Published on Sat Jan 29 2022 06:03:21 GMT+0000 (Coordinated Universal Time) by Alex

Prusa Flex 98A: A Deep Dive into Flexible Filament

Prusa Research, known for its reliable 3D printers and high-quality accessories, also offers a line of filaments. One of their standout materials is Prusa Flex 98A, a flexible filament designed for a wide range of applications. This article will explore the properties of Prusa Flex 98A, how to print with it successfully, and its overall performance as a flexible 3D printing material.

What is Prusa Flex 98A?

Prusa Flex 98A is a thermoplastic polyurethane (TPU) filament, specifically designed to be flexible while still being relatively easy to print. The “98A” designation refers to its Shore hardness. A higher Shore value indicates a harder material. While still considered flexible, 98A sits closer to the rigid end of the flexible filament spectrum. This makes it a good choice for applications where you need some give, but not extreme flexibility, like phone cases, gaskets, or flexible hinges.

Detailed Specifications:

• Material: Thermoplastic Polyurethane (TPU)
• Shore Hardness: 98A
• Diameter: 1.75mm +/- 0.05mm
• Recommended Printing Temperature: 220-240°C (428-464°F)
• Recommended Bed Temperature: 50-60°C (122-140°F)
• Recommended Printing Speed: 20-40 mm/s (Lower Speeds are often Preferred)
• Density: ~1.20 g/cm³
• Spool Weight: Typically 1kg (other sizes may be available)
• Available Colors: Varies, Prusa often offers a range of colors including black, white, grey, and various vibrant hues.
• Layer Height: 0.15-0.3mm recommended

Tips for Printing Successfully with Prusa Flex 98A:

Printing with flexible filaments like Prusa Flex 98A can be tricky at first, but with the right settings and approach, you can achieve excellent results. Here are some essential tips:

1. Direct Drive Extruder (Highly Recommended): A direct drive extruder places the extruder motor close to the hotend. This drastically reduces the distance the filament has to travel unsupported. Bowden setups can work, but are more prone to jamming due to the filament compressing and buckling within the Bowden tube.

2. Slow Down Your Printing Speed: Speed is your enemy when printing with flexible filaments. Lower speeds (20-40 mm/s, and even slower for intricate parts) give the filament time to properly melt and adhere to the layer below. Start with lower speeds and gradually increase them if your prints are successful.

3. Retraction Settings: Retraction can be a significant source of issues. Excessive retraction will cause jamming, as the filament buckles and becomes knotted inside the extruder. Ideally, disable retraction completely, or use the absolute minimum retraction distance possible. A retraction speed of 1-5mm/s is also recommended to minimize this.

4. Turn off Coasting and Wipe: These features can introduce inconsistencies and stringing when printing with flexible filaments. Disabling them usually leads to better results.

5. Increase Flow Rate: Because you’re printing slowly, a slightly higher flow rate (around 105-110%) can help ensure proper layer adhesion and prevent underextrusion. Experiment to find the optimal flow for your printer.

6. Proper Bed Adhesion: Clean your print bed thoroughly with isopropyl alcohol before each print. A PEI sheet usually works well, but you can also try using a glue stick or hairspray for added adhesion, especially for smaller parts.

7. Nozzle Temperature: Start with the recommended temperature range (220-240°C) and adjust it based on your observations. If you see underextrusion, increase the temperature slightly.

8. Part Cooling: Use minimal part cooling, especially for the first few layers. Excessive cooling can lead to warping and poor layer adhesion.

9. Avoid Overhangs: Flexible filaments struggle with steep overhangs. Design your parts with minimal overhangs, or use supports if necessary.

10. Store the Filament Properly: Flexible filaments are hygroscopic, meaning they readily absorb moisture from the air. Store your Prusa Flex 98A in an airtight container with desiccant to keep it dry. If it gets damp, dry it in a filament dryer before printing.

Performance Evaluation (Out of 10):

• Print Quality: 7/10 (Good, but requires dialing in settings)
• Toughness: 8/10 (Durable and resistant to wear and tear)
• Flexibility: 7/10 (Good flex, but not extremely soft)
• Warping: 4/10 (Can be prone to warping if not handled correctly)
• Adhesion: 8/10 (Excellent adhesion to PEI bed with proper settings)
• Moisture Sensitivity: 9/10 (Highly sensitive to moisture)
• Color Range: 7/10 (Decent range of colors typically available)
• Temperature Range: 8/10 (Stable within recommended range)
• Odor & Fumes: 7/10 (Minimal odor compared to some other filaments)
• Spool Winding Quality: 9/10 (Excellent, consistent winding)

Average Score: 7.5/10

Conclusion:

Prusa Flex 98A is a solid flexible filament that delivers good performance when used correctly. It strikes a good balance between flexibility and ease of printing, making it a suitable choice for a variety of applications. Its moisture sensitivity requires vigilance in storage, but the quality and reliability are well worth the effort. By following the tips outlined above, you can consistently achieve excellent results with this versatile material.

Written by Alex