**📐Проектирование моделей под 3D печать — Transcript & Summary | SozAI**
Source: https://sozai.app/transcript/model-design-3d-printing/

Tips and tricks for designing 3D printable models to improve strength, printability, and reduce defects from the design stage.

## Key Takeaways

- Proper orientation of parts relative to the print plane is critical for maximizing strength.
- Design reinforcements as walls and ribs rather than relying on infill for structural integrity.
- Infill is the weakest part of a print; thick infill patterns and wall design improve strength.
- Adding fillets and chamfers prevents layer separation and compensates for common print defects.
- Design for printability reduces the need for complex slicer settings and post-processing.

## What the video covers

- Design parts considering anisotropy of 3D prints; orient models so tensile forces align with the print plane for strength.
- Simplify geometry by leveraging slicer settings for infill and wall thickness instead of complex modeling.
- Use ribs, gussets, and webs inspired by industrial casting to reinforce parts without extra plastic.
- Avoid relying solely on slicer tricks; design models to be printable on any machine with predictable strength.
- Chamfers and fillets help reduce stress concentrations and compensate for printing defects like elephant’s foot.
- Bridging and hole design require careful clearance and orientation to ensure dimensional accuracy without post-processing.
- Use crush ribs or deformable ribs to compensate for dimensional inaccuracies in interference fits.
- Thread inserts can be added post-print for stronger fasteners; they are available online and easy to install.
- Correct orientation and design reduce print failures and improve mechanical properties without extra material.
- The video also briefly promotes buying used 3D printers safely via Avito with secure payment options.

## Chapters

1. 00:00 Introduction and Overview of 3D Printing Design Tips
2. 01:50 Importance of Load Orientation and Anisotropy
3. 04:04 Infill Challenges and Wall Strength
4. 05:58 Using Ribs and Gussets for Reinforcement
5. 07:49 Buying Used 3D Printers Safely via Avito
6. 09:23 Fillets, Chamfers, and Corner Design for Strength
7. 12:48 Bridging, Hole Design, and Dimensional Accuracy

Answers

## Questions about this video

Why is part orientation important in 3D printing?

Part orientation affects strength because 3D prints are anisotropic; they are stronger along the print layers and weaker across them. Aligning tensile forces parallel to the print plane improves durability.

How can I reinforce a 3D printed part without adding extra plastic?

You can add structural reinforcements like ribs, gussets, and webs by designing thin walls and chamfers that act as stiffeners, improving rigidity without significantly increasing material usage.

What are common issues with infill in 3D printing?

Infill is often the weakest part of a print because it is printed quickly and may not fully bond to walls, leading to weak spots. Using thick infill patterns and focusing on wall strength helps mitigate this.

## Full Transcript — Download SRT & Markdown

00:00

Speaker A

Hi guys. Today, we’ll look at a few useful tips and tricks for designing models for 3D printing. How can you simplify printing and avoid defects back at the design stage? How do you make a model printable on different

00:12

Speaker A

printers, and how can you make it stronger without adding extra plastic? It’s going to be interesting. Let’s get started. The idea behind this video is that there are two paths. Either we design a part simply as a part, and

00:29

Speaker A

then try to print it well using all sorts of slicer tricks and fine printer calibration. Or we design the part from the start so it prints on any machine and can withstand print defects and dimensional inaccuracies. This is

00:41

Speaker A

exactly our topic. Let me clarify right away that in this video, I won’t focus on the modeling process. I want to show some elements conceptually, meaning the idea itself, rather than how to build it. I work in Fusion 360,

00:52

Speaker A

and there is a huge, detailed tutorial on the channel that answers the question of how to build things. But here, we will analyze what to build. I want to turn a brief summary of this video, along with your additions from

01:04

Speaker A

the comments, into an illustrated guideline later and post it on my Telegram channel. Subscribe so you don't miss it, and I also look forward to your additions in the comments.

