Overview

General comment

Production covered

Axial flow cooling fan with integrated BLDC (brushless DC) motor for electronics cooling. Outer-rotor configuration with permanent magnet rotor and wound stator. PBT-GF30 frame and impeller for heat resistance and dimensional stability. Oil-impregnated sintered bronze sleeve bearings (standard) or ball bearings (high-end variants). Typical applications include PC case cooling, CPU heatsink fans, server cooling, and general electronics thermal management.

Modelling choices

This dataset is modelled with no water reuse. No reclaim rate is published for this kind of plant, so the water shown is the full fresh intake and no recycling credit has been deducted from it.

Technology: Electromechanical Assembly, Air Mover
Geography: Global average data from equipment vendor specifications and industry literature

System boundary

The figure groups this dataset's unit processes by class. It is not a count of manufacturing steps — each process runs over as many passes as the flow requires, and those pass counts ship with the dataset.

Download this figure (SVG)

Data quality and references

Composite DQI 2.8 Good

Reliability

4.0

Completeness

3.3

Temporal

1.7

Geographic

2.5

Technological

3.0

Pedigree scores follow the ecoinvent data-quality matrix: 1 is the best attainable, 5 the weakest. The composite is their aggregate.

Sampling procedure: Component vendor specifications, academic papers, industry literature
Coverage status: Complete
Pedigree-scored source files: 6 — the source records behind this dataset's manufacturing operations. Each carries the five pedigree axes above; the composite DQI aggregates them.

Technosphere inputs

25 flows. Quantities are not published; they ship with the dataset on Circa.

Electricity, China (CN) ElectricitykWh · -45% / +86.4%

Derivation basis: Calculated from equipment energy across all manufacturing operations. This model includes no facility support, so the total is the manufacturing operations alone.

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

Komax Alpha 530 termination line specifications
Background data: ecoinvent 3.12
Background dataset: electricity, medium voltage
Uncertainty: -45% / +86.4% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kWh

Fresh water WaterL · ±25%

Derivation basis: Calculated from process-water and ultrapure-water demand across all manufacturing operations. This model includes no facility support, so the demand is the manufacturing operations alone. The fresh intake shown is that whole demand: the water-recycling scenario this dataset assumes reuses none of it, so nothing has been deducted, and wastewater follows the same balance.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: tap water
Notes: Process and cleaning water
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: L

H₂ Process gasg · -40% / +60%

Source citations: PM sintering practice
Background data: ecoinvent 3.12
Background dataset: hydrogen, gaseous, low pressure
Uncertainty: -40% / +60% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

N₂ Process gasg · -40% / +60%

Source citations: PM sintering practice
Background data: ecoinvent 3.12
Background dataset: nitrogen, liquid
Uncertainty: -40% / +60% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Sodium carbonate developer Process chemicalg · -59.9% / +350.6%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: soda ash, dense
Uncertainty: -59.9% / +350.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Dry Film Resist Process chemicalg · ±25%

Source citations: dupont.com (date not recorded). DuPont, "Riston PlateMaster PM200" dry film photoresist product page. Vendor web page.
allenwoodsgroup.com (date not recorded). DuPont Riston PlateMaster PM200 Data Sheet, DS02-94 Rev 6.0 (07/07) (allenwoodsgroup-hosted). Technical data sheet.
allenwoodsgroup.com (date not recorded). DuPont, "Riston 200 Series" dry film photoresist data sheet, DS95-17 Rev 6.0 (07/07). Technical data sheet.
Background data: proxy-mapped
Background dataset: methyl methacrylate
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Hydrochloric acid Process chemicalg · -34.6% / +74.3%

Source citations: ResearchGate, Water use in PCB manufacturing
Envirowise, Water use in PCB manufacturing
Patent CN102286761B, Acid Copper Additives
Patent US5151170A, Brightener Consumption
SysPCB, Inner Layer Process
NMFRC, Electroless Nickel Stoichiometry
Background data: ecoinvent 3.12
Background dataset: hydrochloric acid, without water, in 30% solution state
Uncertainty: -34.6% / +74.3% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Hydrogen peroxide Process chemicalg · -34.6% / +74.3%

Source citations: ResearchGate, Water use in PCB manufacturing
Envirowise, Water use in PCB manufacturing
Patent CN102286761B, Acid Copper Additives
Patent US5151170A, Brightener Consumption
SysPCB, Inner Layer Process
NMFRC, Electroless Nickel Stoichiometry
Background data: ecoinvent 3.12
Background dataset: hydrogen peroxide, without water, in 50% solution state
Uncertainty: -34.6% / +74.3% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Potassium permanganate Process chemicalg · -81.3% / +34.1%

