Rarity and Affixes¶

RNGTech treats machines like loot. Every machine, part, and Battery Cell you craft rolls its own rarity, a set of random affixes, and a budget of Refinement Potential (RP). Two Crushers from the same recipe can come out quite different: one might be faster, another might use less power, and a lucky one might do both.

This page explains what those rolls mean, how many affixes each rarity gets, how strong they can be, and how to improve them afterwards.

What rolls traits¶

These items roll rarity, affixes, and RP when you craft them:

Item	Examples
Machines	Furnace, Crusher, Battery Chassis, generators, Fluid and Compressor Tanks
Machine parts (Gear)	Iron Heat Core, Iron Crush Head, Servos, Fluid Pumps, Reactor Chambers
Battery Cells	Iron Battery Cell and every other material cell
Modular tool parts	Tool Heads and Tool Rods for Modular Tools
Companions	The Forestry Companion cart from the Forestry Cart Station, and the Miner's Companion

A few blocks never roll traits: the Affix Forge and Exotic Affix Forge, the Crude Component Recycler, the wooden and silica-gel machines such as the Wooden Composter, the Algae Photobioreactor, and cables and connectors. Assembled modular tools carry no traits of their own. Their Tool Head and Tool Rod do.

Identification¶

A freshly crafted item comes out Unidentified, for example "Unidentified Iron Furnace Chassis". Its rarity, affixes, and RP are hidden, and the crafting preview never shows them, so you cannot reroll a recipe by peeking at the result.

To identify an item, put it alone in a crafting grid and take the result. The preview still says Unidentified; the traits appear when you take the item out. Other ways to identify:

Placing an unidentified machine rolls its traits as it goes down.
Battery Cells made in a Component Assembler come out already identified.

You cannot refine an unidentified item. Identify it first.

Rarity¶

Rarity sets how many affixes an item can hold.

Rarity	Prefixes	Suffixes	Notes
Normal	0	0	Base stats only.
Magic	1	1	Named after its affixes, for example "Hellish Iron Furnace Chassis of Smelting".
Rare	up to 3	up to 3	Rolls three of each when crafted, if enough different affixes fit the item. The name uses its first prefix and first suffix.
Unique	—	—	Found, not crafted. Rolled stat lines, no RP, and only a Volatile Catalyst can change it.

Uniques have their own page: where to find them, how their ranged stats roll, and what each one does.

Rarity odds¶

The odds depend on the item's stage:

Item stage	Normal	Magic	Rare
0	35%	50%	15%
1–4	—	70%	30%
5 and higher	50%	40%	10%

Stage 1–4 items are never Normal, so the gear you build early always shows some affixes. From Stage 5 up, a Normal roll is common, and the Affix Forge does more of the work.

The Miner's Companion and the Forestry Companion roll as Stage 2 items. The Crude and Steel Metal Press roll as Stage 8 items, with Stage 8 tiers and RP, because they have no upgrade ladder to carry your investment forward.

Affixes¶

An affix is a random bonus, such as faster processing, a bigger energy buffer, or a chance for extra output.

Prefixes come before the item name and lean towards capacity, heat, efficiency, and machine-specific tricks.
Suffixes come after the name and lean towards speed, energy use, generation, output, and slots.

An item can only roll affixes that its machine actually uses, so a Solar Panel never rolls Crusher bonuses. An item also never holds two affixes from the same group. For example, a Crusher can have only one processing-speed suffix: plain speed, a named one like "of Crushing", Overclocked, or Bulk Speed. Narrow items may have fewer legal affixes than the rarity allows.

Base stats and fixed traits¶

Rolled affixes sit on top of the item's own identity, which never changes:

Base stats come from the item's material and stage. A Titanium Heat Core is always hotter than an Iron one.
Fixed traits are built-in behaviors listed under Behaviors in the tooltip. For example, the Bronze Furnace speeds up alloy blends, and Copper, Bronze, and Steel Fuel Boxes have Fuel Governor.

Base stats and fixed traits do not use affix slots, and refinement can never remove them.

