UX Designers talk of “the user” but rarely is there just one type of user to consider.
In a previous post I shared a design for a 3D printed wheel. This is intended for use in low cost robot projects. From a functional perspective the design has many good features including reduced friction between the rollers and the hub to improve effectiveness of the wheel.
Reducing friction is good design for the robot user. The implementation is bad design for the manufacturer.
In the photo, you see the before on the left and the after on the right. The change is visually subtle but significant to the person attempting to print this part.
The original roller had chamfers on the ends to reduce the surface area in contact with the hub. This would require some extremely small supports to be added when 3D printing the part. (For those not familiar with consumer 3D printers, they work best when the object has a flat surface and there are no extreme overhangs of portions of the object relative to the base. Anytime there is an overhang, the printing software will build up support material to connect it to the base.)
Moving the chamfers from the rollers to the hub, makes the rollers much easier to print.
This small design change preserves the friction reduction feature for the robot user and improves the usability for the manufacturer.
FYI: Before someone points out the hub is difficult to print, ill mention it gets split into two pieces so each piece is printed with the outer face flat on the printer bed.