Source citations: patents.google.com (date not recorded). US4601783A - High concentration sodium permanganate etch bath and its use in desmearing and/or etching printed circuit boards (Morton Thiokol Inc.; priority 1985-05-31; later MacDermid). Patent.
p2infohouse.org (date not recorded). Pagel, P. (Minnesota Technical Assistance Program), Waste Reduction at a Printed Circuit Board Manufacturing Facility Using Modified Rinsing Technologies, U.S. EPA WRITE Program, pp. 483-492. PDF document.
portlandcleanair.org (date not recorded). Atotech USA Inc., Material Safety Data Sheet: SECURIGANTH P-500 DOSING SOLUTION (Rock Hill SC; PMCODE PKV, 7 pp.). PDF document.
19january2021snapshot.epa.gov (date not recorded). U.S. EPA Design for the Environment - Printed Wiring Board Pollution Prevention and Control Technology: Analysis of Updated Survey Results (grant #X 823856; update to EPA 744-R-95-006). Government report.
zsepb.zs.gov.cn (date not recorded). Zhongshan Dajin Electronics Co. Ltd, annual 5 million m2 circuit-board expansion and retrofit project, environmental impact report form (zhong shan shi da jin dian zi you xian gong si nian chan 500 wan ping fang mi xian lu ban gai kuo jian xiang mu huan jing ying xiang bao gao biao), December 2024, project code 2404-442000-04-01-964388. PDF document.
Background data: ecoinvent 3.12
Background dataset: potassium permanganate
Uncertainty: -81.3% / +34.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Sodium hydroxide Process chemicalg · -30.3% / +45.5%

Source citations: ResearchGate, Water use in PCB manufacturing
Envirowise, Water use in PCB manufacturing
Patent CN102286761B, Acid Copper Additives
Patent US5151170A, Brightener Consumption
SysPCB, Inner Layer Process
NMFRC, Electroless Nickel Stoichiometry
Background data: ecoinvent 3.12
Background dataset: sodium hydroxide, without water, in 50% solution state
Uncertainty: -30.3% / +45.5% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Neutralizer (sulfuric acid or HCl) Process chemicalg · -20% / +50%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: sulfuric acid
Uncertainty: -20% / +50% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Copper sulfate pentahydrate Process chemicalg · -30.6% / +38.9%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: copper sulfate
Uncertainty: -30.6% / +38.9% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Formaldehyde Process chemicalg · -20% / +40%

Source citations: Balaramesh, Venkatesan, Jayalakshmi et al. (2025). Balaramesh, Venkatesan, Jayalakshmi et al. - Influence of conventional and sustainable electroless baths on autocatalytic copper deposition. Scientific Reports. DOI: 10.1038/s41598-025-19231-z.
pcdandf.com (date not recorded). Practices for Sustainability in PCB Metallization. Web page.
nepis.epa.gov (date not recorded). U.S. Environmental Protection Agency (1997). Design for the Environment Printed Wiring Board Project: Printed Wiring Board Cleaner Technologies Substitutes Assessment: Making Holes Conductive, Volume 1 (Draft). Web page.
nepis.epa.gov (date not recorded). U.S. Environmental Protection Agency (1998). Printed Wiring Board Cleaner Technologies Substitutes Assessment: Making Holes Conductive, Volume 1. Web page.
2003. US3532519A - Electroless copper plating process. Metal Finishing. DOI: 10.1016/s0026-0576(99)80316-x.
Background data: ecoinvent 3.12
Background dataset: formaldehyde
Uncertainty: -20% / +40% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Palladium catalyst Process chemicalg · -40% / +60%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: proxy-mapped
Background dataset: palladium
Notes: Proxy mapping uses 60% of the material mass.
Uncertainty: -40% / +60% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Nickel sulfate Process chemicalg · -25% / +37.5%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: nickel sulfate
Uncertainty: -25% / +37.5% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Sodium hypophosphite Process chemicalg · -22% / +33.1%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (specific to this process): ResearchGate, Water use in PCB manufacturing
Envirowise, Water use in PCB manufacturing
Patent CN102286761B, Acid Copper Additives
Patent US5151170A, Brightener Consumption
SysPCB, Inner Layer Process
NMFRC, Electroless Nickel Stoichiometry
Background data: proxy-mapped
Background dataset: sodium phosphate
Uncertainty: -22% / +33.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Gold potassium cyanide Process chemicalg · -33.1% / +33.7%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (specific to this process): Dow AUROLECTROLESS SMT 525G TDS; Florida CirTech IG300 TDS
Background data: proxy-mapped
Background dataset: gold
Notes: Proxy mapping uses 68.4% of the material mass.
Uncertainty: -33.1% / +33.7% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Potassium cyanide Process chemicalg · -40% / +60%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (specific to this process): IPC-4552B; industry immersion gold specifications
Background data: proxy-mapped
Background dataset: sodium cyanide
Uncertainty: -40% / +60% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

