Initial Foray Into 3D Printing 2 - Initial Prints and Beyond

    Ok, so I have a printer, and it's built. I loaded my filament, calibrated the printer using the in-built wizard, and found a list of pre-prepared prints on the included SD card. I haven't even looked at getting the software to make my own models, or prepare them for the printer. However, as a first run, I chose a miniature Triceratops skull... (because it's way more interesting than the other pre-installed options).

    I had ordered several types of filament, from ABS, PET-G, even some carbon fibre infused polycarbonate. Each have their pros, cons, and suited applications. I started with ABS as it's the most common, and one of the most forgiving materials you can use.

    The first try....

    The first attempt didn't work very well at all... it came unstuck from the base mid-print, and was effectively ruined. So I tried something a bit simpler, and a simple plastic "Prusa" logo still came unstuck. So I found out that uneven heating/cooling caused the plastic to curl and lift from the heat bed. So I went online and they said... ambient temperature is too low. Heat it up. So I turned the central heating on in, and things got better. However, a Prusa logo isn't the most exciting thing ever...  successful or otherwise.

    The second try at the Triceratops...

    This one worked, but had loads of support material that was attached. So using the Prusa-supplied needle-nosed pliers and a few minutes later, it was clean! The first successful (and interesting) print!

    Moving beyond the pre-installed models...

    There's only so many Bench testing models (also known as "Benchy's") and pre-supplied models that you would ever want. I think they're fundamentally designed for testing print quality and little else. However, you don't need to be a CAD wizard to print far more useful things. In fact there are whole web sites dedicated to supplying pre-made STL files for free or often-low-cost. But let's first look at the software any 3D printer owner will have access to. The slicer.

    Slicer software explained:

    If you're downloading fun models to print from the Internet, you'll find that many 3D printed object files come in computer-friendly formats like "STL" files (although there are many other types out there that differ... depending on which application was used to create the file). These files, if opened up on a computer, just look like any 3D computer generated graphics. However, your 3D printer can't interpret a 3D object file, instead it needs to be told exactly where and how to move the extruder, and where and in what amounts should plastic be put. These sets of instructions are outlined in a very old language called "G-Code" which has been around since the 1960s, when computers were mere abacuses compared to most peoples modern smart watch. G-code has been used for computer controlled manufacturing for decades... and as such it is both well developed and archaic. Which means two things:

    • It's not intuitive to read. (G code is actually a short version of "G and M Code", based on the fact that most lines/commands start with a G or an M... but if you read other sources, going back even further, G stands for Geometry.. which seems somewhat likely given that geometry is much of what G-code deals with). Although it should be noted that this still isn't the official name. If you care, it's called ISO 6983 (also RS-274)... but that's not meaningful to most people.
    • Since it's designed to run on very slow, old computers, it's incredibly efficient. Even the cheapest modern 3D printer/CNC control boards can easily handle most 3D printing tasks. However, there are advantages to buying better control boards like more accurate/faster prints, as well as quieter operations, better power efficiency, and additional safety features.

    The good news is, that you don't have to know G-Code because the slicer takes care of that for you.

    So a slicer software app basically takes the 3D model, and slices it into numerous horizontal layers, that the printer can build one layer at a time. Much like a brick layer would a brick wall. You start by creating the shape of the house with a layer of bricks on a foundation, and then build the wall up vertically, layer by layer. (Or in this case, slice by horizontal slice). Each slice is then broken down further into a very long list of precise operations, each listed sequentially in the form of G-code. Additional plastic may be laid down between the outline as "infill". Now you can make it solid (100% filled in) but more often than not, a range between 15%-30% is used to give the structure a balance of strength against the opposing forces of print time, final print weight and cost of additional used filament.

    Model to G-code
    Slicer software takes 3D models like this Apollo Lunar Landing Module (in Prusa Slicer) on the left, and converts them to a series of printer-friendly G-Code instructions much like the ones found on the right. Please note that there are hundreds if not thousands of lines more of code to do something as intricate as this. The number of instructions goes up significantly, as the objects size, height, and the number of details included increases. However, it may be significantly shorter if the layers become thicker, and the details omitted.

     

    There are numerous slicer programs out there. Some are free, some are quite expensive. I've only been printing for a couple of weeks at home, so I am just using the "Prusa Slicer" because it has 90% of the features of more advanced models, it's free, and it is specifically designed for my printer, so that substantially reduces the amount of tweaking I have to do in order to get a great result.

    Some of the popular slicing software options include:

    • Manufacturer based options like "Prusa Slicer", "Creality Slicer", and others. (This is the way I have gone at home)
    • Cura, this is a very popular choice.
    • Simplify3D
    • More advanced users might use Fusion360 (Which is actually CAD/Slicer software all in one, and free for hobbyists. I haven't gone this way because I haven't configured the software to use my printer yet.. and I'm in no rush at this point).

