3D printing enthusiasts are all too familiar with stringing, those pesky wisps of filament that stretch between printed parts, marring the surface finish and overall quality of a print. While stringing can occur with various materials, even specialty filaments designed for high-precision applications can fall victim to this frustrating phenomenon. One user recently shared their experience battling stringing with Polymaker PolyCast filament, a material prized for investment casting patterns. Let’s delve into their experience and explore potential solutions for tackling stringing issues.
Initially, the user reported excellent results with Polymaker PolyCast right out of the box. After a brief drying period, they achieved “superb quality prints” across multiple print jobs spanning 12 hours. The filament, stored in a Prusa Enclosure adjacent to the printer, seemed to be performing flawlessly. However, the tide turned on the subsequent day with a new, longer print.
The user described how a print that started as beautifully as the previous ones eventually succumbed to nozzle clogging. This resulted in the printer continuing to run, effectively printing air. A nozzle change didn’t solve the issue, with the replacement also clogging, and this time, stringing became a noticeable problem – a stark contrast to the initial pristine prints.
Frustrated but determined, the user took proactive steps to troubleshoot. Recognizing moisture as a potential culprit, they re-dried the Polymaker PolyCast filament for six hours at 55°C in a PrintDry dryer. To conserve the expensive filament during troubleshooting, they initiated stringing test prints, systematically adjusting slicer parameters to identify the sweet spot.
Their adjustments included:
- Retraction Distance: Increased to 3.0mm.
- Z-Lift: Increased to 0.6mm.
- Printing Temperature: Lowered from 215°C to 205°C.
- Layer Height: Increased to 0.15mm (from 0.1mm).
Despite these changes, and even printing directly from the dryer with a fresh nozzle, stringing persisted, albeit reduced compared to its peak. The user’s objective is to restore the filament’s initial printing behavior – no stringing and no nozzle clogs – a goal they rightfully deemed reasonable.
The user’s model, a figurine intended for phosphor bronze casting, demands a flawless surface finish. While Polymaker PolyCast’s IPA-smoothing capability is beneficial for post-processing, stringing blemishes and support marks can compromise the surface quality, necessitating manual removal and potentially damaging fine details.
This experience highlights a common challenge in 3D printing: material behavior can shift unexpectedly, and troubleshooting requires a systematic approach. While the user’s adjustments are a good starting point, several factors can contribute to stringing, especially with materials like PVB-based PolyCast:
- Moisture Absorption: PVB is known to be hygroscopic, readily absorbing moisture from the air. Even after initial drying, prolonged exposure or humid environments can reintroduce moisture, leading to stringing and clogging. Consistent dry storage and printing directly from a dryer are crucial.
- Temperature Instability: Fluctuations in printing temperature can affect filament flow and stringing. Maintaining a stable printing environment and verifying temperature accuracy are important.
- Retraction Settings: While the user increased retraction, excessive retraction can also cause issues. Fine-tuning retraction speed and distance is key.
- Nozzle Condition: Even new nozzles can have manufacturing variations. Ensuring proper nozzle seating and checking for any internal obstructions is advisable.
- Filament Quality: While Polymaker is a reputable brand, batch-to-batch variations in filament properties can occur.
To further combat stringing with Polymaker PolyCast and similar filaments, consider these additional tips:
- Optimize Cooling: Ensure adequate part cooling, especially for intricate models. Properly directed and sufficient cooling can solidify extruded filament quickly, minimizing stringing.
- Reduce Travel Speed: Lowering travel speed can give the filament more time to solidify and reduce stringing during non-printing moves.
- Experiment with Coasting and Wipe: Slicer features like coasting (stopping extrusion slightly before the end of a path) and wipe (moving the nozzle across the finished path to remove excess filament) can be effective in reducing stringing.
- Material-Specific Profiles: Consult Polymaker’s recommendations for PolyCast settings and consider downloading or creating material profiles tailored to this specific filament in your slicer software.
- Community Resources: Leverage online 3D printing communities and forums. Sharing experiences and seeking advice from other PolyCast users can provide valuable insights and solutions.
Stringing, while frustrating, is a solvable problem in 3D printing. By systematically addressing potential causes, experimenting with settings, and drawing upon community knowledge, users can often achieve the pristine, string-free prints they desire, even with challenging materials like Polymaker PolyCast. The key is persistence and a methodical approach to troubleshooting.
