If you’ve been eyeing resin printing for brackets, housings, or even gears, you’re probably asking, can you use a resin printer for parts? Resin printers have taken the spotlight for their incredible precision, perfect for miniatures, figurines, and detailed prototypes. But when it comes to functional or mechanical parts, you have to keep a few things in mind.
While resin printing offers unmatched detail and smooth finishes, not all printers or resins are up to the task. The success of resin-printed parts depends heavily on your choice of machine, material, and application.
In this article, we’ll break down:
- When resin printing works for functional parts.
- The best types of resins to use (standard resin won’t cut it).
- Recommendations for printers and tips for overcoming common challenges.
If you’re considering resin for practical parts, read on to see what’s possible—and what to avoid.
What Makes Resin Printing Unique for Parts?
Compared to FDM printers, which melt and extrude plastic filament layer by layer, resin printers use light to cure liquid resin into solid objects. This process (SLA or MSLA) produces far higher resolution, meaning smoother surfaces and sharper details. However, resin 3D printing comes with its challenges, especially for functional parts:
- Resin Strength and Durability: Standard resins can be brittle and snap under stress.
- Shrinkage and Warping: During curing, resin custom parts sometimes shrink slightly, which can affect dimensional accuracy if you don’t plan for it.
- Build Volume: Resin printers typically have smaller build plates, making large mechanical parts tricky.
- Post-Processing: Printed parts need cleaning, curing, and sometimes sanding, adding time to the process.
Knowing how a resin printer works is crucial for creating functional parts. With the right resins and careful planning, it can produce parts that FDM printers struggle to achieve.
When Can You Use a Resin Printer for Parts?
Resin-printed parts excel in specific applications, particularly when high detail, precision, and smooth finishes are essential. Here’s where resin printing works well:
- Prototypes and Small Functional Parts: Resin printers are perfect for testing designs before committing to stronger materials.
- Fixed Components: Brackets, covers, or housings that don’t face heavy loads or impact are ideal.
- Low-Force Mechanical Parts: Gears or linkages for light-duty applications.
- Precision Components: Applications like dental models or watch movements that require extreme accuracy.
That being said, if you purchase tough and engineering-grade resins, they have been known to hold up in functional roles as well. Formlabs “Tough 1500” and “Durable” resins, for example, have properties similar to ABS plastic. While these resins are pricier, they have the strength standard resins lack.
Choosing the Right Resin for Functional Parts
Not all resins are created equal. If you’re serious about using a resin printer for parts, you’ll need to invest in specialty resins designed for strength, durability, and functionality. Here are some top options:
- Tough Resins (e.g., Formlabs Tough 2000):
- Mimics the strength and rigidity of ABS plastic.
- Ideal for parts that need to handle stress without breaking, like brackets or enclosures.
- Durable Resins:
- Offers impact resistance and a slight flexibility, similar to polypropylene.
- Perfect for snap-fit parts or functional prototypes.
- High-Temperature Resins:
- Withstands heat without deforming, great for parts exposed to higher operating temperatures.
- Flexible or Elastic Resins:
- For parts that need bendability, like grips, gaskets, or cushioning.
While standard resins are cheaper and widely available, they’re prone to brittleness and cracking. This limits their use for functional parts. Engineering resins are more expensive but essential for achieving practical results.
Overcoming Common Challenges in Resin Printing for Parts
Resin printing is a fantastic tool for detailed, functional parts, but it’s not as “plug-and-play” as some people hope. Small mistakes in the setup or post-processing can lead to failed prints, warped parts, or even pieces that crack when you least expect it.
With a little know-how and a few tweaks, you can solve the most common resin printing challenges. Here’s a guide to getting those functional parts right every time.
1. Minimize Shrinkage
Shrinkage is one of the sneakiest challenges in resin printing. When resin cures, it naturally has a volumetric shrinkage of around 0.9 to 1.8%, depending on the resin type. That might sound small, but for functional parts, even a millimeter of shrinkage can mean a bracket won’t fit or a gear won’t spin.
Here’s how to combat it:
✅ Calibrate Your Printer Properly:
Start by double-checking your printer’s settings. Most resin printers come with a calibration file you can print to test for accuracy (like an XY calibration print). If your dimensions are slightly off, adjust your scaling settings in your slicer software to compensate.