    Now each of them have their pros and cons. I have only used six differing programs in my work places, and at home. I can't really speculate on the majority of them. If you're interested in trying them, feel free! Just don't think you're "stuck" with only one option. Many are free, so you lose very little by installing them. Just remember to read the instructions, and look at how other people have used that software with similar models of printer.

    The basics of using a slicer:

    In short, you install a slicing app, run the app. Download an STL file from your favourite 3D objects site (I like Thingiverse.com) drag/open the file in your slicer. Tweak the settings to suit the material, perhaps adding supports and/or a brim where needed, and slice it into G-Code. Export that G-code to your SD card (or send it to the printer directly if your computer is connected. Once the printer starts printing...

    Wait a few.. hours... or however long it takes. Assuming nothing goes wrong, you should have a finished print at the end.

    Note: This will print someone else's 3D model verbatim without any real possibility of meaningful change. If it's just what you need, then great! However, it's like sticking to a particular recipe, you can make that meal again and again, but you'll never learn to really cook if you don't take control of the ingredients, try differing approaches, and see if you can't find something that works a little better for your tastes/needs.

    But what if I want to design or tweak things myself?

    Slicer software is effectively a translation program that ends up with machining instructions. As such they're sometimes called "Computer Aided Machining" (CAM) apps. Dedicated slicers do not do design work. For that you need some form of Computer Aided Design (CAD) program. Some applications, like Fusion 360 are a CAD app with in-built CAM capability, so they can be used to print 3D objects directly without the help of an additional slicer program.

    CAD apps vary from entirely free, to frighteningly expensive. For the average hobbyist, they're likely to be using apps at the cheaper end of the spectrum. However, everyone is different, so here are some of the popular choices:

    • Fusion 360 (Free for hobbyists, lots of YouTube instructional videos!)
    • Sketchup (Free for web interface use)
    • FreeCAD
    • TinkerCAD
    • BlocksCAD (used for teaching 3D modelling in schools, lots of tutorial videos on YouTube)
    • Creo (not cheap but works very well)
    • Solid Works
    • Blender (free 3D animation/imaging app, but is very good at CAD.... but has steep learning curve)
    • Sculptris (If you're coming from an arty background, this probably works well for you)

    There are many, many others... so find what you like. I use Fusion, and although the interface isn't as intuitive as others, there are some amazing features in there that simplify complex operations. If you're going to give it a try, make sure you watch a couple of introductory videos on YouTube (there's many of them). However, features that I find particularly useful include:

    • S keyboard short cut (search for functions, and potentially add them to your short list, raised by the S key).
    • Offset plane (essential for putting things off your existing object, so you can connect them later)
    • Loft. Want a weird shaped tool dust port to connect to a circular vacuum hose? Let the software join the weird and taper/warp into a circle of specific dimension.
    • Shell. Draw an object, but want to make it hollow? Shell can make it a certain thickness all the way around, by either filling inwards, or outwards.
    • R = rectangle (or square)
    • C = Circle
    • E = Extrude/Cut
    • I = Inspect (measures the length between two points, and other useful things).

    Shortcut keys are much faster than using the menus. Watch your speed increase almost exponentially.

    In any case, whatever app you use to do your designing in. Know that the process from start to finish is a three step process:

    1. Design (resulting in an STL or other file)
    2. Slice (results in G-Code)
    3. Print.

    So for me, when I'm designing my own models, my workflow is:

    1. Measure everything with a vernier caliper, and if needed, take a photo of the things/shapes my models will need to attach to.
    2. Design what I need in Fusion 360 or download the model file from the Internet if it meets my needs.
    3. Save/Export the resulting STL file to Prusa Slicer.
    4. Tweak the slicer to suit the project and material.
    5. Save to SD Card & safely eject it from the computer.
    6. Put SD card in the printer, turn it on, and select "Print from SD card"
    7. Select the file to print, ensure the printer is ok... and off it goes.
    8. I generally keep an eye on my print for the first 10 mins, just to make sure it is properly attached to the heat bed, and that the process looks ok.
    9. When finished, I let the printer cool down for about 5-10 minutes, take the model off, and clean up any brim/support material if needed.
    10. I clean up the heat bed with windex/isopropyl alcohol.
    11. I then unload the filament from my printer, put it in a container with dessicant/silica gel to keep it in good condition for next time.
    12. Shut down the printer.

     Some of the stuff that I've done...

