Table : Summary of machining processes and nanomaterials processed. Machining Process Nano-composite (Nano-objects) Refs. Abrasion sandpaper pad • PA+SiO2 NP • POM+CNT • Cement+CNT • Cement+CSH • TPU+CNT [] “ “ “ [] rotary • PA+SiO2 NP • POM+CNT • Cement+CNT • Cement+CSH • TPU+CNT [] “ “ “ [] • PU+ZnO • Clearcoat+ZnO • Architect. coating+ZnO [] “ “ • Epoxy+CNT [] Taber, linear • PMMA+Cu NP • Polycarb+CNT [] “ • PET fabric + PVC coat + Nano-clay [] Cutting band-saw • (CF+CNT) in epoxy • (Alumina fibres + CNT) in epoxy [] “ disc-saw (wet) • (CF+CNT) in • (Alumina fibres + CNT) in epoxy [] “ • CNF composite [, ] mill • Al-alloy [] None (Li-Ti-MO) [] Drilling concrete drill • Nano-Crete concrete (fumed silica) [] flute-reamer • Bismaleimide / Graphite (Cemented carbide) [] polycrystalline diamond drill • Bismaleimide / Graphite [] abrasive drill • (CF+CNT) in epoxy • (Alumina fibres + CNT) in epoxy [] [, ] EDM tungsten electrode • PMMA+CNT [, ] FSW mill • Al-alloys [] Grinding micro-grinder • thermal spray coating (WC-12Co; Al2O3-13TiO2) [] grinder • aerospace composite []
• Granite • Clay ceramic • Hardwood [] None (Ag NP) [] Laser None [] Nano-mill FIB • PMMA+CNT [] Sanding manual • • Epoxy-CNF composite / CNF Buckypaper laminate [] [] miniature • PU-ZnO • AC-ZnO • AC-Fe2O3 [] “ “ orbital • PVA paint +TiO2 • Acryl paint + TiO2 • Acryl paint+CB • UV Hardcoat + SiO2 sol [, ] [] “ “ belt • Epoxy-CNF aerospace composite [] Turning lathe • Al-alloy, Mild steel, High tensile steel (tool: cermet) [, ] • None (tool: Si3N4 whiskers; TiN NP) [] CNC lathe • Carbon reinforced composite (tool: WC; TiC) [] Weathering UV exposure • PA+SiO2 NP • POM+CNT • Cement+CNT • Cement+CSH • TPU+CNT [] “ “ “ [] • Epoxy+SiO2 • Epoxy+MWCNT [] “ Photocatalytic paint+TiO2 []
[] Abrasive Test (Taber Linear Tester) • PMMA + 10% Cu NP: (PMMA-Cu) • Polycarb. + 3% CNT: (PC-CNT) C / NM • Cu NP • CNT Sealed HEPA filtered glove box, 150 LPM air flow rate. SiC paper: P1200: large no of ultrafine # P120: fewer # and coarser. SEM of PC from ELPI/stage2: PC-CNT: NP found, no CNT. TEM: from NAS: PC-CNT: no CNT PMMA-Cu: Cu detected by EDX; brush: Cu in µm particles. SiC: Cu nearly detached. [] Abrasive Test (Taber) + CNT (0, 0.1, 1 wt.%) C / NM CNT Enclosure chamber surrounding abrasion wheel. Four modes found in each case (Table 1). CNT cause 70nm->90nm shift in mode1. Only few particles from abr. wheel (EDX). Matrix particles, CNT protruding, free individual CNT (!) Authors indicate that TEM images prove CNT are released. [] + suppl. Wet cutting using diamond blade table saw CNF-Composite C / NM CNF • Without controls • Inside ventilated booth Substantial amounts of nanoscale CNF (from EC) and 300-10,000nm • Matrix fragments • Free CNF • CNF agglomerates & bundles CNF quantified by elemental carbon (EC) reading and identified by TEM of collected particles. Dry surface grinding CNF-Composite C / NM CNF LEV: Measurement at edge of LEV Nanoscale and 300-10,000nm • Matrix fragments • Free CNF High concentration of ultra-fine particles, only few CNF. Tabletop belt sanding CNF-Composite C / NM CNF LEV: Measurement at edge of LEV inlet. No nanoscale, but 300-10,000nm present • Matrix fragments • Clusters of spherical carbon particles CNF not detected in BZ with LEV operational Hand sanding inside spray booth CNF-Composite and CNF Buckypaper laminate C / NM CNF • Vent on • Vent off No nanoscale, but present • Matrix fragments • Free CNF TEM shows evidence of CNF, regardless of ventilation conditions.
