Multi Jet Fusion (MJF)

Process Details

Printer Type:

HP MJF Multi Jet Fusion is a process in which parts are built by thermally fusing polymer powders, layer by layer, using infrared light. An inkjet head spreads a fusing agent on specific areas of each layer to promote light absorption and fuse the powder, while also spraying a detailing agent that prevents fusion beyond the part boundaries.
The self-supporting powder eliminates the need for support structures and allows stacking parts to utilize the full build volume. This lowers the cost of each individual part, so MJF generally offers the best production cost among 3D printing technologies.

Visual Aspect: 

HP MJF produces dense parts with low porosity and fine details. While not fully isotropic, MJF parts have excellent mechanical properties. Standard color is gray but an optional post-processing dyeing step can be applied to achieve a uniform black finish

Capabilities

Bounding Box:

Parts must fit within a bounding box measuring 15" x 11.2" x 15" (380 mm x 284 mm x 380 mm)

Resolution:

The MJF inkjet head has a XY resolution of 1,200 dpi. The powder has a particle size of .0024" (60 µm) and the layer thickness reaches .0031" (80 µm).

Accuracy:

+/- .005” (125 µm) for the first inch and +/- .002” for each additional inch (+/- 2 µm/mm). Part geometry, thickness, and orientation can affect tolerances.

Availability:

Lead times will be indicated in your instant quote, typically 2 days.

Materials

Product Range: 

  • PA12 is a robust thermoplastic which produces high-density parts with balanced property profiles, strong structures, and excellent chemical resistance to oils, greases, aliphatic hydrocarbons and alkalies.
  • PA12GB is reinforced with 40% glass beads for higher stiffness and dimensional stability.
  • ESTANE 3D TPU M95A from Lubrizol  is ideal for applications that require elasticity, increased elongation at break, abrasion resistance and compression.


Biocompatibility:

PA12 and the HP Fusing and Detailing Agents and PA12 powder meet the FDA USP Class I-VI requirements for Intact Skin Surface Devices. They pass ISO 10993-5, -10 and -11.
Lubrizol ESTANE 3D TPU has passed skin sensitization and cytotoxicty tests in accordance with ISO 10993-5 and 10993-10.

Design Guidelines

Wall Thickness: 

We recommend maintaining a wall thickness between .039" (1 mm) and .787" (20 mm) to prevent sink marks. Thinner sections are possible for living hinges and short walls (detailed design guidelines are available in your customer portal.)

Hole dimensions:

Minimum hole diameter .039" (1 mm)

Geometry:

Additional design guidelines are available on your customer portal. We provide free DFM feedback on your designs.

Applications

Benefits: 

HP PA12 and PA12GB 3D printing materials are ideal for applications that require strength and detailed geometries while accepting a slight surface roughness (due to the powder grain size). TPU is ideal for soft/flexible parts and has a good resistance to tear and abrasion.

Target markets:

Fixtures, tooling, enclosures, housings, hard or soft mechanical components, wearables.

Recommended Resources

HP MJF PA 12 material datasheet

PA12 technical specifications

HP MJF PA12 Glass Beads material datasheet

PA12GB technical specifications

Lubrizol  Estane 3D TPU M95A material datasheet

TPU technical specifications

Design and printing guidelines

Everything you need to know about file preparation, minimum feature dimensions, geometries, wall thickness and mechanical properties optimization.

Designing for HP Multi Jet Fusion:

10 Tips You Need to Know

This presentation provides an overview of the MJF printing technology followed by 10 tips to help you get the best printing results (tips include design and printing topics)

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