I have a Roland KR-570 digital piano that is in need of repair. One of the keys would stay down and if you moved the key you could tell there was loose bits of broken plastic inside the piano.
After a quick search on the internet it would seem to be a fairly common problem for the weighted arm inside the key which causes the key to come back up is a common failure point on digital pianos of this age. No problem I thought, I’ll just order a replacement arm and swap it with the broken one. This dream quickly started to fade away however. I could find the part for around twelve dollars on a lot of sites but they all said out of stock. I found one that was in stock but for the price of over two hundred dollars it was looking like this piano might end up in the garbage.
A little while ago I acquired my first 3D printer. Being still pretty new to the hobby my mind wasn’t thinking of the possibility of fabricating my own replacement part. Then one day while staring at the piano with the broken key I thought. “I wonder if I could 3D print a new arm to fix that piano?” My question was followed up by a second. “I wonder if someone has already created an STL file of that part.”
https://www.printables.com/model/297356-roland-pa-48-n-key-hammer-for-white-keys
Well a quick google search: Roland KR-570 key weight arm STL quickly led me to exactly what I was looking for. Big thanks to Geklatscht over at Printables for creating the file I needed to fix my piano.
I loaded up some white PETG into my Creality Ender 3, picked 100% infill to make the relatively small part as strong as possible and then hit print.
With the piece printed it was time to start removing screws and pieces of the piano in order to get inside and swap the piece. Then I could remove the broken key weight arm and extract the metal weight from inside. I used some 5 minute epoxy to glue the two sides of the print together around the metal weight and then once dry, could drop the new part into the piano.
Just like that a fully functional piano. While tiny boats, little figurines, and Iron Man armor suits are cool. It is things like this that really get me excited about 3D printing. As someone who regularly saves wood from the garbage to repurpose (much to the chagrin of my wife). Rescuing something that only needs one small plastic part that is no longer available from the landfill is a great feeling. And the perfect justification to your spouse for your 3D printer purchase.
For more information on the process check out the video below:
Luke Merwin Music 
Leave a comment