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Thread: Calling all CNC operators

  1. #21
    Insider
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    I buy all my tooling from Mari Tool I've been very happy with the performance of his carbide tooling.

  2. #22
    Insider Ydna's Avatar
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    Nice, Panda you ever use the 43CB roughers? I find they can drop the power about 10% depending on how they're being used. They're meant to be ran at a lower RPM in order to draw more torque from the spindle, but that high torque comes at the price of stressing the living hell out of the toolholder. I actually prefer weldon flat holders in some situations...there's always a bottleneck somewhere.

    I've used S/Z carb in the past, mostly on contract jobs and the suppliers like them since they're easy to source. I like their bottom plunging geometry. I wouldn't say I go to SGS first, but I often end up with them after looking around for something that's non-standard, like a tapered ballcutter or solid carbide feedmills.

    Myself I prefer Destiny Tool and Lakeshore Carbide for aluminum cutters. Their flute geometries seem to be more aggressive compared to Swiftcarb, Accupro, OSG, SGS, etc. Destiny makes cutters with deeper flutes, but the Lakeshore versions are generally cheaper (probably because they have less markup by selling direct). The thing I like about Destiny endmills is they're larger toward the bottom and have modified flute geometry to strengthen their corners, being as the corners wear quicker than the rest of the tool. They last so long, I'm more liable to drop them than actually wear out by cutting. However the downside is the modified flute makes it harder to plunge or helix/ramp aggressively. Generally need to drill a plunge hole or back off with the entry helix speed. Very application specific.

    I used the Accupro progressive helix cutters with some success, but they have the opposite effect. The bottom of the cutting edge is the weakest part by far. They make a great finish but almost always ended up snapping off in a pocket somewhere. I prefer the standard high helix Accupros. Funny, Accupro used to be probably the cheapest high helix endmill around (aside for Lakeshore), but their prices must have increased somewhere along the years.

    I tend to say most suppliers can give similar results as long as the cutters aren't asian garbage. I think everybody goes through a phase where they want to buy up cheapo carbide from ebay or whereever, but then gradually realize the uselessness as time goes on. In the past I worked a string of automation cells where I was handling the robotics side of things and couldn't touch the machining end, so I could only shake my head at the guys buying endmills that squeak into corners, leave cloudy finish, make rubbing sounds from excessive RPM, leave a tapered wall due to flexing (usually with the aforementioned cloudy finish) etc etc. It's enough to make a grown man cry!

  3. #23
    Insider ElPanda's Avatar
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    yes, it was a 1/2" S carb

    I have never used roughers for aluminum actually, I use roughers alot on steel. I tend to keep everything (code wise) high speed with aluminum, I can usually remove alot of material in a very short period of time.

    and I also prefer the weldon flat holders for more intense operations like heavy roughing, I avoid using the solid holders for most other applications simply to keep tool concentricity true, I have never had problems with tools moving in or out of collets during machining
    Last edited by ElPanda; 01-22-2014 at 04:43 PM.
    ABET accredited level II machinist - CNC Programmer - Mechanical Engineering Technologist
    Rio Grande Inc.

  4. #24
    Insider Ydna's Avatar
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    Yeah I tend to agree, the collets are just too economical to avoid when compared to the higher-end toolholders. Unless you need the balancing benefits.

    The tool companies want you to use heatshrink or hydraulic holders but money doesn't grow on trees. They have better retention force, but the thing is once the tool STARTS to move, well it just keeps moving. Ironically an ER collet will halt tool movement better in that situation. but they're not ideal for roughing..

    What if a tool were to break? I've had that happen in hydraulic holder, where it shattered right toward the base of the holder, and scratched the bore all to hell. Great, it trashed the tool and the ridiculously expensive holder both.

    Anyway, I like using roughers in highspeed situations just the same, by virtue of using that additional 5-10% horsepower to cut slightly deeper. Of course it might not matter in the end, if your deeper max cut doesn't actually save time on the number of passes or anything. Sometime back I got in the habit of full depth slotting-roughing just because it's less muss and fuss, I mean when you do a highspeed toolpath where you're taking more than 2/3% depth of the tool sometimes you mind as well just full slot it to avoid the unnecessary retractions. Of course not applicable to all workpieces...

  5. #25
    Insider ElPanda's Avatar
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    largest part I have worked on so far

    final part is 22" x 40" x 2", we bought the plate ground at 2" already and the profile was .25" oversize. It weighs about 180lbs

    the material alone cost around $520

    I still have to stand it up to put threaded holes on both of the long sides
    ABET accredited level II machinist - CNC Programmer - Mechanical Engineering Technologist
    Rio Grande Inc.

  6. #26
    That's gonna be a hell of a paintball gun
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