PBT-GF30 Materialkg · -20% / +24%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: proxy-mapped
Background dataset: glass fibre reinforced plastic, polyamide, injection moulded
Uncertainty: -20% / +24% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Non-oriented electrical steel Materialkg · ±30%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: steel, low-alloyed, hot rolled
Uncertainty: ±30% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Sintered NdFeB Materialkg · -31% / +29.3%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: proxy-mapped
Background dataset: permanent magnet, for electric motor
Uncertainty: -31% / +29.3% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Copper, cathode Materialkg · -28.6% / +31%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: copper, cathode
Notes: From Enameled copper wire (97.0% copper)
Uncertainty: -28.6% / +31% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Nylon 6-6 Materialkg · -28.6% / +31%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: nylon 6-6
Notes: From Enameled copper wire (3.0% enamel). Polyimide/polyamide enamel coating (~3% by mass)
Uncertainty: -28.6% / +31% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Bronze Materialkg · -24.2% / +36.4%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: bronze
Notes: From Sintered bronze (85.0% bronze). Cu-Sn sintered powder (90/10)
Uncertainty: -24.2% / +36.4% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Lubricating oil Materialkg · -24.2% / +36.4%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: lubricating oil
Notes: From Sintered bronze (15.0% lubricant). Oil impregnation (15-25% porosity filled)
Uncertainty: -24.2% / +36.4% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Outputs and waste

Wastewater Wastewaterm3 · ±25%

Derivation basis: Calculated from the water balance: fresh-water input minus evaporation.

No source is attached to this row.
Source citations: Not stated
Background data: carried, no background dataset
Background dataset: No treatment route recorded for this output.
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: m3

Plastic Scrap Solid wastekg · -25% / +50%

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: -25% / +50% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Steel Stamping Scrap Solid wastekg · -28.5% / +43%

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: market for iron scrap, sorted, pressed
Uncertainty: -28.5% / +43% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Magnet Grinding Waste Solid wastekg · -33.7% / +33.8%

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, underground deposit
Uncertainty: -33.7% / +33.8% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Die Lubricant Waste Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

KZL Industrial Automation. "KZL-224 Automatic Stator Coil Winding Machine." (Details 13.6 kW power consumption and 0.5 Mpa air pressure)

KZL Industrial Automation. "KZL-228 & KZL-310 Stator Winding Machines." (10 kW and 1.5 kVA consumption profiles)

Riley et al. (1996). "Journal of Applied Physics 79:6342." (Empirical 1.72 kJ discharge on 4-pole NdFeB, 3380 A peak)
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, hazardous waste incineration, with energy recovery
Uncertainty: No range defined.
Unit: g

Powder Loss Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

PM sintering practice
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Rejected Parts Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

PM sintering practice
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Wire Scrap Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

KZL Industrial Automation. "KZL-224 Automatic Stator Coil Winding Machine." (Details 13.6 kW power consumption and 0.5 Mpa air pressure)

KZL Industrial Automation. "KZL-228 & KZL-310 Stator Winding Machines." (10 kW and 1.5 kVA consumption profiles)

Riley et al. (1996). "Journal of Applied Physics 79:6342." (Empirical 1.72 kJ discharge on 4-pole NdFeB, 3380 A peak)
Background data: ecoinvent 3.12 treatment route
Background dataset: market for copper scrap, sorted, pressed
Uncertainty: No range defined.
Unit: g

Adhesive Waste Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

KZL Industrial Automation. "KZL-224 Automatic Stator Coil Winding Machine." (Details 13.6 kW power consumption and 0.5 Mpa air pressure)

KZL Industrial Automation. "KZL-228 & KZL-310 Stator Winding Machines." (10 kW and 1.5 kVA consumption profiles)

Riley et al. (1996). "Journal of Applied Physics 79:6342." (Empirical 1.72 kJ discharge on 4-pole NdFeB, 3380 A peak)
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Stripped photoresist Solid wasteg · ±20%

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, hazardous waste incineration, with energy recovery
Uncertainty: ±20% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Developer sludge Solid wasteg · ±20%

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, underground deposit
Uncertainty: ±20% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Copper from treated etchant drag-out Solid wasteg · -89.2% / +125.1%

