3D printing involves heat, moving parts, and chemicals, so safety deserves real attention. FDM printing melts plastic at high temperatures, and the resulting emissions of ultrafine particles and volatile organic compounds are a concern, especially with ABS, which warps easily and releases fumes that demand an enclosure and active ventilation; PLA is generally milder but still benefits from a well-ventilated space. Air filtration units combining HEPA and carbon filters can reduce particulates and VOCs, and a heated bed, hot end, and electronics all present burn and shock hazards if handled carelessly. Resin printing brings its own set of concerns because uncured resin is toxic and can irritate skin and lungs, so gloves and good ventilation are essential, and resin parts require post-processing in isopropyl alcohol followed by UV curing, often in a dedicated wash and cure machine. Generally, resin prints are more brittle than FDM prints, which tend to be more impact-resistant, so resin is favored for detailed models like miniatures, dental work, and jewelry, while FDM remains the choice for functional parts and larger objects.
Filament itself requires care because many plastics absorb moisture from the air, which causes popping, steam, rough surfaces, and weakened prints. Wet filament can be revived by drying it before printing, with PLA typically dried at around 45°C for 4 to 6 hours and nylon at around 70 to 80°C for 8 to 12 hours. For ongoing protection, filaments should be stored in sealed bags or dry boxes with desiccant such as silica gel, and especially moisture-sensitive materials like nylon should ideally be printed fresh from a dryer or from a dry box that keeps them dry during use. After printing, finishing steps like progressive sanding, priming to fill small imperfections, acrylic painting, and a clear protective coat can dramatically improve appearance, while acetone smoothing, which exposes ABS to acetone vapor for a glossy finish, is highly effective but flammable and must be performed with strong ventilation and care.