Castle Themed Cat Tower

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Skills: CAD (Inventor, Inkscape), Design Process, Manufacturing, Laser Cutting

Role and Background: 

This is a personal project that I completed to replace an old cat tower. For the new tower that I was making, I wanted it to fulfill the same basic needs that the previous one did for my cats, and also improve on the aesthetics of how it looked. To do this, I decided to design the bulk of the cat tower using laser cut plywood, and theme it as a castle. I was able to design and build two versions of the cat tower, so I was able to see how the cats interacted with my first tower, and from that change the second version to better match how they used it.

Tools used:
-CAD (Inventor)
-Vector Graphics (Inkscape)
-Laser Cutter
-Miter Saw
-Box cutters

Supplies used:
-A 4x8’ sheet of 1/4” plywood
-4x4” wood lumber post
-Carpet
-Wood glue
-Wood stain and finish

Challenges: 

The main challenge involved in this project included designing the castle in such a way that it could be laser cut using plywood. This included creating a design that fullfilled my design goals, and making sure that all of the pieces could fit in the work space of my laser cutter.

Process:

Brainstorming: To determine the basic functions the cat tower needed to have, I looked through multiple designs online to see what features they included. I was also designing the tower for two cats. From that, I came up with few key design criteria that the cat tower needed to have for the cats to interact with:

  • It needed at least two spots for a cat to lay

  • It needed two enclosed areas that the cats could enter

  • It needed a portion made of sisal rope where the cats could scratch

For the aesthetics portion of the design, I decided that I wanted to theme the cat tower as a castle. To be able to do this, determined that using a laser cutter for the manufacturing of the tower segments would work best. This was mainly so that I could create a finer detail design than most other cat tower designs allow.

Designing: With the basic requirements for the cat tower laid out, I went on to designing a CAD model. For the designing process, I used Autodesk Inventor to create the general design of the cat tower, and Inkscape to finalize the design in a format that could be laser cut. The main reason for this workflow is because in Inventor you can only export flat faces of parts into a laser cutting format. Inkscape allowed me to edit the parts (albeit manually) to add key features like “living hinges” (that allow the plywood to bend), and chopping up the structure into pieces that can fit into my laser cutter.

I made the sisal rope segments using 4x4 pieces of lumber. This had the added benefit of adding mass to the design (1/4” plywood is light), so that it would be more sturdy when cats are on it.

Another major design goal I had, was making sure that the design could be cut on a single piece of 4’x8’ plywood. For both iterations I ended up needing to go back to the assembly and redesign a few key structural parts to reduce the amount of plywood require so that it would fit.

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Version 1:The first version is pictured above. Because I was making two cat towers, I was able to guess how the cats would interact with it, create a design from that, build it, and then see how they actually interacted. In the 1st version you can see how I incorporated all of my main design points; the left column had the sisal rope, the right tower had the two interior spaces, and the top of both sections had a spot to lay. But based on how the cats interacted with the tower, I noticed a few key shortcomings of the design. These included:

  • The cats did not use the bottom enclosed area at all, most likely because it was at ground level

  • The middle section was fairly “cramped” for the cats, which made it difficult for them to use that section

  • While the top towers worked well for the laying spots, in part because of the ramparts around them (and also the height), they were hard for the cats to get to.

Based on these interactions, I worked on a second version that addressed those issues while still fulfilling the original design functions. These included:

  • Raising both interior spaces so that they were off the ground

  • Removing the middle section, and instead incorporating a “Stepping stone design. This design change allowed both easier interaction with each section, but also easier access to each section above it

  • Removing one side of the ramparts on each level, so that each level is easier to access

I also made some improvements to the manufacturing of the tower itself. These included decreasing the number of structural pieces in the design, making it easier to assemble, and also modifying the “living hinge” design, so that it was less fragile when assembling.

Assembly: Once finished with the CAD model, the first step was laser cutting the plywood portions of the cat tower. This involved cutting up the plywood sheet into pieces that would fit into my laser cutter work space. This involved relatively careful measurement when cutting the plywood pieces, because the design needed to use most of the sheet of plywood.

Next involved staining the parts of the tower that would be visible on the exterior, and gluing together the platform levels and sides that would form the interior spaces.

Once the glue had dried, the carpet pieces that will line the cat tower need to be cut. And because the interior spaces will be hard to reach when the tower is fully assembled, I decided to attach the carpet to the interior sides now.

Because of the design, I decided that the simplest way to assemble the tower in a few steps, letting the glue dry between each step (about 24 hours). The part of this process involved gluing together what would become the top tower, and adding the joints that would eventually attach tot he 4x4” posts.

Then, while that was drying I cut the base columns, and screwed them into the base.

With the glue dried, I attached the first level platform to the posts, then added the top level platform, and finally joined them together with the bottom interior siding. With all that done, there were just a couple more rampart siding to glue to the bottom level.

After the structure was dried, the last few steps before finishing included adding the rest of the carpet to the structure, add wood finish tot he exterior, and lastly adding the sisal rope to the posts

Final Thoughts

After going through the building process for my second version, and seeing how the cats interact with it, there are a few design considerations I would take into account if I were to make a 3rd version of the tower. To start, even though I did improve on the living hinge design from the previous version, it was still a little more fragile than I would have like when assembling. Second, one thing that the first version was superior in, were the two laying spots. While the second version, I have found after watching the cats itneract with it, that bottom two laying spots are inferior to the top, likely to the height difference. So, if I were to do another version, I might try to incorporate two laying spots that were at about the same height.

All that said, I am happy with the final design, and believe that it does a very good job incorporating all of my original design goals. I believe the visual appeal of the castle theme works very well with the tower, and the cats interact with it in the way that I was hoping for.

Christopher Fisher