SPC + GR&R System — Control Charts, Western Electric Rules, Cp/Cpk Capability & AIAG Gage R&R (Macro-Free Excel)

Control charts, capability and gage studies — without a subscription or an

add-in install.

SPC + GR&R System is a single spreadsheet system for shops that want ready-made

SPC instead of building it in Excel themselves: automatic control limits,

out-of-control warnings that flag themselves, capability indices your customers

actually ask for, and a proper AIAG gage study — with plain-English guidance on

reading every output.

WHY THIS INSTEAD OF THE ADD-INS

- QI Macros lists at $379, SPC for Excel at $329, SigmaXL at $249 (single-user,

one-time, observed 2026). This is $39 — roughly a tenth of the add-in price

and about 1.6% of one Minitab seat-year ($2,394/yr observed) — one time, no

subscription, no renewal, no license server.

- Nothing to install. Add-ins mean IT friction, trust prompts and lockdown

battles on shop computers; this is one .xlsx file. No macros either — nothing

to "enable", nothing to trust blindly.

- Every computed cell is a live, visible formula: constants arrive by lookup

from on-sheet tables (sourced to the NIST/SEMATECH handbook and the AIAG

average-and-range convention), so an auditor can trace any number to its

arithmetic. Free fragments online can't be checked this way.

WHAT'S INSIDE

- X-bar/R chart sheet — 25 subgroups of 5 (any n from 2 to 10 works: the

constant lookups are live), live limits (UCL/LCL from A2/D3/D4), and a

Western Electric rule engine as visible helper columns: R1 beyond-limit,

R2 two-of-three beyond 2 sigma, R3 four-of-five beyond 1 sigma, R4 eight in

a row one side, R5 six trending. Violations flag red automatically. Two

charts (X-bar and R) with dashed UCL/CL/LCL lines.

- I-MR chart sheet — individuals + moving-range charts for low-volume data

(n = 1 sampling), same rule engine, same live limits.

- GR&R study sheet — the AIAG average-and-range method, 10 parts x 3 operators

x 3 trials: R-double-bar, EV (repeatability), AV (reproducibility), GRR, PV,

TV, %GRR of total variation AND of tolerance, ndc, and traffic-light

verdicts wired to thresholds you can edit. Includes an interpretation block

(EV >> AV means look at the gage and fixtures, not the operators).

- Capability sheet — Cp/Cpk (within-subgroup) and Pp/Ppk (overall) for both

characteristics, with verdict bands and a stability note that tells you when

drift — not potential — is your problem.

- Settings & ReadMe — your spec limits, operator names, instrument, WorkYear

and every decision threshold in one place; the whole workbook reads from it.

- Constants & Guide — every factor table (d2, A2, D3, D4, E2, K1/K2/K3), the

Western Electric rule definitions, AIAG traffic-light bands, full formula

documentation and the provenance of every constant.

THE SAMPLE DATA IS THE DEMO

The workbook ships with a synthetic, clearly-labeled machining story so every

output is demonstrated before you type a thing: an insert-change excursion

trips R1/R2 at subgroups 14-15 and a low run trips R4 at 23-24; a setup spike

and a tool-wear trend trip R1 + MR-limit + R5 on the individuals chart; and the

sample micrometer GR&R lands at %GRR 12.71% — deliberately in the amber

"conditionally acceptable" band with ndc 11 passing, because interpreting a

marginal gage is the situation you actually face. The cover numbers are the

workbook's own output on that data, verified three ways (spreadsheet recalc vs

independent recomputation vs published worked examples).

YOU GET

- SPC-GRR-System-v1.xlsx (the full 6-sheet system, 1,064 live formulas, zero

macros)

- Quick-start guide PDF (setup, what each sheet does, how to read every output,

honest notes) — also inside the zip

- Single-business license (your own processes, parts and gages; no resale)

HONEST NOTES

- v1.0 from a small template studio. Attribute charts (p/c/u) and ANOVA/nested

GR&R are not in v1.0 (v1.1 candidates). Spotted a bug? Message us via Payhip

and it gets fixed; buyers get free v1.x updates.

- Sample data is synthetic and labeled as such. Statistical output supports

process decisions — it is not a substitute for engineering judgment or your

customer's quality requirements (AIAG MSA, IATF 16949 and friends).

- Works in Excel 2016+, LibreOffice Calc and Google Sheets (File > Import >

Upload). No macros, no external links, no subscriptions — ever.