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Modding The 3D Printing Thread

Discussion in 'Modding' started by SkiDave, 6 Jun 2015.

  1. SkiDave

    SkiDave Active Member

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    The 3D Printing Thread

    With a couple of project logs using 3D printed parts, and the increasing ubiquity of 3D printers I thought I'd start a thread on them.

    Types
    • FFF/FDM (Fused Filament Fabrication/Fused Deposition Modelling*)
      *FDM is trademarked by Stratasys and so FFF is used by the open source community

      FFF uses thermoplastic filament that is heated and extruded on to the print surface. Components are built up as a series of 2D layers. This is the most common and easily available type of 3D printing. The likes of RepRap and Makerbot printers are FFF.
      Common materials include: PLA, ABS, HDPE, Nylon. However any thermoplastic could be used. More niche materials are being developed, such as copper or wood filled PLA filament.

    • SLS (Selective Laser Sintering)

      SLS uses lasers to fuse together a fine powder into the required shape. Between each pass more powder is spread over the part to add height.
      This is only available at a commercial level due to the high cost of the printers.
      Common Materials include: Thermoplastics, Thermosetting Plastics, Some metals including Titanium

    I've had alot more experience with FFF printing so the rest of the info will be based around that.

    Printers

    I've used two types of printers extensively, the Makerbot Replicator 2X and the RepRapPro Mendel 3. The Mendel 3 is part of the open source RepRap movement. Where the aim is to reproduce as much of a printer with another one. As a result, joints and connectors are 3D.

    Makerbot
    The Apple brand of the 3D printing world. Prebuilt with limited settings and options for modifications. Works out of the box very well.

    - PLA only - 1.75mm Filament
    - 0.4mm Nozzle
    - Unheated bed
    - The print head moves in the XY plane and the bed in the Z direction

    Mendel 3
    Built from a kit. As it is open source it is encourage to modify and change parts. There are many variants available but I bought the hardware only kit and printed the rest of the parts.

    - 1.75mm filament - nearly any heat softening material
    - 0.5mm nozzle
    - Heated bed
    - Head moves in the XZ plane and the bed in the Y direction
    - Can be upgraded to house 3 more nozzles for multicoloured printing

    This is my Mendel 3 (Please excuse the crap phone photo). All the black parts were printed by me.

    [​IMG]

    Software and File Types

    Any component needs to be saved as an STL file. All CAD packages support this (simple) file format. For my CAD modelling I use Autodesk Inventor (Free student license! :D), however the likes of Google Sketchup are more than adequate. There are also online libraries of STL files, if your CAD skills aren't developed enough: YouMagine, Thingiverse

    The next step is Slicing Software
    This takes the STL file and slices it into 2D layers and converts them to GCode (the operating instructions for 3D printers). This dictates head locations, speeds, extrusion rates and temperatures.

    I use Slic3r with very good results. Makerbot has its own software that can only be used with its printers.
    I haven't used it but there is also Skeinforge.

    Print Settings

    This can get very complex as values are optimised for quality and print time. However the main areas are:

    Layer Height
    The general rule of thumb is to not go above 75% of nozzle width. Most of my printing is done at 0.2 or 0.3mm layer heights. A finer layer height gives a better surface finish but takes longer to print.

    Infill
    This is the amount, expressed as a percentage, the printer will fill the inside of components. A figure of 10-30% is common for structural parts, decorative or draft objects can be done at 2-5%.
    Slic3r gives many options of shape of infill including rectilinear, hexagonal, concentric, octagonal spiral.

    Temperatures
    There are two temperatures that need to be set: the nozzle and bed.
    These values are very dependent on the material you are using. A rough estimate for PLA is 180-230'C for the nozzle and 55-60'C for the bed.
    If the nozzle is too cold, the plastic won't flow well enough. If the bed is too cold or too hot the first layer won't stick and likely come off in the print

    Head Speed
    There are many different settings that can be changed depending on what the head is printing. Usually the slower the head moves the higher quality the print. Too fast and the printer can shake and knock the print off the bed.


    I'll update this thread tomorrow with some more info about print heights, infill density and quality. But for now I'd be keen to hear other people's experiences and inputs. If there is anything that I've missed let me know and I'll update the original post.

    Dave

    EDIT: Updated with more info.
     
    Last edited: 7 Jun 2015
  2. chrisb2e9

    chrisb2e9 Dont do that...

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    I was looking at printers a few months ago. Decided not to shell out the money for a few reasons. First being, I don't really have a use for one! Second, was that they seemed overly complicated and I didn't feel that the quality was there for the money.
     
  3. Teelzebub

    Teelzebub Up yours GOD,Whats best served cold

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    As above I was thinking of building one, I've got most of the parts left over from building my CNC but from what I've read they seem a bit unreliable, still would be a nice addition to my workshop.
     
  4. SkiDave

    SkiDave Active Member

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    Yeah they still have alot of ground to cover before they'll start comparing with machined metal. However the ability to produce incredibly complex shapes with relative ease (certainly compared to traditional subtractive manufacture) is a great reason to use them.

