Stay in the model for multiple layers before traveling

[FalcoGer]

Is your feature request related to a problem?

When printing a lot of disconnected vertical shapes, there is a lot of travel move between those shapes, causing stringing and taking time traveling when the printer could be printing.

Describe the solution you'd like

The printer could instead print each vertical section for several layers depending on the gantry and print head geometry before traveling once to the next feature. This would require knowledge about the physical dimensions about the printer head, but would improve print quality and print time by a lot.

This is similar to the print one at a time option, except it works on a single part. If two vertical sections are very close to each other, only the height that the nozzle sticks out of the print head, typically a few mm, could be considered, which is still a major reduction of travel between printed geometry. Even if only 5mm height is used for this, the print head would stay in the model for many layers (100 with 0.05mm layer height or 16 for 0.30mm layer height), which drastically reduces stringing and travel time.

Describe alternatives you've considered

N/A

Affected users and/or printers

Everybody with a standard Cartesian coordinate (XYZ) FDM printer.

Additional information & file uploads

Red: Current system Blue: Proposed system

As you can see, this would drastically reduce the time the print head spends between the two parts. As each layer is typically only a fraction of a millimeter, several tens of layers could be printed before moving to the next section. With a very long nozzle, this could further be improved. Even if just the height of the nozzle to the rest of the print head is considered, this could easily reduce travel times by a factor of 10. In this image 5 layers are printed at once. The travel between the two sections are reduced from 12 to 3 but only because it's exagerated with very few layers. typically it would be more like a factor of 5 with just the last layer not benefiting as much.

[GregValiant]

Thanks for the thought you put into this. The idea has been brought up previously. The way it currently works is that if a print splits and there are two islands that need to be printed then Cura will do two layers here and two layers over there. Once you get above doing double layers then crashes can happen. My cooling duct end comes out behind the nozzle and is about 1mm above the print. So I could maybe get 4 layers in before the duct hit the model. My print head is about 90mm wide and 56mm deep. So it needs to be around 40mm from an adjacent "island" in order to print something. Every printer is going to be at least a little bit different but most have crash points well below the gantry.

[FalcoGer]

Just very few layers at a time would improve quality and speed by a lot, particularly in models with lots of gaps. Every time the nozzle travels it has potential for stringing. Reducing the time the nozzle spends outside the model will help with that. Every extra layer printed before moving on to another section is one less potential defect.

Obviously every printer is different. Different regions of the print head may be required. Gantry size would be the maximum possible, but if the split is only a few tens of millimeters then only whatever amount the nozzle sticks out the bottom could be reasonably done without bumping into things. for me that's around 5mm, which still would equate to at least 10 layers. This could be even further improved with an extended nozzle.

The only drawback, besides the potential for misconfiguration and the one time requirement to measure out the print head and enter the values, is that printing small sections might not have had enough time to cool before the next layer is printed on top.