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PolyJet and SLA both create parts from light-cured liquid photopolymers, but they work differently. PolyJet jets tiny droplets of resin, much like an inkjet printer, and can combine several materials and colors in one part. SLA uses a laser to cure one resin in a vat, and it is known for smooth, accurate single-material parts.
The simple rule is this: choose PolyJet when a part must combine materials or colors, and choose SLA when you need a detailed single-material part at a lower cost.
How Each Process Works
PolyJet
PolyJet print heads deposit fine droplets of photopolymer across the build platform, and UV lamps cure them immediately. Since heads can jet different materials at the same time, one part can include rigid and rubber-like areas, transparent sections, or full-color regions. PolyJet is associated with Stratasys.
SLA (Stereolithography)
An SLA printer directs a laser into a vat of liquid resin and traces each layer. Supports are usually made of the same resin, and after printing the part is washed and post-cured. Read about SLA alongside other processes in our guide to the types of 3D printing technologies.
PolyJet vs SLA at a Glance
| Factor | PolyJet | SLA |
|---|---|---|
| Material delivery | Jetted droplets | Laser-cured resin vat |
| Typical layer thickness | About 14 to 30 microns | About 25 to 100 microns |
| Multiple materials in one part | Yes | Generally no |
| Color capability | Multi-color and full-color systems | Usually one color per print |
| Support removal | Gel-like support, often water jetted or hand-cleaned | Same-resin supports, removed by hand |
| Surface finish | Very smooth | Very smooth, small support marks |
| Typical cost | Usually higher | Usually lower |
| Long-term use | Mainly visual and prototype parts | Depends on resin; engineering grades available |
Specifications vary by machine and material, so use the manufacturer's datasheet for any critical decision.
Accuracy and Detail
Both processes can produce excellent results, and published comparisons do not fully agree on which is more accurate. PolyJet can run very thin layers, while SLA is highly regarded for accurate single-material geometry. Real results depend on part size, material, machine calibration, and post-processing.
If a dimension is critical, ask your supplier what tolerance they can achieve on that exact feature.
Materials and Multi-Material Capability
This is PolyJet's clearest advantage. A single print can mix hard and soft regions, which is useful for overmold simulations, grips, seals, medical models, and realistic product prototypes.
SLA machines usually print one resin at a time. However, SLA offers a good range of tough, flexible, castable, high-temperature, and dental resins. If you need one specific property across the whole part, SLA may offer a better match.
Strength and Durability
Neither process should be selected for high-strength end-use parts without testing. Photopolymers can be sensitive to prolonged UV exposure, and many standard materials are not intended for long-term structural loads. Engineering SLA resins can be strong options for some functional uses, but always compare the material datasheets rather than the process name. For more on this, read our materials guide.
Cost Comparison
PolyJet machines and proprietary materials generally cost more, and support material adds to material consumption. SLA is usually the more economical option for a single-material model. A general overview of pricing is available in how much 3D printing costs.
Which One Should You Choose?
| Choose PolyJet for | Choose SLA for |
|---|---|
| Multi-color appearance models | Detailed single-color models |
| Rigid and flexible areas in one part | Master patterns and molds |
| Realistic product presentation samples | Dental and jewelry workflows |
| Anatomical and teaching models | Lower-cost smooth prototypes |
If neither fits and you need tough working parts, consider SLS or MJF. A good provider can help; see how to choose a 3D printing service.
Frequently Asked Questions
Is PolyJet better than SLA?
It is better for multi-material and color parts. SLA is often the better value when a single material is enough.
Is PolyJet a type of SLA?
No. Both cure photopolymer, but PolyJet jets droplets, whereas SLA cures resin in a vat with a laser.
Can PolyJet parts be used as end-use parts?
Some can in low-stress settings, but many PolyJet materials are mainly intended for prototyping and visual models. Test any part for its real conditions.