Clutter No More! 3D Printed Shower Shelf With No Fasteners

The shower in our dorm lacks shelving units for storing supplies while showering, which often results in bottles of shampoo and body wash piling up on the floor, creating an overall messy and disorganized space. I have endeavored to fix that by making a shower shelf made of 3d printed parts that slot together and hangs from the knobs on the shower without requiring any fasteners. This shelf design can be easily modified to fit any space by changing only a few dimensions.

1. 3D printer
2. Laser Cutter
3. PLA 3D printer filament
4. 6mm clear Acrylic
5. Metal File
6. Pliers
7. Tape Measure

1.1 Determine Requirements:

1. Measure the dimensions of the knobs and the spacing between the center lines.
2. Measure your shower supplies to know the total area and volume of the shelf.

1.2 Sketch Part Prototypes:

1. Sketch out your shelf area and knobs on paper, then start to sketch the parts that will connect them, making sure to dimension out each part.
2. Determine a method for assembling the parts. In my case, I went with a square slot and pin method to reduce movement.
3. *Keep in mind the dimensions of your print bed when designing parts*
4. Use modular designs when possible to minimize the number of parts you have to design.
5. Keep shapes simple and 2-dimensional when possible for ease of design in CAD.

1.3 Design Parts in CAD Software:

1. You can design the parts using any CAD software, such as Autodesk Inventor, Onshape, or Tinkercad. For this project, I used Inventor as I am most familiar with it.
2. *Check tolerances on 3D printer* This can make or break your design and waste material, having to reprint parts. The printer I am using has a tolerance of +/-0.002mm, which means that any given print could be that much bigger or smaller than the intended dimension. Keep this in mind when designing your parts that fit together, and try to either make your slots slightly larger than your pins or vice versa by the tolerance margin.
3. Start modeling out your parts. You should just be copying the designs and dimensions you had on your paper sketches, then extrude those sketches out.

2.1 Export Your CAD Files:

1. Export all your files in the .stl file format, which is the universal 3D printing file type accepted by almost every slicing software.

2.2 Organize your prints:

1. Take your parts and begin placing them into the slicer associated with your 3D printer.
2. For this print, I was initially using GrabCAD for a Stratasys F170, but a severe hardware error forced me to shift to PrusaSlicer.
3. This design will require multiple prints unless you have a very large print bed. Try to place your parts in the most space-efficient manner possible if you are concerned about minimizing print time.
4. *Make sure you are laying your prints flat on the bed.* This will minimize the amount of support needed.

2.3 Set your print settings:

1. Choose your print resolution. For this project, I used a layer height of 0.2mm, and it worked well.
2. Choose your support style. If you are using Cura or PrusaSlicer, I would recommend using "Tree" or "organic" supports, as they are the easiest to remove.
3. Choose infill. This design does not need to support a heavy load. I used a hexagonal infill pattern at 15% infill, and it was able to hold up all my supplies without any visible strain.
4. Choose Filament: I initially wanted to print this in ABS on the Stratasys F170 due to ABS's good water resistance, but the previously mentioned hardware error forced me to print in PLA. Just make sure you research your filament and its reaction to extended periods of water exposure and high moisture environments prior to printing.

3.1 Slice your parts

1. In the slicer, click the slice button, then move to the preview.
2. Ensure that there are no areas highlighted in red; these are areas where there is either an error in the part, such as a missing face, or there are no supports, and should be addressed.

3.2 Load the 3D printer

1. Load your chosen filament into the printer and make sure the extruder is working properly.

3.3 Begin the print

1. Send your file to the printer, then initiate the print.
2. I recommend staying for the first 15 minutes of the print, as the vast majority of print failures occur within that time frame.

3.4 Check Back In

1. It is recommended to check on your print every few hours to ensure that everything is working correctly and your print is coming out in the desired way.

4.1 Design Shelf in Vector Editing Software.

1. I used Adobe Illustrator for this project, but any free vector editing software, such as InkScape, will work just as well.
2. Make a rectangle in the size you want your shelf to be.
3. Add a drainage method. I added alternating rows of holes to my shelf so that water would not build up on the surface.

4.2 Laser-cut shelf

1. The shelf is not a complicated part, and thus, we can laser cut it out of acrylic. I selected 6 mm-thick acrylic to minimize the chances of the shelf warping if someone were to place an unintended load on it.
2. Export a PDF of your design to the laser cutting software you are using, in my case, it is Trotec Ruby, and place the design in it.
3. Place your material in the laser cutter, align the laser and cutting bed, and watch your shelf get cut out.

5.1 Clean up 3D printed Parts

1. Ensure parts are completely cooled down before removing them from the 3D printer.
2. Remove supports using pliers and, if necessary, an exacto knife or other cutting implement; supports should pull away without damaging the actual print.
3. Use a metal file or sandpaper to file away rough edges and smooth out pins. If a pin will not fit in its slot, it is usually better to just file it down than to reprint the entire part.

5.2 Assemble

1. Slot all your parts together, then set your shelf into the holder. I would recommend using some sort of hot glue or epoxy in the slots to keep all the parts together and prevent them from shifting around, and I would also recommend gluing the shelf into its slot to prevent it from slipping off when you place your supplies on it.

This project was definitely a massive learning experience when it came to 3D printing multi-part structures. Dealing with and keeping track of changing tolerances is difficult, and the follow-on effects of changing a tolerance slightly can result in you having to remake an entire model multiple times. Going forward, I would recommend printing out a pin and a set of slots every time you make a model to make a standardized tolerance by finding out which slot the pin fits in best. And do this before you ever make your first CAD model, it will save so much time, frustration, and filament. But it has been very nice to see a noticeable reduction of clutter in our space, so overall, a worthwhile endeavor.

Thanks for reading!

Files attached below, all dimensions are in millimeters.

(Hooks are currently set for knobs with centerpoints 10.5in apart. To modify, increase the bottom length on the hook to your desired distance in a CAD program of your choice.)