Yes, the nozzle height is the #1 thing to set correctly but if you are willing to print a "raft" under the part rather than just a "brim" around the part. The height is no critical. It does waste plastic and time and requires finish work with #600 wet and dry paper at the place where the raft separates.
Your printer is different from mine in one very important way. The "Ender" places the filament feed motor on the frame and pushes the filament to the hot end via a Teflon tube. This is good because it removes mass from the moving head. My printer is "direct feed" and the filament feed motor is mounted on the moving print head. This is bad because the stepper motor gets hot and adds lots of extra mass to the moving head. But the direct feed head has much better control of the extrusion process as there is only about 10mm of filament between the motor and the brass nozzle. What infill is best for my direct-feed printer might not be best for the in-direct tube feed printer. Your printer has a lag between the time the extruder motor pushes and the time a drop comes out of the nozzle. The direct printer can even "suck" the plastic back as it travels over a freshly printed part minimizing drag. I have an anet-6 printer. It's way-cheap. I only paid about $185. The new Dremel printer you ordered is direct-feed. The trade-off is that with the added mass you get more vibration and slower printing unless you spend more for a more massive frame and bigger motors. Back to infill geometry. I like "gyroid" for low density and just plain old "grid" for high density. But my printer is different. Not better, just different. Gyroid works because the printer lays down "S" shape sine waves and is kind-of self clearing. It shakes off extra plastic. It is just like "grid" be rather than straight lines it draws sine waves. The infill is stronger too even at 10% or 20% Why not just print some "bricks" as tests. Do different settings then put them in a vice and smack them with a mallet and/or bend/twist them with a wrench. After breaking 50 bricks you will be the expert in strenght/weight/time tradoffs. What you might find is that you are over-building the pulley. There is no way a belt can put much force on a pulley and 25% or even 20% gyroid is strong enough if you have 1mm thick walls. and metal hubs. On Thu, Feb 18, 2021 at 1:46 PM Gene Heskett <ghesk...@shentel.net> wrote: > On Saturday 13 February 2021 15:40:22 Chris Albertson wrote: > > > It is very unlikely that your printer is making (say) 99.9% scale > > models of yor parts. It is using stepper motors and toothed belts, > > steppers always do the commanded number of steps and timing belts > > don't slip and always do the integer ratio of teeth, even if the size > > is off. > > I've been scaling it up, about .1% or less per run, differing amounts for > X & Y to get a mre perfect circle yadda yadda, and have it doiin fairly > well, but then the hot end froze up and I had to replace the teflon tube > from the top of th heat sink to the rear face of the nozzle, allowing > around 10 thou of compression between a washer on the bottom of the > shark fitting and the rear of the nozzle, plugging off that src of > leaks. So generally, its back amoung the living and I jst nowam > finishing the top surface of a ETG pulley about 12 mm thick with a belt > track 7mm wide for a 6mm belt, and a 41.6mm hub hole so it can be > pressed oer the existing alu pulley used on the axle of the A drive that > came with a 4 axis 6040. Then I made in openscad, motor pulleys with the > same tooth profile as the 85 toother, in 13,15,17 & 19 teeth. But they > have not yet been transfered to the U-SD card driving the ender-3. I am > very disappointed that files can't be moved to the ender over a USB > cable, and thats one reason I bought the best dremel off amazon. > Supposed to be here last night, but the roads scared off UPS. and we got > a new 6" of snow turning to freezing rain this morning. Roads are black > now but likely icy, so I've no idea if it will arrive today yet. > > > Now back to the pulley you are printing. Why care about a slight size > > issue? As long as the belt never slips a tooth the pulley ratio > > holds. Only with plain pulleys does a tiny size error cause a tiny > > error in speed reduction. Timing belts are like gears, it is the > > ratio of the teeth that matter. > > True, but I started as you'll recall, with a printer that was not well > calibrated OOTB, and I've been piddling the the scales ever since. > Ejector feed is a huge puzzle as it was set so the waving cat was > virtually weightless and see thru. OOTB scale was 35 or there abouts, > when it should have been around 375. Then I found the advice from > MicroSwiss about tension of the ejector, was full of it when he wrote > the end of the screw was to be about 3mm into the thumb but, that was so > loose it just sat there and ground the filament into dust on top of the > head fan. With a corresponding very obvious click. And bringing that > tension up to under a mm inside the thumb nuts face stopped that > slippage so I can now make a feed adjustment that actually worked, and > have played with the feed rate too, so a good part of this last pulley > was made at a 200% feed rate, but it went to hell when it switched to > infill so I slowed it down to improve the looks of the missing infill > and its finish up the best pulley I've made yet. Very well shaped 3mm > teeth. > > So my question, for a cura default 30% infill, is what is a good infill > pattern that isn't subject to being torn out by the moving head, and > eventually thrown clear of the workpiece? > > I tried 40% but the tear out demolition was even worse. > > I did find a better nozzle clearance gage than a sheet of paper, 2 layers > of non-stick coated Reynolds wrap, a sheet of 22lb put it so high from > the glass there is virtually no adhesion even with a good haze of > matterhackers glue. 2 layers is about right, but one sticks so well you > damage the part & feel like its gonna take glass with it when it finally > comes loose. I've actually done that, had to ice cube the glass and > lifted a piece about the size on a little fingers nail out when I did > come loose after I'd put it in the freezer for half an hour. The dremel > has a 9 point auto-zero bed leveler. And its build plate is not square, > the Y is about 30mm less than the endder-3 X. And X is close to 50mm > longer. > > > On Sat, Feb 13, 2021 at 2:06 AM Gene Heskett <ghesk...@shentel.net> > wrote: > > > Greeting all; > > > > > > Messing around with the parametric pulley designer, I have made a > > > larger 86 tooth pulley for the big pulley on the A axis supplied > > > with the 6040 mill. I'll also change the belt pitch as its presently > > > a huge XL. > > > > > > But the chosen belt, a GT2_3mm, is not a good fit, throwing a just > > > detectable slack in the center of the wrap, inicating the pulley is > > > about half a red one too small. > > > > > > Is this a good excuse to add a couple counts to the xy scales in the > > > printer, or to play with the variable > > > > > > additional_tooth_width = 0.2; //mm > > > > > > in the openscad recipe? > > > > > > Doing this in PETG, so the ender-3 is at the top of its heater > > > range, with a 250 degree nozzle and a 70 degree bed. And around 7 > > > rendering hours to try a new fit. > > > > > > Thanks for any advice. > > > > > > 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 > > > 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 > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
