Getting into 3d Printing

XarlyX,

The Extruder seems challenging, but is fundamentally a barrel capable of containing the melted thermoplastic as it enters the nozzle for deposition. You would need a small heater (~7-10 USD each) and can machine the block so it can heat the filament as it is fed into the volume just prior to the nozzle's aperture.

To control the rate of feed, a stepper motor and another Pololu controller are the electronics you need, aside from the thermistor for temperature management. Some controller boards can handle a thermocouple although the cheaper thermistors are more commonly found in home-built 3D printers. Each step of the stepper incrementally advances the filament into the extruder's "hot end" either directly as in most Cartesian style printers or via a Bowden-tube assembly, which is best for Delta style printers as the end effector's mass is greatly reduced by placing the stepper on the printer's housing, feeding the filament through the Bowden tube to the hot end which is all that has to be moved about for deposition. Once the filament reaches the hot end, it is melted by the heater in the block as it enters the nozzle's aperture for deposition on the model.

You can find many different versions of home-built extruders, which often use 3D-printed herringbone gears and simple barrels milled out of higher-temperature plastics using hand tools like drills and such. The block is typically milled from a good metal for thermal transfer (brass is common, along with copper alloys) - small hole for the thermistor, larger hole for the heater element, pass-through voice that accepts the filament from the barrel as it melts and then allows it to be forced out through the nozzle. Most stepper motors from CD/DVD systems lack the torque and force needed, but I have built many printers using the steppers from surplus dot-matrix printers, faxes and scanners. Typically the electronics will be the most costly element, although as their popularity increases, costs are dropping there.

Good fortune on your build and let us know about challenges and successes you find in the process!

Kirk Hausman

Hi Kirk,

Thanks for the fast response, about your "explanation" of a hot end, seriously, i don't understand some things like:

1-What is an "Thermistor", it's like a thermal resistor (like his name says) or a Temperature controller resistor?

2-does the hot end controls the amount of "extruded" plastic that will comes out?

3-looking straigtly at the nozzle, is much like the nozzle of a hot glue gun, could i use the nozzle, and his "thermistor" for my printer?

4-For the stepper motors i need 4, i have 2 from my last inkjet printer unscrewed, one from the printer and another from the scanner, which of those is more powerfull or has more "torque"

As a summary:

-I'm gonna try to "create" my own extruder

-Find a RAMPS platform maded for Arduino UNO

after that i will post another response in a couple of days so you will know my progress into "The Cheapiest 3d Printer"

XarlyX.

Thanks for your help

Hi Kirk,

Thanks for the fast response, about your "explanation" of a hot end, seriously, i don't understand some things like:

1-What is an "Thermistor", it's like a thermal resistor (like his name says) or a Temperature controller resistor?

2-does the hot end controls the amount of "extruded" plastic that will comes out?

3-looking straigtly at the nozzle, is much like the nozzle of a hot glue gun, could i use the nozzle, and his "thermistor" for my printer?

4-For the stepper motors i need 4, i have 2 from my last inkjet printer unscrewed, one from the printer and another from the scanner, which of those is more powerfull or has more "torque"

As a summary:

-I'm gonna try to "create" my own extruder

-Find a RAMPS platform maded for Arduino UNO

after that i will post another response in a couple of days so you will know my progress into "The Cheapiest 3d Printer"

XarlyX.

Thanks for your help

XarlyX,

The Thermistor is as you suspected a thermally-variant resistor (100k Ohm range is typical for 3D printer's electronics). They are fairly tiny, and can be held in place in the heater block using adhesive meant for automotive electronics very easily, though I typically wrap the entire block using Kapton or a similar insulator last to provide bump protection and hold everything together even if you also glue the pieces in using thermal adhesives as well.

The hot end is only the delivery point, the rate of the filament's advance is handled by the stepper motor of the extruder. Each step moves the filament forward a tiny bit, which will force an equivalent amount out of the nozzle once the block's reservoir is initially filled. The nozzle of a hot glue gun can work, but 3D printers typically use far smaller apertures (.3mm or .4mm) so the larger hot glue nozzle would be far too large for print use (mine is around 1mm, for example).

Because most scanners only move the optical element, their stepper motors are typically going to provide less force than an inkjet printer, which also has to move the jet and reservoir's mass around. That is only a general rule-of-thumb though and you should test with weights to be certain.

Kirk

Kirk,

First of all, thanks for all the help you are giving to me.

I have tested my stepper motor and i can say it works perfectly for the "plastic" supply of my extruder, now i need to buy the Hot glue gun in a "chinese" shop of my street, only 4€ with a heating temperature up to 380º , i think it will melt good the plastic wire with no problem.

The next week i'm gonna visit the electronics shop for the other 3 stepper motors for x,y,z axis and i'm gonna ask if they could sell me the "hot plate" and i think with these pieces my 3d printer electronics are done.

I will continue posting my progress

Hi again KKHausman

Today I went to a shopping center searching for 3D printers to "gather" some ideas for mine, and i have a question to you, What's the meaning of installing a fan into the extruder, next to the nozzle?,

Also i have to ask you another question, where i could find some cheap stepper motors, i ask this because in my "printers collection" i only have 1 printer that i could unscrew with no problem, i thought i had any more but with the pass of time i throwed all to the trash and now i have only 2, one still in use, and the other, only for emergencies.

Thanks. XarlyCodeX

The fans commonly found on 3D printers typically cool the stepper motors, or in the case of the fan close to the nozzle, cool the filament as it is extruded to reduce thermal contraction as the thermoplastic adjusts to room temperature. By forcing it to cool as it is being extruded, you get a better bond to the previous layers and it will not retract with the same force as if would at full temperature, so you improve layer adhesion and reduce the curve that occurs in long extrusions as they cool. For inexpensive stepper motors, I find a lot of older 2D printers, scanners and fax machines at local pawn shops and swap meets. You might see if your local hacker-spaces/maker-spaces have swap meets or similar gatherings where you might find them, or talk to your local tech repair center - you do not need a fully functional machine, just the parts inside.

Kirk