Hover an identified item to see its rarity, RP, and rolled affixes. A Corrupted item shows a red Corrupted line instead of its RP, and any corruption implicit in red. Hold Left Shift for material and affix details, and Left Alt for each affix's tier and roll range. To see how affixes, Gear, and Mastery combine into a machine's final numbers, hold Shift over a row on its Stats tab. See Machine Stats.

To show an item to other players, hold Ctrl+Alt and left-click it in any inventory or machine screen. Chat shows its name in its rarity colour, and hovering the name shows its full tooltip. This works for any item with a rarity, including unidentified items and Uniques, but not for items in the creative menu's item tabs. You can link once per second.

Affixes use four words:

increased and reduced add together. Two "20% increased Processing Speed" affixes give 40%. Energy Use is the exception: its reductions add together and then divide the cost, so 100% reduced Energy Use halves it instead of removing it.
more and less multiply separately, after that, so they are worth more when stacked with increases.

Affix tiers¶

Most affixes have a tier from 1 to 7. The tier sets the range, and the affix rolls one value inside it. Most percentage affixes use this table:

Tier	Range
1	2–5%
2	4–10%
3	11–30%
4	40–55%
5	60–75%
6	80–100%
7	110–140%

Crusher yield affixes use smaller tables, because they all feed the Crusher's Output Amount total, which already has diminishing returns.

Crusher Jaws and Crush Head Pulverizing (prefixes) give the most Bonus Output, but also roll reduced Processing Speed. The speed penalty rolls on its own, wider range, so a light penalty is a lucky roll.
The Output Amount suffix on Crushers and Crush Heads is small and has no penalty. It can sit beside Jaws or Pulverizing.

Tier	Jaws and Pulverizing: Bonus Output	Jaws and Pulverizing: reduced Processing Speed	Output Amount suffix
1	2–3%	1–4%	1%
2	4–6%	3–8%	1–2%
3	7–10%	5–12%	2–3%
4	11–14%	8–18%	3%
5	15–17%	11–22%	4%
6	18–20%	14–26%	4–5%
7	22–25%	17–31%	6%

Older Crushers and Crush Heads can carry yield values from earlier, larger tables, without the speed penalty. They keep those values until you upgrade or reroll the affix, which then uses these tables.

Some affixes use their own tables, such as flat FE, extra slots, or durability. A few are untiered and always roll the same value.

Low tiers are much more common than high ones. The item's stage sets a natural tier, and every tier above it is far less likely:

Item stage	Natural tier
0	1
1–2	2
3–6	3
7–8	4

One tier above natural rolls at half the usual weight, two above at 15%, and three or more above at 5%. Stage 3–4 items are the exception: they roll one tier above natural at full weight, so about one in four Stage 3–4 items shows a Tier 4 or better affix. Tool Heads and Tool Rods are slightly luckier with high tiers.

Random rolls reach Tier 6 at most. Tier 7 appears only on Stage 8 Exotic items.

Machine and part affixes¶

Where an affix sits changes what it affects:

Affixes on the machine apply to the whole machine.
Affixes on an installed part are local. They improve that part's own contribution first, and then the part's total is added to the machine. For example, a percentage Max Temperature affix on a Heat Core raises that core's heat, not the chassis's.
Crush Head yield is the exception. The head's own Output Amount and its yield affixes add straight to the Crusher's increased Output Amount total.

Hold Left Shift on a part to see which of its affixes are marked (Local). On generators, a part's generation affix scales the machine's base or recipe output once; it does not scale flat FE/t from other parts.

Machine affixes, together with Machine Mastery passives, are what scale the whole machine.

Attribute suffixes¶

Machines with Machine Mastery and the Gear they take can roll +Control (of Command), +Drive (of Impetus), and +Reserve (of Reserves). Each is a flat number of points, from 3–5 at Tier 1 to 36–45 at Tier 7. Unlike other part affixes, these points count for the whole machine, and they feed the attribute bonuses and attribute scaling exactly like points from the tree. Each attribute is its own group, so one item can roll both +Control and +Drive but never two +Drive.

