Why your 3d printed stuff doesn't fit together and how to fix it!

Comments · 606

• SL

  @Slide100 · 3 years ago

  Thanks for this! &nbsp;I can&apos;t remember the number of times I&apos;ve had this conversation with myself: &quot;Ok, the screw is 3mm, and 3.5 for the hole <s>should</s> be ok&quot; 🙂

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• DO

  @DoctorZombo · 3 years ago (edited)

  One setting that&apos;s kind of hidden by default and makes an enormous difference on Cura is slicing tolerance: it can be set to &quot;exclusive&quot;, &quot;inclusive&quot;, or &quot;middle&quot;, which basically means wether the slicer will place your filament path entirely inside the geometry, outside the perimeter, or average its placement.<br>By default it&apos;s set to &quot;middle&quot; which means it will always make your holes slightly too small, and your pegs slightly too thick.<br><br>Edit: after a quick google search as a refresher I see I learned about that feature on this very channel! What were the odds haha

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• CR

  @CrimsonRegalia · 3 years ago

  “That’s right… It goes in the square hole.” 😂

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• GA

  @gamerpaddy · 3 years ago

  after buying a new roll of filament you gotta print all tests out there to dial it in, but then you run out of filament and repeat that for the next roll.

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• JB

  @JBMetalShop · 3 years ago

  Honestly i am an engineer and i think your channel does a magnificent job and explaining concepts and discussing important topics for people interested in 3D printing, it was a HUGE help on my 3D printing journey.

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• NE

  @nenemydog · 1 year ago

  This is all my jam. I&apos;m a CAD designer that got into 3d printing a few years back. It goes without saying that I am more interested in functional prints and dimensonal accuracy so i always spend a lot of time setting up my printers in order to get them to print right. It takes a huge combination of mechanical tuning the machine, etting up the firmware correctly, and designing using good toleranes. In the end you can fine tune using the slicer. I personally wouldn&apos;t change tolerances using the slicer but I mostly print things I designed myself so I have the luxury of choosing my own tolerances.<br><br>I have printed a lot of tolerance tests as you have and find it always interesting to see how well they fit or don&apos;t. It can be a big help of knowing how a fit will be for designing parts. <br><br>As you have pointed out squares a hard to print because of the corners. That&apos;s why I never really use them. I place radii on all corners on the xy plane to get better prints and better fitting parts. even a small radius with 1mm can go a long way in making square parts fit. And a slightly bigger radius on the adjacent part. In the industry we break edges because of the same reasons. Now with metal you would place chamfers since they tend to be easier to get right but with printers it&apos;s radii all the way. <br>In Z axis i tend to prefer chamfers tho because the 45 degrees allow for overhangs. At least at the bottom.<br><br>Also something I have started playing around with is focusing more on the holes. If you want to get even better fits it&apos;s easier to get good outside diameters than inside diameters. Especially because the seams tend to add too much material that will destroy a tight fit. With an outside diameter you can simply sand the seam off but with holes it gets harder to remove the seam. What I started doing is trying to print even diameters Instead of adding tolerances to the holes. The thing is it&apos;s easier to buy a set of drill bits and ream the seams off using a handheld drill. This means that you only need to apply tolerances to the outside diameter. If you print a cylinder you can then simply sand off the seam and technically you have an ever preciser fit than you would get by just printing.

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• TH

  @TheThrustProject · 3 years ago (edited)

  Wouldn&apos;t it be a great way to integrate PCBway as a sponsor by letting them print this gauge model in their different printing technologies and comparing them?<br>Would love to see something like this.

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• OK

  @okflyer777 · 3 years ago

  I would suggest adding a feature to the pegs to indicate their X-Y print orientation. &nbsp;That would allow the user to diagnose X vs Y axis fit issues if they are present. &nbsp;Good job.

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• BE

  @bensutton3527 · 3 years ago

  I regret that I have but one upvote to give to this video. This solved probably 90% of my dimensional accuracy problems immediately.

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• RI

  @rickharriss · 3 years ago

  As a D&amp;T teacher (retired) I used to do a short exercise with 11 year old students where they were asked to mark, cut and file a square of 3mm Acrylic to some given dimensions. &nbsp;When they presented their work as finished I tested it in a go / nogo gauge that had +/- 0.25mm sized holes in it. Generally first time none of the samples fitted but after a few tries they got the understanding of what tolerance was.<br>When I fit 2 printed parts together I usually print &nbsp;the inside part 0.25mm smaller and then use fine wet and dry paper to get a perfect fit. Fettling, as my engineer friends would call it.

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• SH

  @shiftyjesusfish · 3 years ago

  Its so worth the work to get that interference fit. It&apos;s so satisfying when 2 parts snap together perfectly and holds there.

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• PH

  @PhilWare1 · 3 years ago

  If I&apos;m needing exact tolerances I usually do a couple of test prints on a cut-down version of the part/tolerance in question. I&apos;ve found that even if you think you have allowed for the issue you will still be surprised. To be honest given the relative low cost of modern 3D printers its actually surprising how good the tolerance/consistency of prints are so I&apos;m not complaining!

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