benikigai/ec-1Public

EC-1 Wireless Controller

Synthetic example. Every value is made up to show the format.

Lessons · Variants

Variants

What change would be better, and what does it cost?

5: candidates
92.2%: baseline yield simulated
94.7%: recommended: Stick connector plus battery preload simulated

Filled marks are on the Pareto frontier; the ring is the recommendation. Vertical bars are the yield interval.

Objectives

Maximise yield.rty
Minimise cost.cost_per_good_unit
Minimise throughput.cycle_time

Constraints

takt 36 s (2,000 units a day over two 10-hour shifts)
headcount at most 12
no single new tool over 25,000 USD

Yield and failure shares come from Monte Carlo over the measured spreads and MuJoCo drop runs. Cycle time and line balance are estimates until the discrete-event simulator exists.

Variant RTY Cost per good unit Cycle time Heads Pareto

Baseline

Full scorecard (20)

yield	FPY at sta:a2	0.992 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
yield	FPY at sta:a3	0.996 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
yield	FPY at sta:a4	0.99 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
yield	FPY at sta:t1	0.985 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
yield	FPY at sta:t2	0.978 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
yield	FPY at sta:t3	0.983 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
yield	FPY at sta:t4	0.995 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
yield	rty	0.922 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.Interval 0.905 to 0.935
yield	failure mode ext:controller:stick-drift (iss:stick-drift-flux)	0.24 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
yield	failure mode connector-unseat (iss:battery-unseat)	0.18 simmujocoSimulated with mujoco, 2,000 runs. Low confidence.
yield	failure mode gap-flush (iss:shoulder-gap)	0.16 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
throughput	cycle time	30 s estanalyticEstimated with analytic. Low confidence.slowest station from time studies; needs the discrete-event simulator
throughput	takt	36 s estanalyticEstimated with analytic. High confidence.
throughput	bottleneck station	`sta:t1`
throughput	headcount	11
cost	cost per good unit	$1.92 estanalyticEstimated with analytic. Low confidence.conversion cost per good unit, including scrap and rework
experience	weight	69.4 g measuredMeasured on a line or units. Medium confidence.Evidence: `src:caliper-run-1`
experience	gap flush consistency	0.0493 mm, 1 sigma measuredMeasured on a line or units. Medium confidence.Evidence: `src:caliper-run-1`
experience	predicted field return rate	0.031 estEstimated. Low confidence.
experience	review sentiment	0.42 -1 to 1 measuredreview-analysisMeasured on a line or units with review-analysis. Low confidence.Evidence: `src:reviews`

92.2%

simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.Interval 0.905 to 0.935

$1.92

estanalyticEstimated with analytic. Low confidence.conversion cost per good unit, including scrap and rework

30 s

estanalyticEstimated with analytic. Low confidence.slowest station from time studies; needs the discrete-event simulator

frontier

Second RF shield box at T1
var:split-t1 equipment

Two shield boxes so flashing and RF test run in parallel

add sta:t1: Second shield box and BLE tester

Generated by agent · analytic · 2026-10-30

Full scorecard (6)

yield	rty	0.922 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
throughput	cycle time	25 s estanalyticEstimated with analytic. Low confidence.
throughput	bottleneck station	`sta:t2`
throughput	headcount	11
cost	cost per good unit	$1.98 estanalyticEstimated with analytic. Low confidence.
cost	capex	$9,800.00 estanalyticEstimated with analytic. Medium confidence.

92.2%

simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.

$1.98

estanalyticEstimated with analytic. Low confidence.

25 s

estanalyticEstimated with analytic. Low confidence.

frontier

FPC connector for the stick instead of hand soldering
var:stick-connector design-change

Stick module ships with a flex tail; a ZIF connector replaces six hand-soldered pins

replace op:stick-solder: Solder step becomes a connector mate
modify part:stick-module: Module with flex tail, +0.12 USD

Addresses Stick drift traced to flux under the potentiometer, Flux residue wicks into stick potentiometer

Generated by agent · monte-carlo · 2026-10-30

Full scorecard (5)

yield	rty	0.936 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.Interval 0.92 to 0.95
throughput	cycle time	28 s estanalyticEstimated with analytic. Low confidence.
throughput	headcount	11
cost	cost per good unit	$1.95 estanalyticEstimated with analytic. Low confidence.
experience	predicted field return rate	0.019 estEstimated. Low confidence.

93.6%

simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.Interval 0.92 to 0.95

$1.95

estanalyticEstimated with analytic. Low confidence.

28 s

estanalyticEstimated with analytic. Low confidence.

frontier

Preload fixture and tug test for the battery connector
var:preload-close fixture-sequence

Closing fixture holds the connector down; a 2 N tug test after mating

modify op:close: Preload pad in the closing fixture
modify op:battery-mate: Add tug test

Addresses Battery connector unseats after a 1.2 m drop, Battery connector half-seated

Generated by agent · mujoco · 2026-10-30

Full scorecard (4)

yield	rty	0.932 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.Interval 0.915 to 0.945
throughput	cycle time	31 s estanalyticEstimated with analytic. Low confidence.
throughput	headcount	11
cost	cost per good unit	$1.96 estanalyticEstimated with analytic. Low confidence.

