If you’re in product design, industrial manufacturing, or prototyping, choosing between HP Multi-Jet Fusion (MJF) and Selective Laser Sintering (SLS) 3D printing technologies can feel overwhelming. Both excel at printing with polymers and elastomers, create complex parts without supports, and deliver durable results—but their differences in materials, speed, cost, and part quality make them better for specific tasks. This guide breaks down everything you need to know to pick the right one for your project.
What Are MJF and SLS 3D Printing Technologies?
First, let’s start with the basics. Both MJF and SLS are powder-based 3D printing technologies—they use fine plastic or elastomer powders to build parts layer by layer. The key difference lies in how they melt (sinter) the powder to form solid layers.
HP Multi-Jet Fusion (MJF) 3D Printing
MJF (HP Nylon Multi-Jet Fusion) is a newer technology, commercialized in 2017. Here’s how it works:
- The printer spreads a thin layer of powder (usually nylon) onto a build platform.
- It heats the powder to near-sintering temperature (just below melting point).
- An inkjet array sprays two liquids: a melting agent (on areas that need to become solid) to boost infrared light absorption, and a refiner agent (on part edges) for sharpness.
- An infrared light source scans the entire layer, sintering only the areas with melting agent.
- The platform lowers, a new powder layer is added, and the process repeats until the part is done.
MJF’s claim to fame? It’s fast—especially for high-volume production—and produces consistent parts with smooth surfaces.
Selective Laser Sintering (SLS) 3D Printing
SLS (Selective Laser Sintering) is a more established technology, patented in 1997. Its process is straightforward:
- A thin layer of powder is spread onto the build platform.
- A high-power CO₂ laser scans the layer, sintering the powder into the shape of the part’s cross-section (from a 3D CAD model).
- The platform lowers, a new powder layer is added, and the laser sinters again.
- This repeats until the part is fully formed.
SLS is loved for its material versatility—you can print with everything from nylon to glass-filled polymers—making it ideal for custom or specialized parts.
Key Similarities Between MJF and SLS
Before diving into differences, let’s highlight what MJF and SLS have in common—these are the reasons both are top choices for polymer 3D printing:
- Powder-based: Both use thermoplastic or elastomer powders, so there’s no need for support structures (unlike FDM or SLA). This lets you print complex geometries like hollow parts or interlocking components.
- Layer-by-layer building: Both build parts one thin layer at a time, ensuring precision for detailed designs.
- Durable end parts: Parts from both technologies are strong enough for functional use (e.g., gears, brackets) or prototypes that mimic final products.
- Thermoplastic focus: Both mainly use materials like nylon (PA 11, PA 12) and TPU (thermoplastic polyurethane), though SLS has more options.
Example: A medical device maker could use either MJF or SLS to print a custom nylon surgical tool handle—both would create a strong, sterilizable part without supports.
MJF vs. SLS: Detailed Comparison
To help you decide, let’s break down their differences across 7 critical factors: materials, speed, part quality, cost, recyclability, size, and surface finish. We’ll use tables and real data for clarity.
1. Material Options
Material choice often dictates which technology you use. SLS has a huge edge here, thanks to its longer history.
| Technology | Available Materials | Key Notes |
| MJF | PA 11 (nylon), PA 12 (nylon), TPU (elastomer) | Limited options—only a few materials are certified for MJF (mostly HP-branded powders). |
| SLS | PA 11, PA 12, PA 12 Glass-Filled, PEBA 2301 3D (flexible), Alumide (aluminum-filled), TPU | Wide range—great for parts that need extra strength (glass-filled), flexibility (PEBA), or metal-like properties (Alumide). |
Real-World Case: An aerospace company needs a lightweight, heat-resistant part. They choose SLS with PA 12 Glass-Filled (which SLS supports) because MJF doesn’t offer glass-filled materials—this part can withstand high temperatures in aircraft engines.
2. Processing Time
Time matters, especially for production runs. MJF is faster, but the gap narrows for single parts.
| Scenario | MJF | SLS |
| Single part | ~Same time as SLS (e.g., 2 hours for a small bracket). | ~Same time as MJF. |
| High-volume production | Much faster. Can print 50+ small parts simultaneously (e.g., 100 phone cases in 8 hours). | Slower. Prints fewer parts at once (e.g., 100 phone cases in 12 hours). |
| Total process (print + cooling) | Faster. MJF has a detachable build platform—parts cool outside the printer while the next job starts. | Slower. Parts must cool inside the printer (takes extra hours), delaying the next run. |
Example: A consumer electronics brand needs 500 custom nylon headphone earcups. They use MJF—total time is 30 hours, vs. 45 hours with SLS. This lets them launch their product 1 week earlier.
3. Part Quality: Accuracy, Strength, and Finish
Both make high-quality parts, but there are subtle differences that matter for specific projects.