01:12

Speaker A

Anisotropy is probably the most obvious thing. A 3D-printed part is anisotropic, meaning it has different properties depending on the direction of the load. Specifically, it is stronger along the plastic lines and weaker across them, because while the

01:25

Speaker A

layers fuse together, solid plastic is still much stronger. Try breaking a pack of spaghetti lengthwise and crosswise. It’s roughly the same thing here. A slicer usually fills dense areas in a cross-hatch pattern every other layer, so the part has

01:37

Speaker A

roughly the same strength in all horizontal directions. And in the remaining vertical direction, the part ends up being the weakest, because it’s printed layer perfectly upon layer. Therefore, the first step in designing a model is to determine the

01:50

Speaker A

loads it will bear and orient it so that tensile forces and torques are parallel to the print plane. Let’s look at the example of a simple bracket. If you print it standing up, one half will be strong against bending, but the

02:03

Speaker A

other will not. Unpleasant. Even more unpleasant is the fact that usually the most stressed part of the bracket is this point right here. And in this case, the torque will literally tear the layers apart, and the bracket will most

02:18

Speaker A

likely break right here. If you just print the bracket lying flat, it will become much stronger and more symmetrical in its properties. If we are making a hypothetical wall hanger, something fancy and pretty, printing it flat means the load will tear the

02:40

Speaker A

layers of the hook, but printing it upright will tear the mounting plate itself. You can simplify the geometry a bit, keeping the main tapering shape, and print it like this, on its side.

02:55

Speaker A

And this version will be strong in every load direction. Both in tension of the plate and the hook's SG. The vertical one broke at 10 kg, the horizontal at 15, while the clever hook held up to 26 and didn't even break. In

03:12

Speaker A

general, correct orientation relative to the print plane provides the part with its basic strength. One of the advantages of 3D printing over other manufacturing methods is the ability to create solid bosses of any shape, where wall thickness and infill density are

03:26

Speaker A

adjusted before printing, not at the modeling stage. This allows for significantly simplified design. And where, for example, casting requires thinking about wall thickness to save material, for a printer we just make the body in the desired shape, and

03:39

Speaker A

everything else is set before sending it to print. And this is where you need to be careful. While the printer prints walls as densely as possible, continuously fusing each layer, infill is the weakest print line, printed at high speed and only partially attached

03:54

Speaker A

to the walls. With a poorly tuned printer, infill can literally become a cobweb, which can support overhangs during printing but adds little real strength. For example, this bombulape.

04:04

Speaker A

Branded filament. Standard settings. The lines themselves are printed well, but in some places they just don't reach the walls. Yes, this can be fixed in the settings, but infill is still not a very stable thing. It is generated automatically and doesn't

04:17

Speaker A

always add strength exactly where you need it. Just a couple of years ago, slicers added the ability to make thick infill. It's available in some patterns, and for example, the cubic one creates a really good structural support of triangles inside the part.

04:30

Speaker A

And it sticks to the walls much better, too. But that's still talking about filled-in bosses. Don't forget that a hollow boss also has walls, and walls are very strong, so a simple chamfer becomes a thin-walled rib that we

04:43

Speaker A

created with a single mouse click. If you use these moments wisely, you can simplify a part with practically no extra material. You can even go further and create direct reinforcements out of walls, like ribs, gussets, and webs.

04:55

Speaker A

Specifically to obtain predictable rigidity without wasting time and plastic on filling voids. For inspiration, you can look at industrial cast designs. Ribs between the lid and the wall. Reinforcing screw standoffs, both free-standing and near corners of walls. Gussets on cantilevers,

05:11

Speaker A

triangular webs instead of solid elements, webs of ribs on large thin housing covers, and so on and so forth.

