What Is Fabrication? The Complete Metal Fabrication Guide

What is fabrication? Ask two fabricators and the answers won’t match. One will say it’s assembly work: cutting plate and section, fitting the pieces, welding them together. The other will say it’s simply making something from scratch, which sweeps in machining, forming and half the workshop. Both readings are in active use among people who do the work, and neither is wrong.

The gap between those two definitions matters at the point of purchase. A drawing sent to one of our chinese fabrication companies on the narrow definition gets a welded assembly back. Sent on the broad definition, it might come back machined, formed, or subcontracted to three different places.

So this guide uses the narrow, shop-floor meaning, because that’s the one a supplier quotes against.

Two other meanings, cleared up front. Outside manufacturing, a fabrication is a lie or an invented story, and in academic and research contexts fabrication means inventing data. Neither has anything to do with metal. If the search that brought you here was about either, this is the wrong page.

TL;DR

• Fabrication is building a part or assembly from raw or semi-finished stock. Sheet metal fabrication techniques cover cutting, forming, joining and finishing. Machining removes material to create features; fabrication assembles stock into a shape.
• The three main types are sheet metal fabrication, structural steel fabrication and custom or bespoke fabrication.
• A welder is not automatically a fabricator. Welding is one operation inside fabrication. Fabricators also cut, form, fit and finish.
• Most fabrication problems start on the drawing. Material standard, weld requirements, finish and tolerance are the four callouts most often missing.
• BS 8888, EN 1090 and ISO 3834 are the standards a fabrication drawing should name. Most drawings name none of them.

What is fabrication?

Fabrication is the process of building a component or assembly from raw or semi-finished material by cutting it to size, forming it to shape, and joining the pieces together. The finished item is assembled from stock rather than carved out of a solid billet.

In practice, fabrication covers four operation groups: cutting, forming, joining and finishing. A single job may use all four or only two.

The term is used most often about metal. Plastics, acrylic and composites are fabricated too, but an unqualified reference to “fabrication” in an engineering context almost always means metal.

What is metal fabrication?

Metal fabrication is fabrication applied to metal stock: sheet, plate, bar, tube and structural section. It turns flat or linear raw material into a finished three-dimensional part or structure.

A metal fabricator reads a drawing, cuts the material, forms it, joins it, finishes it and inspects it. That full sequence is what separates a fabrication shop from a shop that only welds or only cuts.

Typical outputs: enclosures and chassis, brackets, frames and weldments, guarding, ducting, tanks and vessels, and structural steelwork.

Fabrication vs machining vs welding

Fabrication assembles stock into a shape, machining removes material to create features, and welding joins two pieces of metal. Each term describes a different relationship to the material, and all three can appear on the same part.

Process	What it does to the material	Typical input stock	Typical output
Fabrication	Assembles stock into a shape	Sheet, plate, tube, section	Weldment, enclosure, frame
Machining	Removes material to create features	Billet, bar, casting, or a fabricated part	Bores, faces, threads, precise dimensions
Welding	Joins two pieces of metal	Prepared parts	A joint
Manufacturing	The whole production activity	Anything	A finished product

Welding sits inside fabrication as one joining operation among several, alongside riveting, bolting and adhesive bonding. The wider boundary, fabrication vs manufacturing, turns on scope rather than process.

Machining and fabrication frequently appear on the same part. A welded frame that needs tapped holes and a flat mounting face goes to a mill after the welding is finished. The job is still fabrication; the machining is a secondary operation.

So, is a welder a fabricator? Not automatically. A welder joins metal. A fabricator interprets the drawing, develops flat patterns, cuts, forms, fits, welds and finishes. On most fabrication jobs the welding itself takes far less time than the layout, cutting and fit-up that precede it. Many fabricators weld, and many welders can fabricate, but the roles are not interchangeable on a quote.

What is the metal fabrication processes?

The metal fabrication process runs in four stages: cutting, forming, joining and finishing, with inspection at the end and usually in the middle. Each stage is covered in more depth in our metal fabrication process guide.

1. Cutting. Stock is cut to size and profile. Method depends on material thickness, edge quality required and volume.
2. Forming. Flat material is bent, rolled or pressed into shape. Press brakes handle most sheet work; rolls handle curves and cylinders.
3. Joining. Pieces are fitted and fixed together by welding, riveting, bolting or bonding. Fit-up before joining decides whether the assembly will be square.
4. Finishing. Deburring, grinding, blasting, then coating, plating, anodising or painting.

