Introduction: 3D Printing Can Be Fragile and Break in Thin Areas

About: Based in San Francisco I strive to incorporate custom lettering in the art that I design, print, and make.

This instructable shows off the accuracy of a 2 part print and also a reminder that when printing parts that are spirals you are likely to break them with very little pressure. Here the entire piece is solid but the sides of the bottom part were very brittle and ended up breaking.

When I tested out the model and used it as a drain in the kitchen sink it was a bit small for the sink and even with the broken area it worked well.

TIP: some people say PLA and things that go in your mouth are not a good mix (this is not yet confirmed)

model on thingiverse:
I made it at Techshop
Submitted by SFlettering for the Instructables Sponsorship Program

Step 1: 2 Part Kitchen Sink Drain Model As Printed by Thingiverse Model Author (not Me)

Here is the image of the model printed by the author of the thingiverse post. Based on experience an author on thingiverse that includes many images and has more than a few models online will be the best choice for model selection and have fewer 3D print errors than  other authors with less posted models and images. When it takes almost an hour to print an object it is worth 30-60 minutes to select and customize before printing your final. A fast test print though is a good idea to find out if there are any early problems that could be hard to fix.

TIP: When choosing a model from thingiverse to test print make sure to read the description and author write up to know if you need to customize the print to get best results. 

Step 2: Printing the Sturdy Base

Like most maker projects you will encounter some unexpected positive results and some hard to plan for issues with your print. Notice the overall quality of this print although the final piece is fragile because of the print settings. I did not print this with a finer resolution for testing although I think the design is fragile and could still be at risk even with finer print settings.

The image shows the 3D print right when the fragile area was starting to print in a spiral fashion which was brittle and where the piece broke.

It might work better if it was sized larger. Thank you to the author of the model for posting and adding to my learning experience.

TIP: In KiSSlicer you can multiply your part by X to change the size by 90% or 110%

Step 3: Printing the Sides

When printing this model I was impressed by the quality of the print overall. The 2 pieces aligned well enough for actual use and the overall print looks great. Their are certain parts of the print that are fragile and the spiral printed area is where I identified as the most likely reason that a fragile object actually broke.

TIP: When printing expect a few final models to break or get ruined and it is still ok. With this print as it required 2 STL files printing out a replacement would be even quicker than if it required printing both parts each time.

Step 4: A Final Fragile Print

Here you can see the final print and it looks good just after it finished. Once a 3D print is done it will be warm for a few seconds but I found that you can take most items off of the build platform within a minute of print completion.

TIP: Depending on your PLA, Z Height between nozzle and platform, and the nozzle temperature your print can be easy or very difficult to remove. Make sure to remove by only pulling on areas that are not fragile. A putty knife works well to remove items from the blue painters tape.

This object did not break during removal - it broke when showing it to other people who liked what they saw and did not know it was so fragile.

Step 5: Good Looking But Fragile

Here are some close up images of the broken area of the print. The images also show off how great the quality of the print came out in other areas. Notice how at the top of the print a circular ball of plastic was printed quite well with high quality and precision.

When printing this object I found that some of the cool model parts like the ball at the top might have made the model more fragile due to the relative width and height of each individual part although that is not where it broke.

TIP: When printing pillars using a spiral print method consider the thickness of the spirals and how rigid or flexible they need to be based on their function and location.

3D Printing Contest

Participated in the
3D Printing Contest