DLP 3D printing (digital light processing) cures an entire layer of resin at once, which makes it fast and very accurate for small to medium parts. It produces smooth, injection-molded-like surfaces in a wide range of engineering resins, from rigid, high-temperature tooling materials to a soft elastomer. Our shop is in Coopersville, Michigan, just west of Grand Rapids, and we ship parts nationwide.
How DLP 3D Printing Works
- A build platform lowers into a shallow tank of liquid photopolymer resin.
- A light source under the tank projects an image of the entire layer at once, curing the resin wherever the part needs to be solid.
- The platform lifts, fresh resin flows in, and the next layer is cured.
- Finished parts are washed, supports are removed, and the parts are post-cured to reach full strength and heat resistance.
The difference from SLA is how each layer is cured. SLA traces each layer with a laser, while DLP exposes the whole layer in one shot. That makes DLP faster for full builds of small parts and gives it very fine, consistent detail.
When to Choose DLP 3D Printing
DLP is a strong fit for small, detailed parts where surface finish and accuracy matter:
- Connectors, housings, clips, and small enclosures
- Mold inserts for short-run injection molding and for urethane and silicone casting
- Jigs, fixtures, and manufacturing aids
- Soft-touch and elastomer parts: gaskets, grommets, grips, and seals
- High-accuracy models and fast design iterations
- Small production runs of end-use parts
DLP, SLA, or MJF? Choose DLP for small, detailed parts that need a molded-quality finish or a specialty resin. Choose SLA for larger parts or clear parts. Choose MJF for tough nylon parts and larger quantities. Not sure? Send us the part and we will recommend a process.
DLP vs. SLA vs. MJF at a glance
| DLP | SLA | MJF | |
|---|---|---|---|
| Maximum part size | 13.9″ × 7.7″ × 13.8″ | 55″ × 27″ × 19″ | 14.75″ × 11″ × 15″ |
| Standard layer thickness | 0.004″ (0.1 mm) | 0.002″ to 0.006″ | 0.003″ (0.08 mm) |
| Accuracy | ±0.005″ first inch, ±0.0025″/in after | ±0.025″ first 5″, ±0.0025″/in after | ±0.010″ first inch, ±0.005″/in after |
| Surface finish | Smooth, molded-like | Smoothest; sands and polishes well | Fine matte texture |
| Materials | Engineering resins and an elastomer | Wide range, including clear and silicone | Nylon 12, glass-bead nylon, TPU |
| Best for | Small, detailed parts and mold inserts | Appearance models, clear parts, large parts | Tough functional parts and production runs |
Accuracy figures come from our part accuracy page.
DLP 3D Printing Capabilities
| Maximum part size | Up to 13.9″ × 7.7″ × 13.8″; larger parts can be printed in sections and bonded |
| Layer thickness | 0.004″ (0.1 mm) standard; 0.001″ to 0.002″ (25 to 50 microns) for mold inserts |
| Accuracy | ±0.005″ for the first inch, ±0.0025″ per inch thereafter (see our part accuracy page) |
| Surface finish | Smooth, injection-molded-like surfaces with minimal layer lines |
| Materials | 9 engineering resins: rigid, tough, high-temperature, and elastomer |
Accuracy depends on part size, geometry, and material. Send us your CAD file and we will give you a realistic estimate for your part.
DLP 3D Printing Materials
Each material has its own page with full mechanical properties, data sheets, and part photos.
Rigid and fast prototyping
| Material | Best for |
|---|---|
| Fast Model | Rapid prototypes, concept models, and fast design iterations |
| Precision Model | High-accuracy models with crisp detail and minimal layer lines |
| LOCTITE PRO417 | High-strength black parts with good impact resistance and an excellent surface finish |
Tough and impact resistant
| Material | Best for |
|---|---|
| LOCTITE 3843 | Tough, semi-flexible black parts with high impact strength; an alternative to ABS or polypropylene |
High temperature and tooling
| Material | Best for |
|---|---|
| Rigid 10K | Very stiff, glass-filled resin for mold inserts, tooling, and high-load prototypes |
| LOCTITE IND147 | Mold tooling for urethane and silicone casting, heat deflection up to 230°C |
| LOCTITE IND249 | Rigid, very stiff black parts with good heat resistance for mold tooling and manufacturing aids |
| LOCTITE IND6845 | Heat resistance combined with toughness for parts exposed to wear |
Elastomer
| Material | Best for |
|---|---|
| LOCTITE IND5714 | Soft 53A gray elastomer for parts that flex repeatedly |
Compare DLP with our other processes on the machine and material comparison guide.
