Widget Redesign Answer Key
Intro to Manufacturing • Unit 4 Teacher Master Key
Lean Systems & Widget Redesign
Class Pacing: 40 Minutes Evaluation & Scoring Guide
Total Score: 25 Points
Pedagogy: TPS / Lean Principles
Activity: Index Card Widget Simulation
Key Focus: TIMWOODS & Line Balance
Part 1
Foundations of Lean Manufacturing (Quick Review)
Originated in the Toyota Production System (TPS). Core premise: ruthlessly eliminate waste (Muda) while maximizing customer-defined Value-Added activity.
① Value
Customer willingness to pay.
② Value Stream
Map card-to-widget steps.
③ Flow
Eliminate bottlenecks & piles.
④ Pull
Produce only on downstream signal.
⑤ Kaizen
Continuous zero-defect pursuit.
Part 2
Identifying the 8 Wastes (TIMWOODS)
Core Industrial Diagnostic Framework
T - Transport: Moving cards between tables.
I - Inventory: Piles of WIP cards on desks.
M - Motion: Reaching, walking, hunting tools.
W - Waiting: Downstream idle worker delay.
O - Overproduction: Making unneeded widgets.
O - Overprocessing: Extra unrequested creases/checks.
D - Defects: Crooked staples, torn cards, scrap.
S - Skills/Talent: Underutilizing student ideas.
Widget Factory Diagnostic Audit • Model Solutions & Rubric
10 Total Points
Simulation Observation
TIMWOODS Waste Type
Financial & Operational Impact (Grading Criteria)
Scenario A: The Card Pile
Station 1 folded cards at top speed, accumulating 18 folded cards on the desk while the hole-punch operator struggled to keep up.
Primary Waste [1 pt]: Inventory (WIP) Accept: Overproduction
Secondary Waste [0.5 pt]: Waiting (or Overproduction / Transport)
Why ties up cash / hides quality errors? [2 pts] Full Credit Criteria
✔ Cash Flow: Money spent on raw materials and labor is locked in non-sellable WIP sitting idle on tables generating $0 revenue.
✔ Hidden Defects: If Station 1 folds off-spec, 18 defective units are built before Station 2 discovers the flaw, producing a massive scrap pile instead of immediate feedback.
Scenario B: Quality Gate Rejection
At the end-of-line inspection station, 5 completed index card widgets were rejected because staples were 0.5 inches off specification.
Primary Waste [1 pt]: Defects (Scrap/Rework)
Root Cause Category [0.5 pt]: Missing Standard Work Accept: Lack of Jig / Mistake-Proofing
Impact on Net Profit [1.5 pts] Financial Impact
✔ Direct Loss: Raw materials (5 cards + staples) and labor hours are completely lost with zero revenue to offset them.
✔ Unit Cost Spike: Cost of Goods Sold (COGS) increases per acceptable widget sold, slashing the simulation factory's profit margin.
Scenario C: Desk Tool Hunt
The stapler operator stood up and reached across two classmates' desks every time a staple reload or ruler measurement was required.
Primary Waste [1 pt]: Motion (Unnecessary bodily movement)
Lean Countermeasure [0.5 pt]: 5S / Point-of-Use Tooling Accept: Ergonomic Cell Layout
5S Workspace Adjustment [2 pts] Specific Fix
✔ Set In Order (Seiton): Place dedicated stapler, extra staples, and ruler directly in the operator's primary reach zone (arm's radius) marked with taped tool outlines (shadow board).
✔ Result: Operator never leaves seat or interrupts peers; cycle time cut by 4–6s.
Unit 4: Advanced Manufacturing Systems • Teacher Resource Manual
Page 1 of 2 • Lean Principles & Waste Identification
Verified Key
Factory Engineering • Application Lab Teacher Solutions
Push vs. Pull & Real-World Scaling
Kaizen Redesign Protocol 15 Total Points
Part 3
Push Production vs. Pull (Kanban) Production System
PUSH SYSTEM (Batch & Queue)
Workstations produce as fast as possible to quota, "pushing" unfinished widgets onto downstream desks regardless of demand. Causes massive WIP buffers and delayed feedback.
