3D printers have become quite popular. Different materials like metal powder, plastic powder or other work pieces that are built in layers with a laser or other construction parts are being built. There are continuous enhancements like regularity of flow distribution on and around the printing plate and the use of other gases.

Different things influence material properties by melting the material in combination with the gas. The lighter the gas becomes the more important are process by-products such as splashes and smoke and the question whether the gas transports these undesired by-products sufficiently away. Another important factor is making sure the laser source is clean because even one grain of dust on the protection glass can cause melting and therefore destroy it. Therefore an even flow across the entire building board is desired.

For some tests a vane wheel sensor ZS25 was built into an existing frame and the corresponding handheld unit put into the building space; to reduce the risk of contamination it was covered in a transparent packaging. The printer version „Glove Box“ as a hermetically shielded space with access through gloves, the vane wheel could be moved within the frame across the length of the building plate and record the velocity profile. With other customers or manufacturers, like operators of 3D printers with metal and plastic powders vane wheel sensors were built into the mobile frames.  That way the interior does not have to be rinsed with the gas that’s being tested before each measurement as the sensor can be moved without opening. Recording measuring range is few millimeters up to about 30 mm above the printing plate.
Vane wheels ZS25 and ZS30 cover this area pretty well. The version with aluminium or titanium vane wheels can start measuring at 0.2 m/s. Specific starting values of the different gases can be compensated with the density correction in the handheld unit. For flow analysis above the printing plate vane wheels with flow direction sensing are suitable to detect changes in the direction of flow.