[] None (weathering) Silica NP in epoxy (EPON 828) C / NM SiO2 NP Enclosure N/A SEM/EDX: particles detected and identified. Exposure in SPHERE UV chamber (NIST) None (weathering) MWCNT in epoxy C / NM MWCNT Enclosure N/A SEM/EDX: no CNT detected in release container Exposure in SPHERE UV chamber [] Weathering + fanning + abrasion) TiO2 paint (Allstar, Taiwan) C / NM TiO2 NP Enclosure Fig5: mode peak initially at 55nm; moves to ≈125nm w time. Not investigated Wear processes: • UV exposure • fan blower • rubber knife [] Milling Li-titanate metal oxide (Li-Ti MO) NM Li-Ti-MO - Data for Wet Mill (Table I), using PVC membrane: 0.026 mg/m3 Use CPC and OPC in combination. [] Grinding Silver colloid and NP NM Ag NP Vent hood above grinder, local Opening grinder 2 modes appear at 20nm and 25nm Ø. [] Grinder (Dremel Multipro 395) • Granite • Clay ceramic • Oak hardwood (C) None Stainless-steel chamber, air (air cleaner ACE mod 73-800G) SMPS-APS data analysed by fitting two modes: ultra-fine: 9-10nm; oak ≈35nm coarse: 0.6–3.8 µm TEM images of mostly coarse particles. [] FSW Aluminium alloys: • 6061-T6 • 5083-H111 (C) None Snorkel fume extractors (LEV): Turned off during exp. High RPM gen. more dust mass / coarse pp. Low RPM gen. more Modes: 550nm from workpiece; 30nm Zn from lubricant. Increase to 125nm by agglomeration; Sampl. locations: TP: at BZ ESP: at source PWRAS: near BZ
ultrafines. Fewer pp at BZ than source Confirmed by EDX and PWRAS / ICP-MS. [] Orthogonal Milling KC725M grade insert (carbide + Al-TiN coating) NM Al-TiN coating (by PVD) Milling process is inside a G-Class Plexiglas box SMPS: no modes identified in spectrum, but: measurements all outside instr. range!
