\section{Intro}
\index{advanced techniques}
\glossary{3D Printer}{Also referred to as additive manufacturing, is the process of fabricating objects from 3D model data, through the deposition of a material in accumulative layers}
After becoming fimiliar with printing with the AO-100 3D printer with the default settings there are a few advanced techniques that may help in getting better and more consistent prints. Some of this instructions include items and materials not included with the AO-100. With any of these additional items or materials, follow safety and usage guidelines as instructed by the manufacturer.

\section{Changing nozzles}
\index{nozzle}
\glossary{nozzle}{The part with the small hole where the plastic filament comes out of the printer}
\index{high resolution}
To achieve higher resolution parts you can change to a smaller sized nozzle, included in the printer kit. Using the 0.25mm or 0.35mm nozzles you can print at smaller layer heights to create smoother parts.

\index{hot end}
%\glossary{hot end}{The hot end is the part where the plastic melts, including the nozzle, heater block, thermistor, and heat sink. The Budaschnozzle is LulzBot's\textsuperscript{\miniscule{\texttrademark}} hot end}
\index{threaded extension}
In most cases the nozzle is best changed when the hot end is completely cool. NEVER try to remove the nozzle when the hot end is at extrusion temperature. At higher temperatures the threaded extension expands in the nozzle causing the nozzle to bind if turned.

\index{wrench}
\index{heater block}
To change the nozzle you will need the 18mm and 13mm wrench from the printer tool kit. Slide the 18mm wrench onto the rectangular aluminum heater block.

Using the 13mm wrench turn the nozzle counter clock-wise. Make sure the nozzle is turning off of the threaded aluminum extension that runs up through the heater block. Do not allow the heater block to turn. This can put strain on and possibly damage the wiring. If the threaded aluminum extension is turning with the nozzle, retighten the nozzle until it touches against the heater block again.

To loosen a stuck nozzle off of the threaded extension, heat the hot end to \texttt{90-100°C}. This will soften the plastic inside the hot end and allow the nozzle to be turned off of the threaded extension. Take care when removing the nozzle while the hot end is hot. Wear leather gloves or use a towel to turn the nozzle off of the hot end.

Once you have removed the nozzle you can then thread on the other nozzle size you would like to use. Make sure the nozzle has threaded correctly onto the threaded extension before trying to turn it with the wrench. Turn the nozzle clock-wise until it tightens against the heater block.

After installing the new nozzle you may need to adjust your Z home trigger setting before printing again. Refer to the Printing Your First Print section (page \pageref{firstprint}) for calibrating the Z home trigger setting.

\index{anti-seize}
If you will be changing nozzles frequently we suggest reapplying a small amount of high temperate anti-seize to the inside threads of the nozzles. You will need an anti-seize capable of temperature of at least \texttt{250°C}.

\section{ABS/Acetone Glue}
\index{acetone}
%\glossary{acetone}{A colourless, volatile, flammable liquid ketone, (CH3)2CO, used as a solvent.}
Acetone is not included or required with the AO-100 3D printer. An acetone safety label is included for the HDPE bottle.

\index{ABS}
%\glossary{ABS}{Acrylonitrile butadiene styrene. A very common type of plastic, used for 3D printing }
\textcolor{red}{Acetone can cause skin irration when prolonged skin contact occurs. It is recommended to use acetone safe gloves when applying the ABS/acetone glue. Use the ABS/acetone glue in a well ventilated space. Leave the mixture bottle closed except when applying a small amount to the wiping towel. Acetone liquid and vapours are highly flammable. Keep acetone away from open flames and high temperature sources, including the 3D printer. Read the warnings label on your purchased acetone packaging for additional warnings.}

\index{warping}
\index{bottle}
You may find that during printing, printed parts lift off of the print surface on the corners. If you are seeing this problem you can make an ABS/acetone glue to apply to the print surface. Using the HDPE acetone safe bottle included in the printer kit, fill the bottle 3/4 full with acetone. Now cut eight, 100mm lengths of ABS filament and put them in the bottle with the acetone. Allow the ABS filament to dissolve for 12 hours.

