Lesson 25: The Gap Check and Capacity Proof | Slides

MATERIAL HANDLING ACADEMY

Part VI. Lesson 25. The Gap Check and Capacity Proof.

DRIVING QUESTION Does this system actually hit its rate, and does the gap survive every check?

PART VI | LESSON 25: THE GAP CHECK AND CAPACITY PROOF

Now You Prove It

Lesson 24 gave the perfect-world numbers their margin. This lesson is the calc itself, run for real, inputs confirmed, your name going on the result.

Final engineering isn't more math than solutioning. It's the same math with the inputs confirmed and the tolerance pulled tight.

PART VI | LESSON 25: THE GAP CHECK AND CAPACITY PROOF

Run It In Order, or Pass the Wrong Check

Package basics, steps 1 to 7. Carton specs, global inputs, weight per foot, curve BF, tumble angle, gap produced, theoretical rate.
Sorter, steps 8 to 13. Required rate, CFPM, SGR, required sorter speed, the gap checks, takeaway spur speed.
Transfer, steps 14 to 16. Lateral distance, cycle time, trunk-line gap check.
One rule under all of it. The required rate drives every number on the sorter tab. Get it in writing, then run the calc.

PART VI | LESSON 25: THE GAP CHECK AND CAPACITY PROOF

The Sixteen Steps in Three Bands

A dependency ladder of the sixteen Product Spec Calc steps in three grouped bands read top to bottom. Package basics is steps one through seven; a gold ribbon reading confirm the rate in writing sits between it and the sorter band; the sorter is steps eight through thirteen with a gold gate on the gap check step labeled clear the model-minimum and the geometry; the transfer is steps fourteen through sixteen with a second gold gate on the trunk-line gap check. — The gold ribbon is the rate-in-writing gate; the two gold gates are the gap checks.

PART VI | LESSON 25: THE GAP CHECK AND CAPACITY PROOF

COMMON MISTAKE

Running the sorter tab before the required rate is confirmed in writing. CFPM is driven entirely by rate. If the rate changes after the calc is done, every sorter number behind it's wrong, and they'll all still pass their own checks. You'll be looking at a clean tab full of numbers that answer a question the customer already moved off of. Get the rate in writing, then run the calc.

PART VI | LESSON 25: THE GAP CHECK AND CAPACITY PROOF

The Sorter Sequence

CFPM. The minimum speed that physically moves enough cartons per minute. It's the floor, never the run speed.
SGR. Pitch over carton length. The smallest carton produces the highest ratio, which is why the min carton binds.
Required sorter speed. SGR times CFPM. Check all three carton columns, the governing one isn't always the min.
The gap check. The produced gap must clear both the model-minimum and the geometry. Both, on purpose.

PART VI | LESSON 25: THE GAP CHECK AND CAPACITY PROOF

Worked on Riverside (20 CPM confirmed)

CFPM = (20 × 20 / 12) × 1.15 = 38.3 FPM
Required sorter speed = 3.2 × 38.3 = 122.6, round up to 125 FPM
Gap produced = (125 × 12 / 20) - 20 = 55 in
Model minimum = 9 in. 55 ≥ 9. Pass. Geometry = (15 × sin 30°) + 2 = 9.5 in. 55 ≥ 9.5. Pass.
Takeaway spur = 125 / cos 30° = 144.3 FPM

PART VI | LESSON 25: THE GAP CHECK AND CAPACITY PROOF

When the Gap Check Fails: Three Levers

Rate. Lower the required rate and the gap opens up. Needs the customer's sign-off in writing.
Speed. Raise the sorter speed, checked against the spur and the conveyor's published maximum at the heaviest product.
Sorter model. Select a model with a lower gap requirement. Changes the line item and the price with it.

Name the lever before you go back to the customer. A number fixed by a lever nobody chose comes back.

PART VI | LESSON 25: THE GAP CHECK AND CAPACITY PROOF

THINK LIKE THE PACKAGE

Be the smallest carton at the sorter induction. You're short, so the gap in front of you is huge relative to your own length, and that ratio is your SGR. It's the highest in the mix, which means you're the carton that demands the fastest sorter speed. The min carton looks harmless on the spreadsheet and it governs the design at the sorter.

PART VI | LESSON 25: THE GAP CHECK AND CAPACITY PROOF

The 90-Degree Transfer and the Trunk-Line Gap

Every transfer is a potential collision point. The trunk keeps running through the whole lift-move-lower cycle.
Lateral distance, cycle time, minimum trunk gap. Worked on the guide's numbers: 22.5 in, 4.75 s, and a 118 in minimum gap.
The four-inch margin is a minimum. On critical transfers add eight to ten inches for presentation and slippage.

DESIGN PRINCIPLE The gap check runs every time. No exceptions.

PART VI | LESSON 25: THE GAP CHECK AND CAPACITY PROOF

Riverside

RIVERSIDE PROJECT

The rate is 20 CPM and Dana put it in writing, so the rate gate is cleared and the sorter clears both gap checks at 55 inches produced. Then the number that moves: Ray's estimate was half a second, his correction email confirms one second under peak load.

Re-run the scan-to-divert distance at the confirmed one second. A carton travels 24 inches in that window at 120 FPM, and the moment belt speed changes the gap checks change with it. Produce the capacity proof and the setpoints package.

Next: When this system fails, how fast is it back up, and can this customer keep it running?