all 0.014 ↑0.015¦ - - - - - guard OK, reduced lubricant flow base-carbon 0.094 ↑0.55¦ 47.6 ↑381¦ - 0.054 - 116•103 broken guard [] - background 0.018-0.020 - - - - - Figs 5A,B Solid-core drilling, base-alumina 0.03-0.05 < ≈0.70> 0.05-1.30 - - - - - 725 RPM, 1-ply <2-ply> 1355 RPM, 1-ply 1/4” drill bit CNT-alumina < 0.1-0.4> <0.2-1.0> - - - - - 725 RPM, <2-ply> 1355 RPM, <2-ply> drilling, base-alumina 0.020-0.025 < ≈0.30> - - - - - 725 RPM, 1-ply <2-ply> 3/8” drill bit 0.05-1.00 < ≈3.00> - - - - 1355 RPM, 1-ply <2-ply> CNT-alumina ≈0.02 <0.07-3.00> 0.02-0.70 <0.05-7.00> - - - - - 725 RPM, 1-ply <2-ply> 1355 RPM, 1-ply <2-ply> [] - background 0.0042 ↑0.0049¦ 12 ↑137¦ - - <0> 9 ↑20¦ Source & BZ Solid-core drilling, 3/8” drill bit base-alumina 0.0500 ↑3.600¦ 0.0190 ↑0.450¦ 0.1600 ↑10.000¦ 31 ↑3877¦ 30 ↑433¦ 128 ↑5602¦ - - - <1.3> <1.0> 13 ↑86¦ 25 ↑666¦ 725 RPM, 3-ply @BZ 1355 RPM, 3-ply
0.0160 ↑0.790¦ 0.0068 ↑0.150¦ 107 ↑304¦ 16 ↑1420¦ @BZ Wet drilling, 3-ply CNT-alumina 0.0850 ↑3.900¦ 0.0430 ↑2.900¦ 0.1800 ↑11.000¦ 0.0460 ↑1.300¦ 0.0087 ↑0.200¦ 12 ↑1746¦ 30 ↑666¦ 96 ↑5849¦ 59 ↑5155¦ 13 ↑136¦ - - - <1.0> <0.7> 23 ↑425¦ 51 ↑686¦ 725 RPM, 3-ply @BZ 1355 RPM, 3-ply @BZ Wet drilling, 3-ply base-carbon 0.1300 ↑4.600¦ 0.0100 ↑0.270¦ 206 ↑2458¦ 195 ↑817¦ - - <1.7> <1.9> - 1355 RPM, 22-ply @BZ CNT-carbon 0.0840 ↑3.900¦ 0.0120 ↑0.380¦ 155 ↑548¦ 178 ↑1100¦ - - - - 1355 RPM, 22-ply @BZ [] - background (TC) - - ≈10 26-29 0.012-0.016 0.033-0.040 0.017 0.000,57 - - PM10 (Indoor) PM10 (Outdoor) TC Inhalable (Tab I) TC Surfaces (TabII) Chopping of epoxied CNF Epoxy coated CNF - - ≈11 ≈0.010 0.221 - - PM10 TC Inhalable (Tab I) Wet-saw cutting of CNF comp. CNF composite material - - 12-17 0.040-0.161 1.094 0.003,68 - - PM10 TC Inhalable (Tab I) TC Surfaces (TabII) [] background - - 7.605 - - - At distance Idle-running drill - - 39.033 195.616 - - - Up-wind Down-wind
Manual drilling Conventional concrete - - 15.960 22.889 - - - Up-wind Down-wind Manual drilling Emaco R4 (BASF) - - 29.545 70.981 - - - Up-wind Down-wind [] ventilation background > 0.000,01 - - - - - Sanding by hand-held Sander properties 0.1180, 0.1850, 0.0007 141 89 303.9 - - - Modes = 9.8, 16, 179, 904, 1320 nm orbital sander Ref. paint 0.0181 2257 482 20.8 - - - Modes = 140, 1020, 2020 nm; Prod Em. (Metabo FSR 200 Intec) NP 1 0.0103 3005 1182 14.5 - - - Modes = 152, 1020, 1840 nm; Prod Em. NP Paint 2 0.0238 3194 599 27.6 - - - Modes = 144, 1020, 2160 nm; Prod Em. [] + ventilation background > 0.000,2 (diluted) - - - - suppl. Sanding by hand-held (PVA) 0.294 0.260 46,600 751 341 80 - - - G1R: Prod Emiss. Sanding / Sander orbital Sander PVA + TiO2 (9.8%) 0.356 0.285 19,300 317 375 90 - - - G1A - Sanding / Sander (Metabo FSR 200 PVA + TiO2 (10.0%) 0.599 0.317 134,000 117 733 416 - - - G1B – (<100nm) Sanding / Sander
