Fastest Pellet Sorter in the Works
- Thread starter Kabayan
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I was thinking more in terms of money. I can't begin to imagine the time and effort it took. It's genius though so it's well worth it.
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18gr .02gr <--- 0.001% this is not realistic, it is beyond the capability of this machine
There will always be some residual noise in any measurement system. I can filter it out by averaging but that will consume a lot of time and slow the process down. I am still looking out for a better weighing system but this is what I have at the moment.
The Test Limits are computed this way. For an 18 grain pellet with a tolerance of +/-1%, the Bin assignments and corresponding weight limits are like this:
Notice that pellets with typical weights are assigned to Bin 3. The pellets in that bin will weigh anywhere in between 17.82 ~ 18.18 grains. In this chart you can also see the weights of the pellets in the other bins.
If the Tolerance is changed to 2%, the Bin assignments and weights will look like this:
Notice that Bin 3 still holds pellets with typical weights but now they will weigh anywhere in between 17.64 ~ 18.36 grains.
H&N the pellet manufacturer! Would be interesting to see how much spread there is in your manufacturing process. Or perhaps further down the road you can put a sticker on your tins showing the range of pellet weights that is inside the tin. (We used to do this kind of "grading" on semiconductors. Still done today but since commercial parts dominate the market now, grading is seldom done.)
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Money-wise, not much because I have most of the stuff lying around the shop. It's just plastic & wood & some aluminum & some .....
Time:
Thinking of the concept, how to arrange the parts, layout, etc.... took more than 2 months of hand-waving while alone by myself
Fabrication took about 2 weeks (CNC programming too)
Software coding about 1 week
Debug plus revisions took 3 weeks, still on-going with some possible(?) improvements
Effort: a little elbow grease, which is much needed in my ageing joints (65yo ATM). I am also happy to see that I can still write SW and perform debug.
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That is truly epic and what a cool machineMoney-wise, not much because I have most of the stuff lying around the shop. It's just plastic & wood & some aluminum & some .....
Time:
Thinking of the concept, how to arrange the parts, layout, etc.... took more than 2 months of hand-waving while alone by myself
Fabrication took about 2 weeks (CNC programming too)
Software coding about 1 week
Debug plus revisions took 3 weeks, still on-going with some possible(?) improvements
Effort: a little elbow grease, which is much needed in my ageing joints (65yo ATM). I am also happy to see that I can still write SW and perform debug.
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This is system noise. It even goes up to +0.08gr sometimes. I have ordered a low noise version of the weighing scale amplifier and hopefully this variation in the readings will go away once the new amplifier is installed.
There's another type of error which you can't see on video: "Thermal Drift", and the readings gradually shift in 1 direction after several minutes. To minimize the effect, I have added a "Tare" function within the SW. The machine will do Tare by itself every 50 moves of the indexer (the rotating circular disc). This way the machine stays nicely zeroed all the time.
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Excellent project. My suggestion is not to compromise on the manufacturing of these pieces of equipment; use the best hardware available. Treat as if it were a metrology equipment.
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Pellet Weight Distribution Comparison
Here I sorted 1 box of fresh pellets, Brand "A". Then I sorted another box of fresh pellets, this time Brand "B". Both brands are locally-made (Philippines) pellets and the results of the sorting can clearly be seen in the photo.
I would conclude that brand "B" is superior in terms of weight control because the pellets are tightly grouped in the middle bins, while brand "A" pellets are all over the place with many rejects (red-colored bin).
Here I sorted 1 box of fresh pellets, Brand "A". Then I sorted another box of fresh pellets, this time Brand "B". Both brands are locally-made (Philippines) pellets and the results of the sorting can clearly be seen in the photo.
I would conclude that brand "B" is superior in terms of weight control because the pellets are tightly grouped in the middle bins, while brand "A" pellets are all over the place with many rejects (red-colored bin).
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Maybe I'm making a mistake, but 0.1% of 18 grains is 0.018 grains, rounded up to 0.02 grains. And 0.1% was the tolerance claim.
1% tolerance, plus or minus, is already a 2% range. That would actually be too much for an H&N production batch.
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You are correct, my bad. I got confused with so many zeroes.
"1% tolerance, plus or minus, is already a 2% range. That would actually be too much for an H&N production batch." <---- impressive control in your mfg process. Would be nice to get my hands on a tin of H&N. I do have a tin of Excite Hammer (Germany) which I can try out soon.
I didn't know. The back of the tin says "H&N Sport GmbH". Same company.
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