Under Fictiv’s MJF vs SLS comparison, a viewer listed what they thought SLS still did better. One point stood out: “what if we ask for white part, can MJF do that?” Another viewer replied that MJF can do white parts now, but that in the UK at least barely anyone runs that setup. Both halves of that are worth knowing if you quote white MJF parts.
Can HP print white MJF parts?
Yes, on HP’s dedicated white system. Standard MJF PA12 comes out gray because the fusing agent is dark. HP’s answer is the Jet Fusion 5420W with HP 3D High Reusability PA 12 W, marketed for “consistent white” from first part to last. HP’s product page for it now also points to the newer Jet Fusion 5400. Users featured there include an orthotics maker and a cast maker, and white is a big deal in healthcare devices.
Are the parts as strong as gray PA12?
Close. HP’s white paper for PA 12 W on the 5420W, in the Balanced print mode, reports tensile strength of 49 MPa in XY and 45 MPa in Z, with elongation at break of 17% XY and 9% Z. HP’s standard PA12 datasheet lists 48 MPa in both directions, with 20% and 15% elongation. The white paper also says PA 12 W supports up to 75% powder reusability.
So white gives up a little Z elongation on paper. For a housing, that rarely matters. For a snap-fit loaded in Z, it might.
Why don’t more bureaus offer it?
It’s a separate machine and a separate powder. A shop with gray 5200s can’t just load white powder. HP lists the 5420W as its own printer, so offering white means buying and filling another line. That’s why the reply under the video rings true.
What else does white get you?
Color. HP’s page pitches white parts as a base for brighter dyed finishes and better light refraction, with DyeMansion dyeing and vapor smoothing shown on several case studies. Gray parts dyed black hide the base color; white doesn’t hide anything, which is the point.
Before you promise a customer white, ask your bureau for a sample off their 5420W and a dye swatch in the color they want. Then put it next to a white SLS part under the customer’s lights.
Related on the Solvi blog: SLS Nylon Yellowing: Why White Parts Turn Yellow; Should You Dye MJF Parts Black or Vapor Smooth Them?; MJF vs SLS Parts: What Should a Bureau Tell Customers?.
Sources: YouTube: Multi Jet Fusion vs SLS nylon (Fictiv), viewer question and reply; HP Jet Fusion 5420W product page; HP white paper: HP 3D HR PA 12 W mechanical properties (PDF); HP 3D High Reusability PA 12 datasheet (PDF).