Seven cutting and forming methods cover most of the metal fabrication processes:

Cutting or forming method	Best suited to	Practical constraint
Laser cutting	Sheet and plate, tight profiles	Cleanest edge, minimal secondary work. Thickness limit is power-dependent, around 20 mm on a 2 kW CO2 laser and 25 mm on a 6 kW fibre
Plasma cutting	Thicker plate, faster than laser	Wider kerf, rougher edge
Waterjet cutting	Heat-sensitive or thick material	No heat-affected zone, slower
Shearing	Straight cuts in sheet	Fast and cheap, straight lines only
Punching	Repeated holes and features	Economical at volume with existing tooling
Press braking	Bends and flanges	Bend radius and flange length both constrained by tooling
Rolling	Curves, cylinders, cones	Minimum radius depends on thickness

How much does metal fabrication cost?

Setup and programming dominate the cost of a one-off fabricated part, which is why a single piece often costs close to what five would.

Fabrication is low-volume work by nature. The machine time to cut and bend one bracket is minutes; the time to program the cut, set the press brake, build the fixture and fit the assembly is hours. That fixed block of labour is spread across whatever quantity is ordered.

Most shops also apply a minimum lot charge, which is why a small bracket ordered as a single piece comes back at a price that looks disproportionate to its size. Nothing is wrong with that quote; the setup simply has nowhere to be spread.

Three things move the number more than material choice does:

Fabrication cost driver	Effect on the quoted price	How to reduce it
Quantity	Setup is fixed, so unit cost falls steeply up to about 10 pieces	Order the realistic annual quantity in one go
Tolerance	Tight tolerances add inspection, fixturing and scrap	Tighten only the features that need it
Operations	Every additional process adds a setup and a handling step	Combine features, avoid secondary operations

Asking for more precision than the part needs is the single most common reason a fabrication quote comes back higher than expected.

One caveat on quantity, because the standard advice to consolidate is not always right. Ordering a year of a part still going through design revisions converts a setup saving into a shelf of obsolete brackets.

Consolidate once the drawing is frozen. Before that, pay the setup twice and keep the option to change something. For cost comparison for custom metal fabrication projects, learn more about our metal fabrication services to get quotations from metal fabricators in China.

What are the three main types of fabrication?

The three main types of fabrication are sheet metal fabrication, structural steel fabrication and custom fabrication. They differ by material form, tolerance expectation and volume.

• Sheet metal fabrication works thin flat stock, typically under 6 mm, into enclosures, brackets, panels and ducting. Tolerances are tighter and the work is closer to precision engineering, and the sheet metal cutting and forming methods involved differ by thickness.
• Structural steel fabrication works beams, columns, angle and heavy plate into load-bearing frames and supports. Tolerances are looser, and the governing concern is structural compliance rather than dimensional precision.
• Custom or bespoke fabrication is one-off or low-volume work built to a specific drawing, often mixing both of the above. Prototype frames, machine guarding and specials fall here.

To learn how the wrong manufacturing method can inflate your quote, and how to choose the right one for your volume, watch our video below.

 

Which materials are used in metal fabrication?

Mild steel, stainless steel and aluminium account for most fabrication work, with copper, brass and galvanised steel in narrower roles.

Fabrication material	Common grades	Why it gets specified	Common failure mode
Mild steel	S275, S355	Cheapest, welds easily, strong	Corrodes without coating
Stainless steel	304, 316	Corrosion resistance, hygiene	Higher cost, distorts more when welded
Aluminium	5083, 6082	Light, corrosion resistant	Needs different welding procedure, softer
Galvanised steel	–	Pre-coated corrosion protection	Coating damaged by welding, fumes are hazardous
Copper and brass	–	Conductivity, appearance	Expensive, specialist joining

Grade matters more than the material name. “Stainless steel” on a drawing invites 304 when the application needs 316, and the difference shows up as corrosion months later.

Four callouts every fabrication drawing needs

Every fabrication drawing needs four callouts that most are missing: material standard and grade, weld requirements, finish, and tolerance. A factory builds precisely what the drawing specifies, and whatever the drawing leaves ambiguous gets the quickest available interpretation.

Incomplete drawings are the single most common theme in what sourcing teams report going wrong on an international fabrication order. A drawing that names the material on one line and a required coating on the line below is a recognised failure mode: the coating reads as secondary, and the part arrives bare.

Four callouts account for most of it:

Drawing callout	What to state on the drawing	What goes wrong if omitted
Material standard and grade	“S355JR per EN 10025-2” rather than “mild steel”	Cheaper or different grade supplied
Weld requirements	Weld symbols on the drawing giving type, size, extent and inspection level	Tacked where it needed a full penetration weld
Finish	Process, thickness, standard, colour	Bare metal arrives, or the wrong coating
Tolerance	General tolerance standard plus critical dimensions	Each shop applies its own default

Name the governing documentation standard on the drawing as well. BS 8888 is the UK national standard for technical product documentation and specification, and it defines how dimensions, tolerances and symbols are to be interpreted. The current edition, BS 8888:2025, was published on 30 October 2025, supersedes BS 8888:2020, and consolidates and references over 200 ISO standards in one framework.

