Conventional or Climb Cut- CNCnutz Episode 223

[@tomcallanan2455]

I had no idea of the difference between climb cut and conventional cut, just used the default settings in the toolpath. The video explains it very well. tks Tom

[@geort45]

great drawn explanation man, now I get how the chips work in relation to the speeds

[@SpeedSeekerMoto]

Awesome job! Seeing it on wood made it much more understandable for me as I could actually see the left over fibers from the thinning chip load. I recently made the move from being a high level cnc lathe machinist to mcam programming. It was real tough for me to comprehend the difference between the two as I rarely even used end mills, let alone had to think about the effects of direction of cut. Thank you mate!

[@U_Kamrc]

Peter: Perfect! Mark Lindsay in his video is also exposing the direction of grains to choose between Climb/Conv.

[@robhampton4929]

Congratulations getting your sponsorship. I have drawn circles and arrows, Tried a trimmer with straight cutter to work it out. Thanks for another great video Peter. Cheers Rob

[@davidboswell9024]

I often use climb cutting to take the bulk out then use small conventional cut depth to clean up takes slightly longer but lowers the load greatly on my machine

[@jimhester2004]

This is an issue that has confused me before now. Thanks for clearing it up substantially.

[@MarkLindsayCNC]

Excellent video as usual, Peter!

[@cncnutz]

Thanks Mark

[@vasyapupken]

one thing you must know about cutting parameters is that almost all information you can find about it was written with cutting METAL in mind. all machinist books and manuals mean that you will cut an homogeneous material like metal or polymer. so vast majority of this information just useless when it comes to cutting wood, foam, rubber or fiber composites.

[@cncnutz]

Very true. Not much grain and fibres in steel and other metals which is what the mills traditionally cut. The same is true of feeds and speeds. Almost all the F&S tables are metal based. Cheers Peter

[@LexMexNow]

Glad to see you have a sponsor. Your deserve one.

[@cncnutz]

Thanks Lex

[@caseym112]

I cut a lot of real wood with sharp 90 degree corners and have found using climb cuts on the finish pass really helps mitigate any blow out while cutting the end grain on the corners of the wood. I definitely get those fibers left behind after the cut, but they usually get machined or sanded right off. Thanks for the vid!

[@cncnutz]

Thanks Casey Thanks for the observations. Will have to give it a try and see how it goes for me. Cheers Peter

[@garethroberts9804]

Another informative video. Thanks Peter. I always use the conventional mode and if you think about it, the cutter is moving in the same direction as it would in a handheld router.

[@cncnutz]

Thank Gareth. That's where the name comes from. It is the conventional way of moving the hand router. I think the other way was called climb because the hand router would want to climb out of the cut. Cheers Peter

[@richardfarwell6759]

I have a nice scar on my index finder to remind me not to climb cut on a standard router. But I've always used climb on my CNC, presuming I will get a better finish - no fear of huge tearouts or broken corners like I would get with a hand held router. But, I'll have to think about what you've said here and run some tests. Wonder if an up-cut vs down-cut vs compression bit would make a difference in the finish.

[@cncnutz]

It's those sorts of lessons you never forget. Cheers Peter

[@braniams]

Thanks Peter that information, I'm quite new to CNC and normally I set all my machining to the conventional cutting but wondered which would be the better option so you have nicely clarified that for me

[@cncnutz]

Thanks.

[@paulvandriel2344]

I moved back to conventional milling, since climb milling (I didn't realise at the time that all that talk was coming out of the metal CNC corner) doesn't work well on wood. Exactly for the reason you showed with the drawings. Your reasoning is perfectly right, Peter. Nice piece of work again!

[@cncnutz]

Thanks Paul. I found the same with all the writings from the metal working point of view. Cheers Peter

[@MegaTopdogs]

Thanks Peter great info as usual.

[@mdawoodalam4086]

lol

[@cncnutz]

Thanks Geert

[@perrybrown4985]

Hi Peter, thanks for another thoughtful and informative video (presented in a friendly and humorous manner). My view of conventional cutting is that it is always pushing the furry bits back into the piece - and all the big loose ends are left on the part which will be removed as the next chip. With climb, the action of the cutter is pulling fibres out of the surface - and the surface they are coming away from is the finished one. Everything is different when the material is not fibrous (acrylic, MDF, metal, flesh etc.) As you said, rigidity is the key to making climb work - and if there is backlash or slop anywhere, it is doomed to fail (broken cutters). Best wishes :-)

[@cncnutz]

Thanks Perry

[@phillhinkler3174]

Hi Peter, another good video. Makes perfect sense. You have converted me to a devout conventional cutter.

[@cncnutz]

Thanks Phill. Does my cutting results match what you are seeing in yours? Does the conventional cut look good while the climb looks like it needs a shave? Cheers Peter

[@constantinosschinas4503]

using climb cut for finishing is safer in the sense that if you run on higher feeds or run into more material in tight corners and chip load peaks, cutter does not dig into material but makes an outer bump, which is easy to correct with a second pass, if desired.

[@solarmandave]

Great video. I believe I read, "conventional cut" the bit is sucked in to the material and with "Climb cut" the bit tries to "climb" out out the material. This can effect the cut with large cnc machines due to deflections in the machine and length of cutter bit.

[@cncnutz]

I think your right Dave. If memory serves it comes from hand routing but I could be wrong. As with feeds and speeds I think this falls into the category of the black arts. Cheers Peter

[@johnhorne3862]

I have always used conventional. Good video.

[@cncnutz]

Thanks John. Good to know I'm not the only one. Cheers Peter

[@thejoinerystudio5029]

Thank u so much

[@alixsonpl7973]

i notice, cutting type need respect the wood grain too. what do you think?

