I’m just getting into aluminum and find the wiki… challenging. There are little tidbits of info scattered about in various sections, including some that seem to conflict. Climb vs. conventional is one of them.
I will happily volunteer to try and clean this up if we can resolve the information. Examples:
…using a climb cut for finishing passes produces a nice finish in aluminium (citing this comment)
Under endmill considerations, we have this… do Shapeoko users own such an “extraordinarily rigid machine” and what is “an extraordinarily rigid bit”?
Doing the finishing pass as a climb cut will give a better finish on an extraordinarily rigid machine and bit.
The section on boring holes (which doesn’t say what material):
Secondly using conventional milling produced the best results. Some with climb milling was [sic] ok as well, but the general result was that anything concerning climb milling (be it complete single cut operations or used as finis passes) gave a little worse result.
The recommendation for 6082 aluminum specifies climb, most don’t say one way or another:
3 flute, 45deg flute, carbide, 4mm diameter … 21k RPM, dry, climb cutting … Spiral downcut along a 1mm radius, .4mm per revolution (leading to a 6mm hole) … feedrate of 500mm/min with a forward step of 0.5mm (12% tool engagement)"
The dedicated wiki page for this is super confusing. We have:
Unless your machine is very rigid… you should always do conventional cutting.
This is immediately followed by:
Another recommendation is to climb mill for roughing passes and conventional mill for finishing passes.
Hopefully it’s clear that this could be challenging to make sense of. The last quote suggesting climb for roughing and conventional for finishing would lead me to think we’re taking a “gentler” cut (less stress) via climb, and applying conventional (more stressful to the machine and/or produce a better surface finish) just for the finishing pass. The quote just before that suggests that climb is more stressful (requiring a very rigid machine). Most previous quotes say climb for finishing pass…
There is also no definition of what “rigid” means. Is the SO3 rigid? When I hear this word, I think Bridgeport, and that any hobby CNC is not rigid. I expect this to be specified since it’s not a general CNC wiki, it’s for this machine.
This thread, started by @Julien is almost a replica of this, except most relevant replies are of the form “this is what I do.” I don’t see any definitive resolution (though it leans in the climb direction). The most data-driven comment was that @gmack didn’t see a big difference between climb/conventional for spindle power consumption.
From a “I just want to make stuff” perspective, my personal list of requirements to decide between these two methods would be:
- which is faster on the Shapeoko (which I think is a proxy for “less stressful to the machine and least likely to break a bit”)?
- which should you use if you need the best accuracy?
- which should you use if you want the best appearance/surface finish (including leaving no “skins” at the top/bottom of a part to clean up)?
- are there particular material characteristics (certain alloys, tendency to work harden) that sway the consideration?
So, to conclude:
- sticking to aluminum to simplify the scope, can we make any definitive, non-debatable recommendations that I could use to clean up the wiki?
- if the thought is that it probably doesn’t matter, I’d propose to just remove these statements altogether. They lead new aluminum cutters (like myself) to spend a lot of time thinking about this, as the comments make it seem like an important consideration… but as it stands, you can’t resolve it.
Final aside, also from a new-ish user perspective: the wiki seems frequently used like a storage space for relevant forum comments people have decided fit into various sections. I would much prefer the wiki to look like wikipedia (user validated reference info), leaving all comments and opinions for people to find if they search the forums.