PVA + Kaolin. (14.7%) 0.459 0.292 63,000 448 522 230 - - - G1C – Sanding / Sander Acryl 0.351 0.241 4,000 148 355 114 - - - G2R: Prod Sanding / Sander (2.5%) 0.332 0.155 6,700 201 339 118 - - - G2A – (95nm) Sanding / Sander Acryl + TiO2 (10.0%) 0.406 0.318 5,600 895 411 93 - - - G2B – (17nm) Sanding / Sander Outdoor Acryl 0.395 0.298 4,900 231 400 102 - - - G3R: Prod Emiss. Sanding / Sander Acryl + SiO2 (≈10%) 0.340 0.232 6,900 190 347 145 - - - G3A – (7nm) Sanding / Sander CaCO3 filler 0.564 0.295 59,900 95 624 329 - - - G4R: Prod Emiss. Sanding / Sander CaCO3 + perlite 0.719 0.336 16,900 102 736 400 - - - G4A Sanding / Sander UV hard coat 2.420 0.271 52,400 157 2470 2200 - - - G5R: Prod Emiss. Sanding / Sander Coat + SiO2 (5%) 0.644 0.279 9,900 706 654 374 - - - G5A – (<50nm) Sanding / Sander [] - Background BSS (<4E-6) - 0.000,03 - - -
Abrasive Test (Taber) Polyurethane (PU), 2-comp BSS - 1.17 0.23 - - - A1 (fibre board) / A3 (steel plate) PU-ZnO BSS - 0.03, 0.07 - - - A2, A4 (see above) Clearcoat, Desmolux U100 (CUV) BSS - 0.45 - - - B1 (UV curable) CUV-ZnO BSS - 0.40 - - - B2 Architectural Coating (AC) BSS - 0.08 - - - C1 AC-ZnO BSS - 0.10 - - - C2 [] background - - ≈0.000,01 - - - 0.2 #/cc in Miniature Sander Polyurethane (PU), 2-comp 0.2 (Ø<100nm: .12) - 1,200 (diluted) - - - 3.5E8 #/cc in 0.3L 2.0E8 #/cc in 10L (Dremel 400 Series) PU-ZnO 0.22 (Ø<100nm: .15) - 1,800 (diluted) - - - 5.5E8 #/cc in 0.3L 2.2E8 #/cc in 10L Architectural Coating (AC) 0.16 (Ø<100nm: .15) - ≈15 - - - ≈.05E8 #/cc in 0.3L 1.6E8 #/cc in 10L AC-ZnO 0.205 - ≈30 - - - ≈0.1E8 #/cc in 0.3L 2.05E8 #/cc in 10L AC-Fe2O3 0.205 - ≈30 - - - ≈0.1E8 #/cc in 0.3L 2.05E8 #/cc in 10L
Overall - - 0.6-63.6 - - - Room 10m2 x 3m [] - background - - - 0.000,03 0.000,02 0.000,45 0.000,01 - - glovebox, no act. Room (closed) Biosaftey cabinet Manual sanding by operator CNT-enforced epoxy composite - - 3.889 3.765 1.742 0.000,06 ↑0.008,00¦ 0.002,68 0.010,60 0.031,50 0.000,03 - - Near source: • glovebox • ambient, no extr. • Fume hood • Biosafety Cab. - - 3.889 1.989 1.350 0.002,68 0.021,40 0.000,20 - - Breathing Zone BZ: • ambient, no extr. • Fume hood • Biosafety Cab. [] + suppl. - background 0.0020 0.0015-0.0040 - - - - - Custom-built test Taber Abraser Custom-built abrasive Test • PA • PA + SiO2 • POM • POM + CNT • Cement1 • Cement1 + CNT • Cement2 0.0005 0.0050-0.0650 0.0004-0.1000 0.0004 BD BD - - - - - • Set up encapsulated • Data from Table1 • Results from cements dominated by sanding paper debris
