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Capacitive Sensing Film Sensor — Rework Cut Risk Assessment
| Elementum | Detalii | Elementum | Detalii |
| Numerus Causae | VMANX-8D-2026-008 | Versio Documenti | A0 |
| Productum | Sensor Pelliculae Sensus Capacitivis (typus FPC) | Codice de Referentia | CS-2026-008 (neutralizatus) |
| Clientem | Europaeus fabricator originarius instrumentorum medicorum (identitas tutela) | Dies | Aug 2026 |
| Paratum a | Centro Ingeniorum VMANX / Assessment Qualitatis | Classification | Confidentialis — Studium Causae |
Nota: Numeri de parte e codices de producto del cliente sunt neutralisati pro protegere confidentialitate.
Summarium Exsecutivum
Un fabricante original de dispositivos medicos (OEM) confrontavit un cambium de disigno in 2.000 sensores finiti de pellicula capacitiva: longitudo del rigidificator FPC debeva esser reducita ab 7,00 mm ad 4,00 mm pro resolver un problema de spatium de montage, et un taglio manuale del area del digitus in le stock existente era proposto.
Le ingegneros de VMANX evaluavit le approchio de reparatione e recomenda fortiter Optione B (nova production) in loco de Optione A (taglio de reparatione). Licet le reparatione appareat plus barata superficialmente, le linea de taglio a 4,00 mm transversat le extremitate final del tractu de argente, exponende argente nuda e provocande defectu latens de migratione electrochimica (ECM) irreversibile — quod pote apparer menses postea como cortocircuitos intermitentes in le sito del cliente.
D0 — DESCRITION DEL PROBLEMA
| Elementum | Descriptio |
| Quid | 2.000 pieces de sensores finiti: cambium de longitudo del rigidificator ab 7,00 mm ad 4,00 mm requiret pro spatium de montage |
| Cum | Durante integratione de montage in le sito del cliente |
| Ubi | FPC finger (connector tail) area of the capacitive sensing film sensor |
| CUM | OEM customer requesting disposition of existing finished goods |
| QUID? | Manual cutting is a destructive secondary process; it damages the carbon protection layer and exposes the silver layer — risk assessment required before disposition |
| Quomodo | Option A: rework cutting (risk uncontrollable) vs Option B: new production batch (4.00mm design) |
D1 — SOLUTION DEFINITION
| Dimensio | Option A — Rework Cutting | Option B — New Production |
| Processus | Manual cutting of 7mm stiffener to 4mm on finished goods | New production batch with 4.00mm stiffener design |
| Qualitas | Destructive secondary processing, inconsistent cut quality | Controlus processus plenus, qualitas constans |
| Iudicium clavis | Linea secans (4.00 mm) transversat faciem argenteam extremam → argentum patet | Coating carbonis integerrimum, nullum argentum patet |
| Cost | Impensae directae parvae (solum labor) | Impensae materiae pro nova catena |
| Periculum | Periculum defectus latens incontrolabile | Nullum (qualitas novae catenae securata) |
D2 — STRUCTURA ET MECHANISMUS DEFECTUS (EVIDENTIA)
2.1 Structura stratorum realis (quattuor strata, sinistrorsum allignata, gradus 0.20 mm ad dextram)
Figura 1 monstrat structuram veram regionis digitis FPC: stratum superius — carbon conductivum 6,80 mm, amplectens et protegens totam traciam argenteam; secundum stratum — argentum conductivum 6,60 mm, protectum a carbono (0,20 mm longius quam argentum, gradus ad dexteram); tertium stratum — substratum PET 0,125 mm, allinatum cum rigidificatore (7,00 mm); stratum inferius — rigidificator 7,00 mm.
Figura 1 structura quattuor stratorum: carbon 6,80 mm / argentum 6,60 mm (allinatum ad sinistram, gradus 0,20 mm ad dexteram) / PET & rigidificator 7,00 mm; linea sectionis ad 4,00 mm transibit per extremum faciem argenti
Positio reoperationis sectionis: linea sectionis ad 4,00 mm (a fine contactus) iacet intra zonas protectionis carbonis (6,80 mm) et argenti (6,60 mm). Sectio amputabit utrumque extremum faciem carbonis et extremum faciem strati argenti, relinquens extremum faciem argenti expositam sine protectione carbonis.
2.2 Migratio argenti (ECM) — periculum irreversibile principale
Migratio argenti est forma migrationis electrochemicae (ECM). Sub campo electrico et humore, argentum ionizatur ad anodum, migrat, et redigitur ad catodum formans dendritas:
• Anodus: Ag → Ag⁺ + e⁻ (argentum oxidadur in ionos argenti)
• Catodus: Ag⁺ + e⁻ → Ag (ionos rediguntur in dendritas argenti)
Factores accelerantes — omnes praesentes in hoc producto: 1) Campus electricus: differentia potentialis inter digitos adiacentes spatio 1,0 mm durante operatione; 2) Humor: humiditas ambientis in ambientes consumerum/industrialium agit ut vector electrolyti; 3) Conductor expositus: sectio transversa recisa exponit argentum sine barriera contra humorem/oxygenum.
