Concept renderSLA cures liquid resin with a laser and gives smooth, accurate parts that suit looks-like enclosure models and fit checks. SLS fuses nylon powder with a laser and gives tougher, grainier parts that suit snap fits, living hinges and field trials. FDM is the quick, rough option for checking overall shape.
Device teams print the enclosure many times before anyone cuts a mold. The process you pick decides what each print can prove. This guide compares SLA and SLS for electronics housings, adds FDM where it helps, and ends where printing stops being useful. Every figure links to a printer maker or service bureau.
Material data from these sources is approximate and depends on geometry, orientation and print settings. Confirm values with the shop that will print your parts.
What is the difference between SLA vs SLS 3D printing?
Both processes use a laser and build a part one layer at a time. Xometry explains the core split: SLS sinters plastic powder, and SLA cures a liquid photopolymer (as of November 2026). That one difference drives the rest. Resin parts come out smooth and precise. Powder parts come out tough and slightly grainy, and they need no supports.
| Point | SLA | SLS | Source |
|---|---|---|---|
| How the part is made | A laser cures liquid photopolymer resin layer by layer. | A laser fuses thermoplastic powder, most often nylon, layer by layer. | Xometry SLS vs SLA |
| Supports | Parts usually need support structures, which leave marks to sand off. Some designs print without them. | The unfused powder holds the part, so no dedicated supports are needed. | Formlabs comparison |
| Typical tolerance at one service bureau | X/Y within ±0.002 in. (0.05 mm) for the first inch plus 0.1% of nominal length. Z within ±0.005 in. for the first inch plus 0.1%. | ±0.010 in. (0.25 mm) plus 0.1% of nominal length. | Protolabs SLA and SLS pages |
| Surface as printed | Smooth. Support nibs remain on the supported side unless sanded. | Grainy. Protolabs says SLS is typically rougher than other 3D printing processes. | Protolabs SLA and SLS pages |
| Thinnest walls quoted | As thin as 0.2 mm on a Formlabs Form 4. | 0.3 mm horizontal and 0.6 mm vertical on a Formlabs Fuse 1+ 30W. Protolabs lists 0.030 in. (0.762 mm) for its nylons. | Formlabs comparison, Protolabs SLS |
| Toughness | Xometry says SLA produces weaker parts than SLS. Tough resins narrow the gap (see below). | Xometry calls SLS parts tough, with good mechanical properties. | Xometry SLS vs SLA |
| Post-processing | Wash off uncured resin, remove supports, then post-cure in light or heat. | Remove unsintered powder, then bead blast. Dyeing and vapor smoothing are options. | Formlabs comparison, Xometry, Protolabs SLS |
Sources, all as of November 2026: Xometry, SLS vs. SLA (updated February 12, 2026), Formlabs, FDM vs. SLA vs. SLS, Protolabs SLA, Protolabs SLS.
The Protolabs tolerances are useful because one shop quotes both processes the same way. Formlabs publishes its own figure for its Fuse Series SLS printers: ±0.5% or 0.3 mm in X and Y, whichever is larger (as of November 2026). Numbers from different shops and machines are not directly comparable.
When does SLA 3D printing fit an enclosure prototype?
Use SLA when the question is about shape, fit or appearance. Formlabs says SLA gives the best surface finish and the best resolution of the three common processes (as of November 2026). That makes it the default for looks-like models and for checking that a board, battery and button stack fits the shell.
Finish level matters for looks-like units. Protolabs says its standard SLA finish is sanded and blasted, though layers still show. Its custom finishes add soft-touch paint, clear finishing, color matching and texture (as of November 2026). For photos and user interviews, plan on a custom finish.
SLA also covers clear parts. Protolabs lists translucent or clear ABS-like and PC-like resins, which help when you need to see how an LED reads through a light pipe or window (as of November 2026). Protolabs says both need secondary finishing to be functionally clear, and the ABS-like grade keeps a light blue tint (as of November 2026).
The weak spot is toughness. Xometry says SLA parts are best used as proofs of concept and that the resin is sensitive to UV light (as of November 2026). Protolabs lists elongation at break of 9% for its ABS-like white resin and 7% for its PC-like clear resin. Those figures are approximate, but they show why a thin snap arm in a general resin can crack on the first assembly.
Tough resins change this. Formlabs lists 155% elongation at break and 8,000 cycles of Ross flex fatigue for Tough 1500 Resin V2 and says it suits snap fits and compliant mechanisms. Formlabs measured those figures on parts printed on a Form 4 at 100 µm layers and post-cured 12 minutes at 70 °C (as of November 2026). Ask which resin the shop will use. For a wider list of resins, nylons, FDM plastics and elastomers, see 3D printing materials for device prototypes.
When is SLS 3D printing the better choice?
