How is the number of passes calculated?

The tool finds the weld cross-sectional area from the groove geometry, adds a cap allowance, then divides by the deposited area per pass and rounds up. More fill area or smaller passes means more passes.

How is the groove cross-section found?

For a single-V groove it sums a rectangular root channel, root gap times depth, with the triangular bevel area, depth squared times the tangent of the half-angle. Wider angles and deeper grooves both raise the area sharply.

What is a backstep sequence and why use it?

In a backstep sequence you weld short segments in the direction opposite overall travel. Each segment shrinks toward the previous one, so the accumulated pulling distributes evenly and angular distortion drops on thicker joints.

Why split passes into root, fill, and cap?

The root pass fuses the joint and sets penetration, fill passes build the bulk, and the cap shapes the reinforcement and finish. Planning the split helps you choose technique, amperage, and interpass cleaning for each stage.

How accurate is the deposited area per pass?

It is an estimate scaled from process and wire diameter, since real deposition depends on amperage, travel speed, and deposition efficiency. Override it with your measured bead area for a tighter pass count.

Multi-Pass Weld Sequence Planner

Fill a thick groove one stringer at a time and the pass count drives your time, consumable cost, and heat input. This planner estimates how many passes a V- or U-groove needs, splits them into root, fill, and cap, and recommends a sequence that keeps the plate from bowing.

How it works

The weld cross-section is built from the groove geometry, then the pass count follows from the deposited area each bead lays down:

groove area = root_gap × depth + depth² × tan(angle / 2)
total area  = groove area × (1 + cap allowance)
pass area   ≈ process_factor × wire_diameter   (or your override)
passes      = ceil(total area / pass area)

The included groove angle is halved because the bevel is a triangle on each face. The process factor reflects that flux-cored deposits more per pass than stick, with MIG in between. For thick joints or high pass counts the planner recommends a balanced, backstep technique to spread shrinkage and limit angular distortion.

Example and tips

A 16 mm plate with a 60° single-V groove and a 2 mm root gap has a fill area near 100 mm². At roughly 8 mm² per MIG pass with 1.2 mm wire that is about a dozen passes — one root, the bulk as fill, and a final cap. Keep interpass temperature in spec, clean slag between every pass, and alternate fill beads side-to-side on heavy sections to pull the joint straight rather than letting it close on one face.