A CoreXY parametric 3D printer fully designed in OpenSCAD. You can clone the repository, change the parameters in general-values-n2.scad and print your very own rosalind. Step by step printing and assembly instructions coming soon.
This wiki can be easily converted to MediaWiki for publication in the Reprap wiki. See convert to MediaWiki for more info.
The bill of materials lists all the parts you will need to purchase to build your own Rosalind.
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Basic Printing Instructions
- Clone the git repository.
- Open general-values-n2.scad and edit as you wish. The comments should help you choose the right values.
- Save as general-values.scad overwriting the existing file.
- Open rosalind.scad and view your build. Does it look right? Not all possible values have been tested so you have to take a good look here and make sure everything looks alright. If unsure just go with the defaults.
- Open the part files one by one and uncomment the print() statement. This is not very straightforward yet but it will be fixed in the next release.
- Press F6 and then export to .stl
- Print the stl files
Basic Assembly Instructions
Coming soon. For the time being use rosalind.scad as a guide if you'd like to print your own rosalind.
WIP: Build Your Own Rosalind
So, you want to build your very own Rosalind. Great. Let's get started.
You will need OpenSCAD in order to customize and then print the parts needed for your build. Go download a copy for your system.
Open variants/general-values-n2.scad with your favorite editor. You can customize most of these values but apart from the defaults and the ones in general-values-n1.scad no other values have been tested yet. In the future as more configurations get tested we will include more sample files, or even a separate repository of configurations.
For this tutorial we will assume you are building an unmodified Rosalind-N2.
In order to build the frame you will need 4 things. Aluminium extrusion profiles (or any other kind of beams you can easily screw on), angle fasteners, M5 bolts and M5 t-slot nuts.
The t-slot nut pictured are generally more convenient as they can easily be inserted and removed in the t-slot, and they secure by rotation. However the variant with ball and spring has the advantage of staying put after unscrewing the bolt so it might be preferable for some parts. If you can, procure enough of both.
If you open rosalind.scad in OpenSCAD and look at the console (If you cannot see the console make sure View > Hide Console is unchecked) you will see some information about the printer being output, including the two lines:
ECHO: "Vertical T-Slot profiles (4 pieces): (mm)", 400 ECHO: "Horizontal T-Slot profiles (8 pieces): (mm)", 360
This informs us of the lengths of aluminium profile required to build our rosalind configuration. We will also need some angles to fasten them together and we can find off-the-shelf ones but since this is a RepRap and one of the goals is to be as much printable as possible we will print the angles ourselves.
Open angle-fasteners.scad in OpenSCAD, press F6 to render and then export to STL. Load the STL file into your slicer, your printer, or order a print from a commercial print service. You will need 26 angles and the file has 30 so you will have a few extra if anything goes wrong.
As long as you have printed the angles you will have to assemble a cube like this. Gather your aluminium profiles and set the 4 longest ones aside. You will use them for the Z axis (the upright frame elements, or "columns") of your Rosalind. Slide the t-slot nut as shown.
If you have the self locking slot nuts pictured in the photo above along the bolts and aluminium profile then the easiest way to assemble is to screw the nut to the bolt before inserting into the frame, like below.
Continue with the rest of the corners until you have a cube.
The base (bottom)
You can use a sheet of acrylic for the base of the printer but I have found that a piece of moderately thick plywood (~10mm) is a safer choice. It's easier to cut it yourself, it doesn't crack and you can later screw on additional equipment easily.
base.stl in OpenSCAD, render it (press F6) and export it in
.dxf. You can now print the drawing in a (2D) printer or a plotter and use it as a guide to cut your piece of plywood and drill holes in the appropriate positions.
Once you have the plywood ready, make sure you sand the edges so that they will be smooth to the touch as the base will be accessible from the outside. Clean it well and make sure that no wood splinters remain.
The next step is to tap threads into the central hole of the vertical t-slot profiles. This can be done using a hand-tap or a power-drill.
You can watch this video to see how you can do that. If you do not have a tap or don't want to bother, you can avoid this step by using sheet metal screws such as this which will thread the aluminium upon screwing on.
Now it is time to start fastening the first functional parts on the frame we just completed. Open
y-axis-clamps.scad, and make sure
print_all_y_axis_clamps(); is not commented out, and that everything else under
/* Print or Preview*/ is. If you are printing the default Rosalind you need not pay attention to anything else.
Depending on the values you have chosen, the parts might need support structures to print successfully. You can do one of the following: (a) enable supports on your slicer, (b) change
trueor (c) change
true. Option (b) prints the part with an extra leg which you will be required to cut by hand and option (c) divides the clamp into two parts which you will need to screw together using bolts.
