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    Default What rpm should I use? Taig milll

    Playing with my taig cnc mill and cutting aluminum. Currently set to 10k rpm on the spindle, if I drop it down 1 groove it’s 6700rpm, then 4200, 2600, 1650 and last 1050rpm.

    What would I gain from going with a slower spindle speed? Pretty much only plan on cutting aluminum for now.

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    Default Re: What rpm should I use? Taig milll

    I thought the lowest was 500.

    In any case, there is less hp available at the spindle at 10,000 than there is at 6,700 due to friction in the spindle bearings. additionally the lower belt contact angle means the belt needs to be tighter.

    you could run a half inch diameter endmill at 10,000 rpm in aluminum, but your machine doesn't have enough hp to make anything but dust at that rpm, and you also have to find an rpm that produces a good surface finish due to the incredible flexibility of that machine.

    if you have access to a welder, you could build a larger two piece weldment, a copy of the frame the machine bolts to now.. and machine the mounting surfaces on your machine. I would go with a minimum of .25" thick 4" square steel tubing.

    rpm will need to decrease with depth of engagement due to hp limitations as well. 10,000 rpm on a .25" end mill might work on that machine at .125" deep in aluminum, but if you're cutting .75" deep you'll need to drop the rpm and feed rate down.

    Tooling Pro

    your machine might have enough hp at the spindle to cut a .25" wide .25" deep slot in aluminum at 8 inches per minute. try doing this at 4200 or 2600 rpm spindle speed.



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    Default Re: What rpm should I use? Taig milll

    The choice of spindle speed depends on the tool you're using. In general, the larger the tool, or the more flutes (these are actually the gutters between the cutting edges, but the number of edges is the same) it has, the slower it should turn. (usually for aluminum, you want to use cutters with 2 or 3 flutes.) What you need to do to get a firm number is figure out the optimal chipload per tooth for the material you're cutting and the size and type (solid carbide, cobalt, HSS) of cutter you plan to use. There are charts online that can help; if the manufacturer of the tool you're using puts one out that's the best one to use. But these charts are based on big industrial machines, so if you're using a Taig mill, you need to realize that the recommended feedrates are not going to apply to your machine (it will cut a lot slower).. Also, if your depth of cut is deeper than the diameter of the tool, you need to reduce the chipload accordingly. I'd recommend sticking with a depth of cut about half the diameter of the tool until you've got a handle on this and feel you can increase it safely. Also, with aluminum, the metal will tend to stick to the cutter, especially if there's no lube/coolant being used. This will lead to broken tools, since the machine keeps pushing even though the clogged cutting edges can't get the material out of the way fast enough. (A similar thing happens when you try to plow through a slot clogged with chips - the cutter can't remove them cleanly, so the chips end up caught between the cutting edges and the material to be cut, interfering with the cutting action, rubbing and chattering, and ultimately dulling and then breaking the cutter. )

    So if you look at a typical chart, like this one: http://www.endmill.com/pages/trainin...d%20Drills.pdf you'll see that they recommend a chipload of .002" per tooth if you're using a 1/4" carbide endmill, feeding a lot faster than the Taig will go. But plug that chipload factor into the formula FR = RPM * T* CL (Feedrate equals spindle speed times number of teeth times chipload), you get 4200 * 2 * .002 = 16.8, which sounds reasonable for a 2-flute 1/4" diameter tool cutting aluminum on a Taig mill. Here's a handy online calculator that does the math for you: https://www.cnccookbook.com/cnc-feed-rate-calculator/
    '

    Andrew Werby
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    Default Re: What rpm should I use? Taig milll

    Quote Originally Posted by Gamble View Post
    Playing with my taig cnc mill and cutting aluminum. Currently set to 10k rpm on the spindle, if I drop it down 1 groove it’s 6700rpm, then 4200, 2600, 1650 and last 1050rpm.

    What would I gain from going with a slower spindle speed? Pretty much only plan on cutting aluminum for now.
    You can figure all this out using SFM formulas..... OR ...... If your machine is a stock Taig unit.... you can use this little method.... looking at the spindle pulley put your belt in the second groove from the top. I suggest you start with a 1/8" or 3/16" 2 flute tool. Those are large enough that they aren't easily broken...but small enough that if you screw up, you haven't damaged a machine. Now, depending on the tool size, make a cut at a SLOW linear travel speed and about 10% of the tool diameter for a Z depth. Look at the finish and the chips. If the cut is clean and the chips look like a comma..." , " then your Linear speed matches your spindle speed. If the chips look like dust... you need to slow the linear speed. Learn as well to listen to the tool & machine. Just remember that smaller tools cannot stand a fast plunge or forward linear speed. The larger the tool, the faster linear speed you can use... TO A POINT. But doing it this way, you have a "Constant"...that being your spindle RPM setting. This makes it simple to find a setting that will give you clean cuts and not snap off tools or hang one up in the material. Just start slow...look & listen and you will be fine. You can speed all this up once you have an undestanding of everything that is going on. Good Luck!



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What rpm should I use? Taig milll

What rpm should I use? Taig milll