05:17

Speaker A

Visual experience is really important here. Just Google "injection molding ribs" or scroll through images on Pinterest. But not all molding techniques provide a benefit in 3D printing. For example, in this manual, what is considered incorrect for molding actually looks more logical for

05:32

Speaker A

a printer in some places. It might seem like creating these elements is a huge hassle, but it's actually not. Modern CAD programs have convenient tools for this. For example, we have this tricky housing cover, made quite simply, like

05:45

Speaker A

a beginner’s block. It’s enough to turn it thin-walled in the first operation, specifying the thickness, create a sketch on the top face, and draw the ribs. Then, with a second operation, which is literally called "web," turn them into ribs of any

05:58

Speaker A

desired thickness, and they will automatically snap to the current geometry. In this case, all that's left is to clear the hole. Everything is ready for printing. By the way, you don't necessarily have to buy a new 3D printer. You can get a used one on

06:13

Speaker A

Avito. I’ve bought and sold them there, and not just them. Smartphones, computer hardware, and all my studio equipment have also come and gone through Avito. I’ve literally been using this platform for half my life.

06:24

Speaker A

Recently, Avito has been adding more and more useful services. For instance, there is local pickup with online payment. That means the money isn't sent directly to the seller, but through Avito, and only after an in-person meeting, inspection, and deal

06:35

Speaker A

confirmation, which is much safer and more reliable. So, if you’re a seller and a buyer arrives, they’ve essentially already paid for the item, and there won't be any sudden "give me a discount, bro" requests. And if you’re a buyer, no one will buy the

06:46

Speaker A

item before you do. You can make sure everything is in order before confirming the deal. For large purchases, if you don't want to freeze a large sum, there is installment payment. The seller gets their money, the buyer gets the product, but pays

06:58

Speaker A

for it in parts according to a chosen schedule. And all of this works perfectly in the smartphone market. Why buy this year’s flagship for hundreds of thousands when you can get last year’s from someone chasing the newest one? You get a flagship

07:10

Speaker A

experience with a previous model without overpaying for a cherry color. Head over to Avito via the link in the description and upgrade smartly. In short, this method allows you to create parts that don't require specific slicer settings or balancing between

07:24

Speaker A

strength and

07:35

Speaker A

extrudes plastic from a nozzle of a known diameter, typically 0.4 mm. So, it makes sense that if you make a wall exactly 1 or 1.4 mm, it won't be possible to print that size without compromises. For example, this test

07:49

Speaker A

shows that thicknesses that are multiples of the nozzle diameter print clearly, while otherwise, the slicer starts adding thin infill. So, the printer will print a line of any thickness for you regardless, but it will fill it with infill, which might

08:01

Speaker A

add a gap between the walls if the printer is poorly tuned. And that is one extra line, meaning it will take a little bit longer to print. Therefore, as a baseline, you should set wall thickness as a multiple of the nozzle

08:11

Speaker A

diameter, just to avoid getting extra lines. PrusaSlicer, for example, shows a recommended thickness based on current print settings, but this thickness isn't very aesthetic and, in essence, not universal. Again, a couple of years ago, a new wall generation

08:24

Speaker A

algorithm called Arachne appeared in slicers, which allows varying the extrusion width of walls and eliminating infill lines from them entirely. That is, the entire wall is printed as a wall, regardless of its thickness. And with that, you can make

08:35

Speaker A

the wall thickness on your model absolutely anything, without compromises. Nevertheless, protruding walls don't make a part look better, and often they can simply be replaced with fillets. Filleting is one of the most powerful and basic tools in design

08:48

Speaker A

software—not in modeling programs that work with meshes and forms, but specifically in CAD. Fillets allow you to get a complex, smooth shape in a couple of mouse clicks, remove excess material, or, conversely, add thickness . Most elements are much easier and

09:01

Speaker A

faster to create with a simple shape plus a fillet than by trying to fit everything into one complex operation.

09:06

Speaker A

Fillets are like butter; you can't spoil the porridge with them. You can add them to all external corners.