    I can't say that I'm an expert, but I have basically been slowly building the complexity of my workflow up. Most of the stuff I've done is limited to printing spare parts for my 3D printer, and vacuum adaptors for various wood working tools, so I can connect my workshop vacuum to my thickness planer, my oversized disk sander, and my electric planer to name a few.

    I started with simple things like a 65mm to 35mm vacuum hose adaptor for the thickness planer... mostly because I keep borrowing the adaptor from my table saw and sometimes forget to put it back. As a 3D model, it's a series of simple tapered cylinders, based on a series of nice circles, all concentrically located on one plane, but stacked on top of one another and connected.

    This is the Fusion 360 model (left) and the same model imported into Prusa Slicer (right). I found that my first print had some bed adhesion issues, so doubting the efficacy of a brim (sacrificial bed adhesion support) I massively over engineered my own sacrificial flange to ensure it wasn't going anywhere. This was massive overkill. However, about 4 minutes on a disk sander ground the entire flange off and the part works beautifully!

     .... and the result:

    Here is the grey adaptor after being successfully used as intended.... Now I just have to empty the vacuum a bit too frequently for my taste

     The next step.... another adaptor for the disk sander:

    This is just another circular vacuum adaptor. Nothing particularly challenging. However, I did find that my tolerances were a little tight at the sander's end. I should have made the adaptor about 0.1mm wider.

    The model of adaptor for the disk sander.

     

    Fluorescent green ensures that I don't lose this adaptor.

     Moving beyond circles... the DeWalt planer vacuum adaptor.

    I have a bit of a love-hate relationship with DeWalt gear. Sometimes DeWalt just loves to make something a little more difficult than necessary. I bought this electric planer years ago and it works well for a hand held electric planer. However, I never received any sort of attachment, or bag to collect the insane amount of wood chips generated by this tool. Instead, it flings the chips out, completely unfiltered, or even unhindered out to the right of the device. If you're a right handed person, you basically send a torrent of shavings and dust into the face of anyone to your right. If you're a left handed person, it spits it directly at you. Neither option is particularly safe.

    To make matters worse...

    DeWalt designed this thing to have an unusually shaped dust port, with motor housings packed close to it. I have never seen a commercially available adaptor, so off to make my own....

    This shows the dust port and the neighbouring protrusions/housing nearby (top left), my attempts at measuring the taper of the dust port (top right), and two different angles of the 3D model I built (bottom left and right). I actually used the top-left image as a "canvas" in Fusion360. Then I scaled the image using the information gained doing the measurements in the top right image, then simply traced the shape of the dust port (very closely) and modelled it from there to suit a 35mm vacuum hose. I found that going much thicker than 3mm was going to hit the surrounding housings, but 3mm with 25% infill works very well.

     

     I have fitted the adaptor to the planer, and it fits as well as any professionally made adaptor. However, I have now tested my vacuums ability to keep up with this planer. The whole adaptor is 12cm long, but with the vacuum hose sticking out roughly 50cm with hose attached, I did wonder if it'll make the planer difficult or cumbersome to use.

    It works! Very well even!

    Firstly, the difference this adaptor has made is significant. I honestly think that 99% of the dust is sucked into the vacuum. However, please note that as soon as the vacuum fills up, planer's own dust ejection system continues to push dust down the line, and the dust rapidly starts to fill the hose, and then it goes everywhere.

    Where to from here?

    While I have been building an enclosure for the 3D printer, it's not going to be heavily reliant on the printer for componentry. I'm also going to use a webcam and Octoprint to manage it out in my cold workshop from the comfort of my home. So this is something I'll definitely be writing about in the not-too-distant future. In fact, I've just finished the enclosure. You can read about that in my wood working projects section by using the following link:

    3d-printer-enclosure-almost-entirely-from-scrap

    Looking beyond that...

    I've 3D printed some cases for my older generation Raspberry Pies (small computers) that include the mounting for a 7" touchscreen. I use it like a digital photo frame.. but instead of showing photos, I use it to display the information gathered by my weather station.

    I continue to make adaptors for dust extraction ports on my tools. I've made some bathroom accessories like soap holders, and shower shelves. I have printed several simple jigs for clamping and routing purposes, and I'm sure more things will pop up over time.

    I'm seriously tempted to build a 3D printed CNC router for my wood working. There are a few on Thingiverse, but perhaps the most famous/cheapest one is the "MPCNC" which stands for "Mostly printed CNC". However, I am thinking of mounting mine onto the wood trolley vertically to save floor space. As such, I'd need to design the vertical axis to run on ball screws instead of a belt.

    I'm sure I'll add things to the site when I have more progress to report.

    Until then, stay safe and happy tinkering!

    Ham.


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