On Sunday 16 August 2020 21:33:29 Bruce Layne wrote: > On 8/16/20 8:40 PM, Gene Heskett wrote: > > And it ran about 5 minutes, broke the cup of the flexgear off at the > > disk junction. Only 1.2mm thick there, concentrating the wall flex > > into that relatively sharp corner. Can I fix that in cura? How? > > Cura should allow you to specify the number of layers. In Simplify3D, > I can set the number of bottom layers, the number of top layers and > the number of side layers... all independently. As Chris and I have > maintained, the outer layers largely determine part strength and the > infill doesn't. I'm printing a small production run of structural > parts and I had the slicer use four outer layers and 20% infill. > They're very strong ABS parts. If I wanted rigid parts such as gears > that were resistant to impact forces or layer separation, I might > specify six outer layers, and possibly more.
I just did that, 7 outer layers and changed the support pattern to gyroid, and amazingly its building up that randomized cookie cutter pattern just fine even though I seen it move on the glass as it didn't "stick" but its working anyhow. But I can see its curling up at the start stop points of the maze its drawing. 180 degrees apart in the pattern. We'll see what the disk pattern looks like when it gets up to that. This one is printing at the same scale as the output shaft, which I just remade after finding they were to big to enter the main bearing even with help from the assembly screws. So this will have a smaller bore, which means I'll have to make a smaller internal spline, and that may demand a smaller bearing carrier, as I need it to push the splines fully engaged, but only enough clearance from pull-in that at the midpoint between the rollers, the tips of the splines clear each other, this condition corresponds to the minimum flex it needs to work=longest life. I also ordered a couple spools of TPU. But I suspect its too soft, but will try one for S&G. ABS has more give, and it may be the right stuff to try, ut its also temp sensitve, changeing at day to day temps. So I'm not convinced it will work for something that may need to work outdoors in 0F weather or in the middle of the summer wiith 90F at 3AM. . > > Looking at that edge with a strong lens, I see 3 layers of wall, > > with quite a bit of air too. So I was still having plastic delivery > > problems even after calibrating it according to Andy, where scale is > > set to deliver 100mm of pla for a 100mm move command. > > That's a good calibration method but it assumes filament that is > within specifications. I've recently encountered some filament that I > bought on Amazon (with good reviews) that was 1.49mm in diameter > instead of 1.75mm +/- .03mm. Undersized filament will cause under > extrusion. You should be able to compensate with a slicer setting, > within reason, but if the filament diameter is too small it may not > feed reliably in some extruders. The software compensation can't > compensate for absolute hardware limitations. I don't expect it to. > Properly calibrated, adjacent layers of extruded filament should touch > each other. You shouldn't be able to see any space between adjacent > layers. The layers will typically be .4mm wide, on .4mm centers, so > they touch. Maybe verify that your slicer knows what size nozzle > you're using. Done. > It sounds like you've made a lot of adjustments to the > settings in Cura and in the Marlin firmware, and it would be easy to > accidentally enter a wrong value that persists and causes problems. > It might be a good idea to return to known good values for Cura and > Marlin. The people who have better luck 3D printing didn't need to do > a lot of configurations. > > > Bruce mentioned TPU with an 85 or better shore as being more > > flexible but I've not found that for sale anyplace. URL anybody? > > https://www.amazon.com/s?k=tpu+1.75 > > Warning - The Priline TPU was the filament I mentioned that had an > outer diameter of 1.49mm instead of 1.75mm. Yoyi is pretty good TPU > but a bit stringy. The higher the durometer (Shore A value) the > easier the filament is to print because it's not as soft and stringy. Amazon showed a D95 version but it was twice the price. What I should have 2 spools of Tuesday was $75 for 2 .8kg spools. > The extruder has less trouble feeding the filament, and there are > fewer problems with stringy parts. Each brand of TPU is different, > but I generally use the following slicer settings for TPU: > > 1500 mm/minute for all motion Thats 3x the top speed setting in merlin. > 220C nozzle temperature I can reach that without the sock. But its slow getting there. > No retraction With TPU's spring, it would need at leasr triple the PLA setting. TBD per spool I suspect. > 25% speed for the first layer, no cooling fan, 60C bed temperature. > 100% speed for all subsequent layers, 100% cooling fan speed, 50C bed > temperature I can do all those. > Avoid crossing outer perimeter I"ll have to look at cura again. Did, I don't see that one. We'll see what this one looks like tonight some time, around 15 hours printing time. > Thanks Bruce > > > > > _______________________________________________ > 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