09:11

Speaker A

Wherever the design doesn't strictly require sharp corners. This will make the forms smoother and the part more pleasant to the touch. Filleting internal corners increases the strength of the corners and the entire part as a whole, because material is added in a

09:23

Speaker A

critical area. That is, for example, our same long-suffering little corner. This is especially important at the junctions of thin walls and on protruding cylinders, especially for fasteners. And the basic rule here is: it is better to add a fillet at any

09:34

Speaker A

sharp change in thickness, for example, when transitioning from a cylinder to a cylinder or from a plane to an edge.

09:40

Speaker A

Any sharp corners in a part are stress concentrators, and fillets very effectively remove them and increase strength. Another useful feature, specifically for FDM printing, is filleting vertical corners. If you are printing a rectangle, for instance, due to the weight and inertia of the print

09:55

Speaker A

head, the printer has to slow down almost to zero when transitioning through a corner. If the printer is well-tuned and calibrated for the current spool of plastic, we only lose print speed due to braking around all the corners. But if you don't bother

10:07

Speaker A

with settings and calibrations, then in and around the corners you can get irregularities, blobs, and bulges, meaning the entire dimensions of the part will drift. If you add a fillet, the printer won't have to slow down as much at the corners, and the print will

10:19

Speaker A

be more stable. Even a small radius already provides a more pleasing result . Yes, the part will lose its sharp corners, but even without fillets, you can't make them absolutely sharp anyway . They will still have the radius of

10:29

Speaker A

the extrusion width. While vertical fillets are almost always a clear advantage, the situation with horizontal ones is not so straightforward. Firstly, they have an uneven shape, meaning the layering of the print is not as noticeable on a vertical segment as it is on a

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Speaker A

horizontal one. If it is important for the part to look nice and not layered in that area, it is better to replace the fillet with a chamfer, as it provides a uniform, solid appearance to the layers. The situation is even worse

10:54

Speaker A

with bottom fillets, because a bottom fillet is very difficult to print due to the severe overhang, and supports won't help much here. Achieving stable quality and a defect-free surface will be very difficult. Now, a 45-degree chamfer is a different story. It will

11:07

Speaker A

print perfectly in any size and on any printer. Another useful point. Even if the part requires a sharp bottom corner , you can add a chamfer half the diameter of the nozzle to compensate for the elephant's foot effect and the

11:20

Speaker A

bulging, uneven first layer from the PEI plate. Yes, this setting can be enabled in the slicer, but it can also be incorporated into the model itself.

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Speaker A

It is not as universal, but it certainly won't make things worse. So yes, fillets and chamfers are very important tools when designing in mechanical engineering software, but they won't help you create an artistic model, like a figurine or something

11:38

Speaker A

that doesn't look like a collection of blocks. For that, there are other programs, for example, Blender. It is a very powerful and complex software, which, let's say, is not easy to figure out on your own. The 3D printing course

11:49

Speaker A

from Home Digital School will help you with this. They will teach you how to model in Blender, specifically considering 3D printing features, generating concepts for models using neural networks, and working with a 3D printer. You will learn to prepare

12:01

Speaker A

models for SLA and FDM printing, understand materials and filaments, configure slicers and printers, and process parts after printing. During the training, you will print your own projects, not models from stock websites. The training is adapted to your tasks, and each homework

12:14

Speaker A

assignment is checked and reviewed in detail by a working 3D artist who will protect you from typical mistakes and lead your project to completion. The course lasts 4.2 months with a flexible schedule and two weeks of vacation. You

12:26

Speaker A

will also get access to the HDS club. This is a private community with streams, a huge library of guides, and useful materials. Right now, there is a 40%discount for early students. And until the end of the month, a pleasant

12:37

Speaker A

bonus personally from me awaits you, up to 10,000 rubles. towards your tuition and participation in the school's prize draw. Follow the link in the description or scan the QR code to reserve your spot and start your professional journey in 3D printing.

