How AO Metal printing works — a step-by-step guide

Dress for powder before you open anything.

Metal powder for LPBF is finer than flour. Anyone who opens a container, the chamber or the sieve wears a respirator, nitrile gloves and a disposable suit or lab coat, and the room is kept clean of dust.

• Titanium and aluminium powders are combustible: keep ignition sources away and clean up only with a vacuum rated for metal powder.
• Ground the printer and the sieve, and keep containers closed when they are not in use.
• Every powder order ships with its safety data sheet.

Five minutes of checks save a failed build.

1. Chiller filled with deionised water and running without alarms.
2. Argon cylinder open, with enough gas for the whole job.
3. Waste container empty and sealed.
4. Recoater blade clean and undamaged; replace it if it is nicked.
5. Enough sieved powder in the dispenser for the build height.

Sieve before every build.

New powder goes through a sieve before it enters the printer, and so does every batch recovered from a previous build. Sieving removes agglomerates and spatter, so each layer spreads evenly and the part density stays consistent.

• Stack the sieves on the shaker, pour the powder in the top and run it.
• Collect the fine fraction for printing; the coarse fraction is set aside.
• Store sieved powder in a sealed container until it goes into the dispenser.

A-Powder metal powders for AO Metal printers

Clean chamber, level plate, full dispenser.

The build chamber is cleaned of powder from the last job, the build plate is installed and brought level with the recoater, and the dispenser is filled with sieved powder. On the A100 this work is done through the glove ports, so the chamber stays closed.

• Remove leftover powder from the chamber floor, the recoater and the plate area.
• Install the build plate and set its height to the recoater blade.
• Fill the dispenser and run a test dose to see an even layer.

Place the parts, add supports, set the parameters.

In AO Build Slicer you load the 3D model, place it on the plate, raise it slightly and add supports under overhangs. Then you choose the parameter set for your alloy: laser power, scan speed, hatch spacing, layer thickness and scan strategy. Every value is open, so you can start from our recommended set and tune it.

• Overhangs below about 40° from the plate need supports.
• Supports around the edges of a part hold it to the plate while it cools.
• Send the finished job to the printer from AO Build Studio.

The laser fires only in an inert atmosphere.

With the chamber closed, argon flows in and pushes the air out. The build starts once the oxygen reading has dropped below the threshold for printing. The flow continues through the whole job and carries away the fumes from the melt pool.

Recover the powder, uncover the parts.

When the build has cooled, the loose powder around the parts is brushed toward a vacuum nozzle inside the chamber, the plate is raised and the remaining powder is vacuumed off to reveal the parts. The recovered powder is sieved (step 03) and goes back into a sealed container for the next job.

• Use a vacuum rated for metal powder, never a household one.
• Empty the waste container after every job and keep its seal in place.

Cut, remove supports, finish.

The parts are welded to the build plate, so they come off by wire EDM or with a band saw. Supports are then removed, and depending on the alloy and the application the parts are stress-relieved or heat-treated, machined and polished. The build plate is resurfaced and used again.

• Stress relief before cutting reduces distortion on larger parts.
• Heat treatment depends on the alloy; each A-Powder page lists the manufacturer's data.