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  • 3D Printer questions

    I would like to add a 3D printer head and extruder etc to my milling machine as a removable accessory. I spent some time looking at what is available online in terms of plans and what I mostly find are various ways to minimize the amount of machining and the tools required to build something. That is not an issue for me as I have the capability to build virtually any complex design. What I would like is some clue to what would be the best design that will take best advantage of the CNC mill I already have. Once I have that running I then may build a stand alone machine if I find additive machining interesting enough using just plastics.

    Anybody know what I should be looking for in order to build an add on additive machining head to my mill? I know almost nothing about the actual required parts and pieces in this field. All I want are the specs/plans/requirements to build what I need. I don't need actual plans if the necessary specs are good enough. However, there is no point in reinventing the wheel so I will happily go with somebody else's proven design.
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  • #2
    Id look at the Bowden Cable remote motor type extruders.
    You can mount the moter / drive unit mostly anywhere, and only have to move the hot end.

    Which plastics are you looking at using?

    Here:http://reprap.org/wiki/Category:Extruders is as good a place to start as any
    Mostly the plans are available in a GIT repositry

    Dave
    Just south of Sudspumpwater UK

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    • #3
      The main thing I am looking for is designs where there are not compromises made to accommodate lack of machining tools. I would rather make my own unless there is something that I cannot feasibly make as well as a "store bought" unit, such as a heating element etc.

      As for plastics, most likely ABS unless there is a better but still reasonably priced alternative. DX sells ABS spools at around $45 for a kilo in various colours. I have no idea if that is a good price or not.

      I am open to all ideas and advice. This is an area I have not yet explored (much).
      Last edited by Evan; 06-05-2013, 03:45 PM.
      Free software for calculating bolt circles and similar: Click Here

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      • #4
        Because of its high resolution at (relatively) low cost, I've been waiting for the Form 1 to become widely available http://formlabs.com/products/our-printer. Instead of buying one initially I'd like to send a file to a service which could print a part for my inspection. I hope such a service will become available, but I have no knowledge of any.
        Allan Ostling

        Phoenix, Arizona

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        • #5
          I wonder what would happen if you used a MIG welder to build up metal with tiny "spot welds", using CNC timing and position control?

          I see that this was mentioned here before but with only one reply it didn't go far. http://bbs.homeshopmachinist.net/thr...der-3D-printer

          I don't want to sidetrack my own thread though. If anybody has knowledge to share about plastic printing I am all "ears".
          Last edited by Evan; 06-05-2013, 04:36 PM.
          Free software for calculating bolt circles and similar: Click Here

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          • #6
            Bear in mind Ive personally only printed 5 parts, but I have been using these technologies for 4or so years.
            That out of the way onto the other words.
            ABS is prone to warping, and all the home printers use a heated printing surface to help, but it apparently doesnt always work.
            If PLA will suit its much more forgiving to print with.

            The extruders are all pretty basic tech. Use a stepper to push the filament a known distance (and therefore a known volume) through a heated tube with a 0.3mm hole in the end and move the nozzle to print the shape.
            The devil is in the detail of course...
            Keeping the transition between solid and melted as short as possible apparently assists in accurate placement and volume of plastic delivered.
            Temperature control is also reasonably critical as far as I can see, overheating will ruin the plastic, underheating makes the push harder to extrude.
            I dont think that all the extruder designs are compromised by lack of machining ability, they are more designed in a different paradigm

            Dave
            Just south of Sudspumpwater UK

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            • #7
              The problem with mig printing metal is the high contraction rate, causing warping. I did some work with some research people into this as an alternative to sls powder metalurgy. As far as I know it still doesnt work properly, even in a heated argon chamber to control cooling rates.

              Dave
              Just south of Sudspumpwater UK

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              • #8
                Evan;

                Digital Machinist (family of sponsors of this forum) had, IIRC, an article on 3D printing on a milling machine about a year ago.

                The LinuxCNC group, including Ed Nisley (author of interesting articles on OpenSCAD in said magazine) is one of a bunch trying LinuxCNC to control machines for 3D printing.

                I would suggest following up one of the other of the above - Ed can be reached; I have one email for him but am unsure if it is one he wants published - he does have a web site - http://softsolder.com

                Might as well see what others have done and decide if that's the direction you want to go?

                (me? 3D printing either work or Shapeways - both come out better than I could do at home, but because of building steam locomotives, plastic is not a material of choice!)

                Another JohnS

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                • #9
                  I have a lot of research to do for sure. I decided to ask here first since there is always somebody on here that knows something about any subject.
                  Free software for calculating bolt circles and similar: Click Here

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                  • #10
                    The feed mechanism is usually just a knurled wheel plus a spring loaded one. You have the advantage you can put it right on top of the extruder as the head doesn't have to fly around. There appears quite some iterations of the extruder. I'd get something like this https://shop.ultimaker.com/en/parts-...-upgrade.html#
                    Or find out exactly on the forums why they design the heads like that.

                    I've always wondered if one could make a crude sintering machine using a tig torch on your CNC with powdered metal......

                    Igor

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                    • #11
                      http://cnc2printer3d.wordpress.com/2...nc-convertion/
                      John M...your (un)usual basement dweller

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                      • #12
                        aostling:
                        Instead of buying one initially I'd like to send a file to a service which could print a part for my inspection. I hope such a service will become available, but I have no knowledge of any.
                        There are several vendors now offering this service. I expect with the proliferation of home and quasi-commercial units that many will come to offer their expertise and this service generally.

                        There is a plug-in for most CAD packages designed to send your model to vendors for quoting:
                        http://www.print3d.com/content/softw...3d-standalone/

                        Here are a few links I know of:
                        http://www.shapeways.com/materials/sandstone
                        http://www.quickparts.com/home.aspx
                        http://shop.seemecnc.com/

                        Cheers,
                        Norman

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                        • #13
                          Originally posted by Norman Bain View Post
                          There are several vendors now offering this service.
                          Do you have a link to a service which will print with the Form 1? I need to hold the tolerance which they claim.
                          Allan Ostling

                          Phoenix, Arizona

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                          • #14
                            Expect the Form 1 to be expensive. It uses Stereolithography which is the one process I know a little about. It works with a UV scanning head much the same as a laser printer which is something I know. The resins they use are very expensive, in the range of $100 per litre and way up from there. It is one of the most accurate processes because of the ability to focus laser light to a very small spot. It was also the earliest process so has the most development behind it.
                            Free software for calculating bolt circles and similar: Click Here

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                            • #15
                              Was looking at an article at work today and they had one they mentioned, I looked at the website and the extruder head was $95. Just need a way to control it.

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