π§ Why Step 1 Matters #
Most weak PFMEAs trace back to poor planning: fuzzy scope, missing stakeholders, no data, or late start. Step 1 fixes that by aligning why, when, who, what, and how before any risk rows are written.
π― Objectives of Step 1 #
- Define scope, boundaries, and assumptions for the process under analysis.
- Establish 5T alignment (InTent, Timing, Team, Task, Tool).
- Collect inputs (DFMEA handover, drawings/specs, Work Instructions, PFD, MSA/SPC status, lessons learned).
- Set cadence, ownership, and document control for the PFMEA program.
𧩠The 5T for This PFMEA (Applied to EWP Assembly & EoL) #
| T | Guiding Question | EWP PFMEA Answer |
|---|---|---|
| InTent | Why are we analyzing? | Prevent process-induced defects that affect flow delivery (πΊ), leak integrity (π§), and electronics handling (π―); launch with zero critical escapes and sustainable FPY β₯ 98%. |
| Timing | When will this run? | Start at process design freeze with PFD Rev-A; update at Tool Buy-off, Pilot, Run@Rate, and after any ECN; freeze for PPAP then maintain as a living doc. |
| Team | Who is involved? | Process/Mfg Eng (owner), Quality Eng (moderator), Test Eng, Maintenance, IE, Operators/Trainer, SQE, EHS, Metrology, IT/MES. Customer rep as needed. |
| Task | What is in scope? | Final Assembly & EoL from kitting β press-fits β seal install β torque β potting β pre-leak β electrical spin β final leak/flow β inspection β pack. Out of scope: upstream supplier mfg unless flagged βspecial.β |
| Tool | How will we execute? | AIAG-VDA PFMEA sheet, PFD, Characteristics Matrix, Control Plan shell, MSA/SPC plan, Traceability map. Collaboration: PLM/SharePoint + MES data. |
π¦ Scope, Boundaries & Assumptions #
In Scope
- Line stations OP01βOP14 (Lesson 5.0 map), all inspections/tests, data capture to MES, rework/quarantine flow.
Out of Scope
- Supplier component manufacturing (unless designated special process), vehicle integration and post-shipment logistics.
Boundaries
- Start: Kitting/serial assignment
- End: Pack & ship, labels applied, traceability closed in MES.
Assumptions (document explicitly)
- Approved coolant-contact materials (per spec); fixtures & benches are CE-marked; ESD program compliant to ANSI/ESD S20.20; humidity control 40β60% at PCB/seal operations; DFMEA Rev-2.1 is current; takt target 36β48 s.
π§Ύ PFMEA Plan Page β Filled Example (copy into your workbook) #
| Field | Example Entry |
|---|---|
| Process/Item | EWP Final Assembly & EoL Testing |
| Plant / Line | Plant-A / Line-EWP-01 |
| PFMEA Owner | Priya Sharma (Manufacturing Engineer) |
| Moderator | Kamlesh (Quality) |
| Rev / Date | Rev 1.0 / 06-Sep-2025 |
| Upstream Doc Links | DFMEA Rev 2.1; Drawing DWG-EWP-HSG-07; WI set Rev-B; PFD Rev-A |
| Special Characteristics | πΊ Flow β₯ 35 L/min @ ΞP 20 kPa; π§ Leak β€ 0.5 ml/min @ 1.5 bar; π― Torque 4.0 Β± 0.3 NΒ·m; ESD < 100 V |
| Takt / Shifts | 40 s nominal; 2Γ8 h |
| Constraints | Cleanliness ISO 16232 class X at seal station; ESD controls at PCB/potting; recipe lock in MES |
| Data & Traceability | Unit serial from OP01; torque/press/leak/flow curves stored; recipe download controlled |
| Escalation Path | Red tag β Quarantine β 8D β MRB; stop-ship on SC excursions |
π₯ Roles & RACI (example) #
| Deliverable | Process Eng | Quality Eng | Test Eng | Maintenance | Operator Lead | Metrology | IT/MES | SQE |
|---|---|---|---|---|---|---|---|---|
| PFMEA authoring | R/A | C | C | C | C | C | C | C |
| Moderation/standards | C | R/A | C | β | β | β | β | β |
| PFD creation | R | C | C | C | C | β | β | β |
| Char. Matrix | R | A | C | β | C | C | β | β |
| MSA plan & studies | β | A | β | β | β | R | β | β |
| SPC plan | R | A | β | β | C | C | β | β |
| Test benches (limits) | β | C | R/A | C | β | β | C | β |
| Traceability/MES | β | C | C | β | β | β | R/A | β |
| Control Plan | R | A | C | β | C | C | C | β |
R = Responsible, A = Accountable, C = Consulted
π₯ Inputs Checklist (collect before Step 2) #
Design & Risk
- DFMEA summary table (SCs, residual risks, test linkages)
