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Hello, I'm a retired engineer and I've been printing a few months. Most of my work is practical/structural and not decorative, so this is very useful. I like your content a lot so far, and I'll keep watching more. First off, I disagree with the several commenters who say it's silly to reinforce plastic with a screw instead of just using a metal part. That's dumb. Might as well say why reinforce concrete with rebar, or resin with glass fiber. It's another tool in the engineering toolbox, for specific purposes. I like having all the tools I can, and choosing the best one for a particular job. If you need a complex shape, and as you say you don't happen to have a lathe, this makes all the sense in the world. It's an efficient means of adding strength, and I'll probably use this technique sooner or later. I like how you warned about how some materials, like PETG, will creep under constant load and lose the preload on a bolt. I've already experienced creep in PETG, and it can matter to the function of the part. It didn't in this case, but it's something to look out for. I totally agree that everyday thread-locking compounds will attack and degrade plastics. They should not be used in plastic, or even in a threaded insert where it can wick over onto the plastic. But there is one made specifically for plastics. I would describe it as similar to a mild superglue. I used it in my work about 15 years ago and I don't remember the compound number, and I'm too lazy to try to go look it up. It's made by Loctite and you'd probably have to contact them to find out; I wouldn't know about it unless our Loctite rep had told me. It would be cool if you could look into that, and add the information here. You can use it for printed machine screw threads, or even on threaded inserts or inserted nuts. You wouldn't need it for sheetmetal or wood screw type, formed threads, but it wouldn't hurt. You could run the screw in to form the threads, back it out, and use some of this locker to make it extra secure.
Thanks Richard, your feedback is much appreciated! As you say, it's another tool in the box. For example the Voron team makes heavy use of this technique in their printer designs. They're awesome and while you can get CNC machined aluminium parts nowadays the design is meant to be printed and works fantastic. Seems like you're talking about cyanoacrylate based threadlocker. The ones I saw all claimed to be used for plastic fasteners.
Pure CA glue is fine for most plastics, but a lot of threadlocker compounds that use CA also include solvents and reactive copolymers to reduce brittleness and retard setting time, and these additional ingredients can often attack plastic resins. So for use in plastic, you definitely need a speciality threadlock compound that’s formulated for use with a specific plastic.
It's sort of crazy how so many 3d printing enthusiasts are completely unwilling to do any form of post-processing or composite materials. A 3d printer isn't a magic bullet that can print any practical part, it will however print 80% of what you need for a practical part, which you can then finish that part by doing post-treatments or reinforcing. screws and threaded rod aren't very durable by themselves, but when you embed them into a stiff plastic shell the two materials really compliment one other.
@0hypnotoad0 absolutely! And on the other hand many people are willing to print a ton of support material instead of designing a two part model with screws
A bolt running across the layer line grain has been my go-to reinforcement technique for a while. Even without the washer it works great, I just make sure the number of perimeters is high enough that when tightening the bolt I’m not just crushing infill.
I feel so stupid for not thinking of this myself. About one second into the video I figured out what he was going to do. Seems so obvious even if you only think about it for a single second.
This gave me the right idea. I will try to reinforce my 3D print with another 3D print so that the layers are perpendicular to each other. Should work for my project
Always great to see other engineering principles spill into the 3D printing world. Havent been thinking about implementing concrete element engineering, but this was great knowledge. Thank you! Im always making compromises with strenght in some direction in my projects.
Thank you for this and your other solid information videos . Its a very welcome change from the common " look at how great this printer is that I've been using for 5 minutes " .
Don't forget about bare threaded rod or "ready rod," it's widely available at hardware stores in either mild galvanized steel or stainless steel formats. You can simply cut it to size, grind/dremel a slot in the top and use a flathead screw driver to sink it flush into your part. A long piece of threaded rod itself can also be used as a tap to prepare a thread in your printed part.
Definitely! I used that for the helmet antennas I mentioned somewhere. But it's a bit tricky to get in compared to screws so I usually don't use bare threaded rods.