Use SLS when the part has to flex, take handling, or ship to people for a field trial. Xometry calls SLS parts tough and better suited to mechanical or end-use applications (as of November 2026). Because the powder supports the part, SLS also handles internal ribs, bosses and complex shapes that would need many supports in SLA. Formlabs rates SLS highest of the three for complex designs (as of November 2026).
Material choice matters inside SLS too. Protolabs lists these approximate elongation figures, as of November 2026:
- PA 11 Black: 30%. The most ductile nylon on the list.
- PA 12 White: 11%.
- PA 12 40% glass-filled: 5%. Stiffer and more brittle.
- TPU 70-A: 210%. A rubber-like option for soft parts.
The Formlabs Fuse Series SLS design guide (March 2023) gives rules worth copying into your CAD checklist. They were developed for its Nylon 12 Powder:
- Minimum hole diameter 1.0 mm. Smaller holes may close during printing.
- Minimum pin diameter 0.8 mm.
- At least two escape holes of 3.5 mm or more for any enclosed cavity, or it stays full of powder.
- Clearance between separately printed mating parts: 0.2 mm for features under 20 mm², 0.4 mm above.
- Keep wall thickness fairly uniform to limit warping, and tilt wide, flat parts at about 20° in the build.
The same guide says Nylon 11 parts are more ductile than Nylon 12, while Nylon 12 GF parts are more brittle, especially across layers. Protolabs warns that parts over 7 in. and parts with thin features are most likely to warp (as of November 2026).
SLS surfaces are rough as printed. Protolabs bead blasts its parts to a matte texture and offers vapor smoothing, which takes the roughness from 250+ µin Ra to 64 to 100 µin Ra. Vapor smoothing is available for PA11 Black only (as of November 2026).
FDM vs SLA: when is a quick print good enough?
FDM extrudes melted filament in standard thermoplastics such as ABS and PLA. Formlabs lists concept modeling as a typical FDM application (as of November 2026). It is fine for checking overall size, hand feel and rough layout on day one.
Its limits show quickly on a small device. Formlabs says FDM parts are anisotropic, show layer lines, and typically need walls around 0.8 mm thick, compared with 0.2 mm on its SLA printer. It also says the heat of extrusion can warp parts. For a wearable with 1 mm walls and small snap features, FDM shows you the shape, and checking the fit needs a finer process. Move to SLA as soon as tolerances matter.
How do snap fits, hinges and inserts hold up in each process?
These are the features that break first on printed enclosures. For the geometry of the joints themselves, see snap fit joint design. This section covers how the print process changes them.
Snap fits
Orientation matters along with material. The Formlabs SLS guide says printed parts are tougher in the XY plane than in Z, and advises aligning snap fits so they bend within the XY plane. Print a test coupon of the snap arm in the intended orientation before the full shell. In SLA, choose a tough resin with a published elongation figure, since a general resin may crack.
Living hinges
A Protolabs design article (November 9, 2018) says that of the processes it compares, only SLS gives a living hinge the function it needs, and that its SL materials are not recommended for living hinges. It steers living hinges to SLS nylon, primarily PA11 Black, and recommends a thickness of 0.020 to 0.040 in. in the horizontal build direction, and a minimum length of 0.050 in. for a 90° bend or 0.150 in. for a 180° bend. It warns that a hinge 0.013 in. thick can break. Protolabs anneals the part at 250 to 275 °F and flexes the hinge through its range before use. It gives no guaranteed cycle count and says it has seen hinges last hundreds of cycles. Protolabs' current MJF page also calls its PA 12 Black the best option for living hinges (as of November 2026); see the prototype injection molding guide.
Threads and inserts
Printed threads wear fast when a device is opened again and again for debugging. The Formlabs SLS guide suggests heat-set inserts for durable threaded connections and dowel pins for precise location. It also says holes and pins are most accurate with their axes vertical in the build. Design the boss for the insert you will use at production so the screw layout carries over.
How do heat, UV and water limit what a printed part proves?
A printed shell can pass a test that a molded shell fails, or the reverse.
Heat. Charging, a power amplifier or a car dashboard can warm the housing. Formlabs lists a heat deflection temperature of 66 °C at 0.45 MPa and 53 °C at 1.8 MPa for Tough 1500 Resin V2 (as of November 2026). High-temperature resins go further. Protolabs says a thermal post-cure can raise the heat deflection temperature of its PC-like Accura 5530 as high as 482 °F at 0.46 MPa, and that the same cure cuts its elongation by 50% (as of November 2026). Heat resistance and toughness trade off, so pick the property your test needs.
UV and humidity. Protolabs says SLA parts should see minimal UV and humidity exposure so they do not degrade (as of November 2026). Do not leave SLA units on a sunny desk for a long trial and then read the results as material data.
