3d printing using a RepRap Ormerod

Posted on 12 Jul 2014

First Installation

Install the latest (stable) Arduino IDE. You won't actually need the IDE itself, but it installs a driver that you need.

Download the latest Pronterface. No installation required, just run the ormerod.cmd file. If you want, rename the "Slic3r-win" folder to "Slic3r", this will enable additional functionality in Pronterface.

Making a 3d Model

There are many different methods, this is just one of them.

Make a model using OpenSCAD and save it as an .STL file.

Convert the .STL to G-code using Slic3r. You should already have Slic3r, because it comes with the reprapppro-Pronterface-package that you downloaded earlier. That package also has default settings for our Ormerod printer.

OpenSCAD

OpenSCAD uses a programming approach to CAD. You define your geometry in the text area, then compile it. All units are in mm (unless you use "Scaling" in Slic3r later.)

Example .SCAD file for a "plug" (just copy/paste this into the text area)

// This is a comment

// This is a "function" definition
// (this function here takes no arguments)
module plug_no_hole() {
    linear_extrude(height=2) circle(17);
    translate([0,0,2]) linear_extrude(height=10) circle(12);
}

// This is the "main" code that is executed. It's just one command.
difference() {
    plug_no_hole();
    translate([0,0,-1.0]) linear_extrude(height=15) circle(5.5);
}

Compile and render this by pressing F6. Click "Design"->"Export as STL" to save the relevant STL file.

Slic3r

Run the Sli3r.exe that came with your Pronterface download.

Verify that the drop-down menus for "Print settings", "Filament", and "Printer" all say something about "Ormerod" or "Ormerod-0.5" or so. These are the default settings for the Ormerod printer.

Drag and drop your file in. You can drop multiple files into the print area, or one file many times, if you want to print several pieces at once!

Important: Under "Printer Settings" -> "Custom G-code", change the line T0; Select extruder to T1; Select extruder!

Click "Plater"->"Export G-code".

Printing

Transferring your files

Important: Open your G-code file with a text editor, and check that there is no line like T0; Select extruder. If there is, change it to T1; Select extruder.

For large files (> 1Mb):
Switch the printer off, take the uSD card out of the printer. (Push on it, it pops out. You might need some plastic object to push on it, if your fingers don't reach.) Using the uSD-to-USB adapter, put your .g-file into the "g-codes" folder on the uSD. Put the uSD card back into the 3d printer.

For small files (< 1Mb):
Use Pronterface (see below), and choose a file in it. Instead of "printing", hit "SD", then "upload".

Turning on the printer

Turn on the power supply and connect the printer's USB cable.

Wait 10s for the printer to boot up, then start Pronterface (ormerod.cmd).

Choose "COM4" (might be different on other PCs) in the drop-down menu and connect to the printer.

Calibrating the printing bed

Make sure the print-bed is clean and sits on the printer with the Kapton tape (yellow stuff) up.

Home the x and y axes by clicking the respective "home"-buttons in the upper left side in Pronterface.

Note: The z-homing does not work. DON'T PRESS THE Z-HOMING BUTTON OR YOUR CALIBRATION WILL BE OFF!

Turn on the heaters (Heat: 200, Bed: 56) and wait for the printer to warm up. The printing bed warps a bit, so you want to calibrate in the hot state.

Automatic bed plane compensation does not work, because it needs a good z-probe. You'll have to do it manually and repeat it for each print.

Send the commands to turn the bed compensation and axis compensation off:

M561; bedplane comp off
M556 S100 X0 Y0 Z0; orth axis comp off

Decide on four points for the calibration. These for points must form a rectangle. The rectangle should be at least as big as your printing aread (but not so big that the print-head collides with the clips on the bed). "0"th point is near the origin, 1st is clockwise from that, ...

The x- and y-axes should have been homed earlier. If they weren't, do it now.

Lift the head to about 5-10 mm above the bed.

Go to first corner:

G1 X30 Y22

By hand, lower the head just above the bed and note the z -position (let's say it's 0.0 because you're close to the origin). Set this as the z=0 point

G92 Z0

Send the calibration point

G30 P0; The current position is the 0th corner of the bedplane-comp rectangle

Move head up by 10 mm. Go to the next corner

G1 X30 Y170

Lower the head by hand and note z-position (somewhere around 0.9mm). Send calibration point

G30 P1

Lift head by 10 mm. Go to the next corner

G1 X190 Y170

Lower the head by hand and note z-position (2.1mm). Send calibration point

G30 P2

Lift head by 10 mm. Go to last point

G1 X190 Y22

Lower the head by hand and note z-position (1.5mm). Send last calibartion point and command the printer to apply this compensation from now on. Don't forget the S.

G30 P3 S

Enable the orthogonal axis compensation again:

M556 S74.5 X0.05 Y-0.3 Z0.1

Final z-Calibration

Lift the head by 10 mm. Go to the middle of the print bed (this is most likely where your print is started, so here the calibration is most important.)

G1 X100 Y100

Lower the head by hand and set this as the new z=0 position

G92 Z0

Lift the head by a few mm, just for safety.

Now you are done with the calibration!

Starting the print

You should always print from the SD card, because sometimes when printing over USB, the commands aren't sent fast enough, and the print will look bad.

Go to "SD" -> "SD Print", select your file and start the print!

Make sure that the first two layers look good

Once the print is done, wait for it to cool down. Otherwise the piece will warp, especiall if it is mostly flat. If it's a pretty solid shape, you don't need to wait.

Remove the finished piece using a thin plastic spatula (a filed-down cable tie works for this). Don't use any metal tools on the Kapton surface.

Turn off the printer by removing the USB connection and switching off the power supply.

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