Hi all, I am starting my build right now. One thing I don’t see in the LR4 instructions is brace spacing. On the LR3 instructions, it says 200mm spacing is max, but it looks like this section was removed in the LR4 directions. The print guide says 4-6 brackets though. I am planning on a ~49"x49" machine so I can feed a full sheet through it.
Is there any official guidance? FYI, my build is using 31.8mm OD stainless tube (found some near me that was a great deal) so using the 32mm brackets and the first two fit perfect. Bit that does mean my gantry will be slightly heavier but also stiffer than using conduit.
Thanks, I did that and it is saying 7 (6 regular + the max) so I will go with that, but I do think this may be an oversight on the documentation. The section talking about that was removed for some reason between V3 and V4.
It sounds like the 200mm aka 8" max spacing is still the design goal, so I would suggest that be added back into the docs like it was on the V3. It was noted explicitly and was removed for some reason. It does say that in the strut calculator, but I thought the older instructions were clearer.
I do have my personal answer and my last two are printing now, but from my end user perspective, that part of the docs regressed a little. That being said, with this conversation in the search index, that may also help people who don’t automatically connect the dots. I did try searching and didn’t get any useful hits.
yup, but the LR3 manual DID say that, and the strut calculator also says it, just not in the new docs.
I am somewhat stuck anyway, bought some fancy PET-CF filament for the core, but had really poor layer adhesion. Tried a few test prints with some different settings and all came out poor. VERY stiff, but I was also able to break smaller prints by hand that were unbreakable by hand in standard PLA. So have some more PLA on order…
did you follow the printer profile recomended by the manufacturer? i printed my pet-cf parts from Siraya tech and they offered a bambulabs & Qidi profile
the qidi one worked for my FF ad5m just tunned the temps. this printer has a max temp of 280 degrees
only had one single part that failed to me and it can be charged as User error/brute force applied by hulk on the asembbly
yea, I was also using Siraya PET-CF, and was using their X1C profile as a baseline. I am printing with a K1 with a hardened .6 nozzle. The prints looked great, but I was able to break them by hand using the X clips as small parts to also look at dimensional accuracy). I tried a few temps with the high end being 300 (max for my printer) and also various speeds (all within their recommended ranges) and all where brittle and broke at layer lines. I did not anneal, but even on their site, that shouldn’t be necessary.
Yes, those parts were very adhered to my build plate! My rolls also were straight from sealed package, but I didn’t dry them first. Either way, I am just going to follow the yellow brick road path and use PLA for now, I can always reprint something if I think there are any rigidity issues.
Maybe I got a bad roll? not sure. I have used Siraya high tech resins in the past and they were great, but I couldn’t find a good recipe for this filament…
Would be willing to bet that’s your main problem right there. PET-CF has to be dried before use and kept dry while printing. I have printed SEVERAL rolls of it and have not had a single part break. Always dried before use and printed from a drybox at the printer.
Interesting. Their own docs say that PET has low moisture absorption, so with this being new I wouldn’t think it was necessary. I did reach out to Siraya both to their support as well as their facebook group for any any ideas. Other hydrophilic filaments I have used you can usually visually see issues, and/or hear popping while printing which I did not encounter.
Also, if anyone with good prints could attach a screen print or something similar of the settings you used, would love to try again.
I had issues with PETG where the prints came out weak and brittle like glass. Stiffer than PLA but way, way weaker. That was on newly opened filament before drying and with the default Creality profile that used significant amounts of part cooling.
Since then I’ve been drying the filament before use and keeping some well-dried silica gel bags in the dryer while it’s off. Between that and turning the cooling fan off for everything but overhangs and limiting the max fan speed to 50%, that seems to have solved those issues. Parts are now rough and moderately flexible. Nowhere near as stiff as PLA but tough enough to be extremely usable, even in some situation where I’ve had PLA parts creep and break in relatively short times.
Maybe it’s a similar combination for the PET. From a quick google, some references say PET-CF isn’t hygroscopic and isn’t sensitive to moisture. The Bambu Lab store says that it’s highly sensitive to moisture and should be dried for 8 hours at 80C before use, bloody hell. There are a couple of posts on reddit that seem to agree with the ‘aggressive drying’ approach having helped.
Yea, had lots of problems with PETG doing this. I actually store all my filament, even PLA which is not overly susceptible in big sealed bins with a large amount of desiccant in them just to be safe, but I also don’t usually worry about factory sealed bags for the first print.
I do have dehydrator turned filament dryer I use for this, so will give it a shot…
out of it and keeping it dry.