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howto:using_the_3d_printer:reprap_pro_huxley

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Using the RepRap Pro Huxley 3D Printer

The space has a RepRap Pro Huxley 3d printer. This page has some information & tips on how to use it.

Please edit this page with discoveries/corrections/tips about the printing process!

The Huxley can print things up to 140x140x100mm.

new-printer-box by devdsp, on Flickr printingdomokun.jpg

Steps to your first print

These are the steps to print something out:

  • Get a 3d model STL file that you want to print.
  • Find the plastic filament you're going to use.
  • “Slice” the 3d model into a “gcode file” that contains instructions for the printer.
  • Prepare the printer and the printer bed.
  • Load the gcode file and use it to print the model.
  • Wait around for printing to finish!
  • Wait for the bed to cool and lift your print off.

Get a 3d model

Your 3d model file should be in the STL file format. You can convert most 3d models to this format.

It can be a model you downloaded yourself from http://thingiverse.com/ or something you created yourself.

Find filament

The printer gets its plastic in rolls of thin 'filament'. The space has rolls of two kinds of filament, PLA & ABS.

PLA is biodegradable but a little softer, less chemical/temp resistant than ABS. Both are quite strong.

Slice the 3d model

The printer isn't smart enough to just load the 3d model to print. A “Slicer” program needs to convert the 3d model into instructions for the printer (like “move up”, “move down”, “squeeze out some plastic”, etc.) These instructions go in a format called gcode, which is generated as a separate file.

There are lots of options on slicer programs to choose from. I (Angus) recommend using the Skeinforge slicer at first, then if you want to get more adventurous try the Slic3r slicer. Both are installed on the workstations in the space.

Slicing with Skeinforge

Setting up Skeinforge

Skeinforge needs the correct settings to work with the Huxley printer and the plastic type. Starting out, it's easiest to copy Skeinforge settings (the .skeinforge directory) from someone else. You only need to do this step once, and you can skip it if you're using the “Guest” workstation account.

  • Log into your account on the workstation.
  • Open a terminal (under Applications menu → Accessories → Terminal.)
  • Run this command to copy someone else's .skeinforge directory to your own (for this example I'm copying combust's)

scp -r morphia:/home/combust/.skeinforge .

Configuring Skeinforge

You need to chose the right Skeinforge slicing profile for the plastic you're going to use:

  • Open the “Pronterface” printer control interface under Applications menu → Electronics → Pronterface.
  • Choose “Slicing Settings” from the “Settings” menu.
  • The profile choice is at the top, labelled “Profile Selection”. For printing PLA filament, choose “Huxley-PLA-05-03”. For printing ABS filament, choose “Huxley-ABS-05-03”.
  • Once you've selected the right profile, choose “Save All” to save your settings.

Slicing a model

  • Click “Load File” in the Pronterface printer control window and choose your .stl model file.
  • On the right-hand side of the screen you'll see output from Skeinforge as it slices your model for printing. Wait for it to say it's complete (large models can take 5-10 minutes or longer to slice.)
  • The gcode file will be in the same place as the .stl file, only with a .gcode extension (ie mymodel.stl makes mymodel.gcode.)
Slicing with Slic3r

If you know how to set up to slice successfully with Slic3r, please put the steps here. :)

Prepare the printer

Connecting Pronterface to the printer

  • Power the printer on by connecting the main power connector (back left corner, to the large black AC adapter in front of the computer), and the USB connector.) It seems to work best if the USB connector is connected before the main power (???)
  • If it's not already running, open the “Pronterface” printer control interface under Applications menu → Electronics → Pronterface.
  • If it's your first time running Pronterface, go to the Settings menu → Options and set the bed size (“build_dimensions”) to the string “140x140x100+0+0+0”, the Huxley bed size is 140x140mm
  • Connect Pronterface to the printer by clicking the “Connect” button. After 2-3 seconds you should see “Now online” pop up in the right-hand side.
  • Sometimes you may need need to power cycle the printer and/or restart Pronterface once or twice before it connects reliably. (any tips?!?!?)
  • Once the printer is connected, check the checkbox “Monitor printer” at the top of the window and the small graphs on the bottom-left will update to track the print head temperature and the bed temperature:

  • You can now drive the print head around and up and down by using the arrows at the top left of the Pronterface window. Try it, it's fun!

Turning the fan off

Our Huxley has a 120mm fan mounted on it that comes on when you power up the printer. You actually want it off, especially during warmup.

To turn it off, type the command “M107” into the text box in the bottom-right corner of the Pronterface window. Then click the “Send” button next to the text box.

The command to turn the fan back on is “M106”.

Taping the bed

'EDIT': At time of writing the bed is covered in transparent orangey kapton tape. You don't need to do anything to the kapton (polyimide) tape, you should be able to print directly on it. The notes below are for the bed when it doesn't have kapton on it.

We haven't had consistent luck getting prints to stick to the plain aluminium bed. Instead, cover the bed entirely with green painter's tape.

Some painter's tape is better than others. The 3M stuff is rubbish (too shiny, nothing sticks to it.)

Try and make the edges as flush as you can so the surface is fairly flat, try and avoid having any large loose bits at each end as they can sometimes flip up onto the bed as it moves around.

Be sure to remove tape near the screws as it may get caught under the screw head and change the level of the bed - resulting in filament lifting.

