If you are working with a completely new powder, creating appropriate print settings from scratch can be challenging, tedious, and risky. Given the hundreds of parameters available and the intrinsic hazards of processing thermoplastic powder, Formlabs recommends identifying an existing print profile in the PreForm print settings library with a similar process window to your new powder and using it as your starting point for print tuning.
When determining whether or not a particular powder will work on a Fuse Series printer, the following factors are key:
Warning:
It is important to understand the safety aspects of the printer, as printing with new materials can come with different risks. Always read the manufacturer’s safety data sheet (SDS) before handling any new materials and follow their instructions, as explosive dust and health hazards are common.
Notice:
Use of Open Material Mode or any third-party material comes with risks, including risk of damage to the printer. Please read the terms of service to understand the risks. Formlabs recommends monitoring the printer during the first print in any given powder.
Thermal behavior of the powder
For a powder to have a chance at working well with a Fuse Series printer, it needs to be possible to melt and re-crystallize the material within the thermal limits of the printer. Fuse 1+ 30W printers are capable of reaching temperatures up to 200 °C. They have no active print enclosure cooling, so they cannot cool the powder below room temperature. While the melting point of your material does not need to be within this range, it is generally recommended that it be close, so that thermal effects such as warpage are minimized.
The best test for this is DSC (differential scanning calorimetry), which generally gives the thermal characteristics of a material with a high degree of repeatability. You will see different behavior depending on the crystallinity of the material, as fully crystalline, semicrystalline, and fully amorphous materials all have slightly different behavior.
Laser absorbance
Fuse Series printers use a 1070 nm laser, which is in the near infrared wavelength range. Your powder will need to be able to absorb this wavelength with enough efficiency to melt and not require so much power that it would begin vaporizing the material at the surface. There is no recommended way to test this outside of the printer, though understanding how different materials absorb light can definitely help inform your choices. For example, carbon black is a well known IR absorber; if it is present in the powder, it may have a better chance of printing successfully.
Physical characteristics of the powder
Powder size and morphology affects the behavior of the powder when dispensing, recoating, and lasing. One of the important properties that stems from this is how flowable a powder is. Typically, the more flowable a powder is, the better. There are several measurements of this, such as angle of repose (the highest angle that the powder sits at when mounded) or powder viscosity (the resistance of a powder to flow, measured on a rheometer). Powder that is not flowable can have difficulty recoating the powder bed, resulting in nonuniform layers. It can also jam the powder hopper so no powder is dispensed at all.
Particle size has a variety of effects, and should generally be around two to three times smaller than your selected layer height. If the particles are too large, single particles can leave print defects from dragging along the powder bed and cause poor packing and density when sintered. If the particles are too small, it will have a higher tendency to aerosolize and will act like an insulative blanket, so the bottom of a layer may not sinter fully.
