Giant 3d Printer for Cheap!

I have been thinking about making a 3d printer that could be easily expanded for a while, and this is the result of my brainstorming. This 3d printer is extremely cheap for it's potential size, and can be expanded even bigger at very little extra cost. The main trouble with this was figuring out how to get the filament to the extruder. This 3d printer can be made with cheap and easily obtainable materials. One of the things that was bothering me about most DIY 3d printer is that they are tiny and need to be made from disk drives, which are kind of expensive if you don't just have them sitting around. Also, they are very difficult to expand. This printer sacrifices a bit of quality for size. You could, in theory, expand this big enough to print a house. It is also easy to disassemble and reassemble, so it doesn't have to take up a ton of space, even if it is huge. It also has quite a few advantages and disadvantages over other DIY printers:

PROS:

• It can be expanded very easily
• It can be made from cheap and mostly easily findable materials, and you don't need any very special tools

CONS:

• It is kind of unstable
• When you are using it it needs to be plugged into your computer

Supplies:

• Arduino (any type as long as it has serial, and at least 4 pwm pins and 6 other pins) (Adafruit)
• 2x L293D IC (Adafruit)
• 3x Very strong motor, or DC motor in servo body (that's what I used) (Adafruit)
• Breadboard (Adafruit)
• Spool of breadboard-friendly wire (Adafruit)
• Micro-servo (does not need to be too strong[this is going to be used for pressing buttons. If you are feeling brave, you can use an optocoupler instead]) (Adafruit)
• 2x 100 μF electrolytic capacitors (Adafruit)
• 90-degree side angle connector that your strong non-sacrificial motor will fit snugly in (Lowes)
• 2x T-connector that your motor will fit snugly in (Lowes)
• 3x Snap connector with threads thingy (Lowes)
• 3x Threaded to slip adapter (Lowes)
• 4 equal lengths of pvc pipe that are compatible with the connectors (Lowes again. The length of these will be the height of the printer)
• 2 equal lengths of pvc pipe that are compatible with the connectors (Lowes. These increase the print area along the x and y axis)
• Paintstick (Lowes)
• 3d printing pen (Amazon, if it is clunky it probably has a fan which is a good thing)
• Filament (Came with the pen for me)
• Power for the pen (Came with pen)
• 6v battery pack that is breadboard compatible (You can probably get this at Lowes near the sacrificial motor)
• Rubber bands (around the house)
• A lot of pennies (around the house)
• Hairspray or (preferably, but I used hairspray) pvc cement (around the house)
• Electrical tape (around the house or Lowes)
• Hot glue sticks (around the house)
• Bobbins or something that can wind string (Sewing or fly fishing shop. Make sure it has as small a hole as possible)
• Thin string that is not stretchable, but strong, like dental floss( I used backing [look up backing fly line], which you can probably get at a fly fishing shop. You know where to get floss)
• Polymer clay (Art shop, don't get Sculpey III, it is too soft) or Hand moldable thermoplastic (Adafruit)
• Some sort of flexible(ish) breadboard friendly wire (around the house for me, but I am weird so...)

Tools:

• Hot glue gun
• Small phillips head screwdriver
• Prying device(a tiny one, I used a tiny screwdriver from one of those eyeglass repair kits)
• Nippers
• Wire stripper
• Scissors

You will have to make 3 of these.

If you have polymer clay or thermoplastic and have a motor in a servo body, read this paragraph. If you don't, just hot glue your winder on the top of the motor. Anyway, the first thing you need to do either way is screw a screw into the servo's gear, but only partially like in the first picture. Then, if you have thermoplastic, soften it with boiling water and roll it around a bit in your hand to dry it. I accidentally did remove the water when I did this on one of my motors and I think it may have messed up the grease; I had to open it up and re-grease it. Shape it into a noodle about as thick as from the base of the gear to the top of the screw and let it cool down a bit. Wrap the noodle around the gear and connect the ends, and then flatten the top. If you are using polymer clay, do the same thing. Make sure the edges don't hang below the line in the pictures. Put it in the fridge for a bit (be patient). Take the motor out of the fridge, and if it is thermoplastic, give it a slight twist. If your servo makes a noise, you are good. If it doesn't, you will need to redo it. Then, unscrew the screw, and remove the polymer clay/thermoplastic from the top. If it is polymer clay, cook it according to the instructions it came with, but make sure to remove the clay from the motor before you bake it.

Now you have a Thing To Attach A Thing To A Servo Body (I know, it's a lot of things so I will abbreviate it to ttaattasb [tats for short] for lack of better terminology [I love big words {and nesting parenthesis!} ] ). Take your ttaattasb and screw it into the top of your motor, and then hot glue your winder on top of it.

After that, hot glue a piece of backing about twice as long as your longest pvc pipe to the winder and wind it up so it isn't hanging off and getting tangled up.

Now you are done making the motor assemblies.

This step is making it so the pen so it is more stable, and can be attached to the strings.

