Different printing methods cost different amounts. The basic service at shapeways is something called SLS , which is laser-sintered nylon powder. It produces very good results in terms of both dimensional & shape accuracy and the toughness of the part, but it's expensive.
The kind of printers people have at home are either FDM or SLA, and there are tons of services that offer those. SLA uses uv light to harden a uv sensitive resin. This produces super-accurate output, but generally too brittle for a useful mechanical part. Though there are a few special resins that are a bit stronger and might work well enough for a battery cover. The problem with a battery cover is it has tiny shapes that just break off, and on top of that, it has shapes that you intentionally have to stress and flex in normal use, without breaking. FDM is the real common one where a nozzle squirts out melted plastic. This is good for mechanical parts that aren't stressed too hard, but isn't super accurate, is pretty weak for small parts. It's just barely good enough for something like a battery cover if the printer operator is knows what they are doing and gets good layer adhesion and no warping and uses a tougher material like petg. The materials used for fdm are tougher than the uv resin, so they can bend a little before breaking, but the layers and lines is a weakness unless the printer (both the machine and the person) actually knows what they're doing. The problem is a lot more people own a printer than know how to get good results out of it. If you take an STL fild and go to CraftCloud.com, you'll get presented with something like 20 or more types of printing, most of them not good for a battery cover, but at least FDM, SLS, SLA (maybe, with the best resin), maybe MJF. (MJF turned out not to be accurate enough for the pcb2molex carrier, but a battery cover ca tolerate a bit more variability than that carrier). You upload the stl, select the printing method and material, and finally it shows you some quotes from different print shops that can produce the part. But none of these are magic. What you get is only accurate within some range of variation. SLA is very accurate, but probably not strong enough. SLS will also be accurate enough and strong enough on the first try, but costs more. For FDM, it's cheaper, but will probably need a few iterations before you get a very good result. Generally for FDM, you burn through all those trial & error by doing it yourself, not by paying some service. There are a TON of small shops out there able print by FDM or SLA. Aside from craftcloud, there is 3dhubs and several other similar marketplace type sites or just google. But it's not cheaper when you wait 2 weeks for a part that isn't good enough, and you end up trying 4 times to get a good one. -- bkw On Wed, Jul 1, 2020, 6:41 PM B 9 <hacke...@member.fsf.org> wrote: > Thanks, Lee! I appreciate the expert insight. I hope Steve is able to > rejigger the hook tabs with slightly less overhang. > > $15 for 50¢ of material sounds crazy, but I don't have a 3-D printer. Are > there any 3-D print services that aren't so expensive? My local makerspaces > have closed their doors to focus on PPE right now. > > —b9 > > > Lee Olivares <l...@braains.net> wrote: > > > The “vertical” hook tabs are on the weak side, simply by nature of their > geometry and the limits of FDM, but they’re certainly functional. > Unfortunately re-orientation of the model isn’t a great option to improve > their strength, nor is beefing them up, simply because of the size of the > slits in the case. > > > > However, making them with slightly less overhang would prevent some > harmful leverage without affecting function, and it would permit “scooping” > the three engagements on the short side, since the tolerances there are > pretty tight as it stands. > > > > Managed to fracture one of the vertical “hook” tabs removing the > support, and it’s a snug fit but a really great design. > > > > Thanks! > > > > > > > > - Lee > > - 909.437.0250 > > - Destroying technology problems. > > > > > On Jun 28, 2020, at 21:39, Lee Olivares <l...@braains.net> wrote: > > > > > > Resident 3D Printer repair guy here: that’s expensive, you’re looking > at .50c in material for an FDM PET print. > > > > > > It’s about an hour on a Prusa MK3S @ .2mm, I’m fairly certain my buddy > gifted me an M200 so maybe I can do some comparison shots. > > > > > > Printer is hot and ready so I’ll just crank out a sample as a > reference, wait 2hrs before making any purchases. > > > > > > - Lee > > > - 909.437.0250 > > > - Destroying technology problems. > > > > > >>> On Jun 28, 2020, at 20:04, B 9 <hacke...@gmail.com> wrote: > > >>> > > >> > > >> Very awesome! One of my M200s is missing the battery cover and looks > a bit janky with the flexible plastic I cut to fit in its place. I got cost > estimates from xometry and shapeways to see how much it'd be and it seemed > the cheapest options were $15 to $20 bucks. For example, here's Shapeways' > prices, but you have to add $3 for black plastic and then there's shipping > on top of that. > > >> > > >> <image.png> > > >> > > >> —-b9 > > >> > > >>> On Sun, Jun 28, 2020 at 7:15 PM Steve Glenner < > steveglen...@hotmail.com> wrote: > > >>> The M200 I just got was missing the battery cover, so I designed up > a replacement and 3D printed it. I donate the model to the community in > case anyone else needs one: https://www.thingiverse.com/thing:4508352 > > >>> > > >>> Tandy Model 200 Battery Cover by SteveGlenner > > >>> I bought a second hand Tandy Model 200, but it was missing the > battery cover. So here is a replacement battery cover. It should be printed > with supports as there are some overhangs but otherwise the settings > probably aren't critical. I printed mine in black ABS so it matches the > rest of the bottom case. > > >>> www.thingiverse.com > > >>> > > >>> > >
