Clear aligners look simple — a thin, transparent tray that nudges teeth into place. But behind every set is a precise clear aligner manufacturing process that turns a single intraoral scan into a series of custom trays, each one engineered to move teeth a fraction of a millimetre at a time. Here's exactly how clear aligners are made, stage by stage, and where quality is either built in or lost.

Key takeaways

  • Clear aligners are made from a digital scan, not a physical impression — accuracy starts at the source.
  • A clinician-reviewed treatment plan decides every tooth movement before anything is printed.
  • Models are 3D-printed, then medical-grade PETG is thermoformed, trimmed and polished into each tray.
  • Every tray should pass dimensional and first-fit quality control before it leaves the lab.

1. Intraoral scanning and case submission

Manufacturing begins in the clinic. Instead of a putty impression, the dentist or orthodontist captures a digital 3D scan of the patient's teeth with an intraoral scanner, producing an STL or PLY file. That file — along with photographs and a prescription describing the treatment goals — is submitted to the aligner manufacturer. Because everything downstream is built on this scan, a clean, complete capture is the single biggest factor in a well-fitting final tray.

2. Digital treatment planning

Next, technicians and treatment planners import the scan into orthodontic software and design the digital setup: a virtual model of how the teeth will move from their current position to the target alignment. The full correction is divided into small increments, and each increment becomes one aligner in the series. This is where the science lives — planning the sequence, the force, and where attachments or interproximal reduction are needed.

Why clinician review matters: software can plan a movement that looks perfect on screen but isn't biologically safe. A responsible manufacturer has an orthodontist review and approve every plan before production — and shares that plan with the treating clinic for sign-off. More on what to look for in a manufacturer →

3. 3D printing the models

Once the plan is approved, each incremental position is exported as a 3D model and printed on a resin printer using SLA or DLP technology. A full treatment might mean dozens of printed models — one for every step in the series. Print accuracy directly determines how well the finished aligner fits, so precision printers and controlled post-curing are essential. Keeping printing in-house gives the manufacturer full chain-of-custody over this step rather than outsourcing it to a bureau.

4. Thermoforming the trays

This is the step most people picture when they think about how clear aligners are made. A sheet of medical-grade multilayer PETG film is heated until pliable, then pressure- or vacuum-formed tightly over each printed model. As it cools, the plastic sets into an exact replica of that treatment step. The material choice matters enormously here: it has to stay optically clear, hold corrective force through the day, and remain comfortable in the mouth.

5. Trimming, polishing and finishing

A freshly formed tray is still attached to its model and has rough edges. Technicians trim each aligner along the gumline — by hand or with a trimming machine — following a scallop that balances retention with comfort. Edges are polished smooth so they don't irritate soft tissue, and where the plan calls for it, the tray is punched or shaped for attachments and bite ramps. Good finishing is the difference between a tray a patient tolerates and one they actually wear.

6. Quality control and dispatch

Before anything ships, each tray should go through quality control: a dimensional check that fit deviation is within tolerance (AlignoDontic holds ±0.1 mm), a first-fit verification that the tray seats fully without rocking, and an inspection of edge finish and optical clarity. Passing trays are labelled in sequence, packaged, and dispatched to the clinic with tracking. Only then does the clinic hand the series to the patient.

The clinic controls the treatment; the manufacturer controls the precision. When both are done well, the patient never thinks about either.

How long does it take to manufacture clear aligners?

Turnaround varies by lab and case complexity, but from an approved setup, a well-run in-house line can produce and dispatch a full series in around five working days. Delays usually come from incomplete scans, back-and-forth on the treatment plan, or outsourced steps sitting in someone else's queue — which is one reason clinics increasingly prefer manufacturers that run the entire process under one roof.

See the process built for clinics

AlignoDontic runs every step — planning, printing, thermoforming, finishing and QC — in-house, with an orthodontist reviewing each setup and live case tracking from scan to dispatch.

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