Certified Robotic Arc Welding (CRAW) common mistakes
AWS CRAW · Understand the traps and how to avoid them.
Treating the AWS weld symbol as a single drawing element and reading the tail, arrow, reference line, and both sides as if they all describe the same joint, instead of parsing the symbol positionally (arrow side vs. other side, tail for process/spec reference, supplementary symbols on the reference line).
Candidates often learned symbols informally on the shop floor and never internalized the standard layout; under time pressure they read top-to-bottom instead of using the reference line as the organizing axis, so a fillet on the arrow side gets confused with one on the other side.
What to do instead
Before answering, redraw the symbol on scratch paper: reference line horizontal, arrow line touching the joint, then place each element by role (tail = spec/process, both sides of reference line = arrow side/other side, supplementary = contour, finish, backing). Practice by taking a joint description and building the symbol from scratch, then reversing the exercise.
Confusing GMAW transfer modes and selecting spray, globular, or short-circuiting transfer without checking current density, shielding gas, and metal transfer implications for the given position and thickness.
Candidates memorize 'spray is hot, short-circuit is cold' but do not link transfer mode to the actual variables (amperage relative to electrode diameter, argon-rich vs. CO2-rich gas, out-of-position work), so they pick a mode that contradicts the stated conditions.
What to do instead
Build a decision table linking position, thickness, gas composition, and current density to transfer mode, and practice reading scenario stems for those cues before choosing. Remember that out-of-position typically pushes toward short-circuiting or pulsed transfer, not axial spray.
Applying the wrong conversion factor or inverting the ratio when converting between SI and inch-pound units (e.g., heat input in kJ/in vs. kJ/mm, deposition rate in lb/hr vs. kg/hr, or travel speed in ipm vs. mm/s) and reporting an answer that is off by 25.4 or 25.4 squared.
Candidates memorize a number without anchoring whether it multiplies or divides, and heat input involves both travel speed and voltage/amperage, so a single inverted factor compounds. Exam stems often mix units deliberately.
What to do instead
Carry units through every calculation and cancel them explicitly; write the conversion as a fraction so the unwanted unit appears in the numerator and denominator. Sanity-check the magnitude: 1 in = 25.4 mm, so a kJ/in value should be about 25.4 times the kJ/mm value, not the reverse.
Describing robot motion using joint-interpolated, linear, and circular moves interchangeably, or ignoring whether the tool center point orientation is controlled, when asked to program a path or diagnose a motion fault.
Candidates treat all move types as 'go from A to B' and overlook that joint moves do not guarantee a straight-line TCP path, that circular moves need a via point, and that singularities or axis limits can force a different move type.
What to do instead
For each move type, state three things: path shape of the TCP, whether orientation is interpolated, and when it is inappropriate (joint moves near obstacles, linear moves through singularities). Practice mapping a described weld path to the correct instruction and justify the choice from the geometry.
Mixing up the six degrees of freedom and the kinematic chain when reasoning about a robot arm, or confusing the distinctions among base, tool, and work-object frames when a question asks where a coordinate offset should be applied.
Candidates learn 'six axes' as a fact but do not connect each axis to its contribution to TCP position and orientation, and frame terminology sounds interchangeable until a question hinges on which frame a taught point is stored in.
What to do instead
Sketch the arm as a chain from base to tool flange and label each joint's axis and motion; then list what changes when a point is expressed in base vs. tool vs. work-object frame. For any offset question, first identify the frame of reference named in the stem before computing.
Answering safety questions with generic PPE statements instead of the specific hazard control hierarchy and the welding-specific hazards named in the stem (fume extraction, arc flash, hot work permits, confined-space gas monitoring, cylinder handling).
Candidates default to 'wear PPE' because it is always true, but exam items test whether they can identify the hazard and select the control at the right level (elimination, engineering control, administrative, PPE) for that hazard.
What to do instead
For each scenario, name the hazard first (fume, radiation, fire, pressure, electric shock), then choose the highest-level control that fits, and only then mention PPE as the last layer. Memorize which controls are engineering (ventilation, shielding, flash screens) versus administrative (permits, training).
Confusing welding procedure qualification with welder performance qualification, or assuming a procedure qualified in one position, thickness, or process automatically covers another without checking essential variables.
The two qualification types share vocabulary and both involve testing, so candidates conflate 'the procedure is qualified' with 'the welder is qualified' and ignore that essential variables (position, thickness range, backing, gas) drive the scope of qualification.
What to do instead
Separate the two in notes: procedure qualification proves the joint/process can meet properties; performance qualification proves the individual can deposit sound weld. For any scenario, ask which essential variable changed, then decide whether requalification is triggered.
Misreading destructive test results, for example treating a bend test failure as automatically a strength failure, or confusing tensile, guided bend, Charpy impact, and hardness tests by what property each measures.
Candidates group all mechanical tests as 'checks the weld' and do not link each test to its purpose and acceptance criteria, so a question about a bend specimen opening or a Charpy absorbed energy value gets answered with the wrong interpretation.
What to do instead
Make a four-column table: test, property measured, specimen orientation relative to the weld, and typical acceptance criterion. For bend tests, remember they primarily reveal ductility and soundness of the joint, not tensile strength.
Skipping the visual and surface examination sequence when answering weld examination questions, jumping straight to radiographic or ultrasonic testing as the 'best' method regardless of the defect type or location.
Candidates associate NDT with advanced methods and overlook that visual examination is the first required step, and that each volumetric or surface method has limits (RT good for volumetric internal defects, PT/MT for surface-breaking, UT for planar internal flaws).
What to do instead
For every examination question, first ask whether the flaw is surface or internal and planar or volumetric, then match the method. State explicitly that visual examination precedes other methods and note what each method cannot detect.
Setting up weld equipment by adjusting one variable in isolation (e.g., changing wire feed speed without checking voltage, or setting gas flow without checking the regulator and hose for leaks) and then diagnosing a poor weld from that single change.
Candidates treat settings as independent dials rather than a coupled system where WFS, voltage, travel speed, CTWD, and gas flow interact; they also skip pre-check steps like polarity, liner condition, and drive roll tension.
What to do instead
Adopt a setup checklist order: power source polarity and process selection, consumables and liner, gas supply and flow, then WFS/voltage/travel speed as a coupled set. When diagnosing, change one variable at a time and verify the arc characteristic (sound, spatter, bead profile) against the expected result.