They roll on the Crusher, Furnace, Alloy Furnace, Metal Press, Melter, Resonance Calibrator, and Forestry Companion, and on Crush Heads, Heat Cores, Servos, Fluid Pumps, Alloy Crucibles, Resonance Coils, Control Boards, and Stabilizer Matrices. A part that sits in a machine without Mastery, such as a Heat Core in a Solid Fuel Burner, gets nothing from them.

Notable affixes¶

Most affixes simply raise or lower a stat. A few change how the machine behaves.

Bulk Speed¶

A suffix for processing machines. Each completed process adds 1% Processing Speed, up to 100%. Powered machines keep the same FE per craft, so their FE/t rises as they speed up. The bonus resets when the chain is interrupted, for example by invalid input, missing Gear, or a different recipe. Topping up the input with more of the same item keeps it.

Bulk Speed works on the Crusher, electric Furnace, Alloy Furnace, Component Assembler, Component Recycler, Metal Press, Melter, Resonance Calibrator, Potential Reactor, and Corrosion Cell. On the two generators it can double FE/t at its cap. It can also roll on the Coal Gasifier, Steam Methane Reformer, and Ammonia Synthesizer, where it has no effect.

Bulk Speed takes the processing-speed group, so it never appears alongside another speed suffix.

Balance Mode¶

A Battery Chassis prefix, shown as Balanced. The chassis fills and drains all installed Battery Cells evenly instead of one at a time. It gives chassis without a built-in Charge Balancer the same behavior. See Battery Chassis.

Fuel Governor¶

A fixed trait of the Copper, Bronze, and Steel Fuel Boxes in a Solid Fuel Burner. While the burner's storage is full, it pauses the fuel burn instead of wasting it, and keeps exporting stored FE. It is not a rolled affix.

Power Grace¶

A suffix that halves the failure strain a heat machine takes when its power drops mid-cycle. It can roll on electric Furnaces, Alloy Furnaces, Heat Cores, Alloy Crucibles, and Servos, and Stage 6 and higher Servos have it built in. See Furnace for how failure strain works.

Other named affixes¶

Affix	Effect
Overclocked	More Processing Speed, but also more Energy Use.
Instant Process	A small chance for a process to finish the moment it starts. Powered machines need enough FE for the whole craft up front. The progress bar flashes gold when it happens.
Super Output	A small chance to add one extra copy of the recipe's base output.
Charged Storage	Battery Chassis only. 100% more installed-cell capacity after the chassis has held energy for 10 minutes straight.
Additional Battery Slots	Battery Chassis only. Unlocks up to four extra cell slots.
Vein Miner	Rare Pick Head prefix. The Pick breaks connected ore of the same type, at an extra FE cost per block.
Self Repair	Tool Head and Tool Rod prefix. Restores durability every 7.5 seconds while the tool sits idle in your hotbar or offhand.

Refinement Potential (RP) is each item's budget for changing its affixes. Every successful refinement spends some. When RP runs out, the item is final, so spend it where it matters. The only way back is a Reforge in the Exotic Affix Forge, which rerolls the whole item, RP included. A Corrupted item keeps its RP but can never spend it, so its RP is hidden.

RP is rolled separately from rarity, and the starting affixes cost nothing. A Rare item keeps its full budget, just like a Normal one. Higher stages get bigger budgets:

Item stage	Starting RP
0	1–3
1–2	6–10
3–4	8–14
5–6	14–22
7–8	22–32

Tool Heads and Tool Rods get 2 extra RP, and some machine parts add a small bonus of their own. The tooltip of an unidentified part shows the range it can roll.

An illegal or failed refinement costs nothing: no catalyst and no RP. If an add or upgrade rolls a cost higher than the RP left, it still succeeds, and the item drops to 0 RP.

Annealed items¶

An item that rolls traits comes out Annealed when you craft it at a crafting table and every plate in its recipe is Annealed. Annealed plates come from a Metal Press with Hydrogen Quench. Only the plates in the item's own crafting grid count, so plates used earlier, for example in a Machine Frame, do not. Items whose recipe has no plates, such as Heat Cores, cannot be Annealed.

