It also includes environment protection and control (i.e. buildings) for the other production functions, and land for industrial tasks. Warehouse space for storage and building space for a factory floor are functionally similar, and in fact one will likely be transformed to the other as the factory expands. Rather than accounting for them under multiple headings, we collect all the environmental enclosures here.
1.7 Assemble Elements - This includes assembly of parts and materials into higher level assemblies (collections of parts), leading to completed elements. It also includes dis-assembly of elements for maintenance or modification, with any draining and cleaning added as necessary. It can use any combination of human labor, robots, or automated processes, with local or remote control. Assembly can be divided into movable elements such as production machines and vehicles, and construction of fixed elements such as buildings. The latter may require temporary structures, weather protection, and cleaning tasks. Fixed elements may use modules assembled indoors to reduce weather delays and increase automation.
1.8 Grow Organics - This includes growing microorganisms, plants, and animals to the point of harvest to provide useful items. It also includes preserving species outside their normal environment range, which can optionally be via inactive storage. Pets and ornamental plants are placed under Personal Items in Habitation. It includes the land space to grow biological products, some of which may overlap with Habitation areas. Total land includes owned and leased land, and crop and timber harvest rights. The latter may be used to reduce costs during early construction. Some early timber may be obtained from construction site clearing if the land was well stocked.
2. Provide Habitation Capacity
The Personal Factory project as a whole is intended to satisfy most of the food, shelter, and utility needs of the owners. Where the previous production top level function makes these items, the Habitation function supplies the fixed locations where they are used. Habitation includes all types human-occupied space except production. This includes residential, commercial, and public use space. Buildings share common parts, like foundations and roofs, regardless of their use, and some buildings can be mixed-use. Therefore our functional breakdown will by by type of human needs being met rather than by use of the building.
The natural environment is often uncomfortable and sometimes hostile to humans, therefore we create shelter to modify the environment to our liking. Functionally we divide this into passive elements that protect us, and elements that actively control and modify the local environment. Once we have safe and comfortable surroundings, we next provide for the internal needs of the human body in the form of food and drink, and maintaining health. Basic items like shelter and food are necessary for everyone to live, but beyond that the majority of most people's time and occupied space is taken up by other activities which are more optional and diverse. We divide supporting these activities into the physical, which are personal items like furniture and clothing, and information, which is not tied to a specific physical item. Once we define these various functions in more detail, their required inputs and outputs then become demands which the production function needs to meet. The main habitation function descriptions are as follows:
2.1 Protect from External Environment - This includes passive protection of people and other habitation elements from weather, water, insects, and other outside factors. It also includes structural support of all habitation elements. This can be considered protection from gravity, uneven ground, and shifting subsoil, but stable support of the protective items is a necessary feature for them to work. In turn, the structural support requires underlying land for it to rest on, so we include all the habitation land under this function. We include outdoor protection for humans in the form of protective clothing.
2.2 Control Internal Environment - This function covers actively managing the internal environment created by the protective shell in terms of temperature, humidity, lighting and other factors. It includes control inputs and sensors (such as thermostats), and active hardware which produces the desired changes, such as heating, ventilation, and air conditioning (HVAC) systems. Passive thermal insulation was included in the previous function, and lighting, windows, and window coverings are included here as active devices. Emergency systems are also included here.
2.3 Provide Food and Drink - This includes supply of food and drink materials at the point of use for residents and guests, local storage within Habitation areas, food preparation, serving and dining, and disposal of food and drink wastes. The latter does not include human wastes, which are covered under Maintain Health.
2.4 Maintain Health - We need to include the actual human residents and guests someplace in the system functions, because they have inputs and outputs, and this is the chosen location. The tasks include supporting basic needs for sleep, sanitation, exercise, cleaning of persons and the environment, and filtering the latter, health monitoring, first aid and emergency services, and local examination and treatment.
2.5 Provide Personal Items - This includes the internal volume for private living and storage space, public or community space such as meeting rooms and athletic areas, and commercial space such as offices and shops. It also includes the physical contents of these spaces such as furniture and decorations. Decorative/non-protective clothing is also included. The total enclosed space from functions 2.2 to 2.5 then becomes a design requirement for 2.1 Protect from External Environment.
2.6 Provide Information - This includes communications (text, voice, and video) for personal or commercial purposes, teaching materials, entertainment, and general information like news and weather. It does not include operational information for production, although this function may share common hardware and software elements used across the location.
3. Provide Transport Capacity
Transport is the last by number of the three top-level functions. It is required partly because the various steps in production and the final point of use are different from each other. Since less than 100% of the owner's needs are being met by the project, we also need to import some items, deliver some items for sale, and some members need to travel from home to a project site, or work offsite from the project. Transport includes the movement of physical items to and from the project locations and internally within the locations. Moving non-physical items, like electricity and data, are covered under their respective production functions.
We divide transport into the next level of functions based on two factors. The first is whether it is internal to a given location, or external to and from one or more locations. The reason for the distinction is internal transport can be designed and built as needed by the project. We cannot easily modify outside transport infrastructure such as roads and water and gas pipelines, and therefore must largely take them as they are. In addition, external transport is typically over much longer distances than within a single location. The second factor is the type of cargo being moved, since the safety and comfort requirements for moving people is different, than, for example, a load of raw rocks. We will use three cargo categories: bulk items, delicate items, and humans. Despite the various functional categories, the eventual hardware design may share common equipment. For example, a conventional light (pick-up) truck can carry all three cargo types at the same time. The functional division of tasks allows us to examine the needs for each, then to consider whether specialized or shared equipment gives an optimum answer.
3.1 Deliver Bulk Cargo - This includes bulk supplies transported to and from or between project locations, including items for sale or to build new locations. Bulk items have relatively large volumes, but low requirement for protection from the environment or the shocks and vibrations of vehicle transport. It also includes piped delivery of items like water and natural gas, where a fixed infrastructure is used rather than a vehicle.
3.2 Deliver Delicate Cargo - This includes external transport of non-human items which need some protection from the environment, and the shocks and vibration of delivery. Environmental conditions which can cause damage or contamination include temperature, rain, insects, and dirt. Some items are fluids or gases, and thus need containers. Quantities are smaller than for bulk items, and thus multiple items may be delivered, rather than dedicated loads. Separate containers then help keep the various items from mixing or reacting with each other. Finally, the vehicle or containers may use devices to reduce shocks and vibrations to acceptable levels.
3.3 Deliver Humans - This includes the transport of humans to and from project locations. Humans have many of the same needs as delicate cargo, but also some additional ones. These include a higher safety level, added comfort features, optional manual vehicle control, and schedule priority.
3.4 Supply Internal Transport - This includes mobile and fixed transport elements within a project location, including between production elements. Mobile transport includes on- and off-road carriers which go from one place to another. Fixed transport elements stay in place, and include items that make it easier for vehicles to move, like roads and rails. It also includes lifting and conveying devices to move objects horizontally and vertically, including both enclosed and open pipes, channels and systems.