12:48

Speaker A

Let's return to the problem of sharp corners. They can bulge not only on the outside but also on the inside, once again distorting the geometry and reducing the dimensions. If we're designing a box for a circuit board, for example, and want minimal

13:00

Speaker A

clearances, the board will likely just get stuck in the corners. The solution is also a fillet, but in the opposite direction, to create free space in the corners, or simply increase the gap between the walls and the board. But

13:13

Speaker A

that depends on the situation. Ironically, the simplest geometric shape, the circle, is the hardest for FDM printing. Let's consider vertical and horizontal cases. Vertical holes and cylinders can be ruined by the seam . It’s not just a surface defect, but

13:28

Speaker A

a change in geometry and dimensions. If something is inserted there, it may not fit or could be offset from the axis.

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Speaker A

Yes, you can perfectly tune the seam on your printer for a specific filament, but that isn't a universal solution.

13:40

Speaker A

You can print with a random seam position to get uniform small defects that won't ruin the geometry like a vertical seam would. But you can also get rid of a protruding seam at the design stage by simply hiding it in a

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Speaker A

groove. It's better to make the groove rounded or tangential rather than triangular, so there’s no chance of creating a bulge on the edge that ruins the geometry again. Yes, it's no longer a perfect cylinder, but if it's hidden

14:04

Speaker A

inside the assembly, like a hinge, there will be no downsides to this solution. It will print with any settings, assemble easily, and just work. Horizontal cylinders and holes, on the other hand, are a real pain. For horizontal cylinders, it's simple.

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Speaker A

It’s best not to print them at all, because achieving accurate geometry on such an overhang is extremely difficult . But there is a compromise: remove a segment and print the cylinder with a flat wall. Even if it's a hinge, this

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solution will work perfectly and won't require post-processing. The same applies to spheres. A sphere without a segment, for example, is used in the famous "dummy 13". It works great there too. Horizontal holes have a similar problem, but in the upper part of the

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Speaker A

circle. Here you get both an overhang and a shallow angle surface, causing the top of the circle to turn into a fringed bridge, while the bottom looks perfect. There are a couple of tricks here. The first and simplest: fillet

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Speaker A

the hole entrance. This will remove excess buildup at the corners due to print head deceleration on an uncalibrated printer, making the hole a bit better. But ruined geometry will still remain across the top of the entire cylinder. The second trick is to

15:11

Speaker A

turn the hole into a teardrop with an apex angle of about 90 to 110 degrees, which is double the safe overhang angle . This preserves the circular geometry, and whatever needs to fit inside will fit. You can go a little further and

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Speaker A

truncate the resulting shape horizontally. Then the printer will print a bridge there, and the geometry will still be saved. The hole entrance can also be filleted to avoid buildup along the cylinder edge if Linear Advance is poorly calibrated for the

15:36

Speaker A

filament. It's the same situation as with printing vertical corners. And here I'll show another trick to avoid seams on critical surfaces; while the seam will still exist, we can create a seam trap as a groove on a surface that

15:49

Speaker A

doesn't matter. For vertical cylinders, we made a trap inside the cylinder itself, but here we can trap the seam elsewhere on the model. This makes printing more predictable. On large holes, it looks quite strange, but it's very illustrative, yes. So, for example

16:07

Speaker A

, here's a large diameter; the cylinder enters more or less from this side. Everything hit a wall here. The geometry drifted and it won't fit.

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Speaker A

Here's the teardrop hole, please, it inserts. Up, it rotates, everything works. But in practice, it's much more interesting to look at small holes. For example, I have 3, 4, and 6 mm. These two are just teardrops, and the six is

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Speaker A

with a bridge. Printed with a 0.1 clearance, so this one is 6.1. Right after printing, with no post-processing , the drill bit just slid in. The four also inserts. The three also inserts. I mean, they don't look like teardrops;

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Speaker A

they look like normal, even holes. On the back, it's just a hole as they were , and here the drill bit...Well, even if I really wanted to, I couldn't push it in. Without post-processing, that's not an option. Not a single one. Well,

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Speaker A

the three definitely won't fit. It’s been completely flattened here. So the teardrops work beautifully. But nothing will save us from the mesh precision.