The Unidentified item shows an aqua Annealed line. When you identify or place it, its RP rolls twice in its stage's range and keeps the higher roll. For a Stage 5–6 item (14–22 RP), that raises the average from 18 to about 19.5. Rarity, affixes, and tiers roll as usual.

Refining¶

Refinement changes an item's rolled affixes with a consumable catalyst. You can:

add an affix (Affix Injector). A Normal item becomes Magic, a Magic item fills its missing prefix or suffix, and a Rare item keeps adding until full.
upgrade a random affix to a higher tier, up to Tier 6.
promote a Magic item to Rare with an Ascension Catalyst or Ascension Matrix.
remove or reroll affixes.
corrupt a finished item with a Volatile Catalyst, a one-way gamble described in Corruption.

You choose the catalyst, but the game picks which affix it adds or upgrades. In the Affix Forge, modifier lenses can tilt the odds towards a family you want.

Where to refine:

Items in the Affix Forge. Its catalyst table lists every operation and its RP cost.
Placed machines in the Refinement tab of the machine's own screen.
Tool Heads and Tool Rods, even inside an assembled tool, in the Tool Bench Refine tab.
Late-game powered operations in the Exotic Affix Forge.

Corruption¶

A Volatile Catalyst corrupts a finished machine part or Battery Cell in the Affix Forge, or a placed machine in its Refinement tab. It costs no RP, and it is the only thing that can change a Unique. Machine and chassis items, Tool Heads, Tool Rods, companions, and unidentified or stripped items cannot be corrupted as items; place a machine first and corrupt it from its Refinement tab.

The catalyst rolls one outcome, and every outcome leaves the item Corrupted:

Outcome	Chance	Effect
Untouched	20%	Nothing else changes.
Blessed	20%	Adds one positive corruption implicit.
Reforged	20%	Rerolls every rolled affix from the item's legal pools, like a Chaos Crystal. Rarity, RP, base stats, and fixed traits stay.
Warped	20%	Each rolled affix moves by its own random amount from −15% to +15% of its value, past its tier's range. 100% increased Processing Speed can become anything from 85% to 115%. Tiers stay, and yield and RP affixes are not changed.
Blighted	20%	Adds one negative corruption implicit.

On a Unique, Reforged rerolls every ranged stat line inside its range, and Blessed or Blighted draw from the pool of the Unique's part. An outcome with nothing to do becomes Untouched: Reforged or Warped on an item without affixes it can change, Reforged on a Unique with no ranged lines, Warped on any Unique, and Blessed or Blighted on an item with no implicit to draw. A Stabilization Crystal in the Affix Forge's focus slot removes Blighted, adds its chance to Untouched, and is used up. Pack makers can change these chances and the Warped range.

A Warped affix uses one roll for all of its effects, so a drawback on a two-stat affix grows or shrinks with its benefit. Hold Left Alt to compare a Warped affix with its tier's normal range.

A Corrupted item can never be refined again: the Affix Forge, Exotic Affix Forge, Tool Bench, Refinement tabs, and a second Volatile Catalyst all refuse it, and nothing is used. Corruption cannot be removed. Nothing is ever destroyed or loses rarity; the worst result is a Blighted implicit. A placed machine keeps its corruption when you break and place it again.

Corruption implicits¶

A corruption implicit is one fixed value, with no tier or range. It sits outside the prefix and suffix limits, and applies after the item's affixes. Each item draws one from its own pool, weighted:

