text: Screw Holes and Solid Infill - Page 2
  04-04-2021, 10:15 AM #11
  I'll try those steps you describe shortly. Not sure I'd have found them without your details!
  04-05-2021, 07:19 AM #12
  depending on your nozzle size your wall count will have to vary. With the standard nozzle of 0.4mm a wall count of 10 will give you a rather thick 4mm wall! I have been using 2mm walls with threads up to G4 (1/4 inch BSP 10mm hole) with no trouble larger than that use the modeled feature in Fusion 360 even if you have to case it afterwards. We use this system for nylon pressure vessel caps up to 6 Bar
  04-05-2021, 07:57 AM #13
  Thanks for your reply Gambo.
  I suppose the thread vs holding power for various materials is what is needed here but I recall from reading years ago that it gets pretty buried in equations and not altogether useful-hands on experience like yours is useful. I am never confident in the holding of PLA threads due to the layered buildup nature of the parts.
  You are working with nylon-something I always wanted to try--it looks to be a lot stronger and more temperature resistant than PLA and apparently the layers have better holding strength. It is advertised as printable in the low cost desktop machines that a lot of us buy--not sure why it isn't more of a standard.
  Do you post treat the nylon assemblies? I know that PLA leaks in water (I do a lot of aquatic work) and usually is pre-treated with methylene chloride to meld the layers. I forgo printing and use a desktop CNC and delrin for cases like that.
  04-05-2021, 08:02 AM #14
  Thanks Gambo. 'Layer height' I understand! But I must read up further to grasp other terms I've encountered like 'wall count', 'number of perimeters', 'perimeter width', 'top & bottom surface thickness' actually mean! Particularly for the main type of model I'm focusing on at this early stage. Namely boxes with screw on lids, slide-on side panels, holes for switches, pillars for PCBs, etc.What would be useful would be a web page showing illustrations of simple models (ideally a box!) with the important printing factors like those identified,
  In Cura if you hover over a parameter say wall count it will pop up a brief description. support.ultimaker.com has a full manual on line.All nylons are not equal and the ones that easily printable are premium products for instance the one I use most is Spectrum Filaments (Poland) PA6 Low warp which costs 41.22 euros inc VAT per Kilo from the factory or £55.00 from a UK retailer. I have tried a good number of Nylon Filaments and with the exception of the US made Taulman Bridge and 230 filaments which cost much the same in UK have not had a lot of success. Having said that between them they offer the range different flexibilities we require for our needs. Spectrum PA6 Low warp prints at 250- 260C nozzle temp and 55C bed onto a dry and sanded sheet of Tufnol (garolite in US) I use a 1mm thick Tufnol sheet clamped to a glass bed because the adhesion of the nylon to the Tufnol is very strong and you need to flex the sheet to get the work released.
  04-05-2021, 08:43 AM #16
  I don't post treat assemblies other than chasing some larger threads. Very large threads like those securing bottle Tops are spiral objects individually drawn in Fusion 360 and sometimes need a little cleaning up because of limitations in the overhang printing capability of FDM we have not yet found it necessary to use support structures when using PA6 LW.
  04-05-2021, 08:44 AM #17
  Thanks again. I don't even know if this information is buried somewhere else. You should write a book! 3D printing is a big industry these days but a quick look at Amazon does not reveal anything that seems to present the information that you mention. There are a lot of industrial and research users out here now, many with low end but perfectly usable machines, and a technically detailed book on plastics, orientation strategy, post-treating, best feed rates, issues like Terrypin are asking and all else is sorely needed. I learned "crank" machining largely by trial and error and it is a shame to do this all over again 50 years latercheersFritz
  04-05-2021, 08:56 AM #18
  Thanks for the compliment. I'm sorry I do tend to lecture but I am glad you found the information useful
  04-05-2021, 03:38 PM #19
  I agree with CA that I typically just let the bolt cut it's own threads, but it takes some experimentation to get the printed hole sized right to make this work. I've also found that the finer pitch on metric bolts is far easier to do this with than with equivalent imperial sizes. For example, I find it far easier to thread in an M3 bolt than a 4-40 bolt.
  04-06-2021, 08:03 AM #20
  Hi Terry you have got to the wrong screen in Cura. This screen is the one allows you to set the parameters which can be changed from the advanced screen one layer of popup back