Source citations: mee.gov.cn (date not recorded). GB 39731-2020, Emission standard of water pollutants for the electronics industry (official MEE PDF) - Table 1 item 13 total copper 0.5 direct / 2.0 indirect mg/L; Table 2 benchmark effluent volumes per wafer / per m2 PCB / per package. Standard.
epa.gov (date not recorded). U.S. EPA Office of Water, "Preliminary Study of the Electrical and Electronic Components Point Source Category", EPA-821-R-22-005, DCN 11197 (2022) - Table 12 indirect Cu median 0.05 / mean 0.213 / max 5.64 / min 0.00015 mg/L (67 facilities, 1,309 results, 996 detects); Table 13 direct; Table 6 named-facility treatment trains; sec. 1.2.3.1 post-1983 process additions. Government report.
19january2021snapshot.epa.gov (date not recorded). U.S. EPA Design for the Environment, "Printed Wiring Board Pollution Prevention and Control Technology: Analysis of Updated Survey Results" (grant X 823856; update to EPA 744-R-95-006) - raw Cu 0.4 to >100 mg/l (sec. 6.2); Exhibit 6-1 permit-limit rows; drag-out Exhibits 4-4/4-5; treatment mix sec. 6.3. Government report.
Background data: ecoinvent 3.12 treatment route
Background dataset: market for copper scrap, sorted, pressed
Uncertainty: -89.2% / +125.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Ablated dielectric debris Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Epoxy smear residue Solid wasteg · -73.9% / +195.4%

Source citations: patents.google.com (date not recorded). Electrochemicals Inc., US6454868B1, "Permanganate desmear process for printed wiring boards", issued 2002-09-24. Patent.
isola-group.com (date not recorded). Young, T. (Isola); Polakovic, F. and Carano, M. (Electrochemicals Inc.), "Thermal Reliability of Laser Ablated Microvias and Standard Through-Hole Technologies as a Function of Materials and Processing", paper S09-6-1. PDF document.
link.springer.com (date not recorded). Cheng, Y.-H.; Hsu, C.-C.; Lan, C.-J.; Munoz, S.; Caparanga, A.; Soriano, A.N.; Li, M.-H., "Desmearing of FR4 Epoxy Resin Using NMP-Based Sweller", Journal of Electronic Materials, 2009, 38(11): 2368-2375. Journal article.
sthjt.hubei.gov.cn (date not recorded). HJ 2058-2018 Technical specifications for wastewater treatment engineering of printed circuit board (yin zhi dian lu ban fei shui zhi li gong cheng ji shu gui fan), National Environmental Protection Standard of the PRC, issued 2018-08-31, effective 2018-12-01. PDF document.
17260206.s21i.faiusr.com (date not recorded). Victory Giant Technology (Huizhou) Co., Ltd. - Plant 9 Intelligent CNC Machining Centre Project (Phase 1), completion environmental-protection acceptance monitoring report, March 2026 (prepared by Huizhou Landing Environmental Technology Co., Ltd.). PDF document.
aivon.com (date not recorded). Aivon, "How We Resolved PCB Solder Mask Opening Design Conflicts in a 2-Layer FR4 PCB" (engineering case, production record #FR4-20260708-079).
kinjipcb.com (date not recorded). Kinji Group (KinjiPCB), product page "10 Layer FR4 ENIG Mass Production PCB" (product/142).
jlcpcb.com (date not recorded). JLCPCB Help Centre, "In what cases will there be charged extra?", section 9 "Too Many Drilling Holes" (page dated "Last updated on Aug 13, 2026").
pcbtok.com (date not recorded). PCBTok (Sony He), "Complete PCB Via Size Guideline", 5 November 2024, section "PCB Density".
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: -73.9% / +195.4% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Manganese sludge (filter cake) Solid wasteg · -86% / +101.2%

Source citations: sthjt.hubei.gov.cn (date not recorded). HJ 2058-2018 Technical specifications for wastewater treatment engineering of printed circuit board (yin zhi dian lu ban fei shui zhi li gong cheng ji shu gui fan), National Environmental Protection Standard of the PRC, issued 2018-08-31, effective 2018-12-01. PDF document.
epa.gov (date not recorded). U.S. EPA Office of Water - Preliminary Study of the Electrical and Electronic Components Point Source Category (40 CFR Part 469), EPA-821-R-22-005, DCN 11197, November 2022. Government report.
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, underground deposit
Uncertainty: -86% / +101.2% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Copper in wastewater-treatment sludge/recovery Solid wasteg · -2.6% / +0.6%