3D Printed Injection Mold Inserts
When you need real molded parts in the production material but are not ready to commit to an aluminum tool, a 3D printed mold insert can bridge the gap. We print mold inserts in Rigid 10K, a very stiff, glass-filled resin with high heat resistance, sharp detail, and a smooth cavity surface. Mold inserts are printed at fine 25 to 50 micron (0.001″ to 0.002″) layers instead of our standard 0.1 mm, for better accuracy and a smoother cavity that releases parts more easily. Inserts can be in hand in days instead of the weeks it takes to cut a metal tool.
How long does a printed insert last?
Insert life depends mostly on the plastic being molded. Unfilled plastics such as polypropylene or ABS often get around 100 shots from an insert. Abrasive, filled plastics such as 40% glass-filled nylon are harder on the tool, and you may see flash along the parting line after about 20 shots. That will not match a prototype aluminum tool, but it is a fast, low-cost way to validate a design, test fit and function, or make a short run. Printed inserts also work well for urethane and silicone casting.
Designing a printed mold insert
Rigid 10K is heavily filled with ceramic, so it does not give under load the way a metal insert does. If the back of the insert is not flat and square to the parting face, one edge or corner can carry all of the clamping force and the insert can crack. Printed inserts should be cleanup machined on their seating surfaces before use, so plan for that in the design. A few other guidelines help inserts run well:
- Leave about 0.5 mm (0.020″) of extra stock on seating and mating surfaces for cleanup machining.
- Use 3° to 5° of draft, keep wall thickness uniform, and avoid thin sections under 1 to 2 mm.
- Keep one mold half flat with the detail on the other, and add alignment features at the corners.
- Open up the gate and add generous vents, about 0.05 mm (0.002″) deep, to lower cavity pressure and reduce flash.
Running a printed mold insert
- Start with low clamping force and low injection pressure and speed, then increase gradually.
- Keep the insert below about 60°C (140°F). Compressed air or alternating two sets of inserts helps manage heat.
- Use a silicone-based mold release, especially with TPU or engineering plastics that tend to stick.
These guidelines combine our own experience with Formlabs’ published guidance for 3D printed injection molds. Send us your mold design and we will review it for printing.
Finishing Options for DLP Parts
DLP parts come off the printer with a smooth surface that often needs little more than support removal. We can also sand, paint, Cerakote, and install threaded inserts. See all finishing and post-processing options.
Designing Parts for DLP
Our engineering team at DeWys Engineering designs parts for resin printing regularly. If your part isn’t ready to print yet, our design for additive manufacturing services can help, from design review to full CAD design.
If you would rather design the part yourself, we strongly recommend starting with our SLA Part Design Guide. Our engineers built it from years of resin printing projects as a place to keep the lessons we have learned, and we publish it so anyone designing for resin printing can benefit. Since SLA and DLP are both resin processes, most of its guidance on wall thickness, supports, and surface finish applies to DLP too.
A few things DLP handles well:
- Fine features, small text, and crisp edges
- Thin walls and small snap-fit details
- Sharp internal corners and no draft required
- Soft elastomer parts that flex repeatedly
- Mold inserts with smooth cavity surfaces
DLP Part Examples
DLP 3D Printing FAQ
Is DLP more accurate than SLA?
For small parts, usually yes. Our published DLP accuracy is ±0.005″ for the first inch, compared with ±0.025″ for the first 5″ on SLA. For large parts, SLA is the better choice because DLP is limited to smaller build sizes.
How strong are DLP parts?
It depends on the resin. Rigid 10K is very stiff and heat resistant, and LOCTITE 3843 is tough and impact resistant. If you need nylon-like toughness or many parts, MJF is usually a better fit.
How big can DLP parts be?
Up to 13.9″ × 7.7″ × 13.8″ in one piece. Larger parts can be printed in sections and bonded, or printed with SLA.
How fast can I get DLP parts?
Typical lead time is 4 to 6 days, depending on how busy the shop is and how complex the parts are. Contact us for current lead times on your project.
Can DLP parts be used as injection mold inserts?
Yes. Rigid 10K inserts typically produce around 100 shots in unfilled plastics like polypropylene or ABS, and closer to 20 shots in abrasive materials like 40% glass-filled nylon.
ISO 9001:2015 Certified Quality
Our quality management system is certified to ISO 9001:2015 and covers engineering, additive manufacturing, post-processing, and inspection, so customer requirements are handled consistently from quote to delivery. Learn more about our ISO 9001:2015 certification.