Under Mathews Engineering’s JLCPCB test video, one viewer vented about a marketplace order. After two weeks, he heard the printer wasn’t big enough for his part. The parts got sliced in half, and then broke before they shipped. His question: is there any way to know up front that the shop has a big enough printer? There is, and it starts with MJF build volume.
What is the MJF build volume on common machines?
HP’s Jet Fusion 5200 brochure lists an effective building volume of 380 x 284 x 380 mm. For comparison on the SLS side, Formlabs lists 165 x 165 x 300 mm for the Fuse 1 and Fuse 1+ 30W, and 330 x 330 x 565 mm for the Fuse X1.
Those are maximums for the whole build. A part anywhere near them is worth a question before you assume it fits, and a marketplace order may land on a smaller machine than you’d expect.
When is splitting the part the right call?
Sometimes it’s the only call. HP’s design guide on adhesive bonding opens with exactly this case: some big parts don’t fit the build chamber of HP Jet Fusion printers, so they’re split and re-assembled after printing.
It gives a second reason, too. Splitting can raise packing density. In a Henkel example HP cites, splitting a box into five sub-components fit 20 boxes in the build instead of 12, a 67% increase.
Why did the viewer’s split parts break?
I can’t know from one comment. HP’s guide does say bond strength depends heavily on how the part was split and how the joint is designed, and that joints should be cut so they see shear or compression, not peel or cleavage. A part cut wherever it happens to fit the machine doesn’t get that thought.
What should you ask before ordering?
Send the bureau the part’s bounding box and ask three things in writing: which machine it’ll run on, whether it fits whole, and if not, where they’d split it. If they plan to split, ask to approve the cut line before printing, since that’s where the part will fail if it fails.
Related on the Solvi blog: MJF Packing Density: How Full Should You Pack a Build?; MJF Warping: Why Large Flat Parts Warp; MJF Tolerances: Clearance for Holes and Nut Pockets.
Sources: YouTube: JLCPCB 3D printing service test run (Mathews Engineering), viewer comment; HP Jet Fusion 5200 Series brochure (PDF); Formlabs Fuse series tech specs; HP MJF handbook: Adhesive bondings, union joint design (PDF).