Take a length of string (short like in the picture) and put it over the end and tape it really well with the electrical tape, making sure you are stretching the electrical tape as it goes around. Then rubber-band it making sure you do not cover the status LED with the rubber bands or electrical tape

Then, weigh your pen, and check the strength of your motor. You don't want to put too much weight on your motors, or they may be unreliable. Anyway, pennies weigh about 2.5 grams each. My motors can lift 1.5 kg at 6 volts, and so I made my pen way a total of about 350 grams. Why? Because 350 is a good weight. Anyway, I used 100 pennies, but I removed about three-quarters of them afterwards because they were too heavy. Put on a conservative amount, because it is a pain to remove them from the pen, but easy to attach more. Make sure there is enough room on the pen so that coins won't go over the buttons, and same with your electrical tape. You are going to want to put your coin roll as low down as you can on the pen. Take your electrical tape and put out a strip. Then, put on the pennies one by one, and press them down. It is very tedious. I found that it is faster to grab a stack, and drop them on one by one. Once it has got too long to fit on your desk, fold it as little as possible,and push back on any pennies that pop off.Once you have put on all the pennies, go back over them with electrical tape on the other side.

Wrap the place where you want your coin roll to go with electrical tape, and then hot glue one end of the coin tape on it. Slowly start wrapping it around your pen, putting a blob of hot glue every coin or two. The coin roll will have a tendency to turn into a coin cone. You do not want this cone to go over the front of the tip of the pen.

Then, take a bit of thermoplastic (or polymer clay) and mold it against the pen, and then squish the servo on top like in the picture. If it is polymer clay, bake it. If it is thermoplastic, let it sit for a bit. Then, hot glue the pen, the thingy that you just made, and your motor like in the picture.

Assemble the frame like in the picture. You will need to only glue specific joints, do not glue all of them. Which joints you glue depends on how collapsible you want it to be. If you want it too disassemble into a bundle, you will need to glue it like in the first picture. If you want it to disassemble flat, glue it like in the second picture. If you don't want it to disassemble, glue everything. This step is a bit difficult to explain in words, so look at the picture and the notes. They are important.

Hot glue the motors into the joint. Make sure the string is pointing towards the centre of the circle when it comes off the spool. Also, make sure the wires go around the tabs, not under them. Then, take the paint stick and cut it to approximately the height of from the crook of the joint your motor is on to the top of the spool, and mark it in the centre about halfway up the spool, and then make a hole there. Thread the string through the hole, and then hot glue it on, and then electrical tape it on like in the picture. Make sure it is pointing towards the centre.

Wire up the Arduino like in the picture, and then attach it to the frame on the arm with two motors (if it can collapse into a bundle) like in the picture. Attach the battery pack as well. After that (or before that like me) attach a solid core wire to each of the motors and run them back to the breadboard, taping it along the tube so it stays out of the way. Wire it to the Arduino like in the picture.

Tie the three strings from the motor to the string on the back of the pen, and make sure they are well attached, and centered on the back of the pen. Also, if the pen tilts you may need to put more pennies on one side or the other. Mark the string at the paint sticks with a sharpie, and then measure the length of each string. Write these down somewhere, and note which motor they are too (whether the motor is a,b, or c. If you are unsure, compare the wiring diagram in the last step to your wiring. I recommend somehow labeling them), as well as the xyz coordinates of the tip of the pen. They will need to be put in the program. Take the servo, strip the ends of the wire that you got from the motor, and stick it in the servo plugs. Use male header pins to make them stay in. Do the same on your breadboard, and wire the positive to the positive, the negative to the negative, and put the 100 uf capacitor in-between them. Then, attach the white wire to a pwm pin.

Put on third snap connector on one of the legs and glue it in place. Make sure the threaded part of the snap connector is pointing towards another motor (It doesn't matter which). Attach the adaptor to a small length of pipe, and if you want to get real fancy put something that sticks up (like a 90 degree elbow join) on the end so your filament won't fall off.

Take the plug and tape it to a leg. Then plug it into the pen. Pretty simple, right? If it is too short, you will need to splice it.

This is the most difficult step for you at the moment. I can't seem to get my programming to work the way I want it to. If you can have any positive input, please do. The math seems to be having some sort of problem *-*. Anyway, once you have finished it, you turn on the pen and hold the button until filament comes out. Then, align the marks on the string with the holes, and you are ready. Your computer will need to be tethered to it during the printing which is a pain in the butt. It uses processing to send the gcode instructions over serial, and interprets them in Arduino. The attached file is the processing file, which will need to be run in processing.

In the Arduino program there are a few variables you need to set, namely, strings.length needs to be set to the length of the string that you wrote down for the motors in step 6. Also, set target.prev to the pen's current coordinates, which you also wrote down in step 6. The motor structs are clearly labelled and commented so they are self explanatory, like the pen struct. Name the start variables to where you want the pen to home to. There are probably a few others that I forgot to mention, just sort of go through and read the comments, and you will figure it out.

If you have any questions, please ask. Also, I worked really hard on this so I would be glad if you could vote for me in the Arduino contest.

Arduino code