Because we can buy gear box from professional gear box factory, so the rotor is the most difficult part for us mower manufacturers.
There is ISO international standard of mechanical vibration, flail mower rotor is G16 grade
View attachment 484143
so after calculation, your mower, I think you mentioned it is AG model, right? so I called it as BCS model in my factory.
View attachment 484150
it means the unbalance weight is totally 3 gram on the rotor. This international standard is quite harsh.
So I don't think any mower manufacturer could really make all the mower like this. I bought some foreign brand mowers these years, all of them are top brand in the market. Obviously, different factory set up different standard for their rotor vibration, from 50 gram to 200 gram. Because I don't buy hundreds of these famous brand mowers, and I don't have contact in these foreign factory, so I cannot know their exact standard. But I know the standard of the Chinese mower manufacturers, normally we define it as 100 gram on rotor, but I m sure very few of them execute this strictly. So I set up standard like this:
1. 30 x ISO standard, for example, BCS model, I define it as 90 gram this year(next step is 20X).
2. at most two pcs balance weight block on each rotor end this year(next step is one pcs each end)
3. fully weld balance weight block on rotor end
And the most important thing, I employ third-part person to inspect rotor balancing and record it, to avoid worker's mistake.
I m now use 1240 gram hammer on BCS mower.
For the hammer, I started to use forging hammer on all of my mowers two years ago, because at that time, I found the casting hammer has bigger weight difference than forging hammer. For example the gram hammer on EFGC mower, casting hammer has nearly 35 gram weight difference, forging hammer has nearly 20 gram weight difference. Because forging hammer doesn't increase much cost than casting hammer, so I decided to shift all the mowers to use forging hammer. For the price and technical reason, hammer factories cannot produce very small weight difference as I expected. So I turned to another solution, I set up weight different standard in my factory, worker weigh all the hammers before they assemble on rotor, so the rotor has the hammers in same weight range, each range has 10 gram difference. And I has record for all the mowers used which weight range hammer.
Anyway, I only started this business 3 years, I realize Chinese mower fall behind a lot than foreign top brand mowers, but I m trying to do my best and keep improving, wish I can catch up or get close in some years, there are still 3 or 4 decade before I retire.
