Additive Manufacturing & 3D Printing

The vocabulary unit, and the one that decides whether the rest of the path is industry-shaped or hobby-shaped. The standard defines seven process families, and a desktop filament printer is one implementation of one of them. Learning the taxonomy first means every later unit has a place to attach, and it stops the extremely common error of generalising a filament printer's behaviour — its layer adhesion, its supports, its tolerances — to processes that work nothing like it.

A part passes through at least four representations before anything is made: solid model, tessellated mesh, sliced layers, machine instructions. Each conversion discards information, and almost every 'the print does not match the model' problem is a conversion artefact rather than a machine fault. This unit exists to make those handoffs visible, including the specific one that catches everyone — a curved surface becoming faceted because the export tolerance was left at its default.

The family with the most accessible hardware and therefore the most practice reps available. Covered properly rather than assumed: how a thermoplastic bead bonds to the one below it, why that bond is weaker than the bead itself, and what nozzle temperature, layer height, cooling and speed each actually change. This unit carries the reps that later units generalise from, so it goes early even though it is not the most industrially significant family.

The first family that trades ease for real hazard. Resolution and surface finish are dramatically better than extrusion, and the price is a liquid photopolymer that is a skin sensitiser and a genuine irritant, a wash step in flammable solvent, and a post-cure that is part of the process rather than an optional extra. The Risk elements here are not ceremonial — uncured resin handling is where hobbyists get hurt, and the mitigation is specific and learnable.

🔴 The industrially serious family, and the one with the most severe hazards in the whole path. Polymer powder bed fusion needs no supports and changes what a designable part is; metal powder bed fusion is where aerospace and medical additive actually lives. The Risk content is unavoidable: fine reactive metal powder is an inhalation hazard and an explosion hazard, inert atmosphere handling is mandatory, and none of that is optional knowledge for someone claiming this certification.

The four families that a hobbyist background never covers and a certification absolutely tests. Each exists because it solves something the others cannot: full-colour and metal green parts from binder jetting, multi-material and near-injection-moulding surface from material jetting, large-scale metal and repair-in-place from directed energy deposition, and cheap laminated volume from sheet lamination. Treated together because the goal is confident discrimination between them, not depth in each.

A printed nylon part and a moulded nylon part share a datasheet and not much else. This unit separates the feedstock's properties from the built part's properties, and explains why the second is what your design has to survive on: porosity, residual stress, incomplete fusion, moisture in the feedstock, and process-dependent microstructure in metals. Every 'it printed fine and then broke' story lands here.

🔴 The single highest-leverage decision in additive, and the one most sources mention in a sentence and move on from. Build orientation simultaneously sets strength direction, surface finish, support volume, build time, cost and dimensional accuracy — and improving any one of those usually makes another worse. This is judgement content, so it must be taught by worked example and critique rather than by recall cards, and it is the prerequisite for the design unit that follows.

Additive removes some constraints and adds others, and designing as if it removed all of them is how expensive parts fail. Overhang limits and self-supporting angles, minimum feature size, trapped powder and trapped resin, escape holes, wall thickness, and the consolidation of assemblies into single parts. Contains a Skill element because the assessable outcome is a redesigned part with the reasoning stated, not a list of rules recited.

What dimension you actually get, as opposed to the one you modelled. Thermal contraction, curl at corners, first-layer effects, scaling compensation, and the reason a hole prints undersized on almost every process. This unit is what makes the difference between a part that looks right and a part that assembles, and it is the prerequisite for talking about quality at all.

The build is rarely the finished part. Support removal, depowdering, solvent washing and UV cure, stress relief, hot isostatic pressing, machining of critical features, and surface finishing. This matters commercially as much as technically: post-processing routinely dominates lead time and cost, and a process comparison that ignores it will pick the wrong process. Risk elements come with the solvents, the abrasives and the powder recovery.

How anyone knows a part is good, given that the defects are internal and the process is one-off by nature. In-situ process monitoring, CT scanning for porosity, witness coupons, destructive testing, and the qualification burden that separates a printed prototype from a flight or implant part. This is the unit that explains why regulated additive is slow and expensive, which is a question every serious learner asks.

Pulled into one place deliberately, because the hazards are family-specific and mixing them up is dangerous. Fine powder inhalation and combustibility, photopolymer sensitisation, solvent flammability, ultrafine particle and VOC emission from hot thermoplastic, laser exposure, inert gas asphyxiation, and high-temperature surfaces. Every element here is a Risk element: the assessment is identifying the hazard AND stating its control, which a definition card cannot test.

The unit that ties the path together and the one an employer actually cares about: given a part, a quantity and a requirement, which process, why, and at what cost. Machine time, material cost, post-processing labour, nesting and build-volume utilisation, and the break-even against machining or moulding. Assessed by a written selection justification for a real part — a Skill, because there is no single correct answer to memorise.

Where the vocabulary in unit A1 came from and who maintains it, what the CAM-F certification covers and does not, and which standards bodies matter for which industry. Last, not first, because a standards tour is meaningless before the processes are understood — but it is the frame that makes the knowledge portable to an employer.