[Solved] Randomization of calibration points
I think a nice improvements would be to add a small area around each calibration point of the bed. As it is now the calibration hits exactly the same spot every time resulting in some clogging (or what to call it) of those specific points. It also puts extra high demand on that the user don't miss to clean the bed at those points every time. If the calibration instead was done in a randomized placement of maybe 1x1 cm you would get perfect result even if you totally forget to clean those spots at all! Easy and effective!
The nozzle is hot enough that it should push down through any residual filament. If your nozzle is leaving filament on the bed every time it means there is a problem with the nozzle. Either the nozzle needs to be cleaned or the valve isn't closing properly. You should open a ticket if you see this consistently.
The wear doesn't seem to be an issue; I have PEI sheets that are five years old with thousands of print hours and they still work fine.
This likely isn't something that will be implemented as the printer works fine as it is, when working properly.
Ok. Great, then I don't have to worry.
My printer has always left a tiny amount of filament at the calibration points since the day I bought it. 3 heads later and it's still the same so I think this is just a characteristic of the machine. The suggestion for some small randomisation is a good one in my opinion.
@jellison It is more likely that you aren't cleaning the nozzles often enough or you haven't calibrated them correctly. When you do the nozzle opening calibration, you should click Present at the very first indication of any ooze from the nozzle, not a full flow. This will give you a better calibration. For the behavior to be consistent over three heads points to a calibration issue and not a mechanical issue. My print heads don't leave material on the bed during the bed mapping.
@bhudson Yes I think I'm following the procedure, just the merest hint of filament showing. Don't get me wrong, it's not like there is a puddle of filament at every cal point, but there is usually residue left behind that builds up if not cleaned off after every print. Some materials seem worse than others, for instance the PETG I'm using at the moment is very clean, whereas PLA or ABS often leaves a blob. It's a minor niggle to be honest, but I thought I'd share my observations.
@jellison You may be looking at wet filament since the water can make it more runny when melted. I just ran a PLA print and had no material left on the bed, even though the mini-purge left material on the nozzle. You may also need to clean the outside of your nozzles. There is a support article on how to do it properly.
@bhudson It's possible, although I keep the reels in a cupboard with silica gel sachets. I use a dremel with a soft wire brush for keeping the nozzles clean. The purge function likes to ruin my shiny nozzles when it plunges into the molten filament, but I guess it needs to do that to stick it to the bed.
@jellison Unless the cupboard is airtight your silica gel is going to be saturated in short order. You need to have the reels stored in an airtight container and you need to recharge or replace the desiccant periodically. It doesn't last very long. Even in my airtight containers I have to dry the desiccant every 4-6 months.
Yes, ovened at 120C regularly.
@BHudson Picture of residue at the cal points. Fresh reel just unsealed, clean print head calibrated. It's minor, I can just scrape it off between prints, but it is not related to filament storage or head calibration. I have always accepted this is something that the machine does.
I will try calibrating my nozzles. I have always wondered if I should click Present at the first tiny flow or at full flow. I think I waited for full flow so it's worth a try. If first tiny visible flow is the correct setting I think that should be better described in the calibration routine.
I have also noticed that Polyflex leaves more on the bed than other materials.
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