A tool distributor returned 18 cases from a single pallet, all split at the same corner. The cases had been formed from 2 mm ABS at a 4 mm corner radius, 120 mm deep. Nothing was wrong with the material; the geometry had asked the sheet to do something it could not do.
ABS sheet for tool cases is a deep-draw problem first and a material problem second. Get the draw and the radius right, and a 2.5 mm textured sheet will outlast a 4 mm sheet formed badly.
ABS sheet for tool cases: thickness and draw limits
- 2 mm: cases up to 300 mm, shallow draws, light contents
- 2.5 mm to 3 mm: the common case shell, draws to 150 mm
- 4 mm: flight cases and heavy tool loads
- Corner radius: at least 5 mm, 8 mm preferred on 3 mm sheet
The draw ratio is the number that governs failure. A wall that starts at 3 mm and ends at 1.8 mm at the base corner has lost 40 percent of its thickness, and that is where a drop test breaks it. Keeping the draw under about 1.5 times the width, with generous radii, keeps the wall above 2 mm.
Forming temperature for ABS sits around 150 C to 170 C sheet surface. Too cold and the sheet whitens at the radius; too hot and it sags before the vacuum pulls. A textured sheet hides the early signs of both, which is why forming trials matter more than the specification.
Hinges, latches and the reinforcement that saves a case
Hinges and latches concentrate load. A latch screwed directly into a 2.5 mm formed wall will crack the shell within a season. The professional detail is a local reinforcement: a bonded or riveted plate, or a formed rib, spreading the load over 40 mm rather than 8 mm.
Low temperature is the other service condition. Standard ABS impact strength falls sharply below minus 20 C, so a case left in a van overnight in winter behaves differently from one tested in a workshop. If the case will live in a cold climate, specify a high-impact grade and test a formed sample in a freezer before the tool is cut.
Surface texture earns its keep. A fine matte texture hides scuffs that would show on a gloss shell, and it also helps release from the mould. For a printed or laminated finish, note that the texture must be taken into account in the artwork, and our ABS wholesale guide covers the standard colours and textures available.
Cost control is straightforward once the geometry is fixed: sheet price scales with thickness and colour, and the ABS price per sheet guide explains how volume and texture affect the figure.
For cases that will be cut rather than formed, the ABS cut-to-size guide covers saw and router settings that avoid a melted edge.
Send your case drawing, load and drop requirement to oversales@rpplexiglass.com for a formed shell quotation.
Frequently Asked Questions
What thickness ABS for a tool case?
2 mm to 2.5 mm for small cases up to 400 mm, 3 mm for mid-size cases, and 4 mm for flight cases or cases that will be dropped loaded. The draw depth and the corner radius decide more than the area.
Why do ABS cases crack at the corners?
Over-drawing at a tight radius thins the wall and locks in stress. A corner radius below about 5 mm on a 3 mm sheet is a crack waiting to happen. Warm the mould and keep the draw within limits.
Can ABS cases be made at low temperature use?
Standard ABS gets brittle below about minus 20 C. For cold-climate use, specify a high-impact or low-temperature grade, and test a formed sample at the service temperature rather than relying on the data sheet.