Figura 2 Mechanismus migrationis argenti: sinistra — revestimentum carbonis integrum (nulla migratio); dextera — argentum expositum in sectione transversa recisa, migratio Ag⁺, connexio dendritarum per spatium 1,0 mm → circuitus brevis
Tempus defectus: cum stratum carbonis integrum manet, periculum migrationis minimum est (plus quam quinque annos vita designata). Post reparationem sectionis, argentum nuda in sectione transversa exposita, sub gradiente campi electrici et interstitio minori quam 1,0 mm, dendritas paulatim crescit per menses aut annos. Cum dendritae pinos adiacentes connectunt, intercursus signorum, circuitus brevis, aut gravis deterioratio resistentiae insulationis evenit — eventus fortuitus et intermittens (dependens a temperatura/humiditate), difficilis ad reproduci in loco clientis, sed realis, qui post-venditionem procentum defectuum vehementer augent.
D3 — MATRIS COMPARATIONIS DIMENSIONUM PLENARUM
| Item comparationis | Option A — Rework Cutting | Option B — New Production |
| Pretium directum | Labor tantum (videtur vilius) | Pretium materiae novae partis |
| Periculum damni physici | Altum — interruptio lineae, exsolutio argenti | Nullus |
| Migratio argenti (ECM) | Extremum — irreversibile, latens | Nullus |
| Dimensionalis tolerantia | Deviatio valde alta (sectio manu) | Controlled by process |
| Carbon protection layer | Destroyed at cut cross-section | Intactus |
| Exposed silver cross-section | Inevitable (cut crosses silver end-face) | Nullus |
| Latent failure cost | Field shorts, recall labor, brand damage, project delay penalties — unpredictable | None (quality assured) |
| Time to delivery | Rework time + unpredictable troubleshooting | Tempus productionis clarum et programmandum |
| Basis fideliabilitatis | Minutum — processus destructivus contra processum normalem | Garantitum — controllo processus plenum |
D4 — DATI EXPERIMENTALES SUPPORTATI (referentia industrialis)
| Statu | Argentum nudum (post sectionem) | Protectum (carbo integer) |
| interstitium ≤1,0 mm, 5 V DC, 85 % RH, 60 °C | Resistentia insulationis cadit infra 10⁶ Ω (limen defectus) in minus quam 500 horis mediocriter | Super 10¹¹ Ω manet post 2 000 horas |
| Conclusio | Argentum expositum in sectione transversali secta = bomba tempore in circuitu | Protectio carbonis plena = vita designata adimpleta |
Nota: Data secundum normas IPC et referentias experimentorum de migratione electrodii argentei in industria; utriusque partis confirmationem requirunt.
D5 — SUMMARIA RISCI (Optio A)
| Res risici | Nivel | Modus Defectionis | Probabilitas |
| Migratio argenti (ECM) | Altissimam | Circuits brevis, defectus intermitens contactus | Media-alta (augescit cum tempore) |
| Damnum physicum circuitus | Alta | Fractura tracae, desectio strati argentei | Altus (operatione manuale) |
| Tolerantia dimensionalis & allignment | Alta | Insertio incompleta, deformatio digitorum | Extremus altus (sectione manuale) |
| Damnum strati protectionis carbonis | Alta | Oxidatio argenti, resistentia contactus aucta | Altissimam |
D6 — PRAECONDITIO SI REREFACIO OPORTET
• Sigillatio praecisa faciei terminalis argenteae (p. ex., recubritio conformis aut sigillans marginis) ad restituendum barrierae adversus umorem — periculum residuum manet, documentandum est et conveniendum
• AOI 100% + examen electricum per probas volantes post rerem
• Examinatio environmentalis (85°C/85%RH, 500 h) in loto exemplari ante liberationem
• AQL 0.65 final audit and extended warranty terms agreed in writing
• Customer to sign a risk acceptance disclaimer (rework is outside normal manufacturing process)
D7 — CONCLUSION & RECOMMENDATION
VMANX strongly recommends Option B (new production). Option A appears cheaper on the surface, but the 4.00mm cut line severs the silver end-face, triggering irreversible silver migration (ECM) with unpredictable latent failure costs far exceeding the apparent savings. Quality and reliability are the foundation of long-term partnership; this design change (7mm→4mm) is a structural optimization, while physical cutting is a destructive process contrary to normal production practice.
Customer is kindly requested to weigh the decision carefully.
D8 — CONFIRMATION
| Decisionem | Agreed Option |
| ☐ Option A — Rework cutting (with D6 preconditions and signed risk acceptance) | |
| ☐ Option B — New production batch (recommended) |