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Speaker A

When exporting to STL format, all geometry turns into triangles, making the circle a polygon. With low export resolution and a small hole diameter, we risk getting a smaller diameter during slicing. We haven't even printed anything, and the geometry is already

17:37

Speaker A

wrong: both vertical and horizontal. What to do? Export the model at a proper resolution and print test circle samples on your printer with small diameter increments to check it, so to speak, in hardware. But here you should ask yourself: why do I even need this

17:52

Speaker A

circle? If you need a tight fit, like for a bearing, or conversely, a smooth slide with minimal clearance for a guide, then the empirically found sizes will only suit this printer and possibly just this spool of filament.

18:06

Speaker A

So we are again designing a non-universal model for our own conditions, creating a situation where a fraction of a millimeter will cause the structure not to assemble. There are a couple of options here too. If you couldn't answer the question of why

18:20

Speaker A

you need this circle, maybe you don't need it at all. There are other excellent shapes, for instance, a hexagon. It will print without seams or overhangs in any orientation and, unlike a circle, it has a tolerance for deformation. That is, it will bend

18:33

Speaker A

slightly and securely clamp the bearing exactly along the central axis. And print precision can be off by a wide margin, because the design allows for a larger range of movement than a standard circular hole fit. The second option is widely used in molding, the

18:47

Speaker A

so-called "crush ribs" or deformable ribs. If the manufacturing method cannot ensure precise dimensions for an interference fit, then the size should be intentionally larger, but compensated for with crushable elements . This is roughly how it might look. To

19:00

Speaker A

simplify the press-fit, you can make the entry tapered. And a design like this will allow you to seat the bearing consistently regardless of the printer, without tweaking tenths or hundredths of a millimeter in diameter. Another interesting element is the fins. It is

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Speaker A

extremely simple to make. One slot in a circular pattern and a circle that clips the fins at the desired diameter.

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Speaker A

Extrude it, and you get this ring spring, which forgives huge errors in both printing and the diameter of the cylinder inserted into it. Meaning you can push something in here that is even 1 mm larger than necessary. It will be

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Speaker A

tight, but it will go in without the risk of breaking anything. It will hold very securely and center automatically, unlike, for example, options with an incomplete circle or other similar side retainers. That was a big block about circles, but we aren't done with them

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Speaker A

yet. Let’s move on to screw connections. Some models may consist of several parts that need to be joined together. This could be a very large part that doesn't fit on the print bed, or a housing cover. In practice, screw

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Speaker A

connections are often used because they are reliable, convenient, and accessible. Plus, the design becomes demountable. Basically, there are two options for where to drive the screw.

20:07

Speaker A

Either directly into the body of the part or into a metal nut. The first option is simpler, but the connection is less durable and can loosen after a few assemblies and disassemblies. The second option is, accordingly, reliable and long-lasting. To screw directly

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Speaker A

into plastic, you can successfully choose the right hole diameter. Again, it’s best to print a test on your printer for standard M3, M4, and M5 screws. In my experience, for small threads, a hole equal to the thread diameter works great, as well as 0.1 mm

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Speaker A

smaller if you need it tighter. And this way, it naturally ends up being a little smaller. Plus the seam. And then the screw cuts its own thread.