PULL SYSTEM (Just-In-Time / Kanban)
Downstream stations signal upstream with an explicit trigger only when customer demand consumes a unit. Zero demand = zero production. Instant defect isolation.
Challenge: Engineering the Index Card Factory 2.0 (Model Solutions)
6 Points
1. Takt Time & Line Balancing Solution [3 pts] Folding: 10s | Punch & Staple: 26s
Diagnostic Analysis: The 26s punch/staple station is the process bottleneck, dictating a slow cycle time of 26s/widget, while the 10s folding station sits idle 61% of the time or creates massive WIP.
Exemplar Countermeasure (Either strategy earns full credit):
Option A (Role Split): Separate the 26s task into two single-operator stations: Station 2 (Hole-punch ~13s) and Station 3 (Staple ~13s). Now all cycle times are roughly 10s, 13s, and 13s. Line output nearly doubles.
Option B (Parallel Stations / Cross-Training): Assign two operators to punch & staple in parallel (effective rate: 13s per unit), or cross-train the folder to assist with hole punching.
Scoring Rubric: 1 pt identifies punch/staple as bottleneck; 1 pt splits or parallels tasks; 1 pt explains how cycle times become balanced.
2. Visual Kanban Mechanism Design [3 pts] Physical Pull Signal
Exemplar Student Design:
Mechanism: Tape a distinct 5"×7" square with blue masking tape on the desk between Station 1 and Station 2 with the label "WIP LIMIT: 2 CARDS".
Operating Rule: Station 1 is authorized to fold a card only when there is an empty space inside the square. When 2 folded cards occupy the square, Station 1 MUST STOP production immediately.
Scoring Rubric: 1 pt for clear physical trigger (tape square, bin, card holder); 1 pt for defined WIP limit (1 or 2); 1 pt for strict pull rule (stop when full).
Part 4
Real-World Case Study Solutions & Kaizen Rubric
9 Points
A. Financial Risk of Inventory (1,000 Push vs. 50/day Pull) [5 pts] Comprehensive Model Answer
1. Cash Flow / Working Capital
1,000 units tie up substantial cash in materials and labor before sales happen. Stored inventory earns zero interest and cannot pay current bills or wages.
2. Damage & Holding Costs
Storing 1,000 units requires warehouse space, racks, and climate control. Goods risk physical bending, moisture damage, tears, or handling accidents.
3. Obsolescence & Design Changes
If the customer updates the hole spacing or specs, all 1,000 units become instant unsellable scrap. A 50/day line pivots overnight with zero dead stock.
Award Points: 2 pts for cash flow link, 1.5 pts for physical damage/holding risk, 1.5 pts for specification obsolescence.
B. Personal Kaizen Proposals (Student Exemplars & Scoring) [4 pts] Zero-Cost Criteria
Exemplar 1: Stapler Alignment Jig (Poka-Yoke)
Tape a small index-card scrap or wooden ruler edge to the stapler base exactly 0.5" from the head. The operator slides cards against this mechanical stop, guaranteeing zero staple defects without measuring.
Exemplar 2: U-Cell Desk Layout
Rearrange desks into a tight U-shape so operators face inward. Widgets pass directly hand-to-hand across designated Kanban zones, totally eliminating standing, walking, and reaching motions.
Rubric Checklist: Must be truly zero-cost (+1 pt), address a specific TIMWOODS waste (+1 pt), be physically practical in class (+1 pt), and prevent recurrence (+1 pt).
Continuous Improvement: Plan-Do-Check-Act (PDCA) • Widget Factory Redesign Lab
Page 2 of 2 • Pull Systems & Real-World Scaling
Complete Teacher Key
