Introduction to +Filament Grouping Strategy for Dual Nozzle Printers
+ +1. Background
+ +When +switching between different filaments for printing on a single nozzle (hot end) +printer, it is necessary to use a certain amount of new material to flush +the residual material in the hot end, to avoid color mixing during printing. +The flushing values vary between different materials, and the specific values +can be viewed on the filament page of Bambu Studio. You can refer to the wiki +to learn more: Reduce +Waste during Filament Change
+ +For +a dual-nozzle (hot end) printer like the H2D, the optimal way to print two +filaments is to print different filaments with different nozzles. In this case, +switching between filaments only requires switching the nozzles rather than +flushing the old filament with the new one. Switching nozzle printing can also +reduce the number of filament flushes when printing more than two filaments. +This article will introduce filament grouping strategies for dual-nozzle +printers to achieve the most efficient or convenient multi-material printing +method.
+ +2. Multi-color printing sequence
+ +Different +printing sequences have different filament switching sequences, resulting in +differences in the flushing volume. The slicer will calculate an optimal +printing sequence based on the flushing volume between the filaments, to +minimize the waste amount. For example, if the total flushing amount of +filament sequence 1->2->3 is greater than that of 1->3->2, the +latter will tend to be used as the printing sequence for this layer. For +detailed information on manually adjusting print sequences, please refer to: Set +the filament printing sequence for different layers
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The flushing
+ amount obtained through the automatic allocation of the printing sequence |
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The flushing
+ amount obtained through the manual setting of the printing sequence |
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3. Grouping restrictions on +filaments
+ +Due +to the physical limitations of the printer, different nozzles have their own +printable area limits (Introduction +to the printable range of H2D dual nozzles). As shown in the figure below, when +the part of the model printed with a filament is placed in the left nozzle or +right nozzle only area, then it can only be printed using the corresponding +nozzle.
+ +In +addition, based on the physical design of the tool head and the characteristics +of the material, each nozzle has other printable filament limitations, with +specific limitations as follows
+ +Group +restrictions:
+ +• +TPU +material can only be printed with the right nozzle. (Priority: High)
+ +• +CF and GF +materials can only be printed with the left nozzle. (Priority: High)
+ +• +When the +height of the part exceeds 320 mm, it should be placed in the printable area of +the right nozzle. (Priority: Medium)
+ +• +When +parts are placed in the left-nozzle-only or right-nozzle-only area, they need +to be grouped to the corresponding nozzle for printing. (Priority: Medium)
+ +• +Filament +can be printed with both left and right nozzles, it's recommended to print with +the right nozzle. (Priority: Low)
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4. Filament-saving mode
+ +Since +material switching between different nozzles does not require flushing, the +entire flushing amount comes from switching filaments from the same nozzle. +To reduce filament waste during switching, the filaments with a large +switching volume should be assigned to separate nozzles. The default +material grouping strategy used in Bambu Studio is the filament-saving mode. +You can see a total of 3 modes in the floating window of the slicing button. +Select "Filament-Saving Mode" and click on slicing to obtain the most +filament-saving printing. The logic of this strategy is briefly introduced in +the following sections.
+ +When +you set the pairing relationship between AMS and the left and right nozzles, +and synchronize the AMS information in Bambu Studio, the slicer can calculate +how many filaments are connected to each nozzle. If no AMS is connected +to the printer, the slicer defaults to allowing the nozzle to load one filament +through the external spool. Then the slicer can achieve an optimal filament +grouping to ensure minimum flushing waste is attained under the calculated +printing sequence. The principle is to group the filaments with more common +layers and larger flushing amounts into as many different nozzle groups as +possible.
+ +To +sum up, the grouping algorithm mainly needs to consider the following points, +and the priority of each point is reduced in order.
+ +1. +Whether +the material is a non-printable filament for the nozzle;
+ +2. +The upper +limit of filament in AMS connected to the nozzle;
+ +3. +Minimize +the filament flushing amount;
+ +4. +Minimize +the color gap (Delta E) to the filament in the AMS connected to the nozzle;
+ +Since +the grouping logic is more inclined to reduce the flushing amount rather than +the closest color, after slicing, the user needs to check whether the filaments +are placed in the corresponding AMS of the left and right nozzles according to +the "Filament Grouping", and appropriately adjust the position of +each filament in the AMS. Otherwise, the filament automatically assigned to the +nozzle may not be selected in the sending task window.
+ +As +shown in the following GIF, once the sliced filament is assigned to a +specific nozzle, it cannot be forcibly changed to a filament from another +nozzle when sending the task. Even if there is a filament of a closer color +from the other nozzle. So we can only manually adjust the position of +filaments in AMS to achieve the most filament-saving printing.
+ +5. Convenient mode
+ +Unlike +the filament-saving mode, the convenient mode groups filaments entirely +according to the filaments placed in the AMS, regardless of the sliced model. +Under this strategy, efforts will be made to match the filament grouping +results as closely as possible with the filaments placed in AMS (color, type, +etc.).
+ +This +option tends to group based on the user's existing filament placement, which +may waste more filaments for flushing, and in most cases, there is no need to +adjust the position of the filaments separately. Suitable for scenarios where +users are not near the printer and remotely initiate multi-material printing +tasks. We suggest that you resynchronize the AMS filament information +before using this mode for slicing. You can select "Convenient Mode" +in the floating window of the slicing button, and the sliced filaments will be +grouped according to the actual filaments placed in your AMS. After slicing, it +can be seen that the optimal grouping (filament-saving mode) saves more +filament amount compared to the convenient mode.
+ +The +grouping algorithm under this strategy mainly considers the following points, +with the priority of each point decreasing in order:
+ +1. +Whether +the material is a non-printable filament for the nozzle;
+ +2. +Consistency +between sliced filaments and filament material types in AMS;
+ +3. +Minimize +the color gap (Delta E) to the filament in the AMS connected to the nozzle;
+ +6. Custom mode
+ +Suppose +you are not satisfied with the auto filament grouping strategy. In that case, +you can click on "Regroup filament" in "Filament Grouping", +and then manually adjust the filaments in the left and right nozzles in +"Custom". After slicing again, you can see that the optimal grouping +(most filament-saving) method saves more filaments than manual grouping. Note: +Filament-saving strategy only considers saving filaments, so sometimes there +may be more filament changes in filament-saving mode than in convenient or +manual mode, which is normal.
+ +You +can also directly select "Custom Mode" in the floating window of the +slicing button, which will allow you to customize the group of slicing +filaments to the left and right nozzles before slicing.
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7. Plate settings and global +settings
+ +For +different scenarios, the grouping strategy is divided into different levels of +parameters: plate settings and global settings. Before slicing, if you +manually set a strategy for the plate, the plate settings will override the +global settings.
+ +On +the right side of each plate, after clicking the corresponding icon, there will +be a pop-up window, where you can see the filament grouping mode used by the +current plate. You can set the mode for a single plate, including Auto +(Filament-saving and Convenient mode), Custom, and Same as Global.
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If +you have separately set the grouping mode for a certain plate, after slicing +the single plate, the floating window at the slicing button will prioritize +displaying the strategy of the current plate. However, there will be a global +setting icon placed after the corresponding mode to remind the user which +strategy is used for global slicing. If no separate mode is set for the plate, +the floating window will prioritize displaying the global settings.
+ +When +slicing all plates, always display the global grouping strategy to facilitate +the setting for all plates. But the filament grouping method set for a single +plate still takes effect.
+ +In +the manual grouping window, only the filaments in the current plate are +displayed when slicing a single plate, and all filaments are displayed when +slicing all.
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