Source citations: mee.gov.cn (date not recorded). GB 39731-2020, Emission standard of water pollutants for the electronics industry (official MEE PDF) - Table 1 item 13 total copper 0.5 direct / 2.0 indirect mg/L; Table 2 benchmark effluent volumes per wafer / per m2 PCB / per package. Standard.
epa.gov (date not recorded). U.S. EPA Office of Water, "Preliminary Study of the Electrical and Electronic Components Point Source Category", EPA-821-R-22-005, DCN 11197 (2022) - Table 12 indirect Cu median 0.05 / mean 0.213 / max 5.64 / min 0.00015 mg/L (67 facilities, 1,309 results, 996 detects); Table 13 direct; Table 6 named-facility treatment trains; sec. 1.2.3.1 post-1983 process additions. Government report.
19january2021snapshot.epa.gov (date not recorded). U.S. EPA Design for the Environment, "Printed Wiring Board Pollution Prevention and Control Technology: Analysis of Updated Survey Results" (grant X 823856; update to EPA 744-R-95-006) - raw Cu 0.4 to >100 mg/l (sec. 6.2); Exhibit 6-1 permit-limit rows; drag-out Exhibits 4-4/4-5; treatment mix sec. 6.3. Government report.
Background data: ecoinvent 3.12 treatment route
Background dataset: market for copper scrap, sorted, pressed
Uncertainty: -2.6% / +0.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Nickel hydroxide sludge Solid wasteg · -39.1% / +49.8%

Derivation basis: calculated from Ni precipitation stoichiometry

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: market for metalliferous hydroxide sludge
Uncertainty: -39.1% / +49.8% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Phosphorus in wastewater-treatment sludge Solid wasteg · -45.6% / +58.6%

Derivation basis: Derived: elemental phosphorus balance, the phosphorus reaching treatment less the post-treatment residual

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, underground deposit
Uncertainty: -45.6% / +58.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Routing dust (FR-4 particles) Solid wasteg · -9.4% / +3.1%

Source citations: circuitnet.com (date not recorded). Oosterhof A. & Nether S. (LPKF), "Depaneling of Circuit Boards", Proc. 20th Pan Pacific Microelectronics Symposium, Kauai, Feb 2-5 2015 (CircuitNet-hosted PDF). Conference paper.
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: -9.4% / +3.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Copper Sludge Solid wasteg · -33.3% / +25%

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: market for metalliferous hydroxide sludge
Uncertainty: -33.3% / +25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Neutralization Sludge Solid wasteg · -48.5% / +54.3%

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, underground deposit
Uncertainty: -48.5% / +54.3% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Packaging Waste Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

KZL Industrial Automation. "KZL-224 Automatic Stator Coil Winding Machine." (Details 13.6 kW power consumption and 0.5 Mpa air pressure)

KZL Industrial Automation. "KZL-228 & KZL-310 Stator Winding Machines." (10 kW and 1.5 kVA consumption profiles)

Riley et al. (1996). "Journal of Applied Physics 79:6342." (Empirical 1.72 kJ discharge on 4-pole NdFeB, 3380 A peak)
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Label Waste Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

KZL Industrial Automation. "KZL-224 Automatic Stator Coil Winding Machine." (Details 13.6 kW power consumption and 0.5 Mpa air pressure)

KZL Industrial Automation. "KZL-228 & KZL-310 Stator Winding Machines." (10 kW and 1.5 kVA consumption profiles)

Riley et al. (1996). "Journal of Applied Physics 79:6342." (Empirical 1.72 kJ discharge on 4-pole NdFeB, 3380 A peak)
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Jacket Strip Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

Komax Alpha 530 / UniCrimp 208 Specifications, Komax Group, Published 2022

JacketStrip 8310 Technical Specifications, Symartech

Model TZ-PT500 & TZ-PT630 Pair Twist + Back Twist Machine Specifications, TaiZheng Machine

HK-500 Triple Twisting Machine for CAT5/CAT6 Cable Manufacturing, HK Cable Machine

48 Spindles Steel Wire Braiding Machine Specifications, Shenzhen Adp Communication Technology

16 Spindle Braiding Machine Product Data, Srichand Engineering
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Conductor Trim Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

Komax Alpha 530 / UniCrimp 208 Specifications, Komax Group, Published 2022

JacketStrip 8310 Technical Specifications, Symartech

Model TZ-PT500 & TZ-PT630 Pair Twist + Back Twist Machine Specifications, TaiZheng Machine

HK-500 Triple Twisting Machine for CAT5/CAT6 Cable Manufacturing, HK Cable Machine

48 Spindles Steel Wire Braiding Machine Specifications, Shenzhen Adp Communication Technology

16 Spindle Braiding Machine Product Data, Srichand Engineering
Background data: ecoinvent 3.12 treatment route
Background dataset: market for copper scrap, sorted, pressed
Uncertainty: No range defined.
Unit: g

Scrapped material (line yield) Solid wastekg · -23.5% / +26.3%

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Notes: Calculated reject material after accounting for a manufacturing yield of 99%.
Uncertainty: -23.5% / +26.3% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Emissions to air

1 elementary flow released to air by this dataset's own operations. Quantities are not published; they ship with the dataset on Circa.

