1st post on this forum, been reading a lot here and I just wanted to add some of my observations and a post that is still under moderation at MB Blog. I still haven't gotten what I consider a great 3D print from the Z18 and nothing that even comes close to the 3D print objects that have at the shows and show on the website or even the large Margo print over at Bold Machines. Until 3.4 comes out to address some of the feed rates I am holding off on this venture being classified as a complete waste of money but I am hoping for some salvation that they can work it out.
This is the post I made on the Blog
Just wanted to add this as I too have purchased a Z18 and have had issue after issue with the extruder, clicking, jamming, globing up, etc. This may help some but again it may not though I have gotten some mileage out of it on my side.
First low and standard quality configs even with creating a custom config have a higher chance of problems through a print lasting more than 1 hour. High Res has given me the best, even though not what a call great quality and no where near the quality of parts they show on the website.
Second, Filament thickness, using the default configs are most certainly causing issues with the extruders. I bought 16 rolls of Makerbot filament when I ordered the Z18. The filament thickness ranges from 1.62 mm to 1.91mm, this is a major difference in the default setting of 1.77 mm. I have measured the same roll and set the custom config to the size of the start and when I started noticing clicking or a jam measured the filament again and noticed that the filament diameter was larger than at the start. This has happened multiple times and from what I can deduce on my side a variation of .05-.09 mm will start a random clicking if the filament gets larger than the config setting. If the filament grows by more than .15 mm you are almost guaranteed a lot of clicking and possible jam. Since Makerbot PLA is the only thing allowed in these extruders it is hard to go to another source that may have better control on their filament tolerances.
Third, if you have a Z18 and are using the bottom tray, there is an excessive drag to pull the filament to the top. locating the roll at the top of the unit an using a bearing carousel to feed the unit eliminates the drag click you may sometimes hear. Things get worse if your dragging and the filament thickens in regards to jamming.
Fourth, also for the Z18, leaving the top on the bend in the tube on the top of the extruder causes a bind point and can push the extruder off its magnets for a second causing a break in connection.
Fifth, use a custom config on everything you print, stay away from default. Some settings I use.
FeedDiameter in the extruder profiles (measure your filament in several place, err on the mid range to minimize the starving or jamming.
Feedrates in extrusion profiles, I have slowed all of these down, I get a better flow even if the extruder is dealing with varying filament thicknesses.
Extruder temps, these can vary as well based on the filament but I have found 218-220 works better than the default 215. Z18 – set the build chamber temp to 35C, default configs do not even enable the build chamber heater. Even on small prints the heated chamber works better in my opinion.