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. 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 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. _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
