update - xmas pudding print finished - got a few failures I think because they probably need brims or might need to clean my build plate (or could be due to purge-to process).
You still do get tiny wisps of purge, then it goes to the tiny prime tower, then to the purge-to objects, before finally doing the multi coloured prints.
Weight of the wisps from 81 colour changes <1g - too little for my scales, plus prime tower is 4g - so might try removing it on another test. Overall though I call this a success.
As well as the xmas puddings I have got quite a few useful other decorative parts plus some more parts of my ‘3d printed table’.
Other print - of cruise Ship print 91% complete and looking good too so far. - about 1hr to go - so might leave that for now and pick it up in the morning.
Ship came out pretty well - unfortunately 3 minor faults - with centre pools mainly - so will have to reprint.
Pretty pleased with purge test though - about 6g of waste (for BS not quite correct as it says 1.47g) - so wonder if the length of those wisps can be reduced. Not bad though for 243 colour changes.
Purge-to table leg pile growing nicely - although my algorithm has chosen quite a lot more female than male segments which I have just piled up without interlocking (which is why it looks a bit uneven in the photo). Easy to fix by just removing the plate of female parts out of my ‘purge-to’ queue.
Update after 3rd test print. 200% scale Xmas pudding tree decorations came out really well. Normal purge was 6g - so about 3 times what was predicted. There was also another 5g due to the brown filament running out and remaining on old roll having to be purged out. Prime Tower 7g.
I think that maybe 15% infill is too much for these models - and also not really sure whether the around 25g of filament saving is worth the effort for this type of print - probably more relevant for prints with more colours where having multiple copies of the same multi coloured object not really needed.
Also having less heavy off bed purges does cause a few of the ‘wisps’ to be dragged onto the prime tower - see photo.
Still running a reprint of ship model with faults corrected.
Will post both models on Makerworld/Facebook with and without ‘purge-to’ objects as next stage to see whether there is enough interest in ‘purge-free’ models to warrant further work in this area.
Internal design of the purge-table done, plus found a better way of simulating likely look - using a F360 Wood appearance - with a photo of the current purge leg imported into the appearance as its texture photo.
For many of the parts it will be possible to alter the height so that top surfaces line up better with the layers with colour changes. This will also mean that the height and width of the table will be easy to alter or grow as more purge-to blocks get created.
As I am keen to print out the whole table - may have to switch around the process - and look for suitable multi colour object to print alongside these parts - in order to get a nice pattern of ‘purge-to’ lines.
Didn’t bother with purge-to objects on 200% version - but got a 75% saving on the 100% version.
On makerworld in xmas competition.
Also encountered some strangle slicer behaviours with Brims on Purge-to objects.
If the purge-to objects initial colour is different to the first layer colour on the main multi colour object then brims keep disappearing off of the purge-to objects.
Next up - more relevant to this thread - glad to see that there is a new totals column in the BS Preview screen showing the prime tower usage separately - rather than including it in the model (not flush) total in previous versions.
Further updates - firstly been doing quite a lot of single colour printing - concentrating much more on print quality than I have done before - mainly creating support free spheres and balls - the reason to mention this is that this has led me to needing to do some 100% infill printing which I have never done before - and 100% infill models are really good flush-into targets - especially parts like the internal double ended screw used to hold the two parts of my spheres together.
Final screenshot showing what happens if you turn off the prime tower - flush-into no longer works - and flush goes right back up to the starting point
Will probably only let it run a few layers to avoid waste - main objective is to a) Check that the printer accepts a patched gcode.3mf file ok over wifi, b) check that movements are ok and c) to see what effect it has on the quality of the flush-into objects.
Test result - success -
went up into infill layers - and printer seemed ok with not having prime tower. Lines went down ok into flush-into objects and colour changes worked ok. Bottom layers of flush-into object put down far more plastic than is needed to flush out the old colour - number of objects determined really by size of infill layers.
Next step - try it on next proper multi colour print.
NB/ This method of removing the prime tower is only relevant when there is sufficient wasted flush to warrant the use of flush-into objects - whose quality probably isn’t as important as the main multi colour object - so can be used from priming as well as flushing.
Thanks - Yes - will release it - once I have refined it a bit and have at least a small version printed - progress has slowed a bit because I am not doing a lot of multi coloured printing at the moment.
I am hoping it works out that once you have created the basic parts and produced a fairly small table (or potentially other shapes) you can then just expand the dimensions as more flush-into parts became available as a byproduct of other prints.
Think I will have a go at doing a smaller scale single test print tomorrow - using low value filament in order to try and make a bit more progress on this initiative.
Update. 28/11. - print now ready to go with most of the essential parts to create a corner of the purge-table - one 1g of flush.