A technique for forcing extra perimeters where the slicer would not otherwise print perimeters is to add a gap through the model that is smaller than the minimum tolerance your printer can produce - say 0.05mm - the slicer will see the gap and create perimeters around it but your printer will likely fuse the gap but you benefit from extra perimeter strength where needed without having to resort to printing it solid (no infill).
Good. Someone also proposed welding paperclips into prints and then covering these places, although I forgot what technique was used to cover paper clips and spaces between parts for large prints and I think they were even painted. Other proposal was pouring epoxy into gyroid infill or hollow object, but i would be careful for larger parts, I already have bad experience with positive loopback - epoxy generates heat as it hardens and it hardens faster when it's warm or hot and even something like cylinder with 2.5cm radius and 2cm height was enough to reach temperature where it started to smoke (it was some highly viscous, fast curing, clear BPA epoxy 15 years ago)
I have been adding 2mm negative cylinders using the slicer for anything that has poor orientation but needs strength. Then i insert either a piece of filament or 2mm metal rod to add strength similar to what you have done here
Great video! If you need to reinforce a part but don't have space for a bolt, hex wrenches can work really well. They're pretty cheap and you can get them with a short leg for a smaller profile.
Interesting! I have been using these techniques for several years, but I never tested them, and never really knew if it actually helps that much or not. I'm glad to get the confirmation that it DOES add strength and apparently a lot more than I thought it would. There is an issue with your second method though ( 4:00 and onward ) if the tolerances are too tight, the screw will pull the layers apart, can be avoided, but it's just something to keep in mind.
I think you could make parts significantly stronger using 3D printed bolts that are printed in the other orientation, and would result in a lighter part, if that's needed.
Simply splitting the print into smaller parts printed in different orientations can make a huge difference. I've had problems printing a big basket for my wife's bike in 2 prints, it always broke during printing, and when I finally got it right - it broke in use when she drove over uneven terrain. I redesigned it to print in 8 smaller parts with different orientations for the bottom and for the walls, and not only I saved lots of support material - the resulting print is much stronger, and when she had a crash - I only had to reprint the part that connected the basket to the handlebars - everything else survived because the weakest point was the 90-degree bend :) Another thing I learned is that it's better to join it to the bike with flexible joins (basically - design holes in parts and tie them with rope) - so that there's some amortization for whatever is in the basket. BTW - instead of a bolt you can use a zip tie through a hole for compression :) Or even just a piece of string or rope.
Yep, this is my go to method to keep the weight down and producing strong parts. Solid cylinders split down the length and printed flat on the bed are much stronger.
Outstanding video! An alternative to inserting a threaded rod is to insert a carbon fiber rod. I have had excellent results with a two piece PLA cigar box guitar neck joined with a dovetail joint and a rectangular carbon fiber rod slid down the center to reinforce the join and stiffen the neck in the middle.
Sometimes I just use 3mm steel pins with epoxy through the length of the part, perpendicular to the layer lines. It's nice for low-profile and/or odd length parts since steel rod can be bought in long sections and then cut to needs with hand tools. I recently did this for an 11mm shaft coupler. Every coupler that I could find was the flexible type, and I needed it to be rigid. So i just designed one and ran those steel pins through the length of it in four places. Works great.
Of course i just realized this earlier today when putting my longboard on the hanger i designed. I've used it for over a year but have been very careful when placing it onto the hanger. Placing a steel rod would ensure that it could withstand a shock to the pla. Can't wait to show the wife this video describing exactly what i was trying to explain.
3d prints tend to shrink in the x and y while growing in the z when warmed. You can use this to make a print shrink tight around a metal center so it never comes loose.
That's a pretty interesting approach! Only occasion where I heard of heating the print afterwards is to re-melt it snuggly tugged in salt or something to not make it deform.
Also ich muss ehrlich sagen, seit ich much angefangen habe in das Potenzial von FDM reinfuchse ist es jedes mal wenn ich vor einem "problem" stehe so das mir direkt ein video mit einer Antwort von dir vorgeschlagen wird, noch bevor ich überhaupt danach gesucht habe! allerdings bin ich noch weit entfernt davon selbst digital zu konstruieren, im moment bin ich sehr dankbar für printables und gridfinity im allgemeinen 😅
Hehe, ist halt schon klasse, was alles geht wenn man sich der Techniken aus anderen Bereichen bedient. So ein 3D Drucker erzeugt auch erstaunlich fetzige Musik, vielleicht mach ich darüber auch mal ein Video 😅 Kannst ja mal kostenlos in meinen Kurs rein schnuppern, da gibt's einige der Techniken direkt in der Praxis.