[@cncnutz]

Very true. The direction of grain makes a difference. Cheers Peter

[@karthikkram4992]

Climb or conventional which is best for Rough machining (volume clear) in vmc in steel material?

[@cncnutz]

While I don't machine steel I would use conventional as climb is harder on the machine. Cheers Peter

[@kenherring2831]

Thanks, great information

[@cncnutz]

Thanks Ken

[@rptrower]

Great video and explanation! I noticed Masso sponsored this video. Are you going to do a video on their control system?

[@cncnutz]

Thanks. At the moment I don't have a Masso to try but if I get my hands on one I certainly will. Cheers Peter

[@qwerty3663]

The chip load is specified at 50% RDOC, and when you are using less than 50% you have chip thinning, which means the thickest part of the chip is less than the specified (maximum) amount that occurs at 50%, regardless of whether it is done conventional or climb. In your raster pocket example, it is doing Climb in one direction and Conventional in the opposite direction. A better way of classifying Climb and Conventional cutting would be to say "thick to thin" for Climb and "thin to thick" for Conventional. Thus for any cut between 50-100% RDOC you are doing both, Conventional followed by Climb. So again, a slot is neither or both depending on how you look at it. This may help clear some things up: www.cnccookbook.com/climb-milling-versus-conventional-milling/ www.cnccookbook.com/cnc-chef-video-chip-thinning-clear-present-danger-ignored/

[@cncnutz]

Thanks Qwerty. That's a good website and I must spend some time looking at it as there is a lot of good info there. Cheers Peter

[@paulvandriel2344]

Yeah Qwerty, indeed great link to that video. Very helpful info there. Missed that one before on CNC Cookbook.

[@iwannaapple7190]

So why use climb at all?

[@IEraiderfan]

Peter, Great video as always thanks.😉

[@cncnutz]

Thanks Lou

[@sjb_rnd]

Are you using a Masso Controller now?

[@cncnutz]

No, I'm still using UCCNC. Cheers Peter

[@darkwinter6028]

Cut quality will vary with cutter, material, and machine: for example, in aluminum, with a brand new end mill, on a VMC in good condition (no slop in the ballscrews, etc) climb cutting will give better results almost always. However, as you showed, on your router, with your cutter, in wood, it doesn’t. 😀

[@darkwinter6028]

The other thing that occurs to me is that your machine doesn’t have a zero backlash drive: IIRC, it’s a rack & pinion system. Consequently, as the cutter engages during a climb cut, it’s pulling the machine axis forwards, effectively generating tool chatter. 🤔

[@cncnutz]

Thanks Dark Knight. I have the distinct feeling that all this falls under the same heading as feeds and speeds. It's a bit of a black art and why the professional machinists deserve the big bucks. Cheers Peter

[@paulvandriel2344]

@@cncnutz We, humble little home machinists, deserve the big bucks just as much. Especially, because guys like you are sharing and deepening the public knowledge with videos like this. I don't agree about being it a dark art. It's more a matter of CNC'ing being a relative new thing, coming into the general public spotlight only in the recent years and getting very popular with hobbyists and small workshops. Material wise, metals and composites are actually much easier to machine with CNC than wood. Metals and composites are predictable materials, manmade to specs and all the knowledge to get perfect results every time is available all over the place. Wood, however, is a natural product and much less predictable. Therefor, the lack of publicly available knowledge and experience in wood CNC, makes us think it's a kind of black art. Everything can be known and in a scientific/empirical way discovered. The internet and solid info channels, like CNC Nutz, will soon enough unveil all we need to know to get excellent results all the time. What we don't need is ballooned self proclaimed experts uttering gaga. Your videos are in my opinion a very valuable contribution to the build up of this much needed general available knowledge and experience. Wow, did I really say all this?

[@cncnutz]

Thanks Paul Well now I just feel foolish out in my workshop with my Black cat, Cauldron and fresh of eye of Newt. Reading the world news lately I had got the impression that facts and science had been abolished in favor of feelings. It's good to see that a few of us cling to the old ways, passed down from father to son, and still believe in science. Cheers Peter

[@darkwinter6028]

CNCnutz (Peter Passuello) - Reality is overrated. Delusion is where it’s at now, bucko! 🙄

[@cnccutter61]

Good video Peter. I happen to us both as the need arises. If I am machining solid wood I almost always use a climb cut because the cutter is severing the grain and not letting stress build that might lead to a split or run in the grain fiber. Erik

[@cncnutz]

Thanks Eric. I'm curious, do you use a slower feedrate for the climb cut than you might for a conventional one? cheers Peter

[@erikland8803]

in the past I have not run slower on a climb cut. after hearing your logic, I will give a few test cuts at a slower feed rate a try. I tend to run pretty fast anyways, 250 in/min, time is money but if I can get better quality and less sanding, it would pay off in the long run.@@cncnutz

[@cncnutz]

It would be interesting to know if it makes a difference. Cheers Peter

[@darkwinter6028]

It’s neither: it’s a slotting cut. Climb & conventional come into play when you don’t have 100% cutter engagement. 🙂

[@paulvandriel2344]

Are you gonna sent the white walkers now?

[@darkwinter6028]

Paul van Driel - Sorry? I think that’s some sort of cultural or media reference... white walkers? 🤔

[@paulvandriel2344]

@@darkwinter6028 To be precise; if it's a slotting cut, actually both climb and conventional coming in play at the same moment. As Peter very well showed and explained. If it would be an outside or inside cut only, with no material on the other side of the cutter, it would be either conventional or climb (not both). White walkers are the horror from the North in Game of Thrones. Expected to come in the Dark Winter. The rest you can probably guess.

[@darkwinter6028]

Paul van Driel - Ahh. Not a Game of Thrones fan. And my username predates it being a major media franchise... 🙂

[@cncnutz]

Your on to it. 👍