I received some more assembled spring samples this week. Machine 1 is still producing approved assemblies. Machine 3 is improved but still needs adjustment. Machine 2 needs adjustment. I’ve asked the factory to start using just Machine 1 so we can get things moving. I sent them a quality control video showing the testing of springs and emphasizing the sound differences of good and bad assemblies. I have asked them to do the basic sound testing as part of the QC – essentially a spring with some reverb is good, but with a buzzing sound or no reverb means it should be detached and reattached, and the spring should potentially be discarded. I am not being overly particular on the length of the reverb or whatnot.
Once the other two machines are set to spec they should produce the 95%+ approval rate observed with spring/flipper attacher Machine 1’s samples.
Even a fraction of 1 mm out of spec in the distance between spring and nub causes performance and sound issues. Also even a few degrees off for the spring angle attachment to the flipper is noticeable. The assembly process delays are frustrating but the factory will keep making adjustments so all keyboards pass my quality control standards. Fortunately all of the parts have been successfully produced and are sitting in storage (they finished production about two months ago), so we no longer have to worry about manufacturing issues.