Cavities Don't Help: Design for Mass Production 3D Printing

[@orange-micro-fiber9740]

Cavities can be useful to break up extremely long layer lines, which can cause stress in one direction and cause the part to warp. However, there are other ways to mitigate that stress, too.

[@slant3d]

Good point. Concentric layer lines or textured surface.

[@imacmill]

What are the other ways?

[@joescalon541]

Infill is generally the fastest movement a 3D printer will do. Remove volume with the infill, rather than add more slower movement areas like walls.

[@slant3d]

Also true

[@3er24t4g1]

Per unit of material, walls provide more rigidity and strength than infill. Walls are towards the exterior of prints, where material matters more. Given the choice between allocating plastic to walls or unfill, walls should be prioritized.

[@GarethMcCumskey]

@@3er24t4g1 For strenght, sure. But the traditional reason to add cavities is NOT to add strength but to reduce material usage. Infil is way better at that

[@twanheijkoop6753]

​@@GarethMcCumskey you shouldn't be printing parts with more than 50% infill anyways.

[@jakegarrett8109]

@@twanheijkoop6753 Makes high stress parts for things that go pewpew... 5 seconds later wonders why they have a spring in their eye, haha! Yeah no 100% if you've properly designed parts where strength is critical, unless of course you've designed it with specific infill in mind (some pewpew parts have been optimized with varying infill depending on the region, and I use these as examples because they are life and safety critical and what's another $1 in plastic when its being loaded near max failure point otherwise?) Another example is mufflers/suppressors. I'm looking at getting some higher powered stuff that has 5,000 psi of pressure (delivering more force than a real 12ga slug), and if I decide to print the can section (only because the government likes to shoot people's dogs if they buy perfectly legal cans for their air toys, and I don't have any dogs), then you bet I'd be making that solid since its better hoop stress and far less fatigue since the internal layers will stretch less since they will be reinfoced by the outer layers (which they basically won't with hollow infill)

[@typeaboutit]

Avoid cavities. Your dentist will thank you!

[@slant3d]

Very true!

[@elleryfg7853]

LOL. Good one

[@enosunim]

You pay dentist when you have healthy teeth?

[@conorstewart2214]

Um, no, your dentist wants you to have cavities so you have to pay them to fix it.

[@typeaboutit]

@@conorstewart2214 good point, lol

[@andrewwatts1997]

In some slicers you can increase the linewidth of infil. Rather than increase printing time by printing circles you can double the linewidth of the infill and increase part strength without having to print at a higher infil density, line wise.

[@orthotron]

Walls still provide more strength because they are printed slower. And the point of using cavities is to only reinforce areas that need it, instead of increasing infill density all over.

[@I_enjoy_some_things]

@@orthotron I pretty much just approach infill as “something for the top layers to lay down on”. If I want strength, I up the shell (bottom/top/perimiter) count. CNC Kitchen did some testing on it awhile back and found increasing infill for part strength is pretty much a fool’s errand.

[@Robinlarsson83]

@@I_enjoy_some_things While I agree in general, there are places where incresead infill gives a lot of additional strength. And of course, depending on the shape, the shell needs the support of the infill to be able to take the loads properly, like a sandwich structure. I've done quite a few parts where I really push 3D printed plastic parts to their limits, like tooling for my roll bender to form stainless steel tubes and such. Some parts have failed in compression in the areas where there were no internal structures other than infill, but a lot of them have failed due to layer bonding issues between the wall lines (not in Z). And I've noticed that PETG gets surprisingly brittle when you make more or less solid parts :D I've printed some parts with 14 walls, 10 bottom, 20 top layers and double infill lines at 40% gyroid infill, so almost a solid piece of plastic :) At 0,25mm layer height and 0,5mm line width. Swichting up to a 0,6mm CHT nozzle soon.

[@lucasgomezortiz]

With PrusaSlicer, you can add internal modifiers and increase the infill density in specific areas or even convert a part into a solid piece. This results in the creation of additional perimeters within the infill, enhancing the solidity and appearance of the printed object. It is a useful feature for optimizing your 3D models before printing them.

