What is 3D printing?
3D printing is a family of methods that build a physical part layer by layer from a digital design.
How it works and where it is used
Filament, resin and powder processes differ in materials, resolution and strength. Supports, layer orientation, tolerances and finishing matter. Prototypes can be fast, but printed parts do not automatically match the load capacity of molded or machined parts.
Limits, safety and selection criteria
Safety-critical or medical parts need material validation and applicable standards. Resins, powders and heated nozzles require ventilation and protection. Publicly available design files do not erase copyright, patent or product-liability concerns. To replace a broken knob, a designer measures it, builds a CAD model and prints a prototype. The first hole or snap fit may miss the needed tolerance, so measurements guide revision. Strength along and across layers can differ. Resin prints require cleaning and post-curing. “Anything can be printed” does not mean printing is economical; other methods can be faster and cheaper at scale. File provenance and licensing should be checked before manufacturing or selling a part.