93.2%

simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.Interval 0.915 to 0.945

$1.96

estanalyticEstimated with analytic. Low confidence.

31 s

estanalyticEstimated with analytic. Low confidence.

dominated by var:stick-connector

Tighten the shoulder gap to 0.10 mm
var:gap-tight design-change

Industrial design asks for a tighter, more premium seam

modify part:top-shell: Tighter tool tolerance and a cooling change on the shoulder wall

Generated by agent · monte-carlo · 2026-10-30

Full scorecard (5)

yield	rty	0.874 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.Interval 0.85 to 0.895
throughput	cycle time	30 s estanalyticEstimated with analytic. Low confidence.
cost	cost per good unit	$2.60 estanalyticEstimated with analytic. Low confidence.
experience	gap flush consistency	0.03 mm, 1 sigma simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
experience	cosmetic defect rate	0.061 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.

87.4%

simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.Interval 0.85 to 0.895

$2.60

estanalyticEstimated with analytic. Low confidence.

30 s

estanalyticEstimated with analytic. Low confidence.

—

dominated by baseline, var:split-t1, var:stick-connector

Stick connector plus battery preload Recommended
var:connector-and-preload mixed

Both fixes together

replace op:stick-solder: As var:stick-connector
modify op:close, op:battery-mate: As var:preload-close

Addresses Stick drift traced to flux under the potentiometer, Battery connector unseats after a 1.2 m drop

Generated by agent · monte-carlo · 2026-10-31

Full scorecard (5)

yield	rty	0.947 simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.Interval 0.93 to 0.96
throughput	cycle time	31 s estanalyticEstimated with analytic. Low confidence.
throughput	headcount	11
cost	cost per good unit	$1.99 estanalyticEstimated with analytic. Low confidence.
ramp	changes needed	3 estEstimated. Medium confidence.

94.7%

simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.Interval 0.93 to 0.96

$1.99

estanalyticEstimated with analytic. Low confidence.

31 s

estanalyticEstimated with analytic. Low confidence.

frontier

Design intent

Characteristic	Target	Lower	Upper	Where	Priority · owner
gap Even, tight seam at the shoulder buttons	0.2 mm InferredEngineering judgement, not measured. Low confidence.No evidence listed.	0.1 mm InferredEngineering judgement, not measured. Low confidence.No evidence listed.	0.3 mm InferredEngineering judgement, not measured. Low confidence.No evidence listed.	Top shell	should industrial-design
button-force Crisp, light press	180 gf MeasuredMeasured across units: CT, calipers, CMM. Medium confidence.No evidence listed.	150 gf MeasuredMeasured across units: CT, calipers, CMM. Medium confidence.No evidence listed.	210 gf MeasuredMeasured across units: CT, calipers, CMM. Medium confidence.No evidence listed.	Face button cap	should industrial-design
button-travel	0.8 mm MeasuredMeasured across units: CT, calipers, CMM. Medium confidence.No evidence listed.	0.6 mm MeasuredMeasured across units: CT, calipers, CMM. Medium confidence.No evidence listed.	1 mm MeasuredMeasured across units: CT, calipers, CMM. Medium confidence.No evidence listed.	Face button cap	nice industrial-design
weight Light enough for long sessions; set from the parts below	69 g MeasuredMeasured across units: CT, calipers, CMM. High confidence.No evidence listed.	—	74 g MeasuredMeasured across units: CT, calipers, CMM. High confidence.No evidence listed.	EC-1, closed unit	must product
battery-life A week of evenings on one charge	30 h InferredEngineering judgement, not measured. Medium confidence.No evidence listed.	25 h InferredEngineering judgement, not measured. Medium confidence.No evidence listed.	—	Li-ion pouch cell, 600 mAh	must product
drop-height	1.2 m InferredEngineering judgement, not measured. Medium confidence.No evidence listed.	—	—	EC-1, closed unit	must reliability
thickness	22 mm MeasuredMeasured across units: CT, calipers, CMM. High confidence.No evidence listed.	—	23 mm MeasuredMeasured across units: CT, calipers, CMM. High confidence.No evidence listed.	EC-1, closed unit	should industrial-design

Targets a variant changes

Tighten the shoulder gap to 0.10 mm

Characteristic	Target	Lower	Upper	Where	Priority · owner
gap	0.1 mm InferredEngineering judgement, not measured. Low confidence.No evidence listed.	—	0.15 mm InferredEngineering judgement, not measured. Low confidence.No evidence listed.	Top shell	should industrial-design

Tradeoffs

gap: 0.2 mm
InferredEngineering judgement, not measured. Low confidence.No evidence listed.
→ 0.1 mm
InferredEngineering judgement, not measured. Low confidence.No evidence listed.

rejected

tr:gap-tighten Tighten the shoulder gap to 0.10 mm against baseline

A tighter seam that reads as more premium, for about 5 points of yield and 0.68 USD a unit

Yield change: -0.048 RTY
simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
Cost per unit change: $0.68
estanalyticEstimated with analytic. Low confidence.
experience.cosmetic_defect_rate: 0.044
simmonte-carloSimulated with monte-carlo, 20,000 runs. Low confidence.
Decision: product (fictional), 2026-10-31 Not worth the yield at this price point