CO₂ Emission to airg

Derivation basis: Stoichiometric estimate

No source is attached to this row.
Source citations: Not stated
Compartment: Air (non-urban air or from high stacks)
CAS number: 124-38-9
ecoinvent 3.12 elementary flow: Carbon dioxide, fossil
Uncertainty: No range defined.
Unit: g

Emissions to water

9 elementary flows released to water by this dataset's own operations. Quantities are not published; they ship with the dataset on Circa.

Cu2+ Emission to waterg

Source citations: mee.gov.cn (date not recorded). GB 39731-2020, Emission standard of water pollutants for the electronics industry (official MEE PDF) - Table 1 item 13 total copper 0.5 direct / 2.0 indirect mg/L; Table 2 benchmark effluent volumes per wafer / per m2 PCB / per package. Standard.
epa.gov (date not recorded). U.S. EPA Office of Water, "Preliminary Study of the Electrical and Electronic Components Point Source Category", EPA-821-R-22-005, DCN 11197 (2022) - Table 12 indirect Cu median 0.05 / mean 0.213 / max 5.64 / min 0.00015 mg/L (67 facilities, 1,309 results, 996 detects); Table 13 direct; Table 6 named-facility treatment trains; sec. 1.2.3.1 post-1983 process additions. Government report.
19january2021snapshot.epa.gov (date not recorded). U.S. EPA Design for the Environment, "Printed Wiring Board Pollution Prevention and Control Technology: Analysis of Updated Survey Results" (grant X 823856; update to EPA 744-R-95-006) - raw Cu 0.4 to >100 mg/l (sec. 6.2); Exhibit 6-1 permit-limit rows; drag-out Exhibits 4-4/4-5; treatment mix sec. 6.3. Government report.
Compartment: Water (surface water)
Formula: Cu
CAS number: 7440-50-8
ecoinvent 3.12 elementary flow: Copper ion
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Mn2+ Emission to waterg

Source citations: epa.gov (date not recorded). U.S. EPA Office of Water - Preliminary Study of the Electrical and Electronic Components Point Source Category (40 CFR Part 469), EPA-821-R-22-005, DCN 11197, November 2022. Government report.
Compartment: Water (surface water)
CAS number: 16397-91-4
ecoinvent 3.12 elementary flow: Manganese II
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Potassium Emission to waterg

Source citations: p2infohouse.org (date not recorded). Pagel, P. (Minnesota Technical Assistance Program), Waste Reduction at a Printed Circuit Board Manufacturing Facility Using Modified Rinsing Technologies, U.S. EPA WRITE Program, pp. 483-492. PDF document.
patents.google.com (date not recorded). US4601783A - High concentration sodium permanganate etch bath and its use in desmearing and/or etching printed circuit boards (Morton Thiokol Inc.; priority 1985-05-31; later MacDermid). Patent.
portlandcleanair.org (date not recorded). Atotech USA Inc., Material Safety Data Sheet: SECURIGANTH P-500 DOSING SOLUTION (Rock Hill SC; PMCODE PKV, 7 pp.). PDF document.
Compartment: Water (surface water)
Formula: K+
CAS number: 24203-36-9
ecoinvent 3.12 elementary flow: Potassium I
Notes: K2SO4 → 2K⁺ + SO4²⁻ (ionic dissociation)
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Sulfate Emission to waterg

Source citations: p2infohouse.org (date not recorded). Pagel, P. (Minnesota Technical Assistance Program), Waste Reduction at a Printed Circuit Board Manufacturing Facility Using Modified Rinsing Technologies, U.S. EPA WRITE Program, pp. 483-492. PDF document.
patents.google.com (date not recorded). US4601783A - High concentration sodium permanganate etch bath and its use in desmearing and/or etching printed circuit boards (Morton Thiokol Inc.; priority 1985-05-31; later MacDermid). Patent.
portlandcleanair.org (date not recorded). Atotech USA Inc., Material Safety Data Sheet: SECURIGANTH P-500 DOSING SOLUTION (Rock Hill SC; PMCODE PKV, 7 pp.). PDF document.
Compartment: Water (surface water)
Formula: SO42-
CAS number: 14808-79-8
ecoinvent 3.12 elementary flow: Sulfate
Notes: K2SO4 → 2K⁺ + SO4²⁻ (ionic dissociation)
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

