3D printer parts and accessories, rated 3.5 stars and up, by sales rank — on offer now, page 14

What actually wears out

A 3D printer is mostly a machine for dragging hot plastic across a surface, and the parts that touch the plastic are the parts that fail. In rough order of how often you will replace them:

• Nozzles. Brass nozzles are consumable. They wear, they clog, and any abrasive filament — carbon fibre, glow-in-the-dark, glitter, wood-fill — destroys them quickly. Buy them in multiples; they cost pennies each.
• Build surfaces. PEI sheets and textured plates lose their grip over time and can be gouged by an over-enthusiastic scraper.
• PTFE tubing. The short liner inside a non-all-metal hotend degrades with heat and is a common cause of mysterious under-extrusion after a few hundred hours.
• Belts. They stretch. Slack belts cause layer shifts and ringing, and a belt is far cheaper than the evening you will spend blaming your slicer.

Buy spares before you need them

This is the whole argument for this page. A blocked nozzle stops a printer dead, and a replacement is a couple of pounds — but only if it is in a drawer. Ordering one and waiting two days for delivery turns a ten-minute job into a lost weekend.

A sensible starter kit: a few nozzles in the size you actually use, one spare in a larger size, a spare PTFE liner if your hotend has one, and a set of cleaning needles. That is under twenty pounds and covers most of what goes wrong.

Compatibility is the thing to check

“3D printer nozzle” is not a standard. The common MK8-style brass nozzle fits a great many machines, but Bambu, Prusa and most modern high-flow hotends use their own shapes. The same is true of build plates, which are sized to the machine, and of hotends generally.

We do not attempt to match parts to printers automatically — the listing titles are not reliable enough to do it honestly, and a confident wrong answer here costs you money. Check the manufacturer’s part number against your machine before ordering.

Note that parts and accessories carry no per-kilo figure on this site. They have no meaningful per-unit measure, and a weight-shaped number pulled out of an accessory listing title would be noise dressed up as data.