I've been doing this for quite some time, I usually use M3 threaded rods. at 0.5mm layer height the 0.5mm pitch cuts into just a straight hole with no threads modeled in pretty easily
M3 is plenty strong - an 8.9 M2 rod has a tensile strenght of roughly 1,66 kN (so you can hang about 170 kg on it until it snaps) - the 0,4 mm thread pitch even fits better on 0,2 mm layer height ;)
I've been using this trick for years, but if you have little parts (were mostly it's needed) you have to take some walls around the metal and so it can be a limit in design. In some cases using very little screws or small nails or, at limit, needles, with some superglue you can solve and go beyond limits.
Definitely! The smallest part I own using a screw is part of the Voron 0 extruder. It's less than a cubic centimeter in size and is reinforced with a 10mm self tapping screw to not break across the layers.
@@SmallBatchFactory In a microphone mount (for the Zoom H2n, that has a non conventional microphone shape ) with elastic suspension, I mounted a 3mm screw inside a 1/4 male printed screw standard for the mic. But in that case you can solve for weight at price to pay a lot of attention to the tightening torque. In small parts is always a compromise.
@@SmallBatchFactory The problem with that things is that when you need you never have it near you, hahaha! I bougt long 1/4x21 screws and relative hot inserts so when i need to pass into functional parts and give them the value of equipments (photo, audio or other) I can go, in design, beyond the limit of lengt that specific photo screws always have.
I actually used silicone oil to get that antenna rod in, it got pressed out through the layers left and right. What I mentioned is no issue on screws that are just a few centimeters long, it applies to really long and tight threads. If you plan to remove a screw later in just give the threads a bit more clearance when designing.
You could use this technique to temper your parts, maybe? Like if you can't have the screw in the end assembly, you can screw or clamp it through out the part, and remove after its cooled? you'd need to see how your part reacts to various torques, but I feel like this could have potential?
I'm afraid as soon as the part gets hot enough it will get soft and loose it's shape. Also the screw will bond pretty strong to the plastic so no chance of removing it anymore
@@SmallBatchFactory Could it still work for something purely structural? You would build in extra clearance on the holes so you're fasteners don't get stuck, and drill/ream them to size after? IDK I guess I'm just building a specific use case for this process instead of building a process for a use case lol.
Thinking that with some designs you could print a shell, then pour resin to fill. Of course the infill in the print, if any, must allow the resin to flow in.
Sure, you still want the resin to be bubble free to work effectively. I just don't like to mess with resin, since metal parts are so cheap in comparison.
An inverse 3d lathe! Could start the SM process by creating an "infill" cylinder printed on a flatbed printer. Deposit structural layers, and outer layers.
I saw a guy on youtube who's done that and more. I don't remember the channel or anything, but I think it was a rotary, multi-axis printer that was very cool. Maybe you can find it. Definitely an experimental one-off, not commercial, but very cool.
6:13 I think unadulterated polycarbonate would mostly stretch. I think most PCs sold for printing use are heavily blended with PET or PETG to make them easier to print in consumer machines. That adulteration compromises the performance of PC.
This was Polymakers "PC lite", it's a bit different from PC max and according to them a bit more rigid than the more expensive stuff. Shouldn't be blended too much AFAIK. It holds up to higher temperatures than ABS so far so I think it's more in the pure side of things.
@@SmallBatchFactory The Tg of PC Lite is about 30C lower than unblended PC. Polymaker doesn't say how much PC is in PC-Lite but PolyMax has more and their data sheet allows PolyMax to have as much as 30% not PC. PC Lite is more diluted.
Resin suffer similar issues to plastics. So typically are used with cloth fibre (glass, carbon) to add strength. Bonding of resin to filament/plastic surface could also present some issues, as very smooth.