'EDIT #2': We are now using painter's tape on top of the orangey kapton tape. The parts are very easy to remove with this combination, but we do have problems with the painter's tape curling up (often wrecking the print) due to the heat. To combat this, you can use a rubber band on each end of the bed to hold the tape down, as shown below. (You should try to do a neater job with the tape than I did in this photo; the bed was already hot from a failed first try when I put this tape down.)

reprap-bed-tape-band-try2.jpg

Heating up

For PLA, you want the print head to be around 180 degrees and the taped bed around 60 degrees (if non-taped, maybe 85?). ABS has to be hotter, the print head at 230 degrees and the print bed at 110 degrees.

You set temperatures by choosing them in the boxes on the left-hand side of the Pronterface window and then clicking “Set” for each:

Set Temps Window

Click “Off” if you ever need to turn the heaters off.

Once you've set the temps, you can load your gcode file while you're waiting for everything to warm up! Note that heating the bed, especially to 110 degrees, can take quite a while. I don't recommending starting an ABS print until the bed is over 100 degrees.

Load the gcode file and print

Loading gcode

Click “Load File” and find the gcode file you sliced up earlier.

Once it loads you'll see a preview in the grid in the middle of the window:

|width=300

The blue/green bar on the right hand side is the Z-axis and will slowly move up as the print continues.

To preview all the layers, you can click the middle of the grid. A new window will pop up, hold down “Shift” and use the mouse wheel (!!!) to zoom through all the layers, up and down.

Kicking off!

Don't start the print until the print head and the bed are up to temperature. Also, check the bed is up as high as it will go on its spring-loaded mounting.

Then check the print head for “plastic drool” and knock it off if there is any. Be careful not to touch the print head itself, it's hot!

Then click “Print” and watch it go!

Waiting for your print

Look in occasionally on your print as it runs, in case something goes wrong with the printer or the print comes unstuck from the bed, or some other problem.

Waiting for the bed to cool

After the print is done, you need to wait for the bed to cool down. You don't want to pull the print off when the bed is hot, or it might warp. However, it's easist to take a print off while the bed is still a bit warm.

The fan helps a lot with cooling, if you type the “M106” command (see above) to turn the fan on then it will cool down a lot faster.

Once things have cooled down a bit, try to take the print off. There are lots of possible techniques:

  • Pull it off. Sometimes you're lucky and it'll just come off without any force.
  • Twist is a bit. Be gentle!
  • Pull the tape off and have the print come with it.
  • Use a flat paint scraper to pop under the print and bring it off (this shouldn't really be necessary if you're using tape.)

Changing Filaments

To change filaments:

  • Turn the extruder print head on and get it up to temp, otherwise there will be a lump of solid plastic jamming the tip.
  • Press “Reverse” on the pronterface panel 3-4 times to back the filament out of the hot end. Check that it's actually moving.
  • You can then insert a screwdriver under the pressure plate on the extruder, lever the pressure plate up slightly and pull the full length of filament out (much faster than reversing the whole lot.)
{{attachment:extruder-lever.jpg||width=300}}
 
* Remember to change temperatures at this point if you're swapping between ABS and PLA!
  • To insert the new filament, press it into the hole on the back of the printer then press the “Extrude” button in pronterface until it grips. You may have to try a few times.
  • Then you can use the same screwdriver technique to push it all the way to the hot end. Once it's at the hot end, use Extrude a few more times until you see the new plastic coming out the tip.

Tips for quality prints

Heating & cooling

Print inside the printer box. On the Skeinforge 'Cool' plugin tab, enable 'Cool' and 'Slow Down' and set the minimum layer time to 22 seconds. There's a similar option in Slic3r.

This means small layers run slower, to give more chance to cool before the next layer goes down.

If you're running outside the box you can probably go shorter than 22 seconds, but at the expense of slower bed warming up and less stable temps overall.

Other Notes

Printing small layers with details & bridges inside the box, without the Cool plugin, is a disaster in non-freezing weather (everything takes too long to cool and harden, so the printer 'smooshes' each previous layer into the next one.

Looks like regular/even airflow and cooling of new layers is good for prints. Printing PLA with two pedestal fans blowing across the bed gave good results.

A few notes about the 120mm fan mounted to the printer:

  • Leaving it on for the entire print cools the bed down (for ABS) and causes the print to warp.
  • Skeinforge has a 'Cool' feature that can pause to cool between each layer. With default settings it changes a 10 minute print into a 70 minute print. Haven't tested.

Please leave notes if you find useful ways to use the fan (maybe the firmware can be made to reduce the fan speed with PWM?)

Printing with Overhangs

In Skeinforge, you can have the slicing step produce “support material” under any big overhangs that you then break away. In Skeinforge can use the “Raft” plugin (under Slicing Settings) to produce these when slicing the model.

Here are some settings that seem to work OK:

On the Raft panel:

  • Activate Raft - yes
  • Add Raft, Elevate Nozzle, Orbit - yes
  • Base → Base Layers - 0 (these disables any actual raft under the print)
  • Interface → Interface Layers - 0
  • Support settings as shown here:

You may want to increase the minimum angle, depending on how steep of an angle you want support added under.

howto/using_the_3d_printer/reprap_pro_huxley.1383303614.txt.gz · Last modified: 2013/11/01 11:00 by 59.167.251.107