[@IronCrown]

You can get the same effect with Cura slicer. You can select a mesh to change almost any setting where it intersects your part. You can create a special shape for your application, or just use a support blocker and scale+change it to a setting modifier mesh.

[@soon3794]

I actually design in cavities as it adds structural support, I usually print with 6-12 walls with no infill. The reason being that i make thin components (3mm) that are relatively large.

[@SiqueScarface]

You could also say: The slicer and its infill algorithms do a much better job at creating cavities than you normally would. If you want to create cavities on your own, at first, make sure your cavities are better than the ones of the software.

[@slant3d]

When mass producing an end use part with additive you should avoid cavities.

[@conorstewart2214]

⁠@@slant3d I think their point was that infill essentially creates many small cavities.

[@daliasprints9798]

Pretty much everything here. Excellent advice. One small consideration where you may want internal structural cavities exposed tho: if integrity of their walls is critical to meeting a structural requirement, ability to inspect and reject based on any problems there may be desirable.

[@theaveragepro1749]

I read a paper that found that most of the parts strength ended up coming from the walls rather than the infill, it would be interesting to see a comparison of a part that has thicker walls and barely any infill (still some as overhang print support), and compare it against the same part with thin walls and more infill, both using the same quantity of plastic.

[@slant3d]

I Beams

[@3DPrinterAcademy]

I usually use cavities to increase the strength of 3D printed axles or long components.

[@atomicsmith]

Love this series. Great practical info with just enough theoretical background. Love that they’re short and fast paced too.

[@quantisedspace7047]

Thank you for pointing this out. I've lost count of the times where I've put cavities in 'to reduce material', only to find that the cavity makes support structures necessary, using /more/ material.

[@TheWhiteTimes]

This cavities you presented with the slice of the wing are actually structural design to allow proper stress transfer. Not the best example imo.

[@slant3d]

Cavities in general are unnecessary. They create larger stress concentrations than are possible with using infill. Additionally circular cavities are a sub-optimal cavity design compared to truss-ribs

[@edwins2595]

This guy has a unique ability to say in 200 words that only require 10.

[@k.k.9378]

"Don't 3D print large cavities. Infill makes better cavities faster"

[@justinwenborn654]

Personally I'd use cavities like that for the wall thickness, Nice way to control the stiffness in certain places

[@slant3d]

Great idea. You should finish watching the video where we talk about that

[@williamfosterXD]

@slant3d This should have been a short.

[@3er24t4g1]

Slant provides some of the highest quality 3DP content on the internet. He is on par with CNCkitech experiments and the 3DPrintGeneral's texts. If you could, please decrease the volume of the background music, hide the microphone from the viewer, and increase the video pace by 20%. I would love to see videos on 3DP post processing at scale: Vibratory tumbling, electrolysis plating, PVA dissolving, UV painting, flame polishing, threaded inserts, and coating.

[@slant3d]

Thak you so much

[@addohm]

You're kidding right?

[@conorstewart2214]

It doesn’t matter if we can see the microphone or not and if you want the video faster then just increase the playback speed, sounds like 1.25x would be what you want.

[@thorlax]

I agree with the music feedback - a little less would be good. Often, I listen to videos in “sub optimal” settings, like cars (or just using my phone’s speakers), where clarity and consistent volume matters a lot! Personally, i didn’t have an issue with pace/mic. Great/informative video.

[@JustInvertedFpv]

It's always people with zero content of their own on their own channels that leave comments like this. Could you make a video on your channel showing him how it should be done?

[@autonoob]

For a wing rib I think you should compare the strength of two parts with the same weight. And since the rib goes on the inside of a wing the surface finish doesn’t matter. Also solid parts are hard to route wires through. I just did this very thing and the easiest way to remove mass is to cut holes in the big surfaces. Since the rib is thin there’s relatively little material in the infill. In the example there’s a pocket and not a hole so what you are saying makes sense but would people really do pockets and not holes in this scenario? I hear what you’re saying but it’s maybe not the best example.

[@ABaumstumpf]

For wing ribs you should use something better than 3d printing

[@802Garage]

It's funny because I didn't really start designing parts a lot until I started 3D printing. It has always sort of been obvious to me to just leave any internal volumes that don't need to be dense hollow or at least fully filled in the design process. Then I just determine the infill and number of walls in the slicer based on the strength and properties I want. Great tips though!

