How To: Use a Bowl Bit on your CNC Router - Feeds and Speeds Guidance

there are some factors to consider when adding bull bits to your CNC Arsenal we're about to expand your tooling options information to make your next CNC project a success is on the way a 3/4 in Bull bit is a large cutter relative to most of the tools you generally use in fact it's three times as wide as the basic 2011 your machine comes with and most people start cutting with the only bit of similar size that may have been in your machine is a 1-in fly cutter similar to our McFly some of the same considerations for that fly cutter are at play with bull bits plunging is difficult and burning of your stock could be an issue ideally you'll want to use ramping to enter any Contour or pocket this drastically reduces the stress on the endmill the material and your machine bullits also a very interesting geometry featuring a flat portion at the bottom that's even smaller than a/ Quin cutter this affects the stepover you're going to have to go a lot smaller to avoid scalloping new libraries and new tools are under your management the Musto here is the diameter of the cutter the rest is really info directed at you by you the name of the cutter the number the vendor the flute length the number of flutes when you get to the 2D cutting parameters depth the cut RPM and step over I'm about to help you dial in a quality starting point but remember it's just that when it comes to setting your initial feeds and speeds let's remember that bull bits even when run in a standard rter table have to be run at multiple depths in order to produce a deep cut now anytime you get a new Jewel you want to add it to your tooling database hey future Kevin here if you don't use carb create you want to skip ahead to the next chapter testing and settings it's in the description below if you do use create we got some great information coming for you right now let's first start with the settings that I whipped over a minute ago with carbide create open you can go up to edit and then you want to go to show tool database and that will pop up all the pre-populated tools that exist inside of carbide create you may or may not have added your own tools sometime before adding a bull bit you can create custom libraries for certain materials you can create custom libraries for extra tools you've added for different manufacturers however you want to manage this area is entirely up to you for me I have a few different added libraries that I regularly use now I've already added a 3/4 in Bull bit to my library if you wanted to start over brand new in the library of your choice rightclick new tool and Mill and then you want to add it in inches or millimeters here I'm going to use inches because it's measured in inches in its diameter but the expression editor would have you covered here anyway so the name this is something optional for you to remember and when I said that you're basically giving information to yourself a lot of this is all about you remembering what tool it is that you've designated inside of carbide create when it comes to running things at the machine inside of carbide motion we'll call this Bullit sample model 3/4 in supertouch Bullit vendor unknown I don't remember where I bought it or who it was from but it's a 3/4 in Bull bit tool number now this is where you can choose Cho so you know what custom tools are give it a tool number you can add something in here you could add 406 doesn't really matter something you're going to remember maybe a series you're going to remember now here's the diameter real simple here 75 and this is the most important measurement because it tells carbide create how to make the G-Code where to constrain the bit so it stays inside of the vector geometry that you have assigned it now 2D feeds and speeds down here plunge rate feed rate RPM depth of cut this is all up to you and this is where I started way too slow I started with 8 in per minute plunge feed rate of 70 in per minute and RPM of 20,000 depth of cut 0689 in these numbers would change rather quickly my first Cuts were in Walnut and I started with those slow numbers eventually dialing it up to 1.5 mm depth of cut and 5,000 mm per minute in terms of a feed rate that is 200 in per minute if you can't do the math during my initial cuts it became obvious that my stepover value was too large we already talked about how narrow that flat portion of the vulet really is I had to reduce my stepover to account for that small flat area if you don't you're going to have big scallops now big scallops might be a feature that you have on some bowls you might just do that as a thing I think people might like it it still features that same nice radius all all the way across give it a whirl a little bit of testing you never know what you might come up with when you're cutting Hardwoods Walnut Maple Cherry you have to make sure you're not burning the material as you cut it the corners are going to be the problematic spots for this as that tool is fully engaged balancing that feed rate along with the RPMs will keep you getting quality cut also you should know those edges are going to be loud because of the full engagement [Music] version one helped me increase my feed rate dial in the depth of cut and showed me that my stepover needed work the look of this tray right off the machine wasn't going to cut it and would require a ton of post-processing to make it even decent in version two I was still left with some pretty obvious tool marks especially in the cross grain portion of the cuts and the step outs of the pockets I wanted to do less sanding so here's what I did in version three I created a finishing pass and to accomplish this I utilize the value of t and a modifier inside of carbide create this is part of our expression editor I initially had a value of tus 5.5 mm meaning it would leave 5.5 mm of material between the bottom of the cut and the bottom of the stock I then set up a finishing tool path to cut from tus 5.5 mm to tus 5 mm thereby creating that5 mm finishing pass with that final shallow pass I also went with a 75 mm stepover and look at this there are virtually no tool marks on here I did not sand this at all it is straight out of the machine and it looks nearly Flawless you could go even a little bit smaller you could go to a 0.5 a 0.25 and just see how clean can you really get those cross Cuts that's an area I'll leave for you to explore let me know in the comments below if you've been able to achieve better results I've uploaded my version 3 file to cut rocket our free file sharing service you can download it inspect it and use as a jumping off point for your own bull bit projects because I did my testing in Walnut I ended up with three beautiful trays and I really like this too where you get a little bit of onural in your items where you run into a knot you have some cracking I like to leave it I don't want to freeze it with epoxy I don't want to make it perfect I think this is natural beauty you can also see the machine Marks here I sanded this particular one and they're still quite prevalent that was the first effort second effort look how much cleaner it got here this is a lot better but still some sanding was done to create that effect so I knew with that finishing pass things were going to be better I didn't know how much better and I was totally Blown Away by the impact that that had that finishing pass that small step over that 05 final depth I did zero sanding in the pocket of this tray and that looks wonderful the other thing is look at those transitions look how beautiful those transitions are from the vertical to the horizontal faces you'll immediately get compliments on how beautiful those trays look and again people don't know why they like it they just know that they do it's because of the geometry of that bull bit really coming into play to make something exceptional all right get out there add bull bits to what it is that you're doing in your CNC shop I think it's a worthwhile opportunity and we'll be back here on the channel again with more information ideas and inspiration [Music] all

Channel: Carbide 3D

Views: 7,173

Keywords: Carbide3D, CNC, Shapeoko, Carbide Create, Carbide Motion, Technology, Machining, Nomad 883, Nomad CNC, Nomad Pro, Desktop CNC, CNC Router, Digital Fabrication, Nomad 3

Id: 1XT2q_o9JvE

Length: 8min 11sec (491 seconds)

Published: Fri May 24 2024