Item	Blessed	Blighted
Heat Core	10% increased Max Temperature, 15% increased Temperature Stability, 15% increased Overheat Tolerance, 10% increased Heat Transfer, 10% increased Fuel Efficiency, 20% reduced Thermal Mass, or Power Grace	20% less Temperature Stability, or 25% increased Thermal Mass
Crush Head	+1 Processing Level (rare), +25% Jam Recovery, 10% increased Processing Speed, or 10% more Processing Speed	25% more Jam Chance, or 15% less Processing Speed
Servo	Power Grace, Auto Purge, 15% increased Overheat Tolerance, 10% increased Processing Speed, 15% increased Stability, 15% reduced Energy Use, or 20% increased Fluid Transfer	15% less Processing Speed, or 20% less Stability
Alloy Crucible	+15% Blend Speed, 15% increased Temperature Stability, 10% increased Processing Speed, 15% increased Overheat Tolerance, or 20% reduced Thermal Mass	20% less Stability
Fluid Pump	50% increased Fluid Capacity, or 30% increased Fluid Transfer	30% less Fluid Transfer
Battery Cell	20% increased Energy Transfer, 30% less Idle Loss, 15% increased Energy Capacity, or 10% increased Efficiency	Doubled Idle Loss
Resonance Coil, Control Board, Stabilizer Matrix	+1 Coil Reach, 10% increased Catalyst Efficiency, 10% increased Calibration Precision, or 10% increased Processing Speed	20% less Processing Speed, or 10% less Calibration Precision
Bio Chamber, Fuel Box	15% increased Fuel Efficiency, or 15% increased Fuel Duration; the Bio Chamber can also roll 10% increased Energy Generation, and the Fuel Box 15% increased Stability	10% less Energy Generation on the Bio Chamber; 15% less Stability on the Fuel Box
Other generator parts	10% increased Energy Generation; most also roll 15% increased Stability or 10% increased Processing Speed	10% less Energy Generation
Other parts	15% increased Stability; most also roll 10% increased Processing Speed or 10% increased Efficiency	15% less Stability
Placed processing machine	10% increased Processing Speed, 20% reduced Energy Use, or 15% increased Stability where the machine has it; +1 Batch Size (rare) on the Crusher, Furnace, Alloy Furnace, Melter, Metal Press, and Resonance Calibrator; 15% increased Fuel Efficiency or 10% increased Max Temperature on the Furnace	25% increased Energy Use; 20% less Fuel Efficiency on the Furnace
Placed generator	10% increased Energy Generation, 15% increased Efficiency, and where the machine has them 15% increased Stability or 25% increased Energy Capacity	20% less Efficiency
Battery Chassis	+1 Battery Slot, 15% increased Energy Capacity, or 20% increased Energy Transfer	15% increased Idle Loss

Machines with Machine Mastery and the Gear they take (Crush Heads, Heat Cores, Servos, Fluid Pumps, Alloy Crucibles, Resonance Coils, Control Boards, and Stabilizer Matrices) can also be Blessed with 10% increased Control, Drive, or Reserve. Like attribute suffixes, it counts for the whole machine.

+1 Processing Level on a Crush Head lets it crush one level harder ore without jamming; it does not change which Gear the Crusher accepts. With a catalyst in the Affix Forge, hover Blessed or Blighted in the outcome panel to see the exact pool and odds for the item in the target slot. Corruption implicits never add yield or RP.

Guides	Automation · Battery Cells · Dormant Machines · Gear · Getting Started · Heat · Machine Mastery · Machine Stats · Modpack Creators · Power Chains · Rarity and Affixes · Stages · Uniques
Processing	Alloy Furnace · Component Assembler · Component Recycler · Crusher · Furnace · Melter · Metal Press · Resonance Calibrator · Wooden Composter
Power generation	Bio Generator · Cavitation Generator · Corrosion Cell · Fuel Cell · Potential Reactor · Solar Panel · Solid Fuel Burner · Syngas Combustor · Vacuum Collapse Generator
Energy storage	Battery Chassis
Fluids and gases	Algae Photobioreactor · Ammonia Synthesizer · Coal Gasifier · Fluid and Compressor Tanks · Silica Gel Dehumidifier · Steam Methane Reformer · Wooden Dehumidifier
Refinement	Affix Forge · Exotic Affix Forge
Logistics	Universal Cable
Tools	Forestry Cart Station · Miner's Companion · Modular Tools · Tool Bench