Update - purge-table starting to take shape - all individual parts now tested.
Just need to build up a few more top parts and legs - big incentive to get on with some nice big multi colour prints
Not strictly related to the subject of purge reduction - but I have just seen this interesting post on Facebook about problems with prime towers in ‘multi material’ support interface prints - Redirecting...
Interesting issue. My thoughts are
Priming is probably even more essential than normal for multi material support interface layer prints - as you need a really clean flow of both of the materials when they are overlapping each other - so turning off the prime tower is probably not a good idea.
In the prime tower the initial inconsistent flow in combination with poor inter layer adhesion between different materials does mean that it is more likely to fail than a single material prime tower.
The solution I think has to involve separate prime towers per material. This then leads to the issue of creating masses of extra material swaps to in this case keep the PETG tower the correct height.
The solution to this issue I think is introducing a variation of the ‘no sparse layer’ prime tower logic in Prusa slicer - which allows the prime tower to have less layers in it than the actual print.
This method though would suffer from the same height restrictions as you get when ‘printing by object’.
I think however that you could work around this issue by keeping the PETG prime tower not too far behind the PLA tower by adding just the occasional extra PETG colour change - which is used to add a few layers to the PETG prime tower - so that it doesn’t get too far behind.
Whilst ideally this should all be done in the slicer - I think it would be possible to write a gcode post processor to
A) split out the materials into separate prime towers
B ). Add ‘no sparse layer’ type functionality
C) enhance ‘no sparse layer’ to stop towers from getting too far behind the main level
Any extra colour changes required for this would have to be created by manually adding them into the model at the correct heights.
Sounds like an interesting technical challenge - for waste reduction purposes I was already considering having a go at creating a GCODE post processor to
a) alter the shape of the prime tower to make it into a more useful shape (such as a section of ‘purge-table’) rather than waste
b) adding in a ‘no sparse layer’ capability -
so might have a look at the splitting the tower into materials too at some point.
Your discoveries are impressive.
This started as a forum thread but feels like a complete research paper when I read it.
In the past few days I began to do the same as you, only I was using the Hive model as purge into object.
I had satisfactory results but I was interpreting the numbers in the BL final table quite bad. Your thread makes it clear.
My question is: do you keep in BL flush volumes auto-calculated with fixed multiplier?
I had good results with my colors that I mostly use with multiplier 0.6 even with prime tower only and poop out the chute.
Increasing the number of sacrificial objects that does not matter the color composition will decrease the wasted plastic with flush.
I am no near able to automate a script to remove prime tower but I am interested in that if you want to share.
I’ll keep a close eye on your thread
Thanks in advance
Thanks, yes I use auto calculate and usually 0.5 multiplier. Using flush-to objects mostly slightly increases the effective flush a tiny bit. Removing the prime tower reduces it a little bit - so I guess it may end up resulting in having to push the multiplier up a little.
Will share the post processor once I have tested it out a few more times, plus worked out the best way of sharing python3 code in such a way that it is easy for others to install.
I have tried out some of the flush checking methods like the AMT_MW test models - bit I think it is probably going to be too complicated for to keep track of all of the different flush volumes for different colour combinations - so will probably just stick with auto calculate for now - because as long as you are flushing into useful objects an extra little bit of flushing isn’t necessarily a bad thing.
This is amazing. Just got the AMS added to my P1S and coloured my first print (turned Barry Bear into a panda) and I was disappointed to see my 90g print was going to make 180g of waste. I figured someone must have found a way to reduce that. I knew about flush-to-object so I had a couple of functional pieces I had waited to print for this reason but they only reduced the waste by 20 g or because they were either too thin or too short. Your experiment (which is how this read like Cmaneaonline said) was extremely helpful and got my waste down to 23g and 330g of functional. So although my filament usage increased to 22% my waste was reduced by 89%. And this was without using your table pieces or your python code (since I felt too inexperience to try it). I hope your research here becomes part of the Bambu Wiki as I think everyone could benefit from it.
Decided to have a go at individual colour swap purge lengths based on the AMT_MW models on maker world. Initial results showed definite benefits over auto calculate for some colour combinations - without a clear pattern.
As am currently away from printers - have used the time to create some automations on top of Bambu Studio using the Mac only ‘Keyboard Maestro’ app.
First macro is an easy one to automate the setting of all flush lengths to 50.
Next set of macros can then be used to store any newly calculated optimal lengths against the associated filament types and colours - so that they can then be easily re-applied whenever required.
It should also be possible to enhance these macros to do more generic enhancements to the build in auto calculate.
Initial ‘set lengths to 50’ macro shared below - if there is any interest in the others let me know.