- Drawings/specs, CTQ list, torque specs, materials/CoC
Process
- PFD Rev-A, line layout, cycle times, changeover method
- Work Instructions (draft), photo standards
Measurement & Data
- Gage list, MSA plan/status, calibration matrix
- SPC starter pack (candidate characteristics + chart type)
- MES tags: serial schema, parameter & curve storage, result codes
Lessons Learned
- From prior pumps/lines: seal damage, mis-press, recipe drift, ESD escapes
Compliance
- ESD policy, Cleanliness limits, Safety/EHS assessments
π§ͺ Measurement & MSA Strategy (high-level plan) #
| Characteristic | Type | Gage/Bench | MSA Target | Notes |
|---|---|---|---|---|
| Press-fit depth | Variable | LVDT probe | GR&R β€ 10%TV; ndc β₯ 10 | 100% + SPC |
| Torque 4.0 Β± 0.3 NΒ·m | Variable | DC tool | Annual GR&R; daily audit | Curve + OK/NOK interlock |
| Leak β€ 0.5 ml/min | Variable | Air decay bench | 3-point GR&R quarterly | Daily master part |
| Flow β₯ 35 L/min | Variable | Flow bench | GR&R with temp comp | Curve stored in MES |
| ESD < 100 V | Attribute | Strap/mat testers | Daily verification | Audit log retained |
π SPC Starter & Reaction Plan (planning view) #
- Charts proposed:
- Press-fit depth β XΜ-R per shift
- Torque β XΜ-R per station/day
- Leak & Flow β I-MR with temp compensation tag
- Rules: Nelson/Western Electric; auto-hold after 2 rule violations.
- Reaction: Contain last OK lot, verify gage, check fixture/tool PM, retrain operator if Method cause; log 8D if SC is impacted.
π‘οΈ Poka-Yoke & Interlocks (declare in plan) #
- Hard-stop + LVDT at press station; signature matching for press force.
- Vision orientation for seal and connector; no-go nests.
- DC tool socket ID sensing; NOK lockout.
- Recipe lock (MES) for leak/flow benches; daily master validation.
- Barcode/serial gate at each critical station (no scan β no move).
𧱠Interfaces & 6M Risks to Watch (to seed Step 4 later) #
- Man: certification, job instruction adherence, ergonomics, shift variation
- Machine: fixture alignment, sensor drift, tool wear, PM compliance
- Method: torque strategy, press profile, potting recipe, clean/ESD discipline
- Material: seal batch hardness, lubricant lot, impeller dimension spread
- Measurement: gage stability, calibration, software version control
- Mother Nature: humidity/temp effects on seal/ESD/leak tests
β³ Cadence & Gate Alignment #
| Milestone | PFMEA Activity |
|---|---|
| Process Design Freeze | Step 1 complete; Step 2β3 drafted |
| Tool Buy-off / FAT | Update risks from run data; lock detection methods |
| Pilot Build | Re-rate O/D from evidence; tune SPC/MSA |
| Run@Rate | Close AP-High actions; residual risk statement |
| PPAP Submission | Freeze Rev; publish Control Plan & records |
| Post-SOP | Living updates from escapes/ECNs; lessons learned log |
𧩠Step-1 Output Pack (what βdoneβ looks like) #
- β 5T worksheet completed and signed by owner/moderator
- β PFMEA Plan Page (this lessonβs table) in the workbook
- β Scope, boundaries, assumptions documented
- β Inputs checklist collected & linked (DFMEA, PFD, WI, MSA/SPC, LL)
- β RACI agreed + meeting cadence set (weekly 45-min until PPAP)
- β Document control set (Rev, storage path, links to MES/PLM)
β οΈ Common Pitfalls (and fixes) #
| Pitfall | Fix |
|---|---|
| Starting PFMEA after tooling arrives | Kick off at process design freeze; use simulated/benchmark data first |
| Vague scope & orphan risks | Use handover matrix from DFMEA with SCs mapped to stations |
| Missing operators/maintenance | Include Operator Lead & Maintenance in the core team |
| No measurement strategy | Lock MSA plan in Step 1; donβt defer to PPAP |
| Ratings by opinion later | Plan to base O/D on evidence (SPC, MSA, Run@Rate data) |
π Internal Links (for your course site) #
- Lesson 5.2: Step 2 β Structure Analysis (PFD & Process Tree)
- Templates Hub: 5T Worksheet, PFMEA Plan Page, Inputs Checklist, RACI, MSA/SPC Plan
π§ Pro Tip #
Treat Step 1 as your contract with reality. If itβs clear and complete, every downstream PFMEA step becomes faster, sharper, and easier to defend in audits.