- For help, check out this step-by-step printer calibration guide.
✅ Adjust Your CAD Designs:
Plan for shrinkage in your 3D design software. For example, if you know your print shrinks by 1.1%, scale your model up by 1.1% to compensate. Test with small prototypes first, it’ll save you time and resin.
✅ Choose Resins with Dimensional Stability:
Some resins handle shrinkage better than others. Look for “engineering resins” that are specifically formulated to reduce warping and maintain accuracy.
2. Nail Your Post-Processing
Proper post-processing is key to turning your brittle, sticky print into a strong, functional part. Doing this wrong can leave you with warped, cracked, or brittle parts.
Here’s how to do it right:
✅ Clean Thoroughly with Isopropyl Alcohol (IPA):
Right after printing, rinse your parts in 91-99% isopropyl alcohol to remove any uncured resin. Give them a good soak for 5–10 minutes. Use a soft brush or an ultrasonic cleaner to get into the nooks and crannies.
- Pro Tip: Don’t over-soak! Leaving prints in IPA too long can weaken the resin surface.
✅ Cure Evenly Under UV Light:
Once cleaned, parts need to be cured under UV light to fully harden. But over-curing can make resin parts too brittle—a common problem for functional pieces that need some give.
Here’s a curing cheat sheet:
- Small parts: 1–2 minutes of UV curing.
- Larger parts: 5-10 minutes.
Make sure to read the manufacturer’s guidelines for your specific resin.
✅ Sand and Seal for Perfection:
Functional parts sometimes need sanding for smooth edges or tight fits. You may want to start with medium grit sandpaper (200-300) and transition to fine grit (1000-2000) to improve durability and water resistance.
3. Support Placement: Get it Right the First Time
Supports are like scaffolding—they hold your parts steady during printing. If you don’t get support placement right, parts can warp, sag, or even fail mid-print. For functional parts, this is detrimental.
✅ Orient Your Prints for Success:
The way you position your part on the build plate matters:
- Avoid flat printing. Printing directly on the plate often leads to warping or elephant’s foot (a bulge on the bottom of the print).
- Angle your prints. Depending on the print, a 15°-30° angle reduces stress on the layers and makes it easier for supports to do their job.
✅ Add Supports Strategically:
For functional parts, you want enough supports to prevent sagging, but not so many that you damage the print when removing them. Use your slicer’s “tree supports” for fewer contact points and easier cleanup.
✅ Test Support Removal:
Gently clip supports with flush cutters and sand any marks. Don’t pull too hard, as this can crack thin areas of your print.
4. Test Your Parts and Iterate
Your first print might not be perfect. Resin parts, especially for functional use, need to be tested, refined, and sometimes reprinted.
✅ Start Small:
Print a prototype before committing to the full part. Test for fit, strength, and flexibility. For example, does your bracket hold weight? Does your gear turn smoothly?
✅ Stress Test Your Prints:
Resin parts can be strong, but it’s worth testing under real-life conditions. For example:
- Flex the part slightly to see if it snaps or holds up.
- Apply gentle weight if it’s a structural piece.
If the part fails, tweak your resin choice, print orientation, or design. Resin printing is a learning process, and even pros iterate to get it right.
Resin printing functional parts isn’t as simple as pressing “print,” but with a little patience and planning, you can make it work like a charm. Start with engineering resins, fine-tune your printer settings, and treat post-processing like a critical step—not an afterthought.
Once you dial it all in, you’ll wonder how you ever lived without the precision and detail of resin printing for functional parts.
Can You Use a Resin Printer for Simple Parts?
Resin printing can absolutely produce functional mechanical parts, but it’s not as simple as hitting “print.” The trick lies in using tough, engineering-grade resins and having a well-calibrated, reliable printer.
For small to mid-sized parts requiring precision, smooth finishes, and low-force functionality, resin printing is an excellent solution. Make sure you either use or hire a printing company to use tough resins and a reliable printer.
Final Thoughts
If you’re a hobbyist or professional with a focus on detail, resin printing opens the door to functional parts that FDM simply can’t match in precision. By investing in specialty resins and understanding the limits of your printer, you can successfully create brackets, gears, prototypes, and more.
For projects where precision matters more than brute strength, resin printers can absolutely deliver. Just be ready for a little extra work along the way.
