On Wednesday 03 June 2020 01:32:50 Bruce Layne wrote: > 3D PRINTING - WHAT WORKS FOR ME AND WHAT I'VE LEARNED > > I print on borosilicate glass. I use Elmer's Xtreme glue stick for > first layer adhesion. The larger 40 gram stick takes less time to > apply. I use a clean dry borosilicate glass plate. Apply the glue > when the plate is room temperature. Press down with 1-2 pounds of > force making contact with the entire flat face of the glue stick and > move the glue stick one inch per second to produce a thin and nearly > transparent layer of glue. You don't want gloppy thick glue. Overlap > the glue stick slightly for complete coverage. Apply the glue > immediately before printing. The glue stick works well when printing > with ABS or PLA. Here are my settings: > > PLA > Nozzle Temperature: 215C > Bed Temperature: 80C for the first layer and then 50C for the other > layers (50C for all layers works well too) > > ABS > Nozzle Temperature: 230C > Bed Temperature: 110C > > If you use hairspray as a first layer adhesive, remove the glass sheet > before spraying it. I see YouTube videos where people fog the inside > of their 3D printers with hairspray that'll gum up whatever precision > linear motion components their printer uses. > > In addition to proper adhesive, a level bed at the correct height is > also a necessity for that critical first layer adhesion. I designed > and printed some oversized knurled thumb wheels to replace the tiny M3 > wingnuts that the printer manufacturer supplied for bed leveling. I > used nylon thread locking M3 nuts as inserts into my thumb wheels to > help the bed stay level. > > https://www.thingiverse.com/thing:4383435 > > If you want to really dial in the bed leveling, do the regular bed > leveling with a thin shim, then print a 30mm square that's .2mm thick > (one layer) over each bed leveling nut. If you see the plastic > smearing, the bed is too high. Stop the print to avoid clogging the > nozzle and lower the bed. If the squares print but when peeled from > the bed they're composed of individual strands, the bed is too low and > needs to be raised slightly. When the bed is level at the correct > height, each of the sample squares will print as a solid plastic > film. Slicers have software settings for first layer printing > parameters. I prefer to leave these as default. If you fix a bad bed > level with slicer settings, the problem will return with a different > slicer profile. > > It's also necessary to easily remove the parts after printing. This > isn't only a matter of convenience. People attack their printed parts > with a sharp scraper and try to pry them off the bed. Many people > have gouged themselves with a sharp scraper blade. Using excessive > force to pull the parts off the bed results in at best a ruined bed > level. Who applies that kind of force to delicate precision motion > components? For PLA parts, I dribble some water around the perimeter > of the part and it dissolves the glue, wicking under the part and > floating it off the print bed in a few minutes. ABS parts are even > easier. ABS is printed at a higher temperature and shrinks more when > it cools. ABS parts pop off the glass bed when it cools. It often > sounds like the glass has cracked when the ABS pops free a section at > a time. If you use any form of violence to remove your printed parts, > you're doing it wrong. > > I find it easier to make dimensionally correct parts with PLA. ABS > shrinkage isn't linear. It depends on part geometry, infill, etc. If > I want accurate ABS parts I'll adjust the design to get the dimensions > I want. > > It's counter intuitive but filament deposition 3D printed parts with > 100% infill are less structural. There is no internal compliance so > the solid part has internal stress and is likely to fail by layer > separation.
That sounds like a heated enclosure might be worthwhile, keeping it warm enough to stress relieve? > 50% fill makes very strong parts, but 20% fill is strong > too. I usually use 20% or 25% infill. If I want stronger parts I'll > increase the number of outer layers. I'll have to ask how you do that with cura? > > I recently bought an MSLA resin printer to complement my FDM > printers. With a structural resin such as Siraya Blu, the resin > printer would make some VERY strong and dimensionally accurate parts, > such as timing belt pulleys. The biggest disadvantage is the > relatively small build volume, but I've been making some very nice > parts that are comparable to injection molded parts. Even with low > cost commodity resin, the solid parts from the MSLA printer are very > strong. > How does that compare to PLA for the expendables $? Thanks Bruce, stay well. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
