| 02:42.59 | *** join/#qi-hardware Jay7 (jay@128-73-158-138.broadband.corbina.ru) |
| 08:40.52 | *** join/#qi-hardware jwhitmore (~jwhitmore@86-44-0-88-dynamic.agg2.cty.lmk-pgs.eircom.net) |
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| 10:08.23 | DocScrutinizer05 | wpwrak: whitequark: https://www.youtube.com/watch?v=YWMjyAoxOfE nice cooling/ointment |
| 10:08.51 | DocScrutinizer05 | + cleaning |
| 10:09.05 | DocScrutinizer05 | lubricant fog |
| 10:09.51 | DocScrutinizer05 | see how debris flies away at end of video when mill starts new job |
| 19:43.45 | whitequark | hmmm |
| 19:43.53 | whitequark | shaking a bit every time it steps down |
| 19:44.09 | whitequark | i'd do a constant ramp down or something, like a helix |
| 20:33.52 | *** join/#qi-hardware pcercuei (~paul@12.206.185.66) |
| 20:48.35 | DocScrutinizer05 | yes. tell that wpwrak |
| 22:02.36 | wpwrak | whitequark: DocScrutinizer05 doesn't believe that endmills (in general) can cut straight down :) |
| 22:14.55 | roh | wpwrak: well.. some can, not all |
| 22:18.33 | DocScrutinizer05 | generally it's tricky |
| 22:19.13 | DocScrutinizer05 | having X/Y movement while going Z+ is always way simpler/easier to the mill |
| 22:20.40 | DocScrutinizer05 | for those endmills which are supposed to be able to to Z+ only, you still might need to match some other requirements like wetting, correct RPM vs advance-speed factor, or whatever |
| 22:20.49 | DocScrutinizer05 | to do* |
| 22:21.08 | wpwrak | roh: yup. some will only cut sideways. but they're clearly marked as such. just like endmills that transport material down instead of up. |
| 22:21.36 | DocScrutinizer05 | nah, the problem is system immanent |
| 22:22.01 | DocScrutinizer05 | even mill heads supposed to be able, are still poor on it |
| 22:22.04 | wpwrak | DocScrutinizer05: you always need to consider spindle speed, feed rate, irrespective of which direction you go |
| 22:22.15 | DocScrutinizer05 | yes |
| 22:22.44 | DocScrutinizer05 | but you deny the fact that there's a system immanent problem with milling Z+ down only |
| 22:23.20 | DocScrutinizer05 | you simply say "that mill head is supposed to be able to do it, so why the heck it doesn't work" |
| 22:23.24 | wpwrak | think of an endmill as a short drill. just that it's not pointy but flat. drills go along Z just fine. the don't like XY because they tend to be long, so they'd snap. |
| 22:23.38 | DocScrutinizer05 | just that an endmill is NOT a drill |
| 22:23.52 | DocScrutinizer05 | exactly, it's not pointy |
| 22:23.59 | DocScrutinizer05 | which is the whole problem |
| 22:25.37 | DocScrutinizer05 | huge endmills even *are* ether pointy or inverse-pointy to compensate for the system immanent problem of zilch cut velocity in center of axis |
| 22:25.38 | wpwrak | pointy vs. flat mainly affects lateral control. e.g., you'd hate to hand-drill with an endmill. but CNC mills are all about firmly holding things in place. |
| 22:25.49 | DocScrutinizer05 | no |
| 22:26.25 | DocScrutinizer05 | the point is about piercing the material instead of cutting it |
| 22:26.29 | wpwrak | any drill has a stationary center axis |
| 22:26.57 | DocScrutinizer05 | yes, and since it's pointy it will just go through the material by pressure per area |
| 22:27.13 | DocScrutinizer05 | an endmill can't do that |
| 22:27.53 | DocScrutinizer05 | the pinpoint is not just for centering |
| 22:28.12 | wpwrak | i suspect it's more force on material off-center that just moves the (infinitely thin) center column as well, but again, that's the same in all cases |
| 22:28.28 | DocScrutinizer05 | it's meant to overcome the system immanent problem of zilch cut velocity |
| 22:28.55 | DocScrutinizer05 | whjatever |
| 22:29.20 | DocScrutinizer05 | you obviously know why it should work, you don't know why in practice it doesn't |
| 22:30.16 | DocScrutinizer05 | I also think I know how it should work (in a different way than your preferred one), and I know it usually works in practice |
| 22:30.56 | wpwrak | i see it work almost every day in practice, manuals from companies making this sort of tools and devices recommend exactly what i'm doing, and other people with experience in the field don't see anything amiss with it either ;-) |
| 22:31.33 | wpwrak | it almost seems as if we're arguing zeno's paradox :) |
| 22:31.35 | DocScrutinizer05 | *shrug* |
| 22:32.28 | DocScrutinizer05 | you evidently got three system immanent problems: zero cut speed, zero transport speed, and zero transport grooves - in the center |
| 22:33.01 | DocScrutinizer05 | huge mill heads avoid those problems by either a positive or negative cone in the middle |
| 22:34.36 | DocScrutinizer05 | a simple never failing way to avoid the problems by operation principle is to add Y/Y velocity when going Z+ |
| 22:34.49 | DocScrutinizer05 | X/Y |
| 22:35.13 | DocScrutinizer05 | so exactly what whitequark said initially |
| 22:36.37 | DocScrutinizer05 | when you insist in doing it the way that's maybe *supposed* to work, but actually gives you problems - I dunno what to suggest |
| 22:39.12 | DocScrutinizer05 | it's just funny that whitequark and me both noticed even that professional mill in the YT vid I lonked had obvious stress wenn doing Z+ only. which is where the whole discussion started |
| 22:40.30 | DocScrutinizer05 | so you hardly can discuss away that there *is* a system immanent problem with doing Z+ |
| 22:41.04 | DocScrutinizer05 | you say it should work nevertheless. I say when it doesn't you should add X/Y velocity |
| 22:41.28 | DocScrutinizer05 | you seem to not like that idea, for whatever reasons |
| 22:51.36 | DocScrutinizer05 | btw zeno seems to have postulated several paradoxes ;-) https://en.wikipedia.org/wiki/Zeno's_paradoxes which one you choose? |
| 22:53.59 | DocScrutinizer05 | "Arrow paradox" sounds like an early version of Heissenberg |
| 22:56.19 | DocScrutinizer05 | "Paradox of the Grain of Millet" exceeds my English, or my logical understanding |
| 23:03.48 | DocScrutinizer05 | (endmill) lemme put it this way: when there wasn't any problem, then why do they make nails pointy instead of flat? |
| 23:05.12 | DocScrutinizer05 | on topic: did you know that you should flatten the nail's pinpoint head a bit (by hitting it with the hammer) when you want to drive the mail into normal wood? |
| 23:05.45 | DocScrutinizer05 | otherwise the nail might just split the wood fibres and that split can grow |
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