Introduction
High-viscosity resins offer distinct advantages in 3D printing, particularly for applications that demand durability, flexibility, or intricate detail. However, their thickness can pose challenges during the printing process.
In this guide, we'll explore these challenges and offer solutions to ensure successful printing with high-viscosity resins. This guide involves good printing principles that are useful for general printing but are especially helpful for our Blu Lava Black, Blu Nylon Mecha, and Tenacious Lava Black resins.
We also want to thank our customers Davide and Pawel for their feedback on this guide.
Understanding the Challenges
The very property that makes high-viscosity resins desirable – their higher performance, often related to high viscosity – can lead to several printing issues:
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Slow Resin Flow: Thick resins flow more slowly, hindering their ability to refill the space between the build plate and the FEP film after a layer is lifted. This can lead to incomplete layer formation, gaps in the print, and even print failures.
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Increased Peel Force: The higher viscosity creates greater resistance when the build plate peels off the FEP film. This increased peel force can cause layer shifting, deformation, and even supports breaking or failing.
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Resin Pooling: Thick resins tend to pool around supports, leading to uneven curing and potentially compromising the print's structural integrity.
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Thick First Layers: Achieving a thin and even first layer is crucial for successful printing. High-viscosity resins can make this difficult, as the build plate may not reach the optimal z=0 position due to the resin's resistance. This can result in a thick first layer that fails to adhere properly.
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Sensor Interference: Some newer printers use sensors to detect objects in the vat. The thickness of high-viscosity resins can trigger false readings, causing the printer to start printing above z=0, leading to the same problems as mentioned above.
Tips for Successful Printing
Here are some tips to overcome these challenges and achieve optimal results with high-viscosity resins:
Pre-Printing Preparation
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Warming the Resin: Warming the resin to around 25-30°C can reduce its viscosity and improve flow. This can be done by placing the resin bottle in a warm water bath for a short period. Newer printers like Elegoo Saturn 16 Ultra, Anycubic M7, and Uniformation GK2/GK3 lines have built-in vat heat that is efficient at directly heating resins. Some printers have air heaters that are much less efficient but are better than not having a heater.
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Mixing the Resin: If the resin has pigments (Blu Nylon Mecha, Blu Lava Black), then thoroughly mixing the resin before printing is essential to ensure consistent viscosity and prevent pigment settling. Shake the bottle vigorously or use a magnetic stirrer for optimal results. Resins without pigments (Tenacious Lava Black) do not need mixing so please don't mix.
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Small Initial Pour: For the first few layers, pour only a small amount of resin into the vat and spread it thinly with a spatula. This reduces the resistance the build plate encounters when homing in on z=0, ensuring a thin and well-adhered first layer.
Printer Settings
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Adjusting Lift Speed and Distance: Reduce the lift speed and increase the lift distance to give the thick resin more time to flow back into the printing area. Experiment with different settings to find the optimal balance for your specific resin and printer. Also, increase the wait after retraction to at least 3 seconds, and for very high viscosity resins, you may need 5 seconds or longer.
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Increasing Bottom Exposure Time: High-viscosity resins may require a longer bottom exposure time to ensure proper adhesion of the first layer. It is best to use our profiles for your printer. If your printer is not listed or you are working with other high-viscosity resins, start with 7 times the normal exposure time and run small test prints.
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Build Plate and Leveling: Ensure your build plate is clean, flat, and that you have properly leveled your printer. Some plates have laser etching to improve adhesion, while users sometimes sand their plates. Do not modify your build plate until you try other adjustments first.
Environmental Control
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Maintaining Optimal Temperature: Print in a room with a stable temperature between 20-25°C. Fluctuations in temperature can affect resin viscosity and print quality.
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Ensure Proper Ventilation: Print in a room with active air filtration or the ability to cycle the air away from the room to prevent VOC concentration.
Troubleshooting
Here are solutions to some common issues encountered when printing with high-viscosity resins:
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First Layer Not Adhering: Increase bottom exposure time, warm the resin, or try a different build plate material. Check to see if the bottom layer is too thick and use the above method of a thin layer of resin to start printing before adding more.
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False Sensor Readings: Use the above method of a thin layer of resin to start printing before adding more. Some users may adjust leveling (z=0) to slightly lower. But be careful with using negative offset on leveling, as it may damage the panel with too much plate pressure.
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Slow Printing Speed: You probably cannot avoid this entirely. Ways to improve print speed are to warm the resin, use a shorter exposure time, and reduce lift waiting. This would require user optimization.
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Supports Breaking or Failing: Use thicker supports, add more supports (but not too densely), or try a different support structure.
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Resin Pooling Around Supports: Ensure supports are not too dense and that resin is not trapped. It may be important to use thicker but fewer supports than thin but dense supports. The support strategy for printing thick resin is very different than printing low-viscosity resins.
Recommended Resins and Printers
Siraya Tech offers several high-viscosity resins that are well-suited for various applications:
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Blu Nylon Mecha: A tough and durable resin with excellent scratch resistance, ideal for mechanical parts and functional prototypes.
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Blu Lava Black: A unique combination of high hardness and good impact resistance with a nice surface finish and solid black color. A very popular resin for production parts.
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Tenacious Lava Black: Similar to Blu Lava Black but with lower hardness and a lot higher impact resistance and good anti-grinding resistance. It is easier to print and is very popular for larger MSLA printers.
These resins have been tested and proven effective on a variety of printers, including:
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Elegoo Saturn 3/4 Ultra
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Anycubic Mono M5/M7
Conclusion
High-viscosity resins offer unique capabilities for 3D printing, but they require careful attention to detail to achieve optimal results. By following the tips and troubleshooting advice in this guide, you can overcome the challenges and unlock the full potential of these versatile materials.
We encourage you to experiment and share your experiences with the Siraya Tech community. Join our Facebook group or Discord server to connect with other users, ask questions, and get support.