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Benefits of the different 3d printer styles

Discussion in 'Off Topic' started by Mikethinks, Mar 22, 2014.

  1. Mikethinks

    Mikethinks Active Member

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    Hi all,

    I've got my mind made up on getting a Robo3d once the updated version is out (so I can wait a few months before making major upgrades). There just aren't many machines out there in the sub $1300 range that are as versatile and dont look like I got them out of a crackerjack box. In my quest for a 3d printer I did notice multiple printers with different basic designs, and I was wondering about the benefits of each. there certainly may be many more, but I'm referring to a main design choices on how the machine moves in space to place the plastic anywhere in the three dimensional build area (I am only talking about the extrusion machines, not the laser cures or powder resign etc.)

    1) Robo3d style, extruder moves in the X axis along rails and up on the Z axis on a screw, the entire build plate moves in the Y axis

    2) Ultimaker style,extruder moves in the X axis and the Y axis, the build plate moves up and down on the Z axis

    3) Affinia style, extruder moves in the X axis, and the build plate moves on both the Y axis and the Z axis.

    4) Delta machines (just cause they are really interesting to watch), the extruder does all the moving on all axises using a little geometry to determine up and down motion of the ends of 3 arms that together that result in the proper positioning of the extruder.


    Just wondering why the different design choices are made and we dont see a more consistent accepted "best way" of doing things. The Delta printers of course are the oddball out, as its very apparent why they are both awesome and limiting (typically they get really big really fast for any kind of large build volumes in the X/Y)

    So any clue why there are so many different ways of doing this?
     
  2. Ziggy

    Ziggy Moderator
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    Take a look a some industrial CNC machines (eg routers) which now have the benefit of several decades of development and experience. Typically the bed is fixed, X/Y carriage moves carrying the Z axis - certainly don't see any delta types.

    I suspect 3D printers will evolve much the same.
     
  3. tesseract

    tesseract Moderator
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    One thing to consider that I believe you have completely forgotten about is the CNC machining is a subtractive process where in the material is removed from a block the necessitates a slow movement. Where as the 3d printing is an additive process so movement can be rapid.

    There are two basic types or families of 3d printers the cartesian and the delta.
    Cartesians like the robo are made to use a flat map x,y position setup and works very well the older printer plotters used the same methodology and have been around for a long time so the migration to a new additive type setup naturally will migrate from the same source into what we see now; A high percentage of the 3d printers are based on this style.
    The basic common factor is that the plane is level and flat

    In many of the case the motion control is completely different in the horizontal movements compared to the vertical movements. Usually the horizontal movements are faster than the vertical.
    This leads to one of the inaccuracies in this style 3 axis 2 different methods on motion. This become more critical when the mass of a bed is moved. There are a lot more variables that have to work together perfectlyto get better quality prints.

    Even when weight is removed from the hotend plate in the cartesain style it still utilizes two different methods usually as the Robo does.

    Deltas do not have a unique X, Y or Z axis it uses the exact same movement styles and process for each of the three sources to calculate the movement required for each sources to translate to the proper x y z position. Math has definitive answers for each calculations for each set of movements needed so it will always be the same.

    Deltas use apples and apples and apples to move to a specific XYZ point where as cartesians use the apples and apples and bananas so there has to be some conversion from one to the other to get to the same XYZ point.

    The net result the deltas although new will be more accurate and faster and able to move just as accurately if the plane is not level to the X Y plane.

    As the motion evolution in 3d printing capabilities improve and change to something that is not flat or level but is simply known about the deltas will be able to move to whatever position it needs to much much faster and far more accurately than any cartesian could ever do.

    The deltas are the new smarter and more accurate kids on the block. If the structure is sound the delta will perform much more accurately and faster then the cartesian are capable of doing.

    It will take a bit more understanding by the user to setup properly but once done the deltas will be a better end product.
     
  4. tesseract

    tesseract Moderator
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    The deltas are simply newer not exactly the oddball out. The actual build shape is determined by the radius of the circle encompassing the base and the length of the arms. The ratio is what determines the perimeter shape (ranging from a triangle to a hexagon) and the height can literally be anything you want. modifications along the z axis is fairly easy where as X and Y are not BUT scaling them is quite easy. The design remains the same.

    In my case I took the concepts from a small table top delta printer with a build plate of about 6 inch diameter and about 8 or 9 high to a floor model with an 18 inch base and 40+ inch height.(Build volume : 10000+ cubic inches) The other benefit is that there are fewer unique parts. Thus actually easier to build up. In my design I currently have only 8 unique pieces all are used in multiples of three. One I use 18 times others 12 all others 3 so fabrication is also easy.(This is for the structure only) the holders for the power supply etc are not done yet but the goal is to use parts for multiple purposes in that area as well.

    The programming the same for both simply changing the params to fit this build and it is done.
     
  5. Ziggy

    Ziggy Moderator
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    Didn't ignore this at all. Just pointing out the evolution of CNC. If you look at assembly line automation (say painting which is an additive process) the robots are generally single articulated arm. Don't think there are any deltas in that role either - but perhaps there are?

    When you think about it a single articulated arm may well have benefits for 3D printing - eg maybe no support structures would be needed?

    BTW I have no issue with deltas at all. Just making some observations.
     
  6. Printed Solid

    Printed Solid Volunteer Admin
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    deltas are heavily used for pick and place machines in circuit board assembly where speed and accuracy are critical but the end effector/load on the delta is light. This is a pretty good comparison to the requirements of a 3D printer with a bowden feed system.
     

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