How much cheaper is thermoforming tooling than injection mould tooling?

Typically 5-20× cheaper. A single-sided aluminium thermoforming tool for a large enclosure runs €1,500-8,000 where a comparable injection mould costs €20,000-80,000+. The gap exists because thermoforming tools see only vacuum and plug pressure, not hundreds of bar of injection pressure.

At what volume does injection moulding beat thermoforming?

Usually between 500 and 5,000 parts per year for large parts, earlier for small ones. Thermoformed parts cost €15-150 each with trimming; equivalent moulded parts drop to €5-40 at volume. The expensive mould crosses the cheap forming tool once the per-part saving multiplies past the tooling gap.

Can thermoformed parts have ribs, bosses or inserts?

No — thermoforming stretches a heated sheet over a mould, so it produces shell geometry only: no ribs, no bosses, no moulded-in threads, no inserts, no snap-fits. Those features must be bonded or fastened on afterwards as secondary operations. Injection moulding forms them all in the same cycle.

How uniform is wall thickness in each process?

Injection moulding holds wall thickness within roughly ±0.1 mm because the cavity is machined steel on both sides. Thermoforming stretches the sheet, so walls thin 30-70% in deep draws and corners; a 3 mm sheet can end below 1 mm at a deep corner. Structural features cannot rely on nominal sheet thickness.

What tolerances can each process hold?

Injection moulding holds ±0.05-0.2 mm depending on feature size, repeatable across the series. Thermoforming holds ±0.5-1.5 mm typical, with trimming defining the critical edges at ±0.2-0.5 mm. Assemblies with snap features, bearings or sealing surfaces generally require moulding.

Which parts are classic thermoforming applications?

Large, shallow, single-shell parts at low-to-medium volume: machine guards, vehicle interior panels, trays, bathtubs, kiosk and equipment enclosures, refrigerator liners. Once the part needs ribs, fastening features, tight tolerances or two finished surfaces, the economics and physics both move to injection moulding.

Injection Moulding vs Thermoforming: Tooling Cost, Features & Part Economics

Both processes make hollow plastic parts, but from opposite directions: thermoforming stretches a heated sheet over a one-sided tool, while injection moulding fills a two-sided steel cavity. Thermoforming tooling costs 5-20× less and wins for large, simple shells at low volume; moulding costs more upfront and wins whenever the part needs features, precision or real volume. The crossover usually sits between 500 and 5,000 parts a year.

How do the two processes compare?

Factor	Thermoforming	Injection moulding
Tooling cost	€1,500-8,000 (single-sided aluminium)	€20,000-80,000+ for the same envelope
Per-part cost	€15-150 including trimming	€5-40 at volume
Typical break-even	Wins below ~500-5,000 parts/yr	Wins above, gap widening with features
Wall thickness	Thins 30-70% in draws; unpredictable corners	Uniform, ±0.1 mm, designed in CAD
Ribs, bosses, inserts	Not possible — bonded on afterwards	Formed in the same cycle
Finished surfaces	One side (mould side)	Both sides
Tolerances	±0.5-1.5 mm; trimmed edges ±0.2-0.5 mm	±0.05-0.2 mm on critical features
Materials	Sheet: ABS, HIPS, PC, PETG, PMMA, HDPE	Thousands of grades including GF and FR compounds
Lead time	2-4 weeks for tooling	6-12 weeks for production tooling
Best part types	Large shallow shells, guards, trays, liners	Feature-rich housings, structural parts

Why is thermoforming tooling so much cheaper?

A thermoforming tool shapes one surface of the part with vacuum — around 1 bar of pressure. It can be cast or machined aluminium, temperature-controlled but not hardened, and needs no ejection system, no runner system and no clamped second half. An injection mould must withstand 400-1,500 bar of cavity pressure cycle after cycle, so it is hardened steel, two precision halves, cooling channels, ejection and gating. That is where the 5-20× tooling gap comes from.

The consequence for budgeting: thermoforming is a low-commitment process. A €3,000 tool that turns out wrong is a lesson; a €50,000 mould that turns out wrong is a crisis. Programmes with uncertain demand or evolving geometry often form the first thousand parts while the design settles, then cut the mould.

How do wall thickness and features differ?

Sheet stretching is thermoforming's physics and its limit. A 3 mm sheet drawn 150 mm deep into a corner may arrive at 1 mm or less there — the wall is a consequence of geometry, not a design choice. Injection moulding machines the wall into both halves of steel, so a 2.5 mm wall is 2.5 mm everywhere, and the wall thickness guide applies literally.

Features decide most comparisons on their own. Ribs, bosses, snap-fits, moulded threads, inserts and living hinges cannot be formed from a sheet; each must be added by bonding, riveting or fastening afterwards, adding labour, failure modes and cost per part. If your enclosure drawing shows more than a couple of ribs and bosses, thermoforming's tooling saving is usually eaten by secondary operations before the volumes even matter.

What about tolerances and assembly interfaces?

A formed part shrinks and warps as the sheet cools against one-sided tooling, so ±0.5-1.5 mm is realistic, with CNC trimming pulling the critical edges back to ±0.2-0.5 mm. That suffices for covers and guards that bolt onto a frame with slotted holes. It does not suffice for parts that locate bearings, seal against gaskets, or snap together — those interfaces want moulding's ±0.05-0.2 mm and, above all, its repeatability across the series.

Surface quality follows the tooling: the mould side of a formed part is good, the free side shows sheet texture and any sheet defects. Moulding finishes both faces from the steel, which is why visible two-sided parts — bezels, handles, consumer enclosures — are moulded almost without exception.

Which economics favour each process?

Run the same break-even arithmetic as any tooling decision. A 600 × 400 mm equipment cover: thermoformed at €45 each on a €4,000 tool, or moulded at €18 each on a €48,000 tool. The €27 per-part gap repays the €44,000 tooling delta at about 1,630 parts. Below that, forming wins on cash; above it, moulding wins — and if the cover needs six bosses and two snap rails, forming never wins, because the secondary operations add €10-20 per part at any volume.

Nordmould's free DFM review settles the question on your actual geometry: send the enclosure STEP file and the review returns a transparent quotation with tooling and per-part pricing, the break-even volume against your current process, and a T1 sampling plan to validate fit and finish before series release.

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Send Nordmould your enclosure STEP file — the free DFM review returns the moulding-vs-forming break-even, a transparent quotation and a T1 sampling plan.