5.3 - Operations Flows
Each type of product made by the factory will require a different process flow. The following examples show some of the major process flows and which of the factory elements perform a given step. Some tasks will require making intermediate items like molds and attachments in addition to the original starter set.
Stone and Concrete - Sized gravel and sand can be used directly for construction, or added to cement to make concrete.
- Excavate rock and sand (Robotic vehicle with backhoe and bucket attachments)
- Transport rock to factory (Robotic vehicle with cargo trailer attachment)
- Crush and size rock (Hydraulic press and screens made with mill and plasma cutter attachment)
- Calcine cement (Solar furnace and limestone/shale ingredients)
- Grind cement powder (Grinding mill made from metal parts and electric motors)
Metals - Early production uses scrap metal. Later in factory growth new metal is chemically extracted from rock.
- Transport scrap to factory (Robotic vehicle with cargo trailer attachment)
- Make molds (Bridge Mill and Lathe to make patterns, sand from Stone and Concrete process)
- Cast rough parts and stock (Solar Furnace and molds)
- Fabricate finished parts:
- - Machine castings to finished size (Bridge Mill and Lathe), or
- - Forge stock to finished shape (Solar Furnace to preheat and Hydraulic Press with inserts to shape), or
- - Make sheet metal parts (Solar Furnace to preheat, Hydraulic press with rollers to make sheet, Bridge Mill to cut sheet to finished shape)
Ceramics - Includes brick, paving, tile, and household wares
- Prepare clay mix (see Stone and Concrete steps)
- Forming green shape (Hydraulic press with molds)
- Drying and preheating (Building storage and waste heat from other processes or thermal storage from Solar furnace)
- Firing (Solar furnace with auxiliary heat as needed, insulated chamber for gradual cooling)
Glass - Early production uses scrap glass (cullet). Later in factory growth makes glass from ingredients.
- Transport scrap glass to factory (Robotic vehicle with cargo trailer)
- Make glass molds (see Metals steps)
- Melt glass (Solar furnace with auxiliary heat as needed)
- Cast or blow glass (Molds plus compressed air if needed)
- Anneal glass (Insulated chamber)
- Cut logs from trees (Robotic vehicle with saw and cable attachments)
- Saw logs to rough lumber (Robotic vehicle with bandsaw attachment)
- Transport lumber to Factory (Robotic vehicle with cargo trailer)
- Dry lumber (Building storage with solar assist)
- Fabricate wood parts (Bridge Mill and Lathe)
Fibers - This cannot be done immediately by the starter set. It requires extensive equipment for growing, spinning, and weaving for natural fibers, high temperature melting for mineral fibers, or chemical processing for synthetic fibers. Once fibers and cloth are made, additional equipment is needed to incorporate the fibers into reinforced products or to sew flexible items. Therefore we leave fiber production out of the starter set and include it in later growth stages.
Electric Devices - This starts with generators, motors, and batteries and adds more types of devices over time.
- Fabricate wires (Hydraulic press with forming rolls for large diameter wire, Electric shop wire drawing machine for smaller wire)
- Fabricate motors and generators (Electric shop coil winding machine and Metals task above for other parts)
- Generate electricity (Solar furnace with concentrated photovoltaic or steam turbine generators)
- Store energy (Solar furnace with dry rock thermal storage or Chemical plant battery ingredients)
Bulk Chemicals - There are a large number of possible products, so a starter chemical plant will be designed for the ones needed for seed factory operation, and then expanded over time.
- Supply raw ingredients (Local air, water, rock, and plant sources, plus outside supply as required)
- Chemical processing (Chemical plant)
- Store products (Building storage plus glass, metal, and plastic containers)
Water - Both for human use, and production tasks. For seed factory simple collection or public supply is used. Water recycling requires building additional equipment.
- Collect water (Building piping and gutters, stream flow, wells, and process outputs)
- Treat water (Sand and absorbent beds, solar distillation)
Production and Growth Rates
Until we have a complete design of all the elements, we cannot make an exact estimate of the production rates and how fast the seed factory can grow. We can make a rough estimate by assuming that the factory buildings, excluding solar furnace, and all their contents have a mass of 2500 kg/m2 (510 psf), typical for a heavy duty building. Chemical and thermal processes require the most energy, and we can use an estimate of 30 MJ/kg including efficiency losses. A typical value for direct sunlight, which is needed for the furnace to operate, is 4 kWh/m2/day. We assume that the collector area is 3 times the remaining building area, and the solar furnace mass is 50 kg/m2, since it consists mostly of relatively thin mirrors. Thus each square meter of collector must produce 833.3 kg x 30 MJ/kg = 26,500 MJ of total energy to copy itself and it's share of the remaining factory. The daily output of 4 kWh = 14.4 MJ, therefore the factory in theory will copy itself in 25,500/14.4 = 1840 days, or 5 years. Since new equipment can increase production rates before the entire copy is finished, the correct way to calculate the growth is take the inverse of the copying time, 20% per year, and compound it. This gives a doubling time of 3.8 years.
Since production rates are limited by available energy, if we assume solar collector areas typical of the ratio of farm fields to their buildings (100:1), then each unit of collector only needs to produce 75 kg of total mass. In theory this would take 78 days. In practice some other part of the factory may become the limiting item at such large collector areas. For now we cay say a doubling time of several months to several years looks reasonable.