HCHO Emission to waterg

Source citations: qxb-img-osscache.qixin.com (date not recorded). Jiangxi Longyi Connection Technology Co. Ltd - annual 1.10 million m2 automotive-electronics supporting-industry project, phase 1 stage 1, construction-project completion environmental-protection acceptance report (jian she xiang mu jun gong huan jing bao hu yan shou bao gao). PDF document.
sthjt.hubei.gov.cn (date not recorded). HJ 2058-2018 Technical specifications for wastewater treatment engineering of printed circuit board (yin zhi dian lu ban fei shui zhi li gong cheng ji shu gui fan), National Environmental Protection Standard of the PRC, issued 2018-08-31, effective 2018-12-01. PDF document.
mee.gov.cn (date not recorded). GB 8978-1996 Integrated wastewater discharge standard (wu shui zong he pai fang biao zhun), Table 4 maximum allowable discharge concentrations of Class II pollutants for units built on or after 1998-01-01. PDF document.
inchem.org (date not recorded). IPCS/WHO, Concise International Chemical Assessment Document 40: Formaldehyde, World Health Organization, Geneva, 2002.
epa.gov (date not recorded). U.S. EPA Office of Water, "Preliminary Study of the Electrical and Electronic Components Point Source Category", EPA-821-R-22-005, DCN 11197, November 2022. PDF document.
Compartment: Water (surface water)
CAS number: 50-00-0
ecoinvent 3.12 elementary flow: Formaldehyde
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

EDTA Emission to waterg

Source citations: cjournal.hep.com.cn (date not recorded). MEI Yining, WEI Zhe, WEI Li'an, Study on resource recycling of copper from spent PCB electroless copper plating bath, Electroplating & Finishing, 2024, 43(2): 149-154 (School of Environmental and Chemical Engineering, Nanchang Hangkong University). Journal article.
p2infohouse.org (date not recorded). Pagel, P., "Waste Reduction at a Printed Circuit Board Manufacturing Facility Using Modified Rinsing Technologies", Minnesota Technical Assistance Program (MnTAP) under the U.S. EPA WRITE Program, pp. 483-492. PDF document.
patents.google.com (date not recorded). C. Uyemura & Co. Ltd, EP0142356B1, "Analytical method for determining formaldehyde in electroless copper plating bath", priority 1983-11-11. Patent.
gesetze-im-internet.de (date not recorded). Abwasserverordnung (AbwV) Anhang 40 "Metallbearbeitung, Metallverarbeitung" (German Waste Water Ordinance, Annex 40).
Compartment: Water (unspecified)
Formula: C₁₀H₁₆N₂O₈
CAS number: 60-00-4
ecoinvent 3.12 elementary flow: EDTA, Ethylenediaminetetraacetic Acid
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Ni Emission to waterg

Source citations: China GB 39731-2020, Emission standard of water pollutants for the electronics industry, Table 1 item 20 total nickel 0.5 mg/L (archived MEE PDF, read verbatim); corroborated by GB 21900-2008 electroplating total nickel 0.5 mg/L; band endpoints from EU STM BREF 2006 Table 3.18 (nine Swedish installations) and Table 3.20 (nickel levels associated with potential BAT)
Compartment: Water (surface water)
Formula: Ni2+
CAS number: 14701-22-5
ecoinvent 3.12 elementary flow: Nickel II
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

CN⁻ Emission to waterg

Source citations: bureau-industrial-transformation.jrc.ec.europa.eu (2019). Reference Document on Best Available Techniques for the Surface Treatment of Metals and Plastics. PDF document.
law.cornell.edu (date not recorded). 40 CFR § 433.15 - Pretreatment standards for existing sources (PSES). | Electronic Code of Federal Regulations (e-CFR) | US Law | LII / Legal Information Institute.
Compartment: Water (surface water)
Formula: CN-
CAS number: 57-12-5
ecoinvent 3.12 elementary flow: Cyanide
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Phosphorus (from hypophosphite) Emission to waterg

Derivation basis: Calculated as a release to water, from a contaminant mass balance on the process chemistry.

No source is attached to this row.
Source citations: Not stated
Compartment: Water (surface water)
Formula: P
CAS number: 7723-14-0
ecoinvent 3.12 elementary flow: Phosphorus
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Flows not quantified

3 flows are recorded for this dataset but carry no quantity — cut off below the significance threshold, or with no background dataset available. They remain inside the declared system boundary; each is listed with its reason.