Where a drawing crosses borders, naming the standard removes an entire class of interpretation dispute before it starts.

Which standards govern fabricated and welded work

Two European standards sit behind most fabrication orders, and neither appears on a typical drawing until something goes wrong.

• EN 1090 covers the execution of steel and aluminium structures. EN 1090-1 sets the conformity assessment requirements for structural components placed on the EU market, and the European Court of Justice has confirmed it as a harmonised standard for CE marking where the component’s structural function is essential to the works. EN 1090-2 and EN 1090-3 give the execution requirements for steel and aluminium respectively.
• ISO 3834 sets quality requirements for fusion welding, in three levels: comprehensive (Part 2), standard (Part 3) and elementary (Part 4). Part 1 explains how to choose between them, based on how much the consequence of a weld defect matters.

A drawing for a load-bearing weldment that names neither has left both the conformity route and the welding quality level to the supplier.

Sheet metal has realistic limits worth designing to. Most drawings default to the ISO 2768 mk tolerance classes.

Achievable bend angle depends on material, thickness, tooling and whether the bend is air bent or bottomed. Air bending thin sheet normally holds around ±1.5°, with roughly a further degree on plate, and bottoming tightens it at the cost of far higher tonnage.

Holes placed across a bend line move as the material forms, so a slot absorbs the variation where a round hole will not fit.

How do I verify a fabrication supplier?

Checking the capability of a fabrication supplier comes down to four checks: equipment, comparable work, the spread across quotes, and whether the business is really a manufacturer.

1. Check the equipment against the part. Press brake bed length and tonnage decide the largest bend; cutting bed size the largest sheet. A shop without a brake long enough will subcontract the part, and the subcontractor's quality isn't visible from the quote. Across Haizol's network, 68% of factories handle two or more processes without subcontracting — the figure worth asking any supplier to match.
2. Check for comparable work. A fabricator that has run similar assemblies has already solved the problems the drawing hasn't anticipated.
3. Read the spread across quotes. Clustered quotes mean the shops priced the same scope. One quote far above or below the rest means a shop declining the work, or reading the drawing differently. A wide spread is a signal to re-read the drawing before choosing on price.
4. Check that the business is a manufacturer. Trading companies quote work they don't perform. On HAIZOL, trading companies are excluded from membership, so every member is a manufacturer

Use the search bar at the top of our website to find a factory, or go directly to our directory of metal fabrication companies in China and filter them by capability. Each factory verified on HAIZOL has its own profile where you can view company details such as ISO certifications, workforce, export experience, factory size, and machinery.

Frequently asked questions

What is an example of fabrication?

A steel machine guard is a typical example of a fabrication. Flat sheet is laser cut to profile, bent on a press brake to form the sides, welded to a frame, then powder coated. Cutting, forming, joining and finishing, in one part.

What is fabrication work?

Fabrication work is the trade of building assemblies from metal stock: reading drawings, developing flat patterns, cutting, forming, fitting, welding and finishing.

Is metal fabrication the same as welding?

No. Welding is one joining operation within fabrication. A fabrication job also involves cutting, forming, fitting and finishing, and some fabricated assemblies are bolted or riveted rather than welded.

What is the difference between a machinist and a fabricator?

A machinist removes material to create precise features on a part. A fabricator assembles stock into a shape. The two trades often work on the same component in sequence.

What is fabrication in engineering?

In engineering, fabrication refers to building a component or structure from raw or semi-finished material through cutting, forming and joining, as distinct from casting, moulding or machining it from solid.

What is fabrication of steel?

Steel fabrication is metal fabrication carried out in steel, covering both sheet and plate work and heavier structural sections. Structural steel fabrication specifically produces load-bearing frames and supports.

What is sheet metal fabrication?

Sheet metal fabrication is fabrication of thin flat stock, usually under 6 mm, into enclosures, panels, brackets and ducting. Tolerances are tighter than structural work and press braking is the dominant forming method, covered in our metal fabrication process guide.

What materials are commonly used in metal fabrication?

Mild steel, stainless steel and aluminium cover most work, with galvanised steel, copper and brass used where corrosion resistance, conductivity or appearance require them.

Getting fabrication quoted

A fabrication drawing with material standard, weld requirements, finish and tolerance stated is quotable by any competent shop. One without them produces quotes that cannot be compared, because each supplier has priced a different part. Incomplete enquiries also tend to sit at the bottom of a shop’s queue, behind the ones that can be priced immediately.

Requests for quotation submitted through HAIZOL reach capability-matched factories in China, and 90% receive quotes from eight or more verified factories within 24 hours. Sheet metal fabrication services covers laser cutting, press brake forming, welded assembly and finishing.