Z Height question for special long foam mill

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This topic contains 7 replies, has 3 voices, and was last updated by  Philipp 3 months ago.

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  • #89682

    Philipp
    Participant

    Hi,

    I nearly got the needed dimension fixed, but I’m unsure about the needed height. I don’t want to go too high, but I’m afraid of not being able to get the mill out or being too low for the thickness of the foam.

     

    My specs are: This mill for milling foam (https://www.sorotec.de/shop/Zerspanungswerkzeuge/sorotec-werkzeuge/3-schneider/category-603/) 6mm and height of 100mm max and 70mm NL.

    The length of the mill also determines the max height of the xps foam I can use, being 600mmx1250mm and 60mm strong, maybe 80mm sometimes, depending on the milling. Max available is 120mm.

    I have no space for the complete 1250mm length, so I’ll do 1000.

    I have a 400W 52mm air cooled chinese spindle which is nice for foam. I had my 3d printer converted to a cnc and laser, but the rigidity is terrible for wood.

    My main cnc working would be xps foam and wood. Maybe!!! rarely plastic (POM) or Aluminum. But foam and wood would be 95%

     

    I would be very grateful for any advice for the needed Z height for the calculator with my specs.

    Thanks

    Philipp

     

     

    #89706

    Philipp
    Participant

    Hi there, I know, this is the 1000th question about z-height, but please, although my question may be causing  a “gnahhh, not again, rtfm”  reaction, there is a slight nuance, as I’m not looking for the max height, but for the min height in regards to the length of the special end mill and the foam height.

    But of course I can understand a sudden barking reflex. If you could swallow it up one more time that would be totally cool 🙂

     

    #89711

    Ryan
    Keymaster

    Hi there, I know, this is the 1000th question about z-height, but please, although my question may be causing a “gnahhh, not again, rtfm” reaction, there is a slight nuance, as I’m not looking for the max height, but for the min height in regards to the length of the special end mill and the foam height. But of course I can understand a sudden barking reflex. If you could swallow it up one more time that would be totally cool ?

    Nope, you are milling foam, well within my specs! You are not doing anything wrong. It’s the people that want a 12″ Z “just in case” but plan on milling mostly aluminum….then the barking starts.

    For Z length you need the length of the endmill+ material thickness. Or more specifically endmill+ cut depth, if the material is thick but you only plan on cutting to a certain depth it is best to make a drop table.

    #89714

    Philipp
    Participant

    Hi there, I know, this is the 1000th question about z-height, but please, although my question may be causing a “gnahhh, not again, rtfm” reaction, there is a slight nuance, as I’m not looking for the max height, but for the min height in regards to the length of the special end mill and the foam height. But of course I can understand a sudden barking reflex. If you could swallow it up one more time that would be totally cool ?

    Nope, you are milling foam, well within my specs! You are not doing anything wrong. It’s the people that want a 12″ Z “just in case” but plan on milling mostly aluminum….then the barking starts.

    For Z length you need the length of the endmill+ material thickness. Or more specifically endmill+ cut depth, if the material is thick but you only plan on cutting to a certain depth it is best to make a drop table.

    Thank you very much for your reply, this was the only measurement missing. And glad you didn’t have to bark this time 🙂

    So if the total endmill length is 100mm and the foam 80mm, but I would leave 20mm uncut my Z height for the calculator would still be 180mm or a drop table to keep the Z low and still being able to insert the 80mm foam?

    Can the length of the Z conduit be higher to have some space left without affecting the rigidity, IF I don’t move the spindle to the extra height AND keep the height of the kegs low? Because cutting a conduit  is easier than lengthening it 🙂

     

    #89715

    Ryan
    Keymaster

    It is a bit hard to follow but Conduit is only a few dollars and at the lengths you want ever millimeter shorter you can make it will result in must faster/accurate cuts. So start short, make an adjustable table.

    If the foam is 80mm and you only need to cut 60mm, do not buy a 100mm endmill, buy something closer to 60. Not only will you save a ton of money but the machine will treat you better as well.

    #89716

    Philipp
    Participant

    It is a bit hard to follow but Conduit is only a few dollars and at the lengths you want ever millimeter shorter you can make it will result in must faster/accurate cuts. So start short, make an adjustable table.

    If the foam is 80mm and you only need to cut 60mm, do not buy a 100mm endmill, buy something closer to 60. Not only will you save a ton of money but the machine will treat you better as well.

    Got it. Unfortunately I already have the endmill, since I did some tests on my converted 3d Printer first. But it is only 75mm of “outside of the spindle length” and 100mm in total. But cutting is awesome, even on my printer that has next to no rigidity. I noticed when I tried to cut wood that my printer cnc is worthless for wood 🙂

    The only fear I have is that I can’t change the tools easily when I need to, without moving the spindle all the way up or taking the spindle off. On my printer I could easily move it as high as needed, that’s why my question about longer conduits for the Z rail.

    #89747

    Bill
    Participant

    If the bit is 100mm in length, a portion of which is up in the collet, to remove and replace the bit requires very little more than 100mm of clearance between the bottom of the collet and the surface of your spoil board. More Z height than this is not needed and so shouldn’t be designed into your build. When the Z is all the way down your bit should be just digging in to the spoil board. When Z is all the way up you should have just enough room to position your tallest workpiece.

    #89790

    Philipp
    Participant

    Thanks Ryan and Bill. I think I got it now. I could actually reduce the needed height now and may eventually be able to nicely cut through wood, too. And in any case, new conduits are really not that expensive for these short dimensions.

    Thank you all!

     

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