[@pipdesignshop]

Love this sharing of knowledge! 3D printing is basically like learning a new language, and there’s so much to unlearn form “how things have always been done.” The limitations of older manufacturing technologies have had years of research, trial and error, and have come up with the “rules” for mass production. 3D printing has hit the next phase of adoption and is becoming more prevalent beyond the early adopters with drops in price and an easier learning curve, but that means more people who don’t fully understand the new rules are going to try to apply the old rules. Plus you can put hexagon cut outs in everything if you want…

[@aardwolfweb]

Thank you! One of my pet peeves is people modeling a replacement for an injection molded part by slavishly reproducing all the walls and ribs. Just use s solid cylinder or whatever.

[@slant3d]

Exactly.

[@nova3k]

1:46 ah yes, the ol' perrine bridge over the snake river canyon. Tell me youre an idahoan without telling me youre an idahoan. That's my neighboring home town. My dad still remembers evil kneival attempting to jump that.

[@AerialWaviator]

That's a nice pun in reference to "mass production". Normally cavities are utilized to reduce a parts mass (weight), but here the objective is to increase the mass (volume) of production. ;) The issue with the initial part with cavities (0:15) is the size and location. The part is an example of a designed for material removal using the least number of (metal) machining steps. The part at 3:40 also uses similar round cavities, but has an uniform infill. There is a balance of part strength, part weight, material used, and amount of tool movement (acceleration as print head changes directions). Key is understanding both engineering design aspects as well as manufacturing design aspects of a part.

[@martylawson1638]

I have designed a few parts using cavities as "custom" infill. In that case the parts needed dense infill and a lot of perimeters in only one spot. I then made sure the walls around the cavities were thin enough to only need 2-3 perimeters which allowed me to save both time and material. Wasn't a high production part though, didn't have any nozzle snags on the 8 I printed.

[@aggese]

I had a discussion about this with a colleague when we was working at a 3d printer manufacturer. Took some tests to demonstrate it to him

[@benjaminjohnson6476]

I would agree on everything but one point you made at the end. Airplane wings. Designing solid for airplane wings, specifically rc airplanes, relying on the infill for strength is still to heavy. But the same principles are true. When Designing a wing you have to alter the outer walls to create the structure internally and print with zero infill to get the strength needed well being light. You also typically have to print with a single wall on the print. Generally though the same is true you reduce weight by reducing part surface area but in this case, you have to include the surface area of the infill.

[@TS_Mind_Swept]

"A proper type of infill, like a triangle" or like cubic; which takes just about as long as grid, but is not only stronger, but strong in all directions

[@Art_Of_Sound]

Prusa slicer/add modifier model...the ultimate way to construct your print...and a feedback loop to your modeller!

[@CopycatStudiosLA]

why did i pay so much for tuitions - this is like a million times more informative

[@meateaw]

If you need high speed prints, AND maxmimum weight reduction and you dont require the shear strength from an end cap, use Vase mode with infimitely thin cuts in the wall. Can get you some rigid prints with minimum print time (because it never stops extruding). I designed my cuts to zigzag so they built that strength in multiple axes.

[@logicalfundy]

Definitely something I can see people coming from other processes doing. They mean well, but don't realize that 3D printed pieces are normally hollow, with a bit of infill. So you're really punching a hole through what's already mostly air. I wonder how often you get designs with holes?

[@derekmitchell209]

I mostly agree with this, but I will say that the airplane wing is not the best example. Cavities in airplane wings are there for a number of reasons-fuel and/or battery space, wing spars, routing for electrical wires and/or hydraulic lines, etc. I will add that minimizing structural mass is a strong design driver in a aerospace, but minimizing material usage is not. While there is a relationship between structural mass and material usage, the two things can diverge due to use of support structure, subtractive post-processing, print failures, and nonconforming parts.

[@dadstruction368]

I thought it was obvious that unless you printing with high infill, most of the material and print time is in the surface of the part. Adding cavities removes sparse infill, but adds expensive surface area.

