Just starting. Need some help with dimensions.

New Home Forum Mostly Printed CNC – MPCNC Troubleshooting – MPCNC Just starting. Need some help with dimensions.

This topic contains 5 replies, has 3 voices, and was last updated by Profile photo of vicious1 vicious1 4 months ago.

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  • #17463
    Profile photo of Josh Williams
    Josh Williams
    Participant

    I am getting ready to begin the journey of building the MPCNC. I hope to not only mill but laser engrave/cut, draw and 3d print. I am trying to decide on the usable area / size to start with. Since I will be building a table as well so I want to make sure I have the right size in mind. I will most likely build the table larger so that I can enlarge the machine if I wish in the future. I have searched the forum and read the documentation but can’t seem to find the answer and would like some feedback.

    I know the assembly says that the recommended start size is 30″. Is this the usable size or total dimension? If it is the total dimension the calculator shows that the usable area is ~19″. Can I safely use a working area of 30-36″. At those sizes would it be necessary to have additional support on the conduit?

    Once I know how much I can do with the X and Y axis I need to consider the Z axis. The milling and laser functions won’t need a lot of height. The most I see myself milling is maybe 2″ for some special boards or projects. The 3d printing is another story. I have seen posts where other users have had issues with a tall Z height and accuracy and strength. I’ve also seen a post or two that people have discussed a removable spoilboard/bed and having a lower platform where the 3d bed is placed which keeps the foot length of the milling platform short.

    Is this viable?

    What effect does carrying the extra Z height around have on the system as a whole? If this is done I would assume with the extra mass the speed of the system would decrease. Is there a chart that shows (in general) cut / print speeds of the system?

    This looks like an amazing system and I’m excited to get started but I want to make sure that (A) I set my expectations within reason and (B) that I build it correctly for my goals to begin with.

    Thanks,

    Josh

    #17464
    Profile photo of vicious1
    vicious1
    Keymaster

    Best to separate 3D printing from all other functions. Unless you want to print large “flat things” then the milling setup works with this. A 48″x48″x12″ won’t work well for anything. The whole setup is half the price of most printers so it’s pretty easy to justify 2 separate builds in my opinion, or mill out some parts for the Mp3DP.

    Build it as small and most importantly as short as possible. There are no guidelines because it us an extremely wide open question. If you are only going to be milling 10″ picture frames make that your usable area. Unfortunately things like “I might want to mill full sheets one day” aren’t a good idea. I use that as an example because I get that a lot. If you are milling quadcopter frames but dream of milling out a lounge chair, really that is two different machines with extremely different tolerance expectations.

    To answer your question about supports it depends on what you are doing, 3D milling, yes supports to add to z axis accuracy, but if you are just 2D milliing or cutting foam, don’t bother. At the same time supports are just about the easiest thing to add, you can just cut some strips and epoxy them on, or make fancy 3D printed ones. Some people don’t even use my legs they build the whole thing on a box/support.

    I know it says multi-machine in my description but unfortunate that doesn’t usually mean with the same build.

    #17466
    Profile photo of Josh Williams
    Josh Williams
    Participant

    Thanks for the quick feedback!

    My thought was that I’d like to be able to offload some of my existing 3d printing work to the MPCNC from time to time. Most items I print are in the 2-4″ tall range 90% of the time. I figured if I allowed for a height of 4.5 – 5 inch of Z height that should let me print parts 4- 4.5 inches tall on top of the spoilboard. The option to remove the spoilboard and print larger parts to a lower bed was one I saw mentioned in the forum and thought it was an interesting idea if it wouldn’t have a huge impact on the rest of the system. I think I’ll leave the huge prints to my main 3D printer (MakerFarm Pegasus 12) as I can print up to 12 x 12 x 13″

    Would an X/Y of 36″ x 24″ (usable) with the 4.5-5″ Z height still retain enough rigidity to mill hardwoods and aluminum? I’m not sure how much metal work I would actually be doing but could see myself cutting plates and brackets for other machines.

    I’ve been working with 3d printing for quite some time now and have had some great success with it but milling and laser work is entirely new to me.

    #17561
    Profile photo of sempul
    sempul
    Participant

    Those are basically the standard dimensions of the mpcnc, I don’t see what the problem would be.

    #18134
    Profile photo of Josh Williams
    Josh Williams
    Participant

    I picked up my conduit this morning. Just some final clarification before I start cutting tonight, the recommended starting footprint of 30″ x 30″, is that the workable area or the entire corner to corner size?

    #18140
    Profile photo of vicious1
    vicious1
    Keymaster

    HAve a look at the calculators on this page, http://www.vicious1.com/assembly/conduit-rails-tubes-pipes/

    I have the values I like filled out in there and it gives you outside vs working area.

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