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Speaker A

Especially if you turn it forcefully, it will also heat up, and the thread will be deeper. A horizontal hole can also be made in the shape of a teardrop . But there is a small downside. The first time you drive it in, it's quite

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Speaker A

tight, especially if you do it by hand and have several screws. If you need a lighter and looser thread, you can simply tap it, especially for large threads. Despite the non-uniformity of a 3 D-printed part, the threads cut

21:00

Speaker A

more than adequately. But this again requires post-processing time after printing, so you can simply design and print the threads directly in Fusion, for example. To do this, just click on the desired spot and select the thread length and type, like M6, and don't

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Speaker A

forget the "modeled" checkbox, otherwise, it'll just be a hole. Another good compromise for small threads is a hole slightly larger than needed with collapsible ribs, like an interference fit. In this case, print accuracy isn't critical, and the screw

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Speaker A

goes in more freely, cutting its own threads more easily. However, such a connection will hold less pull-out force and wear out faster with repeated disassembly and reassembly. But the easiest screwing process and the most reliable thread, of course, come from a

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Speaker A

metal nut. For this, you just need to design a hexagonal hole or pocket where it can be inserted or glued in place.

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Speaker A

Such a connection can be tightened quite firmly, especially if you set the infill to 100%along the screw axis, as I did in my clock project. The body itself is hollow, but reinforced at the joints. It turned out very strong and

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efficient. Another excellent industrial option is a threaded insert. These are often used to assemble the casings of various appliances and electronics.

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They can be cold-pressed or hot-melted into place. They are sold on AliExpress and installed using a soldering iron with a special tip. I have links to various versions of these goodies on my website in the useful 3D printing tools

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Speaker A

section. I'll leave a link in the description. Chinese sellers even offer a small guiding stand for installing these inserts. You attach the soldering iron to it, allowing you to melt the nut in perfectly perpendicular. The soldering iron tip temperature should

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be set about 10-20 degrees higher than the printing temperature of your current filament. Otherwise, the process is fairly straightforward.

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Speaker A

Insert, remove, and you're done. The inserts from Chinese sellers come in at least two types: cheaper and more expensive. I think it goes without saying which ones are more expensive and which ones will hold better. Plus, their threads are cut much better. A

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Speaker A

small life hack. You can make this tool for leveling out inserts using a screw and a washer. Use it to press down the heated insert, and it will sit flush and perpendicular to the surface without leaving marks. Because if you

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Speaker A

press down with the soldering iron, even with steady hands, you might seat the insert at an angle or plunge the iron into the part, which is not cool at all. The diameter of the hole for the insert can generally be chosen

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Speaker A

based on the diameter of the insert without the knurling, or slightly larger. The insert can be placed on the side where the screw enters, or on the opposite side, which allows you to tighten it much more securely. The fact

23:18

Speaker A

that you should place holes for inserts or screws in a thickened area is, I think, already clear to you. Since we're talking about attaching lids to cases, this topic should be covered in a little more detail as well. There is

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Speaker A

a certain subtlety here. Here we have the housing and the lid. You'd think, why overthink it? The lid sits on the housing, gets secured, and in both cases, it fits tightly and the gap is barely visible. The keyword is "barely"

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Speaker A

. And that's not great, because in this plane, it is essentially loose. We can see and feel the walls shifting, especially if we apply some load. We can see a gap if we hold it to the light, especially if it’s ABS and the

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Speaker A

part warped after printing. Small clearances are left for the screws, so the whole thing wobbles. Of course, you can tighten it, sure, I get that, but it still doesn't feel like store-bought cases. In industrial design, this problem is solved by hiding the parting

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Speaker A

line behind a flange. This can be done in various ways. Here are a few illustrative examples. So now the lid centers itself, doesn't slide, and the gap doesn't show light. Now that's better, check out this version. I went

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Speaker A

a bit overboard with the clearance. I mean, it is loose, but the point is that it at least assembles. It will also be a bit more dust-tight this way.

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Speaker A

If you add a rubber gasket, it’ll even keep out moisture and things like that. And a version with this kind of lid. Oops. There. Now this looks beautiful.

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Speaker A

One more point. You don't have to try to clamp that gap down to zero, because you might still need assembly tolerances, and a thin, crooked line will just look like a gap between halves, especially if the lid doesn't

24:52

Speaker A

sit flush but fits in a more complex way. Like this. Yeah, so here you can see the gap, but here you can't.

