Why Precision Matters in 3D Printing
Ever printed a part that almost fits? In HP Multi Jet Fusion (MJF) 3D printing, dimensional tolerancing is key to ensuring parts aren’t just visually perfect—but functionally precise. Even small variations can make or break an assembly.
Unlike machining, where parts are carved to precise dimensions, 3D printing builds parts layer by layer, introducing factors like shrinkage, thermal expansion, and powder spreading that can affect final tolerances.
How Accurate Is HP MJF?
HP MJF delivers repeatable precision, typically achieving IT10 – IT12 tolerances—good enough for most engineering applications like enclosures, brackets, and mechanical assemblies.
| IT Grade | Typical Use Case |
| IT5 – IT9 | High-precision machining, tight-fitting components |
| IT10 – IT12 | General engineering fits (HP MJF range) |
| IT13 – IT16 | Loose fits, casting, large components |
What Affects Dimensional Accuracy?
- Material Shrinkage – MJF parts shrink 1-2% after printing.
- Thermal Effects – Heat changes cause minor warping or expansion.
- Post-Processing – Sanding, dyeing, or machining can shift dimensions.
Measuring & Improving Process Consistency
Process Capability (CpkC_{pk}) measures how well a printer holds tolerances. In MJF, a CpkC_{pk} of 1.33 (4 sigma) is ideal, meaning 99.94% of parts meet spec—reducing defects and rework.
How to Improve Tolerances in HP MJF
✅ Compensate for Shrinkage in CAD – Scale up parts 1-2%.
✅ Use Consistent Wall Thicknesses – Uneven cooling = warping.
✅ Optimize Post-Processing – Leave extra material for machining.
✅ Leverage HP’s Process Controls – The Jet Fusion 5200 series offers real-time adjustment for better repeatability jojo siwa magazine cover.
Final Takeaway: Tolerancing Makes the Difference
HP MJF is one of the most precise 3D printing technologies, but dimensional tolerancing still requires smart design and process control.
Want to get the best fit for your MJF parts?
Contact RapidMade at rapidmade.com to optimize your prints today!