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Jonathon Gillham

3D printers - where to start?

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So this is vaguely rc related, in that 3d printers can print parts...but this is really off topic. I'm asking here as I have googled and nothing comes up, so thought I would ask as I know a few members have them.

Where do I even start researching them? What things should I take into account when deciding on a printer? Can they all use the same material or do you need to take that into account as well?

This has come about as I'm going to a friends tonight to get a lesson on how to draw stuff im CAD and my wife actually brought it up as she thinks they're cool. So i'm striking while the iron is hot

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Best places to start in my view would be budget and your personal skills.

If you are into electronics and hardware tinkering, any self-build model that you can modify, adjust and refine would be a good start. Kits start at a few 100 euros. But expect an investment in time, grey hares and ugly words before it will give nice results. I have a heavily modified Velleman K8200, that prints well but can still be a handfull if it has a clogged head or strange error that needs troubleshooting.

If you want it to be more 'plug and play', get a complete product from a decent manufacturer. At a local hobby show I saw a Dremel 3D printer in action, making custom bodies for matchbox-size cars. It looked really impressive, with very fine details on the bodies and low noise while printing. These are about 1300,- euros new but used prices are much lower.

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I suppose you have to start with your end goals in mind; what exactly do you want to make?  That answer leads to the materials you might use (PLA, ABS, nylon, PETG, TPU), which then determines the temperature range of the nozzle and whether a heated print bed and sealed enclosure are needed.  Also, what you want to make will drive the build volume (X/Y/Z print size).  PLA is relatively safe to print indoors, but the other materials can emit some noxious fumes and are better to print in a garage or workshop away from you.

The machines come in several variations and each does something better than the others.  Delta/Kossel type machines are great if need a lot of Z axis for tall prints.  Some Cartesian type machines have the extruder motor right above the print head; these are better for TPU flexible materials.  The standard Cartesian type machine with a remote extruder motor and Teflon feed tube is most common, though.

There are some amenities/preferences to consider as well.  Some printers have LCD user interfaces and SD card readers built into them; others only have a USB connection and require a PC to be the UI.  Some will connect to a WiFi network.

There's the workflow element to it as well.  Which design tool, which slicer, which UI/controller are a few others aspects to consider.  Rhino, FreeCAD, SketchUp are all programs you can use to make shapes.  Cura, Slic3r are programs that can take those shapes and generate layers for printing.  Marlin, Repetier are common firmware options used in the printers themselves for printing those layers.

I have one of the cheapest, least capable printers out there but it gets the job done (mostly).  It supports PLA, has a a 150x150x150 mm build volume, is Cartesian with Teflon feed tube and remote extruder motor, and has a LCD UI with SD card reader.  I use FreeCAD for design, Slic3r for making the layers and gcode for the printer, and the printer runs Repetier firmware.  It works ok.  It took 2 days to build and calibrate the printer, but it is pretty usable and repeatable now.

Printed parts do not have the surface finish of injection-molded parts.  Be prepared to use filler putty, primer, and sand paper to smooth things out before painting them.  Also note that structural parts are not as strong as injection-molded parts and have to be overbuilt to compensate.  I'm looking into smaller nozzles (0.2 mm vs. 0.4 mm standard) to see if I can get some better quality prints.

3D printing is not a fast technology.  You can invest hours, if not tens of hours, designing parts depending on complexity and printer limitations.  Time to print depends on part size and layer thickness; a custom wheel could take an hour or two.  

As a quick suggestion, take a look at the i3 Prusa style machines out there.  They'll probably do most of what you want and are based on a popular design.

It's an interesting tool to have available for making parts, but it does have limitations.  Good luck!

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I'm currently using a Creality CR-10S and Ender 3 for printing. I believe they are priced around $400 and $180 these days, and require some basic assembly. 

Consumer grade printers have evolved quite a bit since I built my first one in 2010, a MakerBot Thing-O-Matic which still gets occasional use. While you don't need to do as much in terms of assembly and the software now has some pretty good default settings for starting out, there is some tuning to get good results, there is still a learning curve. For many the printer is initially as much a project as it is a tool. Between understanding the material being printed, the hardware of the printer, the software controlling the printer, and the software used to design and prepare files, plan on spending some time with the thing.

You really have to read the specs of each printer to know what it can and cannot print. In general, a FDM printer will always print PLA, which works fine for most RC applications. Other materials will depend on what the hardware is and the temperatures it can achieve.

What I've found is the more expensive hardware options generally have more convenience features that really are not needed once you learn how things work.

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Been dabbling since the advent of Reprap, then came Makerbot and Thingiverse :) sometimes I wish Shapeways appeared sooner & I didn't bother getting into the painful printing side of things. :P 

Hasnt been mentioned above but you really need a suitable permanent place to setup your rig. Can't be draughty, can't be too hot or too cold & definitely as little temperature difference between max & min as possible. (Given here in oz we can go from over 30degC daytime to below 10 at night... that's a real PITA when large prints can run for several days.) You may need to build it an enclosure to keep warmth in.

The machine is just a CNC robot, that digital part is easy. It's the analog bits like material characteristics & cooling that's usually the wrath of much swearing. 

Once you've played with your machine enough to work out its limits, then you can start designing your part to make it print easiest.

Often that means deviating from what that part would look like if injection moulded.

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