Manufacturing Process Comparison Matrix

A side-by-side comparison of common manufacturing processes by typical tolerance, materials, surface finish, and best use. Use it to narrow the process choice before reading the dedicated process page, then confirm the specific capability with the shop that will run the part.

How to read this matrix

Tolerance and materials columns

• Typical tolerance is the dimensional band a process normally holds in production. Tighter numbers cost more, because they call for slower cycles, stiffer setups, and more inspection, so specify tight values only where the part needs them.
• Materials lists what each process can work. Most subtractive and cutting processes handle metals; additive processes are split by material family (thermoplastics, resin, nylon powder). A part material often rules out whole process families before tolerance does.

Finish and best-for columns

• Surface finish uses Ra in micrometres (µm), where lower is smoother, except for cut edges and formed surfaces, which are described qualitatively. Finish drives both appearance and how much secondary work a part needs.
• Best for is the geometry or use case the process is built around. Matching it to the part is the quickest way to cut the list down.

Comparing processes by tolerance

CNC milling and turning hold the tightest tolerances of the subtractive group, around ±0.025mm on suited features, and SLA resin printing is close behind at ±0.05 to 0.15mm. SLS and MJF nylon printing run looser at ±0.2 to 0.5mm, and FDM looser still at ±0.1 to 0.5mm with visible layer variation. Among cutting processes, fiber laser holds ±0.10 to 0.50mm on thin to medium sheet, waterjet around ±0.05 to 0.25mm across a wide thickness range, and plasma only ±0.5 to 1.0mm because it trades precision for the ability to slice thick plate. Sheet metal bending is controlled as an angle, typically ±0.5 to 2 degrees, rather than as a linear dimension. When a drawing calls for a tolerance inside a process band, either move to a more precise process or expect a premium.

Matching process to material and finish

Metals and thermoplastics

• Metals: CNC milling and turning cover prismatic and cylindrical metal parts; fiber laser and waterjet cut flat metal sheet; plasma cuts conductive plate. For internal profiles in very hard metal, EDM is the niche choice.
• Thermoplastics: FDM prints common filaments such as PLA, ABS, and PETG for concept parts; CNC can machine engineering plastics when the part needs precision instead.

Resin, nylon powder, and sheet metal

• Resin: SLA builds fine detail and a smooth surface in photopolymer, good for fit checks and appearance models.
• Nylon powder: SLS and MJF produce functional PA12 parts that take load and need no support removal, useful when FDM geometry or strength falls short.
• Sheet metal: laser or waterjet cut the flat blank, then bending forms it into an enclosure or bracket.

Choosing for the job

Match process to stage and volume

Match the process to the part stage and volume, not just the geometry. For a single concept model, FDM or SLA is usually enough. For a functional prototype that must take real load, SLS or MJF nylon, or a CNC machined part, fits better. For flat sheet parts, start from the cutting process the thickness and tolerance suggest, then add bending. For repeated production volumes, the matrix is a first filter; the real choice also weighs tooling, setup, and lot economics that live on the dedicated process pages.

A worked bracket example

A worked example shows how the columns trade off. A 3mm aluminum bracket that must hold ±0.1mm on two holes rules out FDM and plasma and points to CNC milling or a laser-cut blank plus bending. The same bracket in 12mm steel plate shifts the cutting choice toward waterjet or plasma, and if the tolerance tightens to ±0.05mm, CNC milling of the cut blank becomes the safer path. In each step the material, thickness, and tolerance columns together removed options faster than reading each process page in turn.

Finish and secondary operations

Most processes leave a part that needs some secondary work. As-machined CNC sits near Ra 3.2µm and can be ground below Ra 0.8µm when a surface must seal or slide. Laser-cut edges may carry a thin oxide layer that affects powder coat adhesion, so grinding or a nitrogen-assist cut may follow. FDM parts often need sanding or vapor smoothing to hide layer lines, while SLA parts come out smooth but may need a UV post-cure for strength. Plan the finish column as a downstream cost, not just a number on the matrix.

Limitations

Every value here is a typical production range, not a certified limit. Real capability moves with machine class, material and temper, part size, thickness, and shop practice, and a capable shop can often hold tighter than the general band on the right setup. Confirm the specific tolerance, finish, and material against the governing standard (such as ISO 2768-1 for general machining tolerances or ISO 9013-1 for laser cut quality) and with the shop before locking a specification.