Thread: It's begun....

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  1. #111
    Hi Michael,

    I thought I had tried everything to get CUT3D to do climb only. Can you let me know where the setting is?

    I use CUT2D for standard work like signs etc. and know that has a setting.

    I've also just downloaded a trial of BOBCAD, but that is crashing on my machine and likely something in my models it doesn't like.

    I don't think I'll be looking at a vacuum table just yet, but if you're build logging that I'll definitely keep an eye on it. I'm happy enough with toe clamps and t-slot nuts and bolts so far and I also have a decent machining vice from ArcEuroTrade, which I've yet to try out.

    Cheers


    Chris
    Last edited by Washout; 07-10-2013 at 05:28 PM.

  2. #112
    Hi guys,

    Thought I'd post an update, although this is becoming more of a "learning machining" thread than a build log as such.....

    I've still not found the climb vs. conventional setting in Cut3D, so have been persevering with the alternating raster strategy that get's output. This has been OK and in fact after running over the whole machine and torqueing everything down, it seems to be making less of a noise about it.

    Roughing passes seem to be OK, but I'm not too impressed with the Vectric Cut3D finishing passes, which when using a ball nose cutter are not coming out very smooth (i.e. I have ridge lines), so I probably have a setting wrong somewhere. In the meantime I think I'll be using Jonathan's advise and leaving 0.1mm+ clearance and then run another pass to finish (both using the roughing strategy).

    I've also tried my first 2 sided part, which cut fine apart from my bolts must have moved a few tenths of a mm, as I had an nice offset step in it.....doh. Anyway I also then tried the same part using the precision vice from ArcEuro, which is a great bit of kit. I also had some "fun" here, when my z axis zero to touch plate worked great and then I got cocky and tried the zero wizard (I'm using the 2010 screenset). This resulted in the tool sailing through my touch plate and leaving half of it lying on the bed when it hit the workpiece and continued on....at least I can use the shank as a new touch tool I guess (need to watch the tutorial video again to see what I did wrong there).

    I think it was one of Dean's posts where he reckons more time is spent working out work holding than actual milling and I think I'm finding that to be very true.

    Also I have been using APT for my 2 flute cutters, but I am need of some 3mm end mills which have a 3mm shank rather than APT's normal fatter shanked variant. Any suggestions for suppliers are more than welcome (also need to try 1 flute cutters).

    Still on my to do list are wire up my limit switches, wire up and get the MACH3 spindle control plugin working and also look into a better misting solution than my airbrush, as that's not very elegant (anyone know where you can get misting nozzles and the rest of the stuff required).

    I did however, manage to use some spare sheet Perspex/plexi-glass with some case making extrusions and build a bit of a "fish tank" affair for the machine a. to keep some of the swarf at bay and b. retain the excess "misting coolant".

    I'll try and get some video up again soon, but I will likely be busy with a new lathe this week if all goes well.

    Later


    Chris

  3. #113
    Another update on progress and again machining rather than building the machine, even though I have upgrades queued up waiting for some time.

    Anyway, I have a paying customer now and even though my machine is still in the later stages of build he's an understanding sort, so I'm doing my best to oblige. So the pic attached are the result of a few 2D operations -
    1. was a 0.2mm facing pass to get rid of the "texture" on the aluminium plate (40mm thick 6082 T651)
    2. was a pocketing operation to do the hole in the centre
    3. was the pocketing/profiling operation (on one side only at this stage)

    All were programmed in Vectric Cut2D and this is where some "fun" started - my machine for some reason likes to mill when running in a clockwise direction in a pocket, which I think is conventional milling i.e. the spindle is running clockwise as you look down on it from the top. My understanding however is that climb milling should be better?

    Also another observation is that compared to climb milling around the edges of a pocket my machine actually seems to like doing slotting better?

    All 3 operations above were using a conservative 1mm DOC @ 10000rpm @ 800mm/min using an 8mm 2 Flute HSS End Mill-

    I think I can go much more aggressive in DOC but I do have an issue with getting the chip out of the pockets at deeper than about 10mm - I probably need a more powerful compressor or wing at on blown air alone rather than the heavy mist I'm currently using, which tends to pool cutting fluid/water/chips mix in the corners and bottom of my pockets. Shallower cutting is great as the chip are getting thrown out nicely.

    The results of the main pass and facing is a little rough, but I guess that's why its called a roughing pass. The centre hole pocket is much better.

    I will eventually get some more video once I can trust the machine to run on its own on an operation without me brushing out chips and generally hovering about the thing watching.