Dimensional Accuracy & Resolution
| Technology | Feature Resolution | Max Part Size | Min Feature Size |
| MJF | Very high (sharp edges), but slightly lower than SLS. | 380 x 284 x 380 mm (about the size of a small microwave). | 0.5 mm (can print tiny details like thin ribs). |
| SLS | Slightly better (finer details). | 600 x 350 x 560 mm (about the size of a large cooler). | 0.6 mm (still precise, but not as small as MJF). |
Note: Both can warp if printing large flat surfaces—designers avoid this by adding ribs or curves.
Mechanical Performance
Here’s how MJF and SLS parts compare in strength and durability (using PA 12, the most common material for both):
| Performance Metric | MJF (PA 12) | SLS (PA 12) |
| Tensile Strength (resistance to pulling) | 1700 MPa (X/Y), 1800 MPa (Z) | 1650 MPa (X/Y), 1650 MPa (Z) |
| Tensile Modulus (stiffness) | 48 MPa (X/Y), 48 MPa (Z) | 48 MPa (X/Y), 42 MPa (Z) |
| Elongation at Break (how much it stretches before breaking) | 20% (X/Y), 15% (Z) | 18% (X/Y), 24% (Z) |
| Melting Point | 187°C | 176°C |
What this means: MJF parts are stiffer and stronger in the Z-direction (layer height), while SLS parts are more flexible (higher elongation at break). For example, a SLS-printed TPU gasket would stretch more than an MJF-printed one—great for seals that need to flex.
Surface Finish
| Technology | Surface Texture | Color |
| MJF | Grainy but slightly smoother (like fine sandpaper). | Gray or black (from the dark melting agent)—hard to dye other colors. |
| SLS | Grainy (coarser than MJF). | White or gray—easily dyed to any color (red, blue, black, etc.). |
Case: A toy company wants colorful action figure parts. They choose SLS—they print white parts, then dye them bright red or blue. MJF’s dark parts wouldn’t work for their design.
4. Cost
Cost depends on production volume. For small runs, they’re similar—but MJF shines at scale.
| Production Volume | MJF Cost | SLS Cost |
| Single part | ~Same as SLS (e.g., €15 for a small nylon bracket). | ~Same as MJF. |
| High-volume (1000+ parts) | Lower—MJF prints more parts at once, so per-part cost drops to €8–€10. | Higher—per-part cost stays around €12–€14. |
| Material cost | Slightly higher (MJF-specific powders are often proprietary). | Lower (SLS powders are more widely available from multiple suppliers). |
5. Powder Recyclability
Waste reduction is key for sustainability. MJF is more efficient here.
| Technology | Powder Recovery Rate | Notes |
| MJF | Up to 80% | Unused powder can be mixed with new powder for future prints, cutting waste. |
| SLS | 30%–50% | More powder is contaminated during printing, so less can be recycled. |
Example: A sustainable packaging company chooses MJF—recycling 80% of their powder saves them €500/month on material costs, compared to SLS’s 40% recovery.
How to Choose Between MJF and SLS
Use this simple checklist to pick the right technology for your project:
| Choose MJF if… | Choose SLS if… |
| You need high-volume production (100+ parts). | You need specialized materials (glass-filled, PEBA, Alumide). |
| Speed is critical (tight deadlines). | You want to dye parts custom colors. |
| You need small, detailed parts (0.5mm features). | You need large parts (over 380mm in any dimension). |
| Sustainability (high powder recyclability) is a priority. | You need flexible parts (higher elongation at break). |
Yigu Technology’s Take on MJF vs. SLS
At Yigu Technology, we see MJF and SLS as complementary, not competing. For clients with high-volume, time-sensitive projects (like electronics manufacturers needing 1000+ brackets), MJF is the clear choice—it’s fast and cost-effective. For clients needing custom or specialized parts (like aerospace firms using glass-filled nylon), SLS’s material versatility is unmatched. We help clients weigh factors like cost, speed, and material needs to pick the best option, ensuring their parts meet quality and budget goals. Whether it’s MJF or SLS, we prioritize delivering durable, precise parts that solve real-world problems.
FAQ:
1. Can MJF or SLS print flexible parts?
Yes—both can print with TPU (thermoplastic polyurethane), a flexible elastomer. However, SLS offers more flexible material options (like PEBA 2301 3D), which stretch further than MJF’s TPU. For super-flexible parts (e.g., phone grips), SLS is better; for moderately flexible parts (e.g., gaskets), MJF works too.
2. Are MJF and SLS parts food-safe?
It depends on the material. Some MJF and SLS nylons (like PA 11) are food-safe if they’re certified (look for FDA approval). However, the grainy surface can trap bacteria, so these parts are best for non-contact food uses (e.g., food packaging inserts) rather than direct food contact (e.g., bowls).
3. How long do MJF and SLS parts last?
Both produce durable parts that last for years—even in harsh conditions. For example, an MJF-printed nylon bracket in a car engine can withstand heat and vibration for 5+ years, while an SLS-printed PEBA part (flexible) can handle 10,000+ stretches without breaking. The lifespan depends on the material and use case, but both outperform 3D printing technologies like FDM for long-term use.