\index{PET tape}
\glossary{PET}{Polyethylene terephthalate.}
To apply the acetone/ABS mixture put a small amount onto a paper towel. Now, rub the towel onto the PET print surface to apply a \emph{thin} layer of ABS. Generally only one thin layer of the acetone/ABS solution is needed. However, if needed you can apply multiple coats.

\section{Using 1.75mm Filament}
\index{1.75mm filament}
\index{PTFE tube}
\textcolor{red}{This procedure is highly advanced and involves disassembling parts of the printer, including the hot end. We recommend using 3mm plastic filament as we have yet to see major advantages to using 1.75mm filament. If you would still like to use 1.75mm filament make sure to follow the instructions carefully. If the instructions are not followed correctly you will run the risk of damaging the printer and possibly voiding your warranty.}

The AO-100 3D printer is set up to use 3mm plastic filament by default. Although we recommend using 3mm filament, the AO-100 is also capable of printing 1.75mm filament. To print with 1.75mm filament you will need to change the PTFE tube inside the Budaschnozzle hot end. Included in the printer kit is a 39mm PTFE tube with a 1.8mm inside diameter.

To change out the PTFE tube:
\begin{enumerate}
\item Remove the plastic filament from the extruder if there is any currently loaded.
\item Unwrap the black wiring wrapping leading from the extruder to the electronics.
\item Using the Printrun manual controls, raise the Z axis to 80mm.
\item Using a 3mm hex driver loosen and remove the two 4mm screws from the bottom of the extruder X axis carriage. This will allow you to lift the extruder body off of the hot end and carriage. Set the extruder body aside. Lift the hot end up and out of the X axis carriage.
\item The hot end now has to be partially disassembled to replace the PTFE tube for 1.75mm filament. Along with the following instructions, you can see an instructional video on how to replace the PTFE at \texttt{http://youtu.be/7ExD5lY4-pI}. 
\item Using the 2.5mm hex driver, remove the three 3mm screws from the top of the hot end. Remove the printed mounting plate.
\item Note the path of the wires through the three strain relief slots in the wooden top plate. Gently remove the wires from the strain relief slots. Remove the top wooden plate.
\item With the top wooden plate removed the PTFE tube should now be visible. The PTFE tube is set through an aluminum heat sink. Remove the heat sink from the hot end.
\item The PTFE can generally be pushed out of the aluminum heat sink by hand. Although, you may need to use the 4mm hex driver to push the PTFE tube through and out of the aluminum heat sink. Place aside the PTFE tube for 3mm filament.
\item Push the PTFE tube for 1.75mm filament through the aluminum heat sink. The PTFE tube should be approximately centered in the heat sink with equal links of the PTFE tube sticking out of the heat sink.
\item Replace the aluminum heat sink and PTFE tube back into the hot end. Lightly push down on the PTFE tube to make sure it is completely set into the hot end.
\item Replace the top wooden plate. Make sure to line up the strain relief slots on the side of the wires.
\item Place the printed mounting bracket on top. Screw in and lightly tighten the three 3mm screws through the mounting bracket and top wooden plate.
\item Wrap the wires through the strain relief slots in the correct path of all four wires, snaking through each slot together.
\item Place the hot end back down into the X axis carriage. Make sure the wires are facing the rear of the printer
\item Place the extruder body back on top of the hot end and X axis carriage. Line up the two mounting holes. Push the two 4mm screws through the bottom of the X carriage, through the hot end, and into the extruder body. Thread the screws using the 3mm hex driver but leave loose for now.
\item Rewrap the wire wrap around the extruder and hot end wires.
\item Finally, push 1.75mm filament through the extruder and into the hot end. This will align the filament travel space. Tighten the two 4mm screws from the bottom of the X axis carriage.
\end{enumerate}

Before printing with 1.75mm filament, make sure to make the needed changes in Slic3r for 1.75mm filament. You will need to reslice and previously sliced files with the new settings for 1.75mm filament.