PMMA + Cu NP(10%) 10,200 / 12,500 E-6 460 / 848 E-6 10 70 - - - - Bin max. / TPNC P1200 SiC paper P120 SiC paper [] background 0.0025 – 0.0035 ≈10 - - - - Abrasive Test (Taber Model 5135) Epoxy + CNT 0.008 – 0.020 1000-3000 - - - - [] + suppl. Wet saw cutting, no controls - - (20-300nm) 1.934 5.75 0.39 1.00 - - • Process area • BZ (Breathing Zone) Wet saw cutting inside ventilated booth - - 2.605 1.9 0.48 1.13 0.91 - - • Process area inside booth • Outside booth • BZ Surface grinding with LEV - - 491.599 42.088 0.9 0.045 0.5 0.014 - - • Process area at edge of LEV inlet • BZ Belt sanding with LEV - - 0 - 18.5 0.076 - - • Process area at edge of LEV inlet
0 0.008 • BZ Hand sanding inside booth and CNF Buckypaper - - 0 - 3.09 0.079 ND - - Vent off: • Process area • BZ laminate - - (20-300nm) 0 - 0.16 0.011 0.007 - - Vent on: • Process area • BZ [] - background < 0.000,020 - - - - - simulation box Weathering + fanning + abrasion TiO2 paint (Allstar, Taiwan) 0.000,012 0.000,449 0.000,442 0.000,525 0.000,629 - - - - - simul. time, (mode): 2 min ( 36.5nm) 30 min (107.3nm) 60 min (127.1nm) 90 min (127.7nm) 120 min (119.6nm) [] background - - <0.000,020 - Milling Li-titanate metal oxide (Li-Ti MO) - - - - 0.026 - [] background 0.040 - 0.088 0.026 - - - - - Ø-range 10-200 nm vent operating
Grinding Silver colloid and NP 0.075 - - - - - opening grinder: modes at 20+25nm [] ventilation background - - 0.05 - - - - Grinder (Dremel Multipro 395) • None • Granite • Clay ceramic • Oak hardwood 0.0065 0.0100 0.0500 0.8000 3 19 400 12 - - - - SMPS: Ultrafine mode APS: Coarse mode [] - background ↑0.0081¦ 0.0021 ↑53¦ 20 ↑8.4¦ 2.8 0.007 - 12.2 avg. over 3days FSW Al-alloy: 6061-T6 ↑3.900¦ 0.0300 ↑2.800¦ 0.0350 ↑739¦ 25 ↑1019¦ 20 ↑>500¦ 46.0 ↑>500¦ 13.0 ↑2.09¦ 0.029 ↑0.28¦ 0.018 - 239.0 195.0 Source: 1A: 1500 RPM 1B: 900 RPM ↑0.250¦ 0.0041 ↑0.160¦ 0.0057 ↑17¦ 8 ↑26¦ 11 ↑150¦ 4.6 ↑42¦ 5.1 ↑1.74¦ 0.022 ↑0.81¦ 0.015 0.0132 14.8 19.2 BZ: 1A: 1500 RPM 1B: 900 RPM Al-alloy: 5083-H111 ↑3.000¦ 0.0210 ↑2.600¦ 0.0290 ↑3055¦ 59 ↑2309¦ 30 ↑>500¦ 72.0 ↑>500¦ 11.0 ↑1.74¦ 0.022 ↑0.81¦ 0.015 - 138.0 191.0 Source: 2A: 1500 RPM 2B: 900 RPM ↑0.200¦ 0.0053 ↑0.048¦ 0.0048 ↑282¦ 35 ↑31¦ 15 ↑25¦ 2.5 ↑130¦ 4.0 ↑1.74¦ 0.022 ↑0.81¦ 0.015 0.0279 20.6 18.0 BZ: 2A: 1500 RPM 2B: 900 RPM
[] Orthogonal Milling KC725M grade insert: coating) 20,300 / 2,300 11,400 / 7,100 14,500 / 100 2,500 / 2,000 <22,500> / <3,200> <13,000> / <8,300> <17,900>/ <400> <4,600> / <2,700> - - - - SMPS: nm: APS: Ø=0.5-1 / 1-10µm: wet / dry, Speed = 5 ,15 m/s, feed =0.125 <0.2>