Armrest cover for Kinnarps office chair

thingiverse

Rubber armrest covers on my favorite Kinnarps chair (must be something like 5000 series) torn apart (see the last photo), so I designed this cover printed of TPU to replace it. Printing is not too hard, but it's a bit tricky because of overhangs. First you need to print helper insert of PLA or PETG - it will act as support. Don't print it whole - all you need is outer 1cm, you can skip printing the middle (I achieve this in Cura by making a smaller copy of the part and changing its print settings to 0% infill and 0mm walls, tops and bottoms). Make sure to print it as flat as possible. When you slice the main part, remember the height at which the main overhang begins (in my case it begins around 9.75mm). When you print the main part, when the printer starts printing layer before the overhang - slow down the print (or pause it, but on my printer pausing and resuming print results in worse quality) and insert the support part inside. If the support is lower than needed, you can adjust its height by adding pieces of paper underneath it. See the photo, it's easier to understand. The insert is easily removed after printing is done - TPU is elastic enough. Attention: support part must be slightly smaller than the main part! I print support in 100% scale and main part in 101% scale on X and Y (Z is 100%). Support must not expand the main part when inserted. Be careful not to move the main part while inserting the support (adhesion of TPU to the bed is good, but you can move the walls).