    Cheers


    Chris
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  4. #114
    Quote Originally Posted by Washout View Post
    my machine for some reason likes to mill when running in a clockwise direction in a pocket, which I think is conventional milling i.e. the spindle is running clockwise as you look down on it from the top. My understanding however is that climb milling should be better?
    I plan to cut hardwood but currently I use an overhead pin router with templates, as you say with the cutter running clockwise from above I would be moving the workpiece anticlockwise as this is the only safe way to cut hand held stock. If it's moved in the same direction as the cutter then the cutter tends to acts as a power feed and just pulls it out of your hands but if you can hold onto it the finish tends to be better. So maybe the best plan is to use conventional milling for the most part and leave a finishing pass in the opposite direction ? at least with it being a cnc and everything clamped it should not 'run away' as a hand held would.

  5. #115
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 7 Hours Ago Has been a member for 9-10 years. Has a total post count of 1,840. Received thanks 192 times, giving thanks to others 5 times.
    Climb milling will produce a better finish, but only on a sturdy machine with near zero backlash and flex.
    Any flex or backlash can cause the cutter to grab the workpeice leading to an inconsistent cut and poor finish.

  6. #116
    Quote Originally Posted by m_c View Post
    Climb milling will produce a better finish, but only on a sturdy machine with near zero backlash and flex.
    Any flex or backlash can cause the cutter to grab the workpeice leading to an inconsistent cut and poor finish.
    Exactly what I experience with hand held routing.

    Edit: following Wobblycogs' post below I'll have to clarify that by saying hand held routing I'm not meaning with a cnc machine but just with a standard woodworking router or my overhead pin router. In both cases hand holding the workpiece or at least using some hand held push-stick is the correct method.
    Last edited by EddyCurrent; 21-11-2013 at 12:14 PM.

  7. #117
    Climb cutting and hand held routing is asking for trouble. You'll get away with it in something like MDF where there's no grain but I wouldn't do it with real wood. There's too much risk of stresses in the wood or an awkward bit of grain suddenly causing the router to take a bigger bite than you are expecting and getting away from you.

  8. #118
    Thanks guys - that makes sense - so conventional gives the machine an easier time but doesn't always produce a good finish, whilst climb beats the machine up a bit but finishes better, provided its sturdy enough.

    I'll try a conventional version of the toolpaths and see how that goes on the other side of that block (hence the L Shaped locating bracket seen in one of the pics).

    Whilst I remember I also have a MACH3 query if anyone knows the answer: when I Feedhold (to clear chips) and I hit Cycle Start to resume cutting, the operation I interrupted resumes, but at a much slower speed than before I hit Feedhold. Is there a way of stopping this behaviour as changing my feed rate is a bad idea......

    Cheers


    Chris

  9. #119
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 7 Hours Ago Has been a member for 9-10 years. Has a total post count of 1,840. Received thanks 192 times, giving thanks to others 5 times.
    Is the feedrate, or feedrate override changing after you resume?

    It could be a macro is getting called by some stage during the feedhold, and changing something.

  10. #120
    Could it be anything to do with one of these ?

    10.7.28 Set Feed Rate Mode - G93, G94 and G95
    Three feed rate modes are recognized: inverse time, units per minute and units per
    revolution of spindle. Program G93 to start the inverse time mode (this is very infrequently
    employed). Program G94 to start the units per minute mode. Program G95 to start the units
    per rev mode.
    In inverse time feed rate mode, an F word means the move should be completed in [one
    divided by the F number] minutes. For example, if the F number is 2.0, the move should be
    completed in half a minute.
    In units per minute feed rate mode, an F word on the line is interpreted to mean the
    controlled point should move at a certain number of inches per minute, millimetres per
    minute, or degrees per minute, depending upon what length units are being used and which
    axis or axes are moving.
    G and M-code Reference

    Using Mach3Mill

    Rev 1.84-A2
    10-32
    In units per rev feed rate mode, an F word on the line is interpreted to mean the controlled
    point should move at a certain number of inches per spindle revolution, millimetres per
    spindle revolution, or degrees per spindle revolution, depending upon what length units are
    being used and which axis or axes are moving.
    When the inverse time feed rate mode is active, an F word must appear on every line which
    has a G1, G2, or G3 motion, and an F word on a line that does not have G1, G2, or G3 is
    ignored. Being in inverse time feed rate mode does not affect G0 (rapid traverse) motions. It
    is an error if:
    ♦ inverse time feed rate mode is active and a line with G1, G2, or G3 (explicitly or
    implicitly) does not have an F word.
    Last edited by EddyCurrent; 22-11-2013 at 12:23 AM.

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