â–¶What are the seven wastes of manufacturing and how do I spot them?
The seven wastes (muda in Japanese): (1) Inventory—parts waiting to be processed, tying up space and capital; (2) Waiting—machines idle, people standing around, bottlenecks; (3) Defects and rework—scrap and correcting mistakes cost time and material; (4) Overproduction—making more than the customer ordered, wasting inventory and storage; (5) Overprocessing—unnecessary steps or precision (gold-plating); (6) Movement—unnecessary walking, bending, hunting for tools; (7) Transportation—moving parts between distant machines. Spot them by walking the floor: Are parts piled up between machines? Is anyone standing idle? Are people walking long distances for tools? Is the scrap bin full? Each waste is an opportunity to improve. Lean practitioners map wastes and prioritize improvements by impact.
â–¶What is a kaizen event and how does it work?
A kaizen event is an intensive 1-5 day focused problem-solving session where a cross-functional team (operators, engineers, supervisors) deeply dives into one specific problem and implements a solution before leaving the event. Example: a team notices that setup on a particular molding machine takes 90 minutes; they block time (maybe 3 days), map the setup step-by-step, identify non-value-adding steps (hunting for tools, waiting for coolant to drain), redesign the process (organize tools by sequence, pre-stage coolant filler), and implement changes (build a tool cart, pre-position liquids). Result: setup drops to 45 minutes. Kaizen spirit is bottom-up: frontline operators know the process best and identify the simplest fixes. Leadership removes barriers (time, budget, authority) so the team can implement.
â–¶What is value-stream mapping and how do I build one?
Value-stream mapping (VSM) is a visual diagram showing every step in a process, from raw material to finished goods, including: process steps (machine cycles, inspections, moves), information flows (who talks to whom, scheduling), inventory buffers (waiting parts), and lead times. You draw boxes for each process, arrows for material flow, and clouds for batches sitting idle. The map reveals bottlenecks and wastes: maybe parts wait three days between Process A and Process B because nobody scheduled them, or a quality check is in the wrong place (you should check earlier, before rework is expensive). Creating a VSM is collaborative: go to the floor, ask operators and supervisors, draw the map in real-time, photograph it. A good VSM is a revelation: suddenly everyone sees why the customer waits, and improvement priorities become obvious.
â–¶What is SMED and how much time reduction is realistic?
SMED (Single-Minute Exchange of Dies) is setup time reduction, targeting changeovers in under 10 minutes (hence 'single-minute'—one-digit minutes). Tools: parallel external setup (prepare the next tool while the current job runs), quick-change couplings, standard tool kits, written checklists. A molding press changeover might be 120 minutes baseline (remove old mold, clean, install new mold, set temperature, test); after SMED: 40 minutes (quick-change clamps, pre-stage mold, automatic temperature ramp). Realistic reduction: 30-50% first kaizen, another 20-30% after refinement. A 50% setup reduction doubles machine availability—you can run more jobs in the same shift. SMED is especially valuable in job shops and small-batch producers, where setup is a large part of total production time.
â–¶What is OEE and how is it calculated?
OEE (Overall Equipment Effectiveness) is a single metric summarizing machine utilization and quality: OEE = Availability Ă— Performance Ă— Quality. Availability = actual run time / planned run time (penalized by downtime, maintenance, breaks). Performance = actual cycle time / theoretical cycle time (penalized by running slower than capability). Quality = good parts / total parts produced (penalized by defects and scrap). Example: Machine planned for 480 minutes (8-hour shift). Actual run: 420 minutes (60 min downtime for maintenance = Availability 87.5%). Theoretical cycle time: 2 minutes per part = 210 parts theoretical in 420 min; actual: 180 parts (Performance 85.7%). Defects: 170 good parts / 180 total (Quality 94.4%). OEE = 87.5% Ă— 85.7% Ă— 94.4% = 71%. World-class machines hit 85%+ OEE. Tracking OEE weekly reveals trends: if Performance drops, the machine is wearing (needs maintenance); if Quality drops, the process is drifting (needs adjustment).
â–¶What is pull-based (kanban) manufacturing vs. push-based manufacturing?
Push-based manufacturing: you forecast demand, build inventory based on that forecast, and push parts downstream (hoping someone will use them). Result: if forecast is wrong, you overproduce (waste) or underproduce (shortage). Kanban is pull-based: you only make a part when the next process requests it (pulls it). Inventory is tightly controlled by physical kanbans (cards or containers): when a container is empty, it signals upstream to make more, but just enough to refill. Kanban reduces inventory, improves flow, and catches problems early (if demand drops, fewer kanbans are pulled, and overproduction stops immediately). Implementing kanban: map demand (how fast does each downstream process consume parts), set kanban quantities (typically 2-4 containers per product), and train everyone on the pull signal (when a container empties, it goes back upstream as an order). Kanban is especially powerful in job shops where demand is variable and unpredictable.
â–¶What does '5S' mean and why is it foundational?
5S is a simple, proven discipline for workplace organization: (1) Sort—remove everything not needed daily (defunct tools, broken fixtures, old parts—throw out or archive); (2) Simplify—arrange what remains by frequency of use (tools used hourly within arm's reach, tools used weekly on a shelf nearby); (3) Shine—clean everything (a clean machine is easier to inspect for leaks, wear, damage); (4) Standardize—write procedures (how tools are stored, how machines are cleaned, what times); (5) Sustain—audit and maintain (daily 5-minute check, monthly audit). 5S sounds basic, but it's transformative: less time searching for tools, easier to spot anomalies (a leak is obvious on a clean machine), and safer (less clutter to trip on). 5S is a cultural starting point for Lean: once people see the benefit of an organized workspace, they're receptive to deeper improvements. Every Lean initiative begins with 5S.