Water. In its comparison guide, Formlabs cites University of Rhode Island tests in which FDM enclosures failed to keep electronics dry underwater, SLA parts stayed watertight to very high pressure, and SLS parts kept electronics dry at moderate pressure, with vapor-smoothed SLS doing better (as of November 2026). Treat any printed seal test as a check of the gasket design only. Formal ingress testing belongs on parts made from the production material.
When should you move to urethane casting or a mold?
Printing fits the period when CAD changes every week. Once the shape settles and you need a set of units that look alike, cast urethane parts usually make more sense, and once you need the production resin for drop and seal tests, you need a mold. Urethane casting for low-volume parts covers the casting step. Prototype plastic injection molding compares printing, casting and aluminum tooling side by side, so we do not repeat that here. For metal parts, or plastic parts that need real material strength before a mold exists, see CNC machining prototypes.
The table below maps common enclosure questions to the process that answers them. The rows are engineering reasoning from the sources above, and none describes a specific project.
| Question the print must answer | Process | Note |
|---|---|---|
| Does the board, battery and button stack fit inside the shell? | SLA | Tight tolerances show interference early. Print the mating halves in the same build. |
| Does it look right in a photo or a user interview? | SLA, sanded and painted | Protolabs offers soft-touch paint, color matching and clear finishing on SLA parts, as of November 2026. |
| Will a light pipe or a clear window work? | SLA in a clear or translucent resin, with clear finishing | Protolabs lists ABS-like and PC-like translucent or clear resins, as of November 2026. |
| Does a snap fit survive repeated opening? | SLS in nylon, or SLA in a tough resin | Check the elongation figure for the exact material before you test. |
| Does a living hinge work? | SLS in a ductile nylon such as PA11 | A 2018 Protolabs design article does not recommend its SL resins for living hinges. Its current MJF page calls PA 12 Black the best option, as of November 2026. |
| Do ten units survive a week of field use? | SLS | SLS nylon is the tougher of the two. Results describe nylon, and the production resin will behave differently. |
| Is the CAD shape roughly right? | FDM | Fast and cheap. Layer lines and anisotropy limit what it proves. |
What to ask your hardware team
Use these questions before each print order, and write the answers into the build notes.
- Which question is this print meant to answer: fit, look, flex or field use?
- Which exact material is quoted, and what elongation and heat deflection figures does its datasheet list?
- Are mating parts printed in the same build and the same orientation?
- Are snap arms and hinges oriented to bend in the XY plane of the build?
- Which tolerance does the shop quote for this process, and on which axis?
- Is there a written list of tests that must be repeated on cast or molded parts?
- At which revision do we stop printing and move to casting or a tool?
Prints, casts and molded parts each belong to a stage in our gated prototype development process, so each stage proves only what its material can prove.
Questions about SLA and SLS
Is SLA or SLS more accurate?
Is SLS stronger than SLA?
Xometry says SLA produces weaker parts than SLS (source, as of November 2026). The gap depends on the resin. Formlabs lists 155% elongation at break for Tough 1500 Resin V2 on Form 4 printers (source, as of November 2026), while Protolabs lists 9% for its ABS-like white resin (source, as of November 2026). Compare datasheets, not process names.
Can I use SLS parts as the final enclosure for a small batch?
It can work, since SLS needs no tooling and Xometry says SLS parts suit end-use applications (source, as of November 2026). Protolabs lists vapor smoothing and dyeing as SLS options (source, as of November 2026). Check the finish, color and any regulatory test against the printed material itself, since a later molded part uses a different resin.
Which is cheaper, SLA or SLS?
It depends on part size, quantity and how many parts fit in one build. The Formlabs Fuse Series guide says the whole SLS build volume can be packed with parts (source, as of November 2026). SLA parts need supports removed, then washing and curing. Get quotes for the same file from both processes.
How can Duobay help with enclosure prototypes?
Duobay develops custom devices with a Shenzhen engineering team that covers mechanical, electrical, firmware, app and test work. Enclosure prototypes are part of the gated process, and all source files are assigned to you at every paid gate. Initial calls are free, and we do not publish prices. Tell us about your device.
If you want an enclosure plan that says which print answers which question, tell us about your device.
Sources. All pages accessed November 6, 2026. Material data and service limits change, so confirm current values before you decide.
- Formlabs, FDM vs. SLA vs. SLS: 3D Printing Technology Comparison (link)
- Formlabs, Fuse Series SLS Design Guide (March 2023) (link)
- Formlabs, Tough 1500 Resin V2 product page (link)
- Protolabs, Stereolithography (SLA) service page (link)
- Protolabs, Selective Laser Sintering (SLS) service page (link)
- Protolabs, Multi Jet Fusion (MJF) service page (link)
- Protolabs, How to Design 3D-Printed Living Hinges (November 9, 2018) (link)
- Xometry, SLS vs. SLA: Differences and Comparison (updated February 12, 2026) (link)
Planning a device like this? Tell us what it needs to do. A Duobay engineer replies within 1 business day. Send a project brief →