What Wall Thickness Can a Thin Wall Burner Liner Hold?

A 1.8 mm wall is the working thickness for this thin wall burner liner, and 1.5 mm is the local minimum at window frames and stiffening ribs. A 1.0 mm wall has not been used here, because distortion and powder removal both get harder below 1.5 mm.

What thin wall thickness can a burner liner hold?

1.5 mm is the practical floor for a GH3536 burner liner built in a 250 mm chamber; the alloy is the nickel-chromium-iron-molybdenum grade listed in ASTM B435. At that thickness, a 40 µm layer and a 285 W laser still produce a continuous wall, but the process window narrows: every overhang needs support and the scan path must avoid long unsupported spans.

The nominal thin wall is 1.8 mm. That is 0.3 mm above the floor and leaves room for the ±0.9 mm profile band applied at final inspection. The extra thickness is not cosmetic; it keeps the wall inside the band after solution treatment and hot isostatic pressing.

Powder removal sets a second floor. A 1.5 mm wall with 0.6 mm cooling holes clears at 0.2 MPa, but a 1.0 mm wall traps powder in the same passages and the endoscope check becomes unreliable.

Wall thickness is measured on the finished part, not on the powder bed. A blue-light scan compares the outer and inner surfaces against CAD, and a check on the opening edges confirms that the wall has not thinned during machining.

Thin walls also move during machining. We leave 1.0 mm on the flange faces and 0.4 mm in the holes, and clamp the liner at 0.5 MPa or less with soft jaws and a plaster fill. A heavier clamp will spring a 1.8 mm wall before the cutter reaches it.

Where does a 1.8 mm wall need local thickening?

A burner liner thickens at load paths, not everywhere. The bottom flange, the three window frames and the bolt bosses run at 3 mm, because each carries a bolted joint or a quartz window seat.

The window frames also get a 3 mm land around each opening. The land gives the machining pass something to cut and keeps the frame from springing when the opening is finished.

Tie bars are a temporary thickener. Three 3 mm bars bridge the openings during printing and solution treatment, then are cut away. They are not part of the delivered wall.

The added metal has a cost. Each thickened land is a slower scan and a heavier part, so the design keeps 3 mm only where a bolt, a window or a machining cut needs it.

When does a thin printed wall stop being safe?

Below 1.5 mm the answer is no for a burner liner of this geometry. The wall loses stiffness faster than it loses weight, distortion after solution treatment exceeds the 0.3 mm opening limit, and powder removal stops being verifiable.

A pressure boundary is also out of scope. The liner carries no seal, so the wall is sized by handling and thermal distortion, not by hoop stress. A pressure vessel at the same thickness would need a different design and a different test.

Sheet metal is the alternative below about 1.0 mm. A 0.8 mm formed shell can be made, but it needs welded window frames, and the welds reintroduce the distortion the printed wall avoids.

The same limit applies to any alloy. A thin wall that prints in GH3536 at 1.5 mm will not necessarily print at 1.5 mm in a crack-sensitive grade, and the design rules for thin-wall superalloy parts cover that difference.

Inspection follows the same logic. The wall is checked on the blue-light scan, the opening edges on the CMM, and the M4 thread with a go/no-go gauge. A 1.8 mm wall does not get its own ultrasonic scan, because the liner has no internal feature that needs one.

Send the wall thickness, the window layout and the gas temperature. We will confirm the local thickening and the powder-removal path, and quote the printed liner through our superalloy 3D printing route.