I was thinking of the integrated screw method, and wondered about hiding the screw with a modified washer - do they make washers that have a little negative extrusion for the Nut to sit in? Kind of like a top had with a hole in the cap? That would hide the nut and screw on both ends.
Adding wood is an option too by the way. I have a student using a small block of wood with a drive in nut to attach large printed part securely to a tripod.
I prefer electric for the mustache region but if I want a really clean result I'll do a second pass with the safety razor. They're so much better than the fancy plastic ones with a bazillion blades.
you concept is good, buy your dimension are overkill a "tension wire" would be enough in principle, since a wire anchor is very difficult to model in, you can use threaded rods with nuts (or heated inserts) on both sides, so basically the same strategy, "prestressed concrete" does it a M2 threaded rod from zinc coated steel is plenty strong: M2 8.8 threaded rod has a core crossection of 2,07 mm² x 800 N/mm² resulting in a nominal tensile strenght of 1,65 kN so roughly 170 kg - M3 8.8 is roughly 2,7 kN or 275 kg you 8 mm Bolt is not just overkill in the context of hunting deer with a nuclear weapon but more like overkill by hunting deer by throwing the moon on the earth ;)
Can't argue with that ;-) it's just what I always have in stock. M3, M6 and M8 is what I usually have at home. For the light stand it makes sense though sonde the head is large enough to save everything in case anything breaks. I said it right at the beginning, this is total overengineering :-)
@@SmallBatchFactory Thanks. I had it on my HiFi btw. It's just that some ppl (like me) have difficulties in understanding speach when there's other noise at the same time (so called "coctail party effect").
That's a good hint. Everyone hears differently. I think it doesn't add much and is mostly more work so I'll stick with a short beat for the chapter introduction and leave the rest out from now on.
That's fair. Although the plastic still serves a purpose. I totally would've made the camera holder with a lathe, if I had one casually standing around.
Yeah, why 3d print from plastic, when you can use CNC mill. From titan. Or extrude from aluminum. At Home. Or maybe even metal casting in sand. Just like people in slippers from Pakistan do. 3d printers are obsolete!
Some of these designs you could have just used the threaded rod on its own. What's the point of designing your own product if 90% is an item ends up being purchased anyway?
yeah this is kinda monkey. This is kinda coping for shortcomings in your designs. use 100% infill and design the part for the stresses at hand or don't use 3D printing for that part of the project. this is like treating everything like a nail when you found a hammer.
@williammorris1763 I'd love to make that camera holder or the razor handle with a lathe, it's just I don't have one standing around neither do I have the space.
@@SmallBatchFactory I suppose..tho evidently candy corn has never had a single ad, yet no one seems to forget about it ¯\_(ツ)_/¯ Maybe if these big companies didn't divert so much money into advertising, and instead put it into their products, they'd actually have good stuff that didn't cost a small fortune just to acquire SuperVinlin (not that's every advertised product is bad, but unfortunately, more often than not they leave much to be desired..)
Am I missing something, or were all these methods "put a metal bar through the middle of the plastic"? Not to sound pedantic, but if the plastic is now essentially just a shell around a metal bar, of COURSE it'll be hard to break. This feels like that "You can print a watertight bottle for potable water" video from Sland3D, where he was making a shell for a pre-existing collapsible water bottle.
No one limits you to "the middle of the plastic", it's just what I had already lying around. Check out the Voron printers design to see more use cases.
@mikedixonphoto alright, next video no music. I always felt it's something "you have to add" but it's really hard to balance for it to work good on every sound system.
It's already lowered by 20-25 dB, that's the thing. What's the point of having extra work (around and hour per video to sync everything with the title transitions) for music that barely anyone can hear anyway?
@@max_imus to be honest the over exaggerated text is what made me click onto the video, and maybe adding an actual 3d print picture onto the thumbnail would make it better
For the first method, if you need to be more flush, could you substitute T-nuts and threaded rod? Leave one T-nut standard, turn in the threaded rod and lock in place, then on the other T-nut cut off the prongs before you turn it into place. You might have to make some kind of spanner tool to turn the second T-nut. en.wikipedia.org/wiki/T-nut