As the mounting screws of the y-axis clamps don't allow the smooth rod to slide in after being mounted on the frame we will need to assemble the two sides and then mount them on the printer. This is arguably a little easier too.
Once you have printed the parts, get yourself 4 M5x12 or M5x16 screws, 4 t-slot nuts and 2 M3x12 plus nuts for each side.
Slide the smooth rod into the y-axis clamps like this. Make sure that only one of the clamps has the two vertical belt slots. While sliding the rod through the clamps don't forget to slide two LM8UU linear bearings over the rod.
After you install and clamp it at both sides you should add the frame bolts to the two holes in each clamp. Just screw the t-slot nuts on the backside for one or two turns so it looks like this:
After you have completed the assembly you will have to attach it to the frame like this:
Tighten the bolts enough so that it stays in place. Don't bother too much about the exact Z position. We can adjust later.
There are three kinds of y-axis clamps. Make sure you install them at their correct positions. Take note of the shelf where the timing belt idlers will later be mounted and the endstop position (Red arrows). Don't mount the ensdtop yet, it's just shown for reference.
In the default rosalind-n2 v1.1 configuration the clamp that will hold the endstop does not have a visible difference. This is not always the case depending on the values you selected in general-values.
As before open
z-axis-clamp.scad, and make sure
print_all_z_axis_clamps(); is not commented out, and that everything else under
/* Print or Preview*/ is.
You will get these parts.
Set the pillow block aside for the moment and take the four z-axis clamps. The longer one mounts to the top horizontal frame beam to the back of the printer along with a smaller one. The other two mount on the bottom directly below. The x-position in which they mount is roughly 1/3 of the available space, such as so:
Now it's time to slide the z-axis smooth rods from top to bottom into the z-axis clamps. You might need to pry the z-axis clamps open with a flat head screwdriver (especially the longer one) in order to be able to pass the rod through easily. While sliding downwards and before fitting into the bottom clamps, slide two LM8UU bearings through
With the z-axis rods installed we will proceed to install the x-axis clamps (or in a different terminology, the y-carriage). That is, the part that moves (along with the x-axis smooth rods) along the y-axis.
Open the file
x-axis-clamps.scad, render F6 and print. Make sure that there is just enough space for the linear bearings. If they are too tight the smooth rod clamps will start to diverge and it will prove difficult to mount them. If you use lightweight materials for the x-axis rods like aluminium or carbon-fibre the rods will bend out of parallel and make x-carriage movement difficult.
Thread screws in the four holes of the larger part, mount it over the two LM8UU bearings and clamp them with the other side. Add nuts to the hexagonal slots and tighten just enough so the bearings cannot move inside the clamp.
Do the same thing for the other x-axis clamp, and then slide the x-axis rods through their clamps. Don't forget to add two LM8UU bearings to each rod, as pictured
Time to mount the XY axes motors. Due to the kinematics of CoreXY there's no one motor responsible for X or Y movements. Both XY motors work to move either along the X or Y axes.
XY Motor mount assembly
First remove the screws from the bottom of the motor. Take care so that your motor does not fall apart. Usually the motors need some force to come apart but keep the shock to a minimum during the time these four screws are not tight.
Place the bottom mounting plate below the motor as displayed and reattach the screws. You might need to use a bit longer screws depending on the motor. You don't want to use too much longer screws because they will interfere with the screws we will use later to mount the top plate.
First let's assemble the right-hand motor (as you look at Rosalind from behind, i.e. from the side that the z-axis rods are mounted on).
Place the top plate on top of the motor so that the plastic rod of the bottom plate goes in the hole. Depending on the accuracy of your printer and the layer height of the printed parts this process might need some force and might be irreversible.
Now screw the top plate using three M3x8mm screws. If the screws cannot go all the way in add washers as required, both to the top and the bottom screws (they share the same holes). Notice the missing screw. This interferes with the y-axis clamp so we will skip it. (You can use a countersunk screw if you have one)
Slot now the pulley on the motor shaft and tighten the grub screws. If your motor has a flat side on its shaft make sure it is perpendicular to one of the grub screws to benefit from mechanical coupling, instead of just friction.
The process for the other motor is the same.
Mounting the XY motor on the frame
It's now time to mount the XY motor on the printer frame.
If we look at rosalind from behind (i.e. the side where the z-axis rods are mounted), the right hand side motor should be mounted so that its top mounting plate is touching the bottom of the y-axis-clamp.
Slot the screws through the mounting slab and add t-slot nuts. Then tighten on the vertical aluminium profile as shown below.
Repeat the same procedure for the left motor mount but this time you can install all four screws, as there is an 11mm distance between the y-axis clamp and the motor mounting plate.