Welcome to 3D-Printing!

Congratulations! You’ve bought yourself a nice shiny new 3d-printer and it’s now time for you to change the world, maybe. You hope.

Hold on a minute, you don’t know the first thing about 3d-modelling or the software you need just to print, if only there were someone to help you along. Are you using FDM, SLA, what do they even mean? Fused deposition modelling and stereo lithography by the way.
Sure, the internet has a lot of information, and some sweet existing models to boot, but not all printers have support guides!
Here is my experience of setting up and getting into the 3d-printing world.

I got a Wombot Exilis XL in a kit, Aussie company making filaments in Oz too.
One big box, two big bags, a whole lot of metal bars and rods and about 3 days later I finally had a ‘printer’, aside from a few missing parts. To their credit Aurarum sent out my missing parts basically the next day so good job on the support side.


The Assembly:

You really should get a set square, a metal right angle sometimes with a ruler, its key in getting prints to come out looking right. Assembly of the base was fairly straightforward but I’d recommend double checking all the sliding bolts and or mounting points on the base before tightening it completely. Always check the squareness of the bed when you tighten anything, it’ll save you time later.

Next up was the heated-bed assembly, simple enough to do. If you can though, try to make your levelling screws have the same amount of thread exposed, you won’t need to adjust it so much later if you do it now.
Attach the upright frame to the bed, making sure that you use the set square.

The extruder assembly is next, here you’ll need to be a bit more careful, and it’s easy to break things here or put them in the wrong way. There should be a threaded hollow tube somewhere in your kit, it will have a plastic PTFE tube inside of it, one side will be metal and one will expose the plastic.
It is crucial that the plastic end goes into the heater block; you will need to come back to the extruder once the wiring is complete. Remember to leave some room for the nozzle to be tightened.

Attach the lead screws to the motors, my recommendation is to attach the coupler to the lead screw first, then put the coupler onto the stepper motor, push the bottom part of the coupler down a bit and then tighten it onto the stepper motor. Put the X axis bracket on next and attach it to the lead screws, nothing special here, but I required an extension on my screwdriver kit, I don’t have a spanner for the 3mm nuts my kit had for this so it was difficult.

Wiring is pretty standard here, my only real tip here is use some kind of tape every 20cm or so to hold the wires in place while you wind the covering over. My kit had the kind that is a long black spring and needs to be twisted around, very repetitive and quite boring but it looks great.
Never forget to use cable ties wherever you can, they keep all your wires nice and clean.
Also depending on your kit you might need to wire mains voltages, be very careful and do not have it plugged in when you’re working on it. Seriously, don’t mess at all with the wiring if the system is powered.

First Use (Power On...):

Step one, turn power on, step two…uh…right, step two…
Honestly I had some real issues trying to print to begin with.
First and foremost you need to do one thing, preheat your nozzle to PLA temperatures; there should be a menu option for you somewhere. This is something I learned after three extruder clogs, not a trivial task to fix. Then, carefully it is ~200°C, tighten the nozzle into the heater block.

At this point it’s a good idea to use the move axis options to check the tightness of the belts, if you notice slack in the belt just tighten it a little bit at a time. You also should adjust the axis stops, X and Y will need to be at the very edge of the board, Z is a little more complex.
Note that I have auto Z leveling so I don’t need to do as much calibration.
For the Z axis, I recommend moving the Z axis so the nozzle is about 1mm above the bed, turning off the printer and then doing the following. Move to the most left of the X axis, and centre on the Y axis, with a piece of paper on the bed turn the lead screw so that the nozzle touches the paper. You should be able to move it still, then move the extruder to the other side of the bed and do the same thing, repeat until both sides of the bed are the same height above the bed. You should set the Z axis stop for this point as well; you can change the offset later with software in most cases if it’s not quite right.

Then you can try to print something! Don’t forget to add something to your print bed so it will stick, I use UHU glue stick on my glass bed.
I ended up trying to print a rocket that came on my SD card, I wouldn’t actually advise this.
The model I had actually starts printing one layer above the bed, it always prints to about 60% of the height and then it breaks off the bed because the first layer doesn’t stick to the bed.
Very frustrating and time consuming. Now is a good time to talk about software.

Slicers and Software

There are two key pieces of software you may need, a slicer and a modeller. I use Fusion 360 to do most of my modelling; you can get a hobbyist license for free. There are plenty of guides online about using this, I would recommend just searching online if you’re interested in building your own models. The slicer is more important for being able to use the printer itself. I use Cura as my slicer as its free, versatile and only lacks a few features that are available in Simplify3D like print in multiple processes and manual support placement. A slicer takes a model, typically a .STL file, and coverts it into individual layers to be printed.

When you first set up the printer you’ll need to create a profile for your printer and adjust the opening G-code. In Cura you can set up the printer by going to “Settings->Printer->Add Printer…”
My printer is set up as a “Custom” where I manually put in the printer settings. Unless your assembly says to do so, leave the boxes checked as they are by default.  My printer is a RepRap based on Marlin firmware, so I changed the setting “GCode Flavor” to RepRap (Marlin/Sprinter).

Starting G-code is critical; my printer specifically needs to have G28 and G29 as the only entries here, you should be able to find the relevant code for your printer, if not, try the default as it may work for you. I messed around here with a few settings but never ended up being able to print, so find something that works and then leave it alone. Ending G-code is far more important, my first few attempts at doing this ended up with the extruder being pushed into the centre of my models after they’d printed perfectly. I use the code below, it will turn off the extruder and the bed, move the model away by 1cm in all directions and then turn off the motors. Many hours of failed prints made this code come alive.

The main settings you’ll need to begin printing are nozzle temperature, bed temperature if you’ve got a heated bed like me and infill percentage.
Infill is a way of reducing the amount of filament you need to print a model by replacing a solid inside with a pattern like a grid, if you have any flat tops in your model I’d recommend infill of more than 15% with at least 4 top layers. My printer likes to print PLA at 200°C but you should experiment to find what works for you.

Once you’re convinced of your settings look at the individual layers by selecting it in the view and use the slider to make sure you’ve got a decent surface area for adhesion. You can use a setting called Build Plate Adhesion, I use brim and skirt depending on the size of the print, to increase the first layer surface area.

Other Things

Once you’re up and printing there are a few things you should do.
Print any available replacement parts that you can, you never know when it will save your bacon. While I’m not thrilled about some of my kit’s parts failing within a month of setting up the printer I will say that even a mostly working printer is still able to repair itself, but it is much easier to just swap in an existing spare part.

Never leave the printer unattended as it can potentially be a fire hazard and also you will encounter large spaghetti monsters of filament if you don’t check on it regularly.
Occasionally you should tighten all the screws you can so that the printer doesn’t vibrate itself apart, you should do this after every 10 or so prints.

Most importantly you should remember to have fun!


Written by Andy Elsegood (media@mueec.com)

Melbourne University Electrical Engineering Club


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