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Speaker A

Because of the small clearances, the lid shifted and it doesn't look very uniform anymore. Therefore, the gap can be increased, creating a wide line that will no longer look like a seam in the housing, but simply as a design element

25:13

Speaker A

. A groove, of sorts. This element can be found very often in plastic housings for home appliances and electronics: remote controls, gamepads, laptops, mice, keyboards, various devices, and everywhere, everywhere, everywhere.

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Speaker A

Actually, you can use this feature in your own projects too. This is much better; in fact, I just took a slightly smaller lid, but it now creates this uniform groove along the edge. And despite any shifting of the lid, it

25:42

Speaker A

will still remain a groove all around and looks much more symmetrical. Let’s return to geometry and the printing process. Everyone knows that supports are usually used for overhangs , without which the printer simply wouldn't be able to print them, as the

26:03

Speaker A

plastic has nothing to rest on. Supports usually ruin the surface of the part, as they fuse to it and have to be peeled off. Beyond clever tricks like printing supports or using soluble materials, you can solve this issue at

26:14

Speaker A

the design stage, especially for technical parts. First, it’s sometimes enough to simply orient the model so it can be printed without any supports. You can think ahead about how it will sit on the build plate and design accordingly, including creating

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Speaker A

self-supporting geometry, adding chamfers, and angled sections. Yes, the model might get a bit bulkier, but it will print easily and without defects.

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Speaker A

For example, here is my project of Bender’s head. To print the internal dome without supports, I added a huge conical surface. For a solid model, that’s a lot of extra material, but 3D printing allows you to make this

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Speaker A

cone virtually empty. Basically, it’s just a support that is part of the model itself. Also, don't forget about bridges. Modern printers handle them great, so you can add flat horizontal sections where a support might otherwise be needed. If you look at a

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Speaker A

Benchy, it might seem like it has an angled roof, even on the inside, but that’s an illusion. The lower inner part of the roof is horizontal, so it prints as a bridge in any direction. In a similar situation, instead of

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Speaker A

creating an overhang at a shallow angle that would need support, you can make its bottom part strictly horizontal, provided the design allows it, and print without any supports at all.

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Speaker A

Here’s another great example using a bridge. Printing a horizontal surface with a hole that doesn't rest on the bed. Hmm-hmm-hmm. You can’t bridge this because the hole gets in the way.

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Speaker A

But you can make a thin bridge instead, right? Close the hole with a lid one or two layers thick, and the printer will easily print that whole roof using bridges. Then we just cut out that thin bridge later. Again, in the Bender

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Speaker A

project, this trick helped me replace a huge support coming all the way from the bed with just a couple of centimeters of filament. There are actually two such sacrificial bridges here, and it worked perfectly.

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Speaker A

There’s also a slightly trickier option of printing with small bridges around the hole. Two passes are enough: one for two segments and another for the remaining halves. From there, the printer will handle the rest on its own . So, I ended up printing this one with

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Speaker A

support after all. Let’s take a look. This is with the bridge that I cut off.

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Speaker A

And this is the tricky bridge. Gray plastic. This one here is the most confusing for me. I didn’t adjust anything for it at all. It was meant to show defects, but in principle, the bridges on it didn't print very well

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Speaker A

either. It’s messy, but the task was completed—meaning it was printed without supports. Honestly, it’s not much worse than with support. Phew.

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Speaker A

That’s probably enough for today. Let me know in the comments what other tricks and techniques you know to simplify 3D printing back at the design stage. And remember, when designing for print, you shouldn't ask how to make your printer print this, but how to

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Speaker A

design the model so any printer can print it. In other words, you need to design not just the model, but the method of its manufacturing. That’s all for now. As always, this was Alex Gyver. See you later. Bye.

Topics: 3D printing model design print orientation anisotropy infill ribs and gussets Fusion 360 print defects thread inserts 3D printer tips

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