01 — How the Tool Works
You Enter
Heated Tunnel Length
Heated zone only, not overall machine length.
Required Dwell Time
Total seconds needed in the heated zone, from preheat entry to reflow peak.
Board Length
In direction of conveyor travel. For panels, use the full panel dimension including any frame.
Load Factor
Board pitch ratio. Default 90% means boards are spaced 10% of board length apart.
P&P Cycle Time (Optional)
Slowest placement machine cycle time. Leave blank for oven capability only. Fill in to get a bottleneck check.
You Get
Max Process Speed
Max belt speed the oven can run while still delivering the required dwell time. This is the hard ceiling.
Required Belt Speed
Speed the line demands to match P&P cycle time. Shown only when P&P cycle time is entered.
Throughput
Boards per hour at current process speed. Assumes continuous loading.
Board Spacing on Belt
Gap between boards at process speed. Below 10 cm warrants a closer look at conveyor entry clearance.
Bottleneck Status
Green / Amber / Red verdict with speed margin percentage.
02 — Mode A — Input Parameters
Oven Parameters
Heated Tunnel Length
e.g. 250 cm. Heated zone only, not total machine footprint.
Required Dwell Time
e.g. 270 s. Typical SAC305 total dwell: 240–300 s. Check your paste datasheet.
Load Factor
Default 90%. Tighter than ~85% risks board-to-board collisions at conveyor entry.
Board & Line
Board Length
e.g. 20 cm in direction of travel. For panels, use the full panel dimension including any tooling frame.
The unit toggle (cm / inches) at the top converts all inputs and outputs simultaneously.
Optional
P&P Cycle Time
e.g. 40 s. Cycle time of your slowest placement machine. Leave blank to skip the bottleneck check. When filled, the tool compares oven process speed against the speed the line demands.
03 — Mode A — Reading the Results
Max Process Speed
The maximum belt speed at which the board still receives the full required dwell. Running faster than this cuts dwell short.
Throughput
Boards per hour the oven can deliver at its max process speed with the given board pitch and load factor.
Board Spacing
The physical gap between consecutive board trailing and leading edges at process speed.
Required Belt Speed
The belt speed the P&P cycle time demands. Compare this to Max Process Speed to see if the oven can keep up.
Speed Headroom
Percentage margin between process speed and required speed. Positive = oven has headroom. Negative = oven is the bottleneck.
Example: 250 cm tunnel | 270 s dwell | 20 cm board | 90% load | 50 s P&P → Max process speed 27.8 cm/min | Required 24.0 cm/min | +15.7% headroom | 74 boards/h
04 — Bottleneck Status — The Three Verdicts
Oven can keep up
When: Process speed ≥ Required speed + 10%
The oven is not the bottleneck. You have room to slow the belt slightly if your profile needs more dwell without creating a throughput problem. Board spacing and throughput figures are your reference for scheduling.
Marginal — tight headroom
When: 0% to +10% margin
Any profile change demanding lower belt speed will make the oven the bottleneck. Verify your dwell time with a proper thermal profile run. A 5% longer dwell requirement could flip this into red.
Oven is the bottleneck
When: Process speed < Required speed
At the belt speed the line demands, dwell time falls short of the required value. Options: longer-tunnel oven, a shorter dwell profile if the paste spec allows, or accept a lower throughput target.
05 — Mode B — Size an Oven for a Target Throughput
You Enter
Target Throughput
e.g. 180 boards/h. The output rate your line needs to hit.
Board Length, Load Factor, Dwell Time
Same definitions as Mode A. These define how fast the belt must run and how long the board must be in the oven.
You Get
Min. Heated Length
The shortest heated tunnel that can deliver the required dwell at the speed the throughput target demands. Shown in cm, m, and mm.
Required Belt Speed
The belt speed needed to hit the throughput target with your board pitch.
Oven Class Reference
5-zone (~180 cm), 7-zone (~250 cm), 10-zone (~360 cm) typical heated lengths. Each row shows Sufficient or Too short against your calculated minimum. Reference data from Indium Corporation. Always verify against the specific oven model datasheet.
Mode B gives you the minimum. Add at least 10–15% margin before selecting an oven model. Profile headroom and future product mix changes will consume that margin fast.
06 — The Math Behind the Calculator
Process Speed
Speed = Tunnel Length / Dwell Time × 60
[cm/min] = [cm] / [s] × 60
Max belt speed at which the board still receives the required dwell. Hard ceiling for the oven.
Board Pitch
Pitch = Board Length / Load Factor
[cm] = [cm] / [0.90]
Centre-to-centre distance between boards. 90% load factor means a 10% gap between consecutive boards.
Throughput
TPut = (Process Speed / Pitch) × 60
[brd/h] = [cm/min] / [cm] × 60
Boards per hour at maximum process speed. Assumes continuous loading.
Required Speed (Mode A)
Req. Speed = Pitch / P&P Cycle × 60
[cm/min] = [cm] / [s] × 60
Belt speed the line demands. If this exceeds process speed, the oven is the bottleneck.
Min. Tunnel Length (Mode B)
Min. Length = Req. Speed × Dwell / 60
[cm] = [cm/min] × [s] / 60
Shortest heated tunnel that delivers required dwell at the speed the throughput target needs.
Heated vs. Overall Length
Overall = Heated + 0.5 to 1.5 m
cooling + load/unload conveyor
Always size from heated tunnel length, not overall machine length. Ovens with identical zone counts vary by manufacturer.
07 — Tips & Best Practices
01
Use heated length, not machine length
A 10-zone oven is typically 3.6 m heated but 5+ m overall. The datasheet is the only reliable source.
02
Dwell time comes from your paste spec
Use heated-zone duration from preheat entry to reflow peak. For SAC305, typically 250–360 s. Do not include cooling zone time.
03
Load factor 90% is a safe default
At 90%, boards are 10% of board length apart. Tighter than ~85% risks board-to-board collisions at the conveyor entry.
04
P&P cycle time is the constraint check
Without it the tool shows oven capability only. Fill it in to know if the oven is your bottleneck or the problem is elsewhere on the line.
05
Mode B gives you minimum heated length
Add at least 10–15% margin before selecting an oven model. Profile headroom and future product mix will consume that margin.
06
cm / inch toggle converts everything
Switch units at the top. All inputs, outputs, and the oven class reference table update simultaneously.