[@AlexeyGopachenko]

Thanks for sharing your insights! Explore your process, design/optimise with its strengths and weaknesses in mind.

[@slant3d]

Always!

[@senoreljoynes6442]

I tend to design things that I 3d print to be so thin that the walls take up the whole inner volume. In that case I do use cavities to save material, but if I have a shape with significant volume I will keep it solid.

[@KingJellyfishII]

Interesting, I've recently designed a super light model glider wing to be 3d printed, and went with a hollow design with ribs that allow it to be printed at all. Now I'm going to see how heavy it would have been if it was all filled with low density infill instead.

[@bradykirk9932]

Interesting. I design in voids and holes where I specifically want to increase strength because of the added walls,

[@dreieinhalbeck]

i only do this when I have known stress points. If for example I want a triangle to work as a lever with one egde pivoting around an axle I would try to minimize volume where material is not needed for strength and then print the part with 100% Infill. It's easier to controll the outcome of the piece and to repair it without printing a whole new piece when breaking (soldering iron and loose filament)

[@efremtommasi1387]

Totally agree with this! Good contents and tips, keep up the good work!👍🏻

[@RobinGerritsen1995]

This should be a feature in each slicer... Hope Prusa is willing to take a look into this...

[@ThantiK]

Only this guy would say printing circles would increase his part failure rate.

[@slant3d]

Try making 1 Million parts. A defect 1/1000 makes a difference

[@abrahamf6124]

In some cases cavities are still the best idea. As cheep as the print material is getting to reduce the price it comes down to print time

[@TheRealFOSFOR]

I usually only use through-holes for big flat and relatively thin pieces to reduce the top and bottom layer area.

[@geauxracerx]

NGL the title and beginning had me ready to rage, but you pulled it together in the end. Though a better title could have been “How to correctly use cavities in your 3D printed designs” or “Not your Grandfather’s cavities”

[@onbedoeldekut1515]

Cavities CAN and DO help when they're designed by anyone with competency. It's not about just putting them in designs to reduce weight, but implementing them with structure deformation IN MIND. Factor expected deviances into your creations. Expect stresses in specific areas, implement cavities to act against the individual forces applied upon them where needed rathe than just plonking them about a design because it looks nice.

[@onbedoeldekut1515]

Test, test, test and test some more. Slice your designs apart afterwards, and look at what happened where. Understand what works best for each individual element and modify future designs. CAVITIES CAN HELP. (if you have the intelligence to understand why).

[@b1tw0nder]

Cavities can reduce warping with abs, though. If done right, that is.

[@larryturnertclan]

Even tough cavities are inside the part and not visible, they create surface area. You want to reduce surface area in 3D printing. Perimeters generally print much slower and are the thickest area of the print.

[@thedabblingwarlock]

Regarding the no through-holes thing, what if we're designing a wing and need to have a place for wiring and the wing spar that holds the sections together?

[@slant3d]

Then design holes. But dont have cavities be through-holes.

[@thedabblingwarlock]

@@slant3d Got ya. Just curious, what about keys for assembly? Do you have a video on how to design those for 3d printing?

[@PaulG.x]

Include a wiring conduit in the design

[@timothymusson5040]

@@thedabblingwarlockyes, a couple of weeks ago he did one on that

[@julianfreto1666]

You should consider creating a 3d print design course on Udemy, a book or something. I would definitely purchase

[@TOT3m1c]

How about in the case of side walls for an open front case? The walls are thin enough that there isn't much infill between the inside and outside perimeters. I made diagonal sliced holes to reduce material in the sides.

[@helipilotuh1]

Can you do a video on clips to attach 3d printed parts together without needing glue. Sometimes mine work great and sometimes I gotta break out the glue.

[@kurtnelle]

Would it be possible to embed cavities inside of the part? That's something I've never thought to try.

[@slant3d]

Yes: kzbin.info/www/bejne/Zqi7kqaum7V1n5Y

[@davidhope5875]

Great video, can we have it at about 1/2 the speed now please?

[@patrickunderwood5662]

Makes great sense for FDM! But what about resin? Just wondering about curing in a fully enclosed print. (Noob question.)

