ASEEM BHANDARI / FACTORY LAB
A small line.
A big decision.
You have four weeks to deliver 4,950 units. The line is falling behind. What do you change first?
THE LINE / ASSEMBLY → TEST → PACK
Follow the work. Find the wait.
A repeating 30-minute flow sample with unlimited materials. The four-week forecast below includes supplier limits.
01 / REMOVE THE CONSTRAINT
Make the right station faster.
Start with one operator at each station. Add test equipment, assign a second test operator, or qualify a better assembly fixture. Watch the constraint move.
Each active test station requires its own operator. Extra operators are paid even when no equipment is available. Fixture and test-method changes must be qualified; their one-time costs are included below.
02 / TURN STARTS INTO GOOD UNITS
More output. Less fallout.
A line can run faster and still miss the target. Explore the effect of a process improvement that raises final yield.
Find and validate the cause of failure. This yield is an assumption to test; failed units do not return as rework in this model.
03 / GIVE THE LINE WHAT IT NEEDS
A fast line still needs parts.
Demand rises each week. Your first two decisions carry forward, but early kit shortages can keep the line from using its capacity.
TEST A SUPPLIER DISRUPTION
Compare both plans under the same delivery delay. Expediting can recover the schedule only if the factory has capacity. A Week 4 delay arrives outside this four-week horizon.
THE ECONOMIC TRADE-OFF / USD
What does the decision cost?
Four weeks of modeled operating costs,
plus the full one-time investment.
| Cost category | Starting plan | Your plan | Change |
|---|
Edit the cost assumptions
Illustrative estimates, not supplier quotes. Changing a rate recalculates both plans.
This is a comparison of selected costs, not total manufacturing cost or profit. It excludes good-unit component purchases, existing equipment, overhead, taxes, financing, revenue, and late-delivery penalties. One-time investments are charged in full, with no depreciation or payback claim.
THE DELIVERY COMMITMENT
Does your plan hold up?
Weekly shipments against demand.
Inventory and backlog carry forward.
| Period | Demand | Kits | Good output | Shipped | End backlog | End inventory |
|---|
What this model assumes
The weekly forecast: one product follows assembly, test, and pack out. Assembly and pack have one station and one operator each. Test has one or two installed stations and one or two dedicated operators; active lanes equal the smaller count. Assembly takes 90 seconds, or 75 with the improved fixture; test takes 90–120 seconds; pack takes 60. Each operator is paid for 40 hours per week over four weeks, excluding breaks. Every station has 90% availability. No shared labor or overtime.
Weekly starts are rounded down and limited by the slowest station and available kits. Final yield is applied once; good units are rounded down. Demand is 1,000 / 1,200 / 1,350 / 1,400 units. Opening inventory and backlog are zero. Finished goods and backlog carry between weeks. Kits are weekly usable allocations; unused kits do not carry and raw-material inventory is not modeled. A disruption shifts up to the entered number of scheduled kits by one week; expediting restores the original week. Week 4 delayed kits fall outside the horizon. Both alternatives face the same selected delay.
The moving line: a separate, deterministic 30-minute sample starts with an empty line and unlimited materials and buffers. Availability stretches each cycle evenly. Staffed test stations run as parallel FIFO lanes, and the fixture changes assembly timing. Parts fail at pack out to match the final-yield assumption. The sample loops; it is not a forecast of queue sizes or a replay of the weekly totals.
Queue delays, start-up losses, changeovers, rework recovery, and outbound shipping delays are excluded from the weekly forecast. Cost rates apply equally to both plans; all investment is charged in full. Labor includes all assigned operators, scrap excludes labor, and inventory holding is the sum of ending finished stock multiplied by the unit-week rate. Delay and cost assumptions transfer through scenario links and briefs; the ramp-planner handoff carries the production schedule only. All data is illustrative and does not represent any employer’s production.