Project Planning, Drawing Interpretation, and WPS Development

Why Planning Comes Before the First Arc

In structural and pipe fabrication, mistakes made on paper cost nothing. Mistakes made in steel cost time, material, and sometimes lives. The capstone project treats planning as a deliverable equal in weight to the finished weldment itself. Before a single piece of base metal is marked or cut, you will produce three documents: an annotated orthographic drawing, a draft Welding Procedure Specification (WPS) for every process you intend to use, and a complete Bill of Materials (BOM) with a cutting list. Each document must be signed off by your instructor. No sign-off means no material requisition.

Reading the Orthographic Drawing

An orthographic drawing presents a three-dimensional object as two or more flat views — typically front, top, and right-side — so that every surface and dimension is shown true to scale in at least one view. Your first task is to orient yourself: identify the title block, revision level, drawing scale, and units (inches or millimeters). Then walk the views systematically.

Every welding symbol on the drawing follows AWS A2.4, the industry standard for welding symbols. The reference line runs horizontally. The arrow points to the joint. Symbols below the reference line apply to the arrow side of the joint; symbols above apply to the other side. Tail notes reference the applicable WPS or process. Read each symbol and record it in your markup: joint type (butt, fillet, groove, plug, or slot), weld size or throat, weld length and pitch if intermittent, and any supplementary symbols such as weld-all-around or field weld flags.

Mark every joint on the drawing with a colored pen and assign it a sequence number. That number ties the drawing to your welding sequence in the project plan.

Joint-by-Joint Welding Sequence

Sequencing controls distortion. Heat applied to one side of an assembly causes that side to shrink as it cools, pulling the structure out of square. Standard strategies include:

• Backstep welding — depositing short segments in the direction opposite overall travel to balance heat input.
• Balanced welding — alternating passes on opposite sides of a neutral axis.
• Pre-setting (pre-cambering) — tacking parts slightly out of position so that weld shrinkage pulls them to the correct final position.

For the capstone assembly, list every joint in the order you plan to weld it. Note which joints must be completed and allowed to cool before adjacent joints are started. Pipe joints in particular must reach interpass temperature limits before the next pass is deposited — a detail that goes directly into the WPS.

Drafting the WPS

A Welding Procedure Specification is the written instruction that tells a welder exactly how to make a code-compliant weld. Both AWS D1.1 (structural steel) and ASME Section IX (pressure-containing welds, including pipe) require a WPS before production welding begins.

Essential variables are the parameters whose change requires re-qualification of the procedure. For your draft, fill in every essential variable on the standard form:

• Base metal: material specification and, for ASME, the P-number that groups metals with similar weldability.
• Filler metal: AWS classification (e.g., E7018 for SMAW, ER70S-6 for GMAW), and for ASME, the F-number that groups filler metals by usability characteristics, and the A-number that describes deposited weld metal chemistry.
• Process: SMAW, GMAW, FCAW, or GTAW.
• Position: 1G/1F (flat), 2G/2F (horizontal), 3G/3F (vertical), 4G/4F (overhead), 5G or 6G for pipe.
• Preheat temperature: minimum temperature the base metal must reach before the arc is struck, preventing hydrogen-assisted cracking in higher-carbon steels.
• Interpass temperature: maximum temperature permitted between passes, preventing excessive grain growth and loss of toughness.
• Shielding gas: type, mixture percentage, and flow rate for GMAW, FCAW, and GTAW.
• Current type and polarity: DCEP, DCEN, or AC, as required by the filler metal classification.
• Travel speed and voltage/amperage ranges: the operating window within which the welder must stay.

After completing the draft, compare it side-by-side with the program's reference WPS library. Check every field. A missing essential variable is not a minor omission — under both AWS D1.1 and ASME Section IX, an incomplete WPS is a nonconforming WPS.

Building the Bill of Materials and Cutting List

The BOM lists every piece of base metal by material specification, size, and quantity. The cutting list breaks each piece down to exact cut lengths with saw-kerf and squaring allowance added. Calculate total linear footage of filler metal by estimating deposition requirements joint by joint, then applying a standard deposition efficiency factor for the process (SMAW runs roughly 60–65% efficiency due to stub loss and slag; solid wire GMAW runs roughly 90–95%).

Enter all data into the fabrication planning worksheet. This worksheet becomes a permanent portfolio document and will be reviewed alongside the finished weldment.

Safety Points for the Planning Phase

Planning is a desk activity, but safety rules still apply. Review the Safety Data Sheets (SDS) for every filler metal and shielding gas before you specify them in the WPS — the SDS lists fume hazards, ventilation requirements, and PPE. Confirm that the preheat method you specify (torch, induction blanket, or resistance pad) requires a hot work permit in your facility. Note any material that requires special handling: galvanized or coated steel releases zinc fumes and demands local exhaust ventilation at the arc. Document these requirements in your project plan so they are in place before fabrication begins — not discovered mid-weld.