[@elliejohnson2786]

Would have been nice to see some numbers and better examples, especially for someone like me who has never 3d printed before. For instance: Why is removing material "adding material"? I'm confused about that. I can understand the concept of reducing the quality and strength of the part, but how does literally removing material somehow literally add material in comparison to a fully solid part?

[@HellHoundzProductions]

i often wonder how much i could learn if i was able to hang out and pick your brain for a day XD. really love your videos and pretty much always learn a few things, kudos for keeping the spirit of the industry/hobby pure by pushing your wisdom back into the system so others can learn more quicker and do the same.

[@richy3454]

I only use cavities if i have an insert that will be fully enclosed in the part like a magnet or nuts and washers

[@KeithOlson]

An interesting look at the issue. Ironically, though, *YOU* committed a cardinal sin with that arch full of cylindrical cavities: to optimize a design for speed and economy, you need to remove as many line segments as you possibly can. Those cylinders probably have a dozen or two per layer *EACH,* when they could be made with as few as three and thus be *FAR* faster to print and use less material. (Yes, if your machine is tweaked to the nines and/or can use G02/G03 codes, you *might* be able to make circular cavities faster than triangular ones at the cost of the extra material. Might.)

[@rondlh20]

Very useful insights! Thanks

[@slant3d]

Glad it was helpful!

[@bcubed72]

"Lightening holes" are there to save weight and maximize strength-to-weight ratio. You put the holes where the stress is lowest. Has nothing to do with Savin money, per se.

[@schrottinator]

I like adding cavities for looks.

[@antoniomonteiro3698]

I'm not convinced you're right.

[@aviphysics]

It is weird that you used an airfoil as an example. Normally they are designed to print in vace mode and have cavity designs to force an internal structure.

[@CliffKajun]

If printing dentistry visors, don't use cavities...

[@teytreet7358]

The cavity looks much better at holding up to bending moment.

[@janoshorvath9430]

Insightful!

[@paradiselost9946]

another point is if you have to have cavities... try to have things as multiples of nozzle diameter. well, any feature really. the longest print cycles are always those annoying little jiggers between two walls that are just over the nozzle diameter... "wow, you just did the walls and the infill faster than you can do that 0.7mm gap around the perimeter... and why did you just rapid all the way to this side just to rapid back over to that side for one blob??" sometimes the paths that slicers choose has my head aching... meh. that they do it at all is still sorta amazing.

[@conorstewart2214]

Slicers can adjust the line width, they aren’t limited to the size of the nozzle any more, they can go slightly thicker or thinner, that help with those gaps you are on about, it just slightly thickens it’s lines so there is no gap. Like if you are trying to print a 0.9 mm thick section with a 0.4 mm nozzle, slicers can expand it to 0.45 mm instead and print the 0.9 mm section with just two 0.45 mm lines.

[@paradiselost9946]

@@conorstewart2214 i know that. then you get the same effect as it applies it to the entire print rather than selectively going "this center line requires 1.5 nozzle diameters to fill completely... lets over extrude rather than jog back and forth for the next twenty five minutes".

[@conorstewart2214]

@@paradiselost9946 no slicers now as far as I am aware can do it automatically and as needed, so it adjusts the line thickness throughout the print.

[@conorstewart2214]

@@paradiselost9946 just checked cura, if you have an up to date version, you can slice a model then go to preview and change the view to line width, you can see it does change the line width automatically to best fit the print.

[@swivel84]

do you have a tutorial on how to set it up in cura? :)

[@esra_erimez]

Good to know,. thanks.

[@slant3d]

You bet

[@3DJapan]

I use Lightning infill so my prints are almost completely hollow. Infill doesn't affect the strength. To make it stronger make the wall thicker.

[@slant3d]

Incorrect. If infill does not affect strength, try removing the trusses in a bridge.

[@conorstewart2214]

Infill significantly affects strength. Yes you may not need much infill if you only print decorative pieces but for anything structural infill plays a significant role, both the percentage of infill and the infill pattern, some are only good in 2D others are better in 3D. Print a few cubes with varying amounts of infill and infill type and see how much weight it takes to crush them. If infill didn’t add strength then everything would be hollow.

