I originally posted these requests over on the Cura Lulzbot Edition Workboard as I'm a Taz 6 user, but figured it might be better to go to the source.
Option 1: Define Model Print Order
When printing multiple duplicate parts, several efficiency issues arise as objects are often printed in a non-uniform sequence requiring additional unnecessary travel between models. This effect is particularly noticeable when printing an array of duplicate objects which require supports. Support layers for each duplicate object are printed prior to printing corresponding layers of each object which effectively doubles the travel time for each layer of the array. Experimentation with the order in which models are duplicated or added to the build plate within Cura seems to have no noticeable bearing on the sequence in which the models are printed. Model grouping also does not appear to affect model print order. Existing potential options to influence this process including the “one at a time” and “all at once” options as well as z-seam alignment customizations produce inconsistent results. An option to manually define the sequence in which models are printed could solve this issue.
In my experience, even on seemingly simple arrays of duplicated objects, Cura often prints objects in an order that increases the number of unnecessary moves. I've included 2 screenshots of an array of parts where I have overlaid the order in which the parts are printed (actual print order vs. desired). Beginning in the bottom left corner User Specified Z Seam Alignment where X=0 and Y=0), the actual print order skips a model altogether and then backtracks to complete it which does not seem to be the most efficient path. Perhaps I'm doing something wrong, but I can't figure out why Cura has decided that this is the preferred sequence for this particular array. It would be preferable if the order in which objects are printed is displayed and editable to prevent this from happening. This could also come in handy for those wanting to print a "priming" object. I've seen several inquiries on various message boards where folks have requested the ability to print a skirt for priming and a brim for build plate adhesion. When printing with a brim only, sometimes extruded filament has cooled slightly when it first comes out of the nozzle and does not promptly adhere to the build plate. When it eventually sticks, the cooled string of filament may have been dragged across the bottom surface area where the object will be printed. This can result in issues with first layer quality. To circumvent this and minimize the need to babysit the first layer, I've attempted to print a "priming object" first. However, since print order of different objects cannot be manually defined, it's luck of the draw as to whether or not the "priming object" actually prints first.
Option 2: Uniform Tool-path Cloning
When a model is duplicated multiple times models are often sliced in a way such that the path of the extruder is not identical for each duplicated part. This results in inconsistency in surface finish between models. Manual adjustment of Z-seam alignment settings can be used to influence the starting position of the extruder for each model in the array but does not guarantee identical tool-path travel for each layer. An option to clone the tool-path relative to the model would provide greatly enhanced surface finish consistency between duplicate models.
Currently, in order to ensure that 10 objects are virtually identical, the same object must be printed in 10 separate jobs which requires start-up and cool-down time for each job as well as time for part removal. Even if the additional tool path travel adds 5-7 minutes per print job for an array of 10 parts, it would save time in not having to run the start-up and cool-down sequence for 10 different parts. The integrated cost savings over time of reducing start-up, cool-down, and part removal labor could be significant. Most importantly, tool path cloning ensures identical surface finish and structural strength between parts without having to run multiple print jobs. This is particularly valuable to small businesses who may not have the luxury of running multiple machines.
Option 3: Per Model Settings – Build Plate Adhesion
An option to manually select build plate adhesion on a per model basis would be beneficial in printing multiples of different models in a single print job where each model may require unique brim or raft settings would be beneficial in improving efficiency.
I welcome any suggestion which might help to achieve the desired result with Cura's existing features.