Production Science Pack Ratios - Purple Science Setup for Space Age

The Production Science Pack (Purple) is the mid-game gate in Factorio Space Age. Each craft takes 10 seconds and produces 3 packs (up from 2 in Factorio 1.0). The three ingredients force you to scale up steel production, start lubricant-based manufacturing, and build your first module factory. | Ingredient | Per Pack | For 5 SPM | Source | |-----------|:--------:|:---------:|--------| | Electric Engine Unit | 0.33/s | 1.67/s | Engine + Red Circuit + Lubricant | | Productivity Module 1 | 0.33/s | 1.67/s | Red Circuit + Green Circuit | | Rail | 0.33/s | 1.67/s | Steel + Stone | If you are coming from [blue science](https://factorioguides.com/science-packs/blue-science-guide/), purple science is a different kind of challenge. Blue science tests your oil refining. Purple tests your raw resource scaling -- specifically steel throughput and circuit production.

5 SPM is a comfortable mid-game target when first setting up purple science. It unlocks the main Space Age tech tree without forcing a megabase. | Component | Machines | Input | Notes | |-----------|:--------:|-------|------| | Purple science assemblers | 5 | 3 ingredients each | Craft time 10s, output x3 | | Electric engine assemblers | 2 | Engine + Red + Lube | 1 assembler feeds ~2.5 science assemblers | | Engine unit assemblers | 2 | Steel + Gears + Pipes | AM2, direct feed to electric engines | | Productivity module 1 assemblers | 1 | Red + Green circuits | One AM1 handles up to 10 SPM | | Rail assemblers | 1 | Steel + Stone | One AM1 handles more than 5 SPM needs | | Green circuit assemblers | 2-3 | Copper cable + Iron | Shared with other sciences | | Red circuit assemblers | 1-2 | Plastic + Copper + Green | Shared with blue science | | Lubricant chemical plant | 1 | Heavy oil | 1 plant at basic output is enough | | Steel furnace (stone/steel) | 9 | Iron ore + Coal | Steel for rails + engine + modules |

Purple science is the first point where you need lubricant. If you already have oil processing set up for blue science, adding lubricant is simple: | Step | Machine | Input | Output | |------|---------|-------|--------| | Heavy oil extraction | Refinery (advanced) | Crude oil + Water | Heavy + Light + Petroleum | | Heavy oil cracking | Chemical plant | Heavy oil | Light oil (optional) | | Lubricant | Chemical plant | Heavy oil | Lubricant | **The trick:** Do not crack all your heavy oil into light oil. Reserve at least one full pipe of heavy oil for lubricant production. Each electric engine unit needs 1 lubricant, and at 5 SPM you consume about 1.67 lubricant per second -- that is roughly 3 chemical plants worth of heavy oil cracking diverted to lube. If you are using basic oil processing, a single refinery on crude oil produces 30 heavy oil per cycle. That feeds about 1.5 chemical plants making lubricant -- barely enough. Switch to [advanced oil processing](https://factorioguides.com/production-ratios/oil-processing-guide/) as soon as your blue science is stable. Advanced processing doubles heavy oil output per cycle.

The optimal layout for purple science follows a straight line: 1. **North side:** Steel furnace column feeds into a splitter that sends steel to rail production, engine production, and productivity module assembly 2. **Middle row:** Engine assemblers feed into electric engine assemblers. Productivity module assemblers sit on the circuit bus 3. **South side:** Rail production on stone/steel input. Red and green circuits come from the main bus or a dedicated circuit sub-factory 4. **Output:** All three ingredients meet at the purple science assemblers. Belts merge using a 3-to-1 balancer

When you decide to push purple science higher, these are the bottlenecks to watch for: | SPM Target | Purple Assemblers | Steel Furnaces | Electric Engine Assemblers | Key Constraint | |:----------:|:----------------:|:-------------:|:-------------------------:|----------------| | 5 | 5 | 9 | 2 | Steel throughput | | 15 | 15 | 27 | 6 | Lubricant + Red circuits | | 30 | 30 | 54 | 12 | Module factory space | | 45 | 45 | 81 | 18 | Entire bus redesign needed | **Scaling tip at 30+ SPM:** Switch electric engine assemblers to Assembling Machine 3 with speed module 1s. The recipe is slow (10s base), and speed modules directly increase purple science output per assembler without adding complexity to the ingredient belts. A dedicated electric engine sub-factory becomes necessary around 30 SPM. You can use [circuit network control](https://factorioguides.com/blueprints/circuit-network-guide/) to balance lubricant between electric engine production and battery manufacturing for your other science packs.

- **Underestimating steel:** Purple science consumes steel for rails, engine units, and productivity module component chains. A single yellow belt of steel (15/s) supports about 10 SPM of purple science only. Share with other sciences and you will run out quickly. - **Neglecting module production:** Productivity module 1 requires 5 red circuits and 5 green circuits per unit. At 5 SPM, each minute you burn 50 red and 50 green circuits just on modules. That is comparable to the circuit consumption of blue science. Building a dedicated module assembler early saves you from circuit starvation later. - **Not planning rail output:** One rail assembler at a full belt of steel produces 2 rails per second. That is enough for 5 SPM, but if you are also building rail networks for your factory expansion, the purple science demands will eat into your construction supply. Build a separate rail assembler just for science.

Purple science is where Factorio starts demanding real resource throughput. You need steel at scale, lubricant from your oil setup, and a small circuit factory running alongside everything else. Start at 5 SPM with 9 steel furnaces and 2 electric engine assemblers. Scale up in chunks rather than trying to build a 45 SPM setup from scratch -- the mid-game is about iteration, not perfection. **Next step:** After purple science, the logical next milestone is setting up a space platform for [space science](https://factorioguides.com/space-age/space-platform-guide/). Or you can tackle utility science (yellow) to unlock logistic robots and upgrade your factory logistics.

- [Factorio Wiki: Production science pack](https://wiki.factorio.com/Production_science_pack) -- Recipe reference and crafting times - [Factorio FFF-419: Space Age science changes](https://factorio.com/blog/post/fff-419) -- Official changes to purple science output from 2 to 3 per craft