At two of the companies I've worked for so far, I've run into a strange issue with my boss. I come up with an idea to solve a problem, and it gets ignored, or at most gets barely any reaction. As soon as someone else presents the same idea (so far, it doesn't seem to matter who else suggests it), suddenly it's great and important and we need to implement this solution right away. For example: I, along with another co-worker, had to organize a bunch of parts for multiple projects. I told our boss that if we get a bunch of bins and rearrange some shelves, we can find everything quickly and easily and keep everything sorted by project. He said no. Later, the woman who managed everything in the front office and one of the boss's friends both suggested the same thing I did, and then our boss suddenly wanted to do this. What exactly is happening in this situation? I can't tell if it's something I'm doing or not doing, or if this is a common occurrence and it happens to everyone.
I've definitely experienced this in more than a few workplaces... It's annoying to say the least, but it's not usually deliberate.
I usually chalk it up to a manager not realizing that something is worth worrying about until they've heard it from more than one person. Often it helps if the second person is more experienced, but that isn't always the case, sometimes it really is just repetition.
Try not to take it personally, just keep plugging along. When you get another idea to improve production it may help to bring backup.