    I'll admit that aesthetically it doesn't compare to well made metal components but quality and accuracy wise they are very good. I'll try and take some photos to show some of the parts I've made.

    The reliability does need improving. Sort of one of the reasons I wanted to start this thread - to help get more reliable prints. The main reasons for the lack of reliability are stiffness of printer chassis, quality of filament, print speeds and print temperatures. I've found that a lot of trial and error is need to find what works - particularly with my printer. The Makerbots are plug and play and far more reliable however you are paying for that.
     
  5. Teelzebub

    Teelzebub Up yours GOD,Whats best served cold

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    Where's the best place to get plans for building one? and component supply shops etc
     
  6. IanW

    IanW Grumpy Old Git

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    RepRap wiki :thumb:
     
  7. SkiDave

    SkiDave Active Member

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    If you've already got parts from a CNC you'll probably only need the main board, print head, bed and extrusion assembly.

    As IanW said a good place to start is the RepRap wiki, in particular the build options page as it has loads of information on the different approaches and software to use to build your own.

    For actual components have a look at the RepRap Buyer's Guide. It's a list of shops that sell full kits as well as individual components. I've had a good experience with RepRapPro's Shop but I don't know how it compares in price to some of the others.
     
  8. Teelzebub

    Teelzebub Up yours GOD,Whats best served cold

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    Just looking at the parts, seems apart from the electronics I have most of the parts although the bearings and motors I have are heavier duty than the shop stuff.

    You got any info about printing with metals?
     
    GaryP likes this.
  9. SkiDave

    SkiDave Active Member

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    FFF printing metals is almost impossible unless with low melting point metals (and as a result tend to be pretty useless)

    It is quite common for metals to be used in SLS printing but due to the cost of printers only really available at a commercial level. When using metals in additive manufacture it is known as Direct Metal Laser Sintering (DMLS)
     
  10. Teelzebub

    Teelzebub Up yours GOD,Whats best served cold

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    Been doing some research, apparently the controller + software my CNC uses will also do 3D printing
     
  11. lilgoth89

    lilgoth89 Captin Calliope

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    i have been thinking about getting myself a 3d printer for some time... but i really have no knowledge on the subject,

    http://www.amazon.co.uk/3D-printer-...ie=UTF8&qid=1438131000&sr=1-2&keywords=Wanhao

    came up while wandering the expanse that is the interwebs, but i figured it throw it out to you guys if there are any better for the price / better for cheaper 3d printers, accuracy is a must as i plan to be printing some rather small components ( war-gaming terrain and potentially some conversion parts if the quality of the print is good enough )
     
  12. David

    David Take my advice — I’m not using it.

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    The prices are really coming down now - this time last year bog standard kits were £700+
     
  13. Kovoet

    Kovoet New Member

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    Hits the 500 Mark then I think I might just get one

    Sent from my HTC One M9 using Tapatalk
     
  14. David

    David Take my advice — I’m not using it.

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    Some are nearly half that already, mate.
     
  15. Kovoet

    Kovoet New Member

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    Right time to start looking I think.

    Sent from my HTC One M9 using Tapatalk
     
  16. lilgoth89

    lilgoth89 Captin Calliope

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    the one i posted is £375 ;)

    but i wanted peoples thoughts on it before pulling the trigger
     
  17. Teelzebub

    Teelzebub Up yours GOD,Whats best served cold

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    As when I bought my CNC kit I jumped in and realised it was to small and not rigid enough research is everything, the one you linked looks a tad small tbh only 8x8x7

    I would try to find a place that sells all the parts needed to build your own and has the knowledge to advice you on building one that can be made to suit your needs as they change.

    Looks good though if you do buy it keep us posted on it
     
  18. lilgoth89

    lilgoth89 Captin Calliope

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    well its size doesnt bother me to much ( that unfortunately is not what she said ) as it will be for miniature terrain / converting where a transport is about 5 inches long, and anything larger can be printed in sections and assembled

    but i did like that its ready assembled


    it does look pretty good for what i want to use it for
     
  19. EnviousMods

    EnviousMods Active Member

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    It's awesome to see a thread based on 3D printing. I used to build/design custom 3D printers before I got into case modding. If I can help answer any questions; I'm always available. I just started a scratch build here called Dark Matter. It will feature a lot of custom 3D printed parts as well.

    As far as 3D printing goes, the tech has started to become more reliable and affordable. If you don't have a need for one I would wait. They are advancing very quickly so you wouldn't have to wait to long.
     
  20. IanW

    IanW Grumpy Old Git

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    Resurrection time!

    Last week I bought a REALLY cheap "Anet A8" printer from GearBest for around £160 inc shipping & taxes.

    [​IMG]

    Got it going last night to great results. This is the "test piece" that comes on the included SD card (I think it's an AA battery holder?), printed using 1.75mm PLA:-

    [​IMG]

    This is without any calibration except bed levelling!
     

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