Orca Slicer: Optimize Filament Ramming Length

Are you an Orca Slicer user who's been scratching your head about the filament ramming length setting? You're not alone! The default setting adds an extra 10mm of filament to every prime tower, and many users are questioning why it's there in the first place. Let's dive into the issue, understand the problem, and explore why changing the default to 0 could be a game-changer for your 3D printing experience.

The Problem: Unnecessary Filament Waste and Time

The core issue revolves around the filament_change_length setting, also known as "Filament Ramming Length" in the Orca Slicer UI. By default, this value is set to 10mm. This means that before every multi-material tool change, the printer adds an extra 10mm of filament to the prime tower. The intention behind this, according to the tooltip, is to prevent oozing. However, many users, including myself, find this explanation questionable.

Think about it: the process involves transitioning from printing on the model to printing on the prime tower, then retracting and removing the filament. How does adding an extra 10mm of filament before retraction actually reduce oozing? It seems counterintuitive. This is especially noticeable and wasteful in setups like H2D printing with dual nozzles, where every tool change gets this unnecessary 10mm bump. This leads to:

• Increased filament waste: That extra 10mm adds up, especially in multi-color or multi-material prints with frequent tool changes.
• Longer print times: The extra printing time for the prime tower extends the overall print duration.
• Questionable benefit: The anti-oozing effect is debatable, leading to wasted filament and time for minimal, if any, improvement.

To illustrate, imagine you're switching from Tool 0 (T0) to Tool 1 (T1), and your prime volume is set to 2mm³. With the default setting, the sequence looks like this:

1. T0: Prints approximately 7.65mm³ (equivalent to 10mm length) onto the prime tower.
2. Tool switch: The printer switches tools and performs the necessary nozzle flushing.
3. T1: Prints the intended 2mm³ volume for priming.
4. Prints your layers.
5. T1: Prints another 7.65mm³ onto the prime tower before the next tool change.

Notice that the extra 7.65mm³ (10mm) is added before the tool change, not after, raising questions about its effectiveness in improving print quality after the tool change.

Why the Default Should Be Zero

Changing the default value of filament_change_length to 0 makes more sense for several reasons:

• Eliminates unnecessary waste: By removing the extra 10mm, you directly reduce filament consumption and contribute to more efficient printing.
• Reduces print time: Less filament to extrude means faster print times, especially for complex multi-material prints.
• Allows for targeted oozing control: Instead of a blanket 10mm addition, users can fine-tune retraction settings and prime volumes to address oozing more effectively.

Interestingly, the default value is already tweaked for some filaments. Bambu Lab's (BBL) PETG HF and PLA Tough+/Basic profiles actually reduce this value from the default of 10mm. This suggests that even BBL recognizes the default might not be optimal for all scenarios, further strengthening the argument for a default of 0.

Instead of a one-size-fits-all approach, setting the default to 0 empowers users to customize their settings based on their specific filament, printer, and printing needs. They can then use more targeted methods like adjusting retraction settings, wipe while retracting, or adjusting the prime volume. This results in more efficient and effective control over oozing and stringing.

Who Benefits from This Change?

This change would benefit all Orca Slicer users, regardless of their printer type. Whether you're using a single-extruder machine or a multi-material setup, reducing unnecessary filament waste and print time is always a plus. It's a small change that can have a significant impact on your overall 3D printing workflow and efficiency.

Moreover, users of printers with dual-nozzle setups, such as those used for H2D printing, stand to gain the most. In these configurations, tool changes are frequent, making the unnecessary 10mm addition particularly wasteful.

Potential Concerns and Mitigation

One potential concern is that setting the default to 0 might increase oozing for some users. However, this can be easily addressed by:

• Providing clear documentation: Explain the change in the Orca Slicer documentation and suggest alternative methods for preventing oozing, such as adjusting retraction settings and prime volumes.
• Offering pre-configured profiles: Include filament-specific profiles with optimized retraction and priming settings for common filaments.
• Adding a warning message: Display a warning message when users first update to the new default, suggesting they review their retraction settings.

By proactively addressing these concerns, the transition to a default value of 0 can be smooth and beneficial for all users.

Alternatives Considered

While some users might prefer to keep the default at 10mm, the arguments for changing it to 0 are compelling. Other alternatives, such as allowing users to set a global default value, are more complex to implement and don't address the core issue of unnecessary filament waste.

The most straightforward and effective solution is to simply change the default value to 0 and provide users with the tools and information they need to fine-tune their settings for optimal results.

Conclusion: A Small Change, a Big Impact

Changing the default value of "filament_change_length" to 0 in Orca Slicer is a simple yet impactful change that can benefit all users. It reduces filament waste, shortens print times, and empowers users to fine-tune their settings for optimal print quality. By addressing potential concerns and providing clear documentation, this change can be implemented seamlessly and improve the overall 3D printing experience for everyone.

It's time to rethink the default and embrace a more efficient and customizable approach to filament management in Orca Slicer.

For further reading on 3D printing best practices, visit All3DP. This resource offers a wealth of information on troubleshooting, optimizing settings, and exploring advanced techniques to enhance your 3D printing journey.