[@BrazenRain]

Cavities are a way to add material and strength in the form of perimeters

[@slant3d]

Absolutely. We dive into this a bit toward the ending 1/3 of the video.

[@lord_scrubington]

cosmetic error is completely invalid the cavities are never going to be visible, thats kinda the point

[@TommiHonkonen]

mathematically and mechanically speaking there is no such thing as 'half arc'. Circle is circle and anything less is arc.

[@PuntoLeo3DPrints]

Cool 😎

[@PaulG.x]

Cavities in 3d prints have a purpose - it shows that the designer has no clues.

[@slant3d]

You should really watch the video rather than just reading the title

[@mechadeka]

@@slant3d Damn you got some real reading comprehension issues.

[@ColbyFreeman]

In my experience cavities are added to increase strength in one way or another. It doesn't help that your example looks like a cross section of an airfoil.

[@walktime]

so many stls i've seen with all kinds of modifications to "save material"........ good model that does what i need to, but ruined by "smart" choices to "save" material that actually makes part consume 2x plastic and time.... sometimes it's relatively easy to modify that stl but sometimes designing from scratch using that part as a reference/inspiration is faster

[@andrewut7ya511]

As a new designer about 1.5 years in and all self taught , this channel is by far the most valuable resource ive found for real useable knowledge. I work in prototyping and making work fixtures but cant afford school, this channel makes me feel like i can progress and make better things with my limited resources. Most sincere thank you for sharing all this stuff. your mouse ears video alone has saved me dozens of failed prints on my most commonly printed part. This stuff might be basic for real designers but i was a pipefitter for 18 years so im a little behind the pros lol, but ill get there. Thanks again, slant has been a real inspiration. I dont plan on opening a print farm but my goal is to print as many things as humanly possible so i never have to fit pipes again🙃

[@slant3d]

Thanks for watching. Glad it is helpful

[@DailyFrankPeter]

Use cavities to add material (i.e. the opposite effect as in machining).

[@t.mollov566]

Printed vertically... uhh that hurts.

[@feliwein_cc]

i was just thinking about the bridge with the structure and designing it in fusion, it would be dope that you make a series of "designing it like a pro" and showing us the most efficient way to design features in fusion, so many times in fusion i have a super simple idea that cant translate properly and ended up wasting a lot of time, for example idk how i would use the circular pattern to achieve it but i'd think thats the way. something ultra dope would be that we could send you easy snipets of a super specific and short idea and see how you would design it. something like the stackoverflow of design

[@conorstewart2214]

Play around with the tools for a while and you will find the easy ways. To use a circular pattern to make the semi circle thing he showed you can either sketch or extrude one hole then use the circular pattern with the pivot point set as the centre of the arch circle and then there are settings for number of copies, spacing, etc.

[@NickFajardo]

5:51 Maybe instead of "ancient" technology, you could call it a "legacy" technology xD Otherwise, a pretty solid vid :D

[@slant3d]

Carved from stone. Lol

[@sti9754]

Sorry dude - really wanted to watch this BUT that numbing bass beat just pissed me right off.

[@mitchellreece3711]

"Stop emulating the restrictions of injection molding"

[@habiks]

Looks like a rib from an airfoil.. which is worst example for the point you're trying to make lol. Also you're comparing a part with top and bottom layers and a part with none...

[@slant3d]

The point is cavities are the worst solution to lightweight and strengthen a part. The airfoil is a perfect example.

[@habiks]

@@slant3d then why all the 3d printed planes use it? You're talking about the extra toolpath but optimized 3d model will make head print whole layer without ever retracting...

[@ignasanchezl]

It's a pretty poor example, lets be honest, but it's good information.

[@conorstewart2214]

@@habiks they do it so like you said they can print the whole layer without retracting, often they are meant to be printed in vase mode for that purpose. Then there will be no infill, hence they use outer walls to make cavities instead. It helps with lightweight PLAs that foam and work best when extruded continuously and not stopped and started and can’t retract properly.