Cut off - below the significance threshold (1)

Other Materials Materialkg · -35.2% / +29.6%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: cut off
Background dataset: Not applicable: this flow is not quantified in the inventory.
Reason: Catch-all for minor unspecified materials, recorded in this inventory. The combined contribution falls below the declared cut-off threshold, so no upstream production dataset is attached.
Uncertainty: -35.2% / +29.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Not modelled (2)

Complexing agent (EDTA or Rochelle salt) Process chemicalg · -20% / +50%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: not modelled
Background dataset: Not applicable: this flow is not quantified in the inventory.
Reason: Proprietary plating-bath additive consumed in trace quantity, recorded in this inventory. Formulations vary by supplier and no representative public production dataset exists, so the upstream burden is left unlinked rather than approximated with an unrepresentative proxy.
Uncertainty: -20% / +50% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Complexing agent (citrate, malate, or lactate) Process chemicalg · -40% / +60%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.
REEL derivation: engineering estimate of connector and electromechanical component mass and material split, built from vendor catalogue and product-page data for representative parts; no single published inventory covers this component class

No source is attached to this row.
Source citations: Not stated
Background data: not modelled
Background dataset: Not applicable: this flow is not quantified in the inventory.
Reason: Proprietary plating-bath additive consumed in trace quantity, recorded in this inventory. Formulations vary by supplier and no representative public production dataset exists, so the upstream burden is left unlinked rather than approximated with an unrepresentative proxy.
Uncertainty: -40% / +60% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

The flows above are this dataset's own records. What follows are the scope rules set once for the whole database in the methodology report, repeated here so every dataset page carries them.

Database-wide boundary policy — applies to every REEL dataset

These boundaries are set once for the whole database, in Chapter 2 of the methodology report, and apply to this dataset wherever they are relevant to it. The excluded flows listed above are specific to this dataset.

Use phase: Product operation is outside the cradle-to-gate scope.
End-of-life treatment: Recycling and disposal are outside the cradle-to-gate scope.
Distribution and retail: The gate is a finished component ready for integration into a higher-level assembly.
Inbound transport of raw materials: Transport of purchased raw materials to the manufacturing facility is already inside the upstream "market for" datasets that users link to a background database, so it is not modelled a second time here. This does not cover freight between REEL production stages, which is modelled where a dataset authors it.
Returnable shipping containers: Where freight between production stages is modelled, the mass moved is the product itself. The shipping container (FOSB, SEMI M31) is returnable capital equipment whose per-trip share is unsourced, so its tare is excluded from the transport effort.
Photomask fabrication: A mask set's embodied burden is amortised across a high-volume production run and is not attributed per wafer. Users assessing low-volume production should add mask fabrication separately; the methodology report gives the basis for the exclusion.
Employee transport, administration and R&D overhead: Employee transportation, facility administration and R&D/pilot-production overhead are outside scope.
Capital goods: Manufacturing equipment, cleanroom construction and facility infrastructure are excluded, on the grounds of absent public data on equipment embodied energy, uncertainty in equipment lifetime and allocation, common practice in electronics LCA, and a focus on the operational inventory. Future versions may include capital goods when sufficient public data becomes available.
Precious metal recovery credits: Scrap recovery credits for precious metals are excluded pending data availability.
Wafer reclaim: Test wafers and scrap are outside the system boundary.

Inside the boundary, linked rather than modelled

Silicon ingot growth and wafer slicing: Inside the cradle-to-gate scope, but treated as upstream material inputs linked to background databases rather than modelled as REEL processes.
Freight between production stages: Where a dataset's product moves between REEL production stages - wafer fabrication to the packaging site, for example - that leg is authored as a transport service and linked to an ecoinvent freight activity. It is measured as a transport effort in tonne-kilometres, not as a mass. Route distances are authored per route class with a stated band; a lower bound of zero is a modelling statement that the two sites can be co-located, not a missing value.

Cut-off criteria

A flow is excluded from a process inventory when it contributes less than 1 % of the total mass of inputs to that unit process, or less than 1 % of its total energy input. The denominator is total process inputs, not product mass. That distinction matters in semiconductor manufacturing, where the input mass of water, chemicals and gases greatly exceeds the product mass, so the threshold removes only genuinely minor flows.

Included regardless of the cut-off

Perfluorocarbons (CF4, C2F6, SF6, NF3) - high GWP, EPA regulated
Heavy metals (Pb, Cd, Hg, Cr(VI)) - RoHS regulated, high toxicity
Volatile organics (photoresist solvents, PGMEA) - air quality
Precious metals (Au, Ag, Pd, Pt) - high embodied impacts
Ozone-depleting substances (legacy CFCs, HCFCs) - Montreal Protocol