Custom Tank Covers Thermoforming in PMMA acrylic for Aerospace Interiors at 3 mm

Vacuum formed tank covers are used across aerospace interiors because they can be produced without the tooling spend of injection moulding and without the weight of sheet metal. This page covers how 3 mm PMMA acrylic sheet is formed for aerospace interiors, what tolerances are realistic, and what has to be on the drawing before tooling starts.

The route below is the one used for most of the tank covers shipped from this plant: sheet is heated on the forming machine, drawn over an aluminium or composite mould, cooled on a jig, then trimmed on a 5-axis router. For tank covers the sheet gauge is selected from the load case rather than from habit, and PMMA acrylic is the material most often specified for this combination.

Typical specification

Where these parts are used

• galley liners for aerospace interiors
• lavatory panels for aerospace interiors
• seat back shells for aerospace interiors
• stowage bin trays for aerospace interiors
• tank covers in general aerospace interiors builds

How the part is made

1. Drawings are reviewed and a manufacturability report is issued with wall thickness, draft and radii marked up.
2. Tooling is cut: aluminium for production volumes, composite or printed moulds for samples and first articles.
3. Sheet is dried when the material needs it, then heated to forming temperature on the machine.
4. The sheet is formed over the mould with vacuum and, where the draw is deep, with plug assist.
5. The part cools on a jig so the shape is held while the material stabilises.
6. Trimming is done on 5-axis routers or with a dedicated trim fixture to meet the drawing.
7. Parts are inspected, fitted with inserts or hardware if required, packed and shipped.

Material notes: PMMA acrylic

PMMA gives the glossiest surface and the best UV stability, which is why it is used for light housings and outdoor sign faces.

Design tips for this part

• keep a draft angle of at least 3 degrees on vertical walls so the part releases cleanly
• hold the draw ratio near 1:1 for deep parts, or specify plug assist
• add ribs or returns instead of increasing sheet thickness to save weight and cycle time
• call out the finish on the drawing: mould texture, paint, or as-formed gloss
• plan the trim line on a flat face so the router can hold tolerance

Quality and inspection

Sheet thickness is checked on the formed part at the points shown on the drawing, and the readings go into the report. First article inspection covers critical dimensions, wall thickness, colour and texture against the approved sample.

Cost and lead time

Tooling is the main cost driver at low volume, so a 3 mm tank covers for aerospace interiors is usually quoted with a composite or printed mould first and the aluminium tool cut once the design is frozen. That keeps the first article cost low and gives a real part to test before the production tool exists. The result is lighter weight compared with the alternatives, and a piece price that stays stable across repeat releases.

• Sample tooling: 7–15 working days
• Production tooling: 3–4 weeks
• Repeat orders run on stored tooling with no new proving run

Frequently asked questions

What quantities make sense?

Vacuum forming pays off from roughly 25 pieces up to several thousand a year. Below that, printed or composite tooling keeps the setup cost low.

Do you supply certificates?

Material certificates, dimensional reports and flame retardancy or food contact declarations are issued with the shipment where the specification requires them.

How long does tooling take?

Sample and first article tooling is usually cut in 7 to 15 working days. Production aluminium tools take 3 to 4 weeks depending on size and cooling layout.

Getting started

Send the drawing or a photo of the current tank covers with the quantity and the finish. The first reply is a manufacturability review with the wall thickness, material and a quotation, so the decision is made on facts rather than on a price alone.