[@jpjokela1]

Regarding "bygone era", injection moulding is definitely still in use, much more than 3D printing, I'd say. Also, most of what you said, mostly affects only FDM printing.With resin printing, you can't really do similar "pockets of air inside the model" infill, as that would also mean "pockets with uncured resin inside" (liquid resin can be bad for your health, while solid resin is just fine) Otherwise, a nice video. Good thing you also covered the (still) useful usecases (except the one, where you want holes for other reasons, like connecting to other parts, letting air pass through etc.)

[@sjoormen1]

yes and no. cavities can strengthen part if done correctly.

[@valdolandar534]

Remember that the infill triangulated is the more strong in structures. Dont use the grid way.

[@slant3d]

Yes. But each infill has its application area.

[@MandoMTL]

Seems like machining logic carried to 3d printing.

[@Jkauppa]

too much talk

[@cattaraugustonawanda4426]

Not true for resin printing

[@toobian2]

Pretty lazy video, how about some giving us some print times, material usage and strength tests instead of "cavities are bad because I said so"

[@jimbotron8552]

clickbait not gonna lie

[@slant3d]

How?

[@LawnMo]

@@slant3d I'll give a try at making their comment more constructive, I guess the title feels or was left incomplete to carry your point in the video (ie. "cavities don't help [to reduce weight]") but around 5:29 you make it clear "cavities do have their place (but)" which is misleading. If someone were to watch that specific video without prior knowledge or experience on designing parts for FDM printing in an efficient manner, they would assume cavities are bad, period, which is not your point and how you present cavities to slim parts is moot because if someone modeling something they care about making lighter, they'd also consider structural integrity and see those two points as a whole, my point being you're trying to separate those two points in this video and close to the end say "never mind what I just said but still cover those holes" and... yeah, in the eyes of a newbie it's confusing because they have or will eventually see designs with cavities and for a more experienced person it might feel confusing because cavities don't just serve the purpose of reducing weight. I have to admit I clicked for the title (because it was either common sense or a genius new trick) and I read the comments to feel the room and how people perceived the informations provided, I have an issue with how the cavities are positioned on that green part as they definitely should be larger and connect with the outer perimeters to have the biggest impact on that part both in weight reduction and structural integrity, thus making infills close to unnecessary except for the top layers to print decently. While what you explain in this video is a good advice for people running a print farm and reducing rejects and print issues, it's really targeting a niche of users and those passing by might feel deceived because they're not trying to juice as much parts per day their printer(s) can, but to... make structurally sound, lightweight parts. Tim Station has a video on printing wings specifically ("How I Designed a 3D Printed Wing") which from an engineering point of view makes a lot of sense for extra-lightweight structural parts. Anyway, hope this helps and isn't poorly received, did my best to turn a mean comment ;) Have a nice day.

[@SirSpence99]

@@LawnMo A title shouldn't be a paragraph. Further, if someone interprets the title of the video incorrectly and never watches the video, that is on them, not the person who made the video. No, his advice isn't for a niche market, unless you consider anyone doing 3d printing part of a niche market. Tim Stanton has a video on how to do wings in vase mode, which is very different from what was talked about in this video. Ironically, there is some overlap because Tim's solution was to use the "cavities" (not really) to reinforce the part, not to reduce weight, which is the same conclusion anyone who is paying attention to the video will come away with...

[@jimbotron8552]

@@slant3d I find it annoying when the title implies something different to what is actually said in the video.

[@ABaumstumpf]

If you want structurally sound and light parts - dont use 3D printing. You are already starting with failure.

[@slant3d]

Very incorrect

[@ABaumstumpf]

@@slant3d if you say so - then all manufacturers should learn from you and switch to 3d printing cause it is oh so great? Or maybe 3D printing is good for getting a decent enough shape for rapid prototyping but does not have the structural integrity, dimensional accuracy or productivity as other forms of manufacturing.... Nah, can't be that you are wrong, surely everybody else is.

[@pmermino]

Et dire qu'il y a des niobets qui utilisent encore des cavités pour leurs pièces.... il sont vraiment taguenets

[@RyuuOujiXS]

Arbitrary cavities* don't help. Cavities based on structural integrity DO help. The goal is not to get rid of random mass. The goal is to get rid of unnecessary mass.