At the place I work for, we like to offer a cup of coffe and some biscuits to our customers when they come to visit our place. The machine used for this task is a sturdy Nespresso professional ES100. We also take the it to fair trades or expositions. I am not very fond in coffee, I am part of the tea team but the knob that operates the tap for hot water/steam was missing long time ago. The back of a spoon was used as temporary solution until we could order a replacement. By the time we tried it was already discontinued.
Alone as I was in my quest for a decent cup-o-tea at work, I was starting to get frustrated after the tenth page of google search for the replacement (yes, there is more than just one page!). A decision was made; the design and build had to be made by myself.
The original knob was made of injected plastic and the torque to make it work was very little. Nothing fancy was needed and a printed PLA knob was more than enough. I was thinking to design and print one white PLA prototype to see if the measurements were correct and then print it in black “stylish posh” color to blend in and give it a finish to look like a new one. Measurements of the hole were taken from pictures with just a caliper and ruler. The design was completely made in Solidworks. PLA may shrink a bit after printing so no tolerances were considered during the design. The part was easy enough to design it with OpenScad but it was decided to add a customized logo on the end of the knob and I am not familiar enough with the software (Is it possible to do it in OpenScad?)
After roughly an hour of printing with 20% infill, 0.3 mm layer height and 5 minutes for some minor details, the prototype was ready. The finishing touch was painting the logo with a black marker. The piece fitted the first time. It was just small enough to enter into the compartment but big enough to stay in place due to friction.
Sometimes you are lucky and get it just right the first time and this was the case. Not only it fitted properly, it also worked! There was no mechanical tension at all in the part so the “make it work before make it look good” was really easy.
My boss liked so much the solution we came with that he did not want to print a new one, so in the end the first prototype was the final part. Now my boss can show his company logo to customers and I can drink tea without having to MacGyver a knob with the back of a spoon. A new print is planned in the future because the line surrounding the logo is slowly falling off. For now, we are happy with the results and more importantly, my boss accepted the solution the very first time.