{"id":74020,"date":"2025-09-02T16:46:15","date_gmt":"2025-09-02T08:46:15","guid":{"rendered":"https:\/\/xometry.asia\/?p=74020"},"modified":"2025-09-02T16:46:19","modified_gmt":"2025-09-02T08:46:19","slug":"mjf-3d-printing-design-tips-9-best-practices","status":"publish","type":"post","link":"https:\/\/staging-wp.xometry.asia\/en\/mjf-3d-printing-design-tips-9-best-practices\/","title":{"rendered":"MJF 3D Printing Design Tips: 9 Best Practices"},"content":{"rendered":"\n

Hi, I\u2019m Niko Mroncz, Head of Sales Engineering at Xometry. I\u2019ve been working with 3D printing since 2010, and MJF has always been a go-to process for complex and functional parts. However, without careful design, issues like warping, powder entrapment, or uneven surfaces can still occur. In this article, I\u2019ll share key tips to help you design more reliable, high-performance parts for Multi Jet Fusion 3D printing.<\/p>\n\n\n\n

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Multi Jet Fusion (MJF) is a powder-bed fusion technology developed by HP that uses heat and chemical agents to produce detailed, high-strength plastic parts. Unlike extrusion-based methods, MJF creates dense, isotropic parts with excellent surface finish and mechanical performance, making it well-suited for both functional prototyping and industrial production.<\/p>\n\n\n\n

MJF offers many advantages: fast build speeds, precise detail resolution, and the ability to produce complex geometries without support structures. It is also one of the most cost-efficient options for medium to high-volume production, thanks to its efficient nesting and short cooling times. Common materials include PA 12, PA 11, polypropylene, and TPU\u2014each selected for their durability, flexibility, and heat resistance.<\/p>\n\n\n\n

Nikolaus Mroncz<\/h4>\n\n\n\n

Head of Sales Engineering<\/p>\n\n\n\n

If you want to get high-quality MJF parts, smart design is essential. Many common issues\u2014like warping, powder entrapment, or poor surface finish\u2014can often be avoided by following key design principles. Paying attention to factors such as wall thickness, powder drainage, and part orientation can significantly improve performance and print success, keeping in mind that these are always design-related. Here are the most important design tips for MJF 3D printing.<\/p>\n\n\n\n

1. Maintain Proper Wall Thickness<\/strong><\/h2>\n\n\n\n

Walls that are too thin may deform or become brittle, while overly thick walls can lead to heat accumulation during printing and cause warping or uneven cooling. These problems are especially critical in MJF due to the thermal dynamics of powder-bed fusion. <\/p>\n\n\n\n

Sudden variations in wall thickness can also generate internal stress, impacting dimensional accuracy and structural performance\u2014especially on flat surfaces or large parts.<\/p>\n\n\n\n

Rule of Thumb:<\/strong><\/p>\n\n\n\n

    \n
  • Design walls at least 0.7 mm<\/strong> thick for PA 12<\/strong>, and up to 2.0 mm<\/strong> for more rigid materials.<\/li>\n\n\n\n
  • Walls as thin as 0.6 mm<\/strong> are possible with internal support, but 1.3 mm<\/strong> is preferred for consistent results.<\/li>\n\n\n\n
  • Avoid walls thicker than 7 mm<\/strong>, as excess material can cause internal stress and distortion. <\/li>\n\n\n\n
  • Maintain uniform wall thickness<\/strong> across the part to reduce warping risks.<\/li>\n\n\n\n
  • Add ribs or fillets<\/strong> to reinforce thin areas and distribute stress more evenly.<\/li>\n<\/ul>\n\n\n\n

    2. Reinforce Long and Thin Features<\/strong><\/h2>\n\n\n\n

    Slender features like cantilevers, hooks, or clips are particularly vulnerable in MJF. Without proper reinforcement, they may bend, snap, or warp due to unsupported geometry or concentrated stress.<\/p>\n\n\n\n

    This risk increases with high aspect ratios or sharp transitions, especially in the Z direction, where MJF parts are more exposed to uneven heating and cooling.<\/p>\n\n\n\n

    \"Design<\/figure>\n\n\n\n

    Rule of Thumb:<\/strong><\/p>\n\n\n\n

      \n
    • For cantilevers with width < 1 mm<\/strong>, keep the aspect ratio (L\/W) < 1<\/strong>.<\/li>\n\n\n\n
    • Use a minimum cantilever base thickness of 1 mm<\/strong> for durability.<\/li>\n\n\n\n
    • Add fillets or ribs<\/strong> at stress points or extended features.<\/li>\n\n\n\n
    • Avoid sharp edges and use smooth, gradual transitions<\/strong> to minimize mechanical stress.<\/li>\n<\/ul>\n\n\n\n

      3. Optimize Hollow and Internal Structures<\/strong><\/h2>\n\n\n\n

      Enclosed spaces such as hollow bodies, ducts, or lattices tend to trap unfused powder. Without proper drainage, the trapped material increases part weight and complicates post-processing, especially for complex geometries. If unaddressed, this can lead to poor surface quality or blocked ducts\u2014making the part unusable or harder to clean.<\/p>\n\n\n\n

      Rule of Thumb:<\/strong><\/p>\n\n\n\n