Stage 5 - 101superhero

I don’t expect a 3D printer selling at USD49 in kickstarter (Now at USD99 in their eshop) can provide decent print. However the 28BYJ-48 just can’t do the job. You can find more information about the 28BYJ-48 from https://grahamwideman.wikispaces.com/Motors-+28BYJ-48+Stepper+motor+notes.

101hero team knew the problem, instead of using the standard 1/64 reducing ratio motor, they use a special built 1/32 ratio motor to reduce the steps per mm from 975 to 539. As the torque of the motor will drop dramatically at high speed, the max speed of 101hero stock motor is 14mm/s. Since it is impossible to get the 1/32 motor in the market, some users replace their broken motor with 1/64 one but need to reduce the print speed to 6mm/s to get the acceptable quality.

Luckily, 101hero is using the controller with bipolar stepper motor driver A2988, We able to replace the 28BYJ-48 with NEMA stepper motor without changing the electronics. 

To replace the 28BYJ-48, you need an adaptor to mount the NEMA motor to the pylon. There are two type of NEMA motor widely used in 3D printer. They are NEMA 14 and NEMA 17. NEMA 14 is smaller in size and in general NEMA 17 is lower at cost.

Download NEMA 14 Adaptor from here

Download NEMA 17 Adaptor from here

I used to use the adapter design by Dan Delaney to mount the NEMA 17 motor, it is sample and work. The only drawback is printer only stand on the three motors that is not very stable. I has to add a base to the pylon to stabilized the printer. 

Eventually I combined the design from Don Delaney and Matt Dolan into an adapter in one piece.

To replace the motor, first release T2 belt, then you can easily remove the 28BYJ-48.

After release the T2 belt, release the two screw of the 28BYJ-48 and take it out.

Remember to put the two screw back after took out the 28BYJ-48

Take out the timing belt pulley from the 28BYJ-48 and install it to the NEMA motor and mount the NEMA 17 to the adapter with 4 x M3 screw

This is how the adaper mounted to the pylon

There is two holes at the bottom of the pylon, use two short screw to join the adapter to the pylon

You can use the 6 pin to 4 pin cable that came with the motor to connect to the 5 pin connector in 101hero. Please refer to the below picture for wiring method. Follow the pin location not the color as the color arrangement is not always the same. The 1-3-4-6 pin on the motor side is mapped to 4-3-2-1 pin on the controller side.

Remember to insert the M92 command before printing or moving the arm, otherwise, the controller will use the default setting for the 28BYJ-48 that is 5 times faster than the standard NEMA 1.8 degree motor. I am using M92 X101.4 Y101.4 Z101.4 E95.2. You may need to calibrate the setting and I am using the XYZ 20mm Calibration Cube as the reference.

Stage 4 - 101pyro (unofficial biography)

Bowden setup with existing extuder

If you only want to replace the hotend and continue using the existing extruder without changing the Gcode, Per Knutas had successfully converted the direct extruder to bowden type.

https://www.facebook.com/groups/101herounofficial/permalink/1243777029033192/

Below is my mod to his design, you can use the existing heaksink to fix the position of the Bowden tube.

Handmade E3D carrier

If you really want to hand made the E3D-v6 carrier, think again if you can find somebody or company to print the carrier for you. It will be the best solution.

www.thingiverse.com/thing:2127629

OK. Buy the E3D-v6 with all the below accessories


1 x Heatsink shroud with 12V High Speed Fan
1 x Metal J-Head hotend 1.75mm / 0.4mm nozzle / 12V 40W Heater / NTC3950 Thermistor
1 x One meter long bowden PTFE/teflon tubing 4mm OD 2mm ID
1 x Hotend Throat

1 x E3D v6 Circular Aluminum Mount
2 x M3/M4 screw
2 x M3/M4 nut

You need to cut the aluminium brick so that it can sit on the heat isolator without touching the plastic extruder carrier. The thickness of the brick also need reduced to 10mm to enable the perfect contact between the nozzle and the hotend throat even the isolator is inserted between them.

No assemble instruction of the handmade hotend will be provided as a picture is worth a thousand words. Please leave me message if your really need help.

Stage 4 - 101pyro

Many 101hero users have problem with their hotend, including hotend not heat up, cannot reach to desired temperature, under extrusion etc. Upgrade to better hotline (like E3D-v6) may resolve most of those issues. Here is the strip down of the 101hero hotlend. The heating elements only provide 15W power that is not capable to raise the temperature of the hotend to over 210C

The nozzle of 101hero should only be used in 3D pen but not in 3D printer that need precise position and flow. The nozzle of my 101hero is oversized and ellipse in shape.

I recommend E3D-v6 as hotend upgrade. It is widely used in many 3D printer and you can find many low cost clone product in Amazon or eBay.

Thanks Matt Dolan (workshoptinkerers) who designed a E3D printhead carrier for 101hero and you can now download the STL file from thingiverse (http://www.thingiverse.com/thing:2127629), I am also using this carrier. It is well design and perfectly fit to the 101hero.

I highly recommend to use the above carrier. Just in case you cannot print that carrier, you can consider using hand made carrier that I had built before Mattew Dolan launch his design to thinkiverse

There are two prerequisite condition before upgrade to E3Dv6. One is Bowden extruder and the other is a power supply with at least 5A output. Let's do some simple calculation on the power consumption. E3Dv6 hotend with 30W heater need 2.5A and four 28BYJ-48 motors need 1.6A that already add up to 4.1A. However I recommend 7A one to prepare for the NEMA motors upgrade in the future. 

Stage 3 - 101spiderman (Part 2)

The 101hero using A4988 stepper driver that is designed to work with bipolar motors. 28BYJ-48 is a unipolar motors but able to work in bipolar mode. You can get more information from here.

However I don’t see the motor using in 101hero had cut the common red wire inside the motor. Anyway I don’t care why they not do so but what I am sure is we can replace the 28BYJ-48 with NEMA motor directly without modify the circuit.

More information about stepper motor and stepper motor driver can be found from below.

http://reprap.org/wiki/Stepper_motor

http://reprap.org/wiki/Stepper_motor_driver

The default setting of the steps/mm of the extruder motor is 975. Base on my calculation, the 28BYJ-48 should be running at 8 microstep mode.

To replace the 28BYJ-48 with NEMA motor, we only need to connect 4 wire to the connector using the 6 pin to 4 pin cable and leaving the pin for the red wire empty.

The step angle of the 28BYJ-48 is 5.625°, with 1/64 reduction gear, it take 4096 steps to rotate one circle. While the NEMA motor with 1.8° step angle only need 200 steps. However when I tuning the steps/mm with the NEMA motor, I expect it need 48 steps but finally found that it take 95.2 steps to move 1mm, This mean the stepper motor driver is using 16 microstep mode. I don’t understand why 28BYJ-48 and NEMA is running at difference step mode. May be it is because the red wire had not been cut. I hope some expert can figure it out. 

To change the extruder to bowden type is fairly easy, we only need to remove the motor and door from the extruder. Connect the bowden extruder to the hotend with a bowden tube and change the steps/mm setting for the extruder motor to 95.2 with the G-code ‘M92 E95.2’ (you may need to calibrate this figure).

Weight of the hot end reduced to 75g

To use the NEMA as the extuder motor, you need to add M92 E95.2 to your G-code file or the 101hero file if you are printing from SD card. Printing with Cura, you need to add this command in the printer start.gcode

Manually feed filament to the hot end through the Bowden tube is not difficult when the Bowden tube is short. However, I recommend to use some control program like Repetier to control the extruder, it is more convenience especially when you always need to change the filament.

Bowden extruder not only improve the print speed and quality, it is also the prerequisite setup if you want to upgrade the hotend. 

Stage 3 - 101spiderman (Part 1)

101hero is using direct extruder that is mounted directly on top of the hotend. Filament is tightly hold between the wheel and roller. The wheel is rotated precisely by the stepper motor to pull the filament into the hotend. However this setup increase the weight of the moving parts that limit the printing speed as more momentum need to be solved when changing direction.

With the bowden extruder, we can remove the stepper motor and the filament door from the hotend assembly. The weight of the moving parts can be reduce to 75g from 135g. A the result, we can