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Thread: Very rough surface finishing recently with c-beam build

  1. #25
    *Registered User* user834342's Avatar
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    Default Re: Very rough surface finishing recently with c-beam build

    Quote Originally Posted by cyclestart View Post
    Edit/ I looked at a feed/speed calculator for HSS and you're kind of between a rock and a hard place with the available rpm.
    The Makita 700C has RPM adjustment but I have no way to tell what the rate is, I can just make it faster and slower.

    Should I an end mill made of different material?



  2. #26
    Community Moderator ger21's Avatar
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    Default Re: Very rough surface finishing recently with c-beam build

    Try a bit like this, with the router set to it's lowest speed.

    https://www.amanatool.com/51401-soli...outer-bit.html

    Gerry

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    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


  3. #27
    Registered Biggs427's Avatar
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    Quote Originally Posted by user834342 View Post
    I tried lower feed rate but it didn't really help.
    It probably make the problem worse. What is "lower feed rate"?

    I had this router on my first machine and the lowest rpm is around 10000 rpm.



  4. #28
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    Default Re: Very rough surface finishing recently with c-beam build

    Occasionally squirting some WD-40 can help keep chip welding at bay and maybe in cleaning up those feathered edges. Won't help for chip clearing though.
    There's been a bit of back and forth on downcutting bits. Normal bits (like what you've got,) are up cutting. (turn the bit clockwise, like it would be when cutting and see if it spirals up or down.) Downcutting bits are good for keeping the top surface of what you're cutting with a crisp edge, especially on materials prone to chipping/pull-out (like wood.) Problem is that they push what's been cut down into the cut rather than pulling it out, so with metals (Especially gummy ones like aluminum,) they lead to chip re-cutting which will wear out the bit faster, but usually just cause chip welding and break the bit in pretty short order. I'd echo the recommendations for 1 or 2 flute cutters as well. Higher quality (sharper,) cutters are your friend as well, they will do better at the low feeds per flute you're stuck with because of the lack of rigidity you've got.
    Looking at the construction of your router, I'd try and keep your workpiece centered over that central beam under the machine table, over wherever it's attached. That should be the stiffest part of the table.



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    Default Re: Very rough surface finishing recently with c-beam build

    Quote Originally Posted by user834342 View Post
    The Makita 700C has RPM adjustment but I have no way to tell what the rate is, I can just make it faster and slower.
    Some of the smart phones these days have tachometer apps. You really need to ahve some idea of the tools speed under opration or you will never be able to determine ideal feed rates. finding an ideal combination of feed rates and spindle RPM's has never been perfect operational science as machines of old seldom hand continuously variable RPM's. Even today optimal feedrate and rpm combos are often achieved by tuning the machining operation. However you need to go through the steps to get close to the right figures or you will never learn optimal conditions.

    So you need to determine those spindle RPM's to some extent and then calculate the suggested feedrates. It is very likely that you will never achieve the calculated feedrates though. You need to get as close as possible though. at that point try experiementing with depth of cut. On a flimsy machine like this I would start with one tenth of the cutter diameter for depth of cut and work up from there.
    [quote}
    Should I an end mill made of different material?[/QUOTE]

    It always help to buy end mills designed fothe material you are cutting. Given that you can buy end mills for aluminum built from different materials and with different coatings. YOu will likely need a single flute cutter due to high spindle RPM's and slow potential feed rates. However be careful because a single flute cutter could introduce harmonics that are not desirable.

    By the way yes WD40 can be a good lube/coolant for aluminum processing. However it will get everywhere at these spindle RPM's.

    Im still of the opinion that you have chuip weldign or a worn out end mill. It might help to post picitures of that end mill. close ups.



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Very rough surface finishing recently with c-beam build

Very rough surface finishing recently with c-beam build