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REVISION and CHANGES in FDM 3D Printing: All You Need to Know

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In additive manufacturing, modeling plays a crucial role. Once a design is finalized, it's imperative to ensure its successful execution by fine-tuning printing parameters. These adjustments are typically made within the slicing software tailored to the specific machine being used, allowing users to minimize potential printing flaws. Popular slicer software options in the market include Cura and PrusaSlicer and many more. In FDM 3D printing, careful consideration is given to the movement of the print head within the print area. To delve deeper into this aspect, we've examined various types of movements achievable in 3D printing, along with the significance of revision in managing filament flow during printing.

What is Revision of 3D Printing

To begin, we first need to talk about revision. This is a mechanism adopted by the 3D printer when its head has to move between two parts of the part to be printed. revision essentially pulls the filament back to prevent the material from flowing during the movements and displacements performed by the vacuum extruder during the 3D printing process, thus reducing the pressure inside the nozzle. If revision is not applied, the extruded material may remain suspended between the 3D printed parts.

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The parameters configuring this related to the revision distance itself, which varies according to the material and the type of extrusion system chosen, especially when referring to the use of a Bowden or direct drive extruder. If we use the Bowden extruder, the movements will be cleaner because the filament will pass through a tube called a Bowden and the extruder will be mounted directly on the printer chassis. On the other hand, if we opt for the direct drive extruder, revision will be better and the result more precise, as the filament will be pushed directly towards the nozzle. When working with flexible materials, it's important to manage the feed carefully to maintain control over the printing process. This involves adjusting the settings to prevent delays in movement that could disrupt the print. Additionally, users need to pay attention to the speed of the extruder motor when retracting the filament. High speeds might cause damage to the filament, rendering it unusable for further printing, although it reduces the risk of fluid leakage. Conversely, lower speeds increase the chance of leakage but keep the material intact and shorten the printing time. revision plays a crucial role in preventing "stringing," which refers to the formation of thin strands of plastic between 3D printed parts. By implementing proper revision techniques, users can achieve cleaner prints with improved results.

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Two important parameters that significantly impact the revision process and contribute to our analysis of displacement types are the revision extra prime amount and the revision minimum travel. The revision extra prime amount refers to the additional material extruded post-revision to compensate for any material loss during displacement movements.

This is particularly relevant for flexible filaments, as they often require added pressure during 3D printing. On the other hand, the revision minimum travel determines the minimum distance the print head must travel before initiating feeding. It's crucial to strike a balance with this value, ensuring it's not set too high. Short distances can save time by skipping revision, but maintaining control and grip over the printing material is paramount. These settings are instrumental in optimizing the revision process and ensuring successful 3D prints, especially when working with challenging materials like flexible filaments.

Types of  Displacements in FDM 3D Printing

When it comes to displacement types, it's important to understand the three fundamental categories. These must be tailored and fine-tuned based on specific design parameters and the desired outcome for our 3D printed component.

Combing Mode Combing mode in 3D printing dictates how the print head transitions between different areas of the printed object. It governs the movement of the nozzle from the endpoint of one layer to the starting point of the next layer, minimizing the necessity for filament retraction. This enables smoother filament flow within the print, particularly in less visible areas. While there are instances where retraction is unavoidable, combing mode aims to minimize it by strategically moving the print head. By employing this mode, the slicing software automatically determines when retraction can be avoided. This approach prioritizes resolving and anticipating potential issues within the internal structure of the print. Retraction is only employed if issues arise on the exterior surface, ensuring optimal print quality.


Z-hopping is a nifty technique often paired with retraction in 3D printing to tidy up prints by minimizing material leftovers between the part and the nozzle. It works by adjusting the distance between the print surface and the nozzle during movements, ensuring cleaner and more precise prints. One way to implement Z-hopping is through Z-skipping, where the print surface gradually lowers with each retraction, effectively increasing the space between the part and the nozzle and preventing material residue. In FDM 3D printing, various Z-jumping methods come into play. Take, for instance, the Z-jump after the purge tower. This maneuver creates a gap between the purge tower and the part, curbing material residue from clinging onto the exterior of the part. Another example is the Z-jump during layer change, executed as the print head transitions to the next layer. This helps safeguard the integrity of the printed layer and minimizes the chances of filament mishaps between the tower and the part.

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Avoid Printed Materials While Traveling When you opt for the "Avoid Printed Parts While Traveling" feature, your printer's printhead navigates around existing prints rather than traversing over them. This precautionary measure minimizes the risk of nozzle contact with already printed sections, which could cause imperfections or material blending issues. It's worth noting that this feature is only accessible if you've activated the Combing Mode beforehand. Employing both functions concurrently typically enhances print precision and minimizes surface irregularities. Moreover, it serves as a preventive measure against potential issues like warping, stringing, or part distortion arising from unintended movements during printing.

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