Calculator Suite | Product Spec Calc Material Handling Academy

Product Spec Calc

The web edition of the Product Spec Calc r4.1. Enter your package mix and conveyor inputs, calculate each step, and read what governs and why. Each section works on its own, and the sections chain the same way the tool does: package basics set the parameters, rate feeds the sorter, the gap check gates the selection.

Read Alongside

This implements the MHA Calc Logic Guide and reproduces the formulas of the Product Spec Calc r4.1 workbook. Open the guide side by side: Calculation Logic Guide. For all of the math laid out under the hood, see the Calc Addendum.

Where the r4.1 tool and the guide's hand examples differ, this calculator follows the tool. The tool chains at full precision and feeds the sorter the smallest gap in the mix, the min carton's gap produced, so the sorter numbers here read lower than a hand example that rounds intermediates and uses the max carton's gap.

Section 1 Package Basics

Characterize the package mix and set the parameters every downstream calculation depends on. The minimum package drives roller centers and gap. The maximum package drives width and curve geometry. Run each against the worst-case carton, not the average.

Roller CentersLeading Dimension / 3
What to watchAt least three rollers must stay under the product at all times, so roller center spacing is the leading dimension over three. The minimum package drives this. After a 90 degree transfer the carton travels hard way, so size the takeaway rollers to the hard way dimension, not the trunk dimension.
Weight per FootWT / (L / 12)
What to watchThis is a per-carton output. The worst case is the heaviest carton at the shortest length, not the average. It feeds roller capacity and incline belt checks.
Minimum Curve Between-Frame WidthSQRT((IR + W)^2 + (L/2)^2) - (IR - 2)
What to watchRound up to the next catalog between-frame width. Never round down. Run it against every carton. The largest result sets the curve width, and one outlier can force a much wider curve than the average carton would.
Tumble Angle and Incline CheckATAN(L / (3 x H)) x 180 / PI
What to watchThe tumble angle is the theoretical limit where the carton tips forward. Design inclines to the minimum tumble angle in the mix with a safety margin, never to the theoretical limit. The short, tall carton is the worst case.

Section 2 Rate and Required Sorter Speed

Establish the gap and rate, then work the sorter chain. The min carton produces the smallest gap and is the binding case fed to the sorter. Confirm the required rate with the customer in writing before you run these numbers.

Gap Produced (Speed Change)SpeedOut x (L / SpeedIn) - L + StartingGap
What to watchRun this for min, max, and average length. The max carton at L=20 gives 44 in here. The min carton at L=9 gives 33 in, the smallest gap, and that is the binding gap the sorter uses at induction. Feed 33 to Section 2's sorter chain.
Theoretical RateSpeedIn / ((L + StartingGap) / 12)
What to watchDesign to the max carton length. If theoretical rate is below the required rate, raise belt speed or cut the gap. Confirm the required rate is achievable with this product mix rather than designing to the minimum.
PitchGap + L
What to watchCenter to center spacing. If pitch looks wrong, check Gap Produced first, because everything derives from it.
Sorter Speed Chain (CFPM, SGR, Required Speed)CFPM = (L x Rate / 12) x SF | SGR = (L + Gap) / L | Required = SGR x CFPM
What to watchCFPM is a floor, never the run speed. Check all three carton columns: the max carton drives CFPM, the min carton drives SGR, and the column with the highest required speed governs. Round the governing speed up to the next practical belt speed. Gap at sorter is informational here; the gap check uses the induction gap.

Section 3 Gap Check

The gap check answers the one question the sorter section exists for: can this sorter run this mix at this rate without a gap failure. Compare the gap produced at induction against both requirements. The larger requirement governs.

Gap Check (Model Minimum and Geometry)Geometry = (MaxW x SIN(angle)) + 2 | Model minimum per r4.1 spec table
What to watchMeet both requirements, and never design to the exact minimum. Leave margin for product presentation and belt slippage. The model minimum comes from the r4.1 spec table by model and max carton width. Those are manufacturer-specific reference values. If it fails, raise sorter speed, cut the rate, reduce the divert angle, or select a model with a lower gap requirement.

Section 4 Takeaway Spur and 90 Degree Transfer

The takeaway spur must run faster than the sorter because the carton exits at an angle. A 90 degree transfer is a potential collision point on every cycle. Work out how long the transfer is busy before you check the trunk gap.

Takeaway Spur SpeedSorterSpeed / COS(divert angle)
What to watchSpecifying the spur at sorter speed is always wrong. At 30 degrees the spur runs about 15 percent faster than the sorter, at 22 degrees about 8 percent faster. Feed the required sorter speed from Section 2.
Lateral Travel DistanceBF + ((OAW - BF) / 2)
What to watchAssumes the worst-case carton position on the side opposite the divert direction. This distance feeds the transfer cycle time.
Transfer Cycle TimeLift + (LateralDist / 12) / (TransferSpeed / 60) + Lower
What to watchThis is the window the trunk line cannot deliver the next carton. Confirm lift, lower, and transfer speed against the actual mechanism rather than assuming them.

Section 5 Trunk Gap Back-Calculation

Back-calculate the minimum gap the trunk line needs so the transfer finishes its full cycle before the next carton arrives. Compare it to the gap you actually have on the trunk line.

Minimum Gap Required on Trunk Line(CycleTime x TrunkSpeed / 5) + 4
What to watchThe 4 in margin in the formula is a floor. On critical transfers add 8 to 10 in more for product variation and belt slippage. If the available gap is short, reduce trunk speed, add gap upstream, or use a faster transfer. The min carton's 33 in gap is far short of the 118 in this transfer needs, so it collides unless the trunk gap grows.

Utilities Skew and Lookup

Two supporting calculations. The skew length sizes an alignment section. The lookup time is the physical basis for any scan-to-divert distance check.

Skew Conveyor Required Length((BF - MinW) x BF / RollerCenters + MaxL) / 12
What to watchThis is a minimum. Add length for connection to adjacent sections, and check both the narrowest and widest carton if the mix varies a lot in width.
Lookup Time (Time Between Points)(Distance / 12) / (Speed / 60)
What to watchThis is the response window between two points, for example scan to divert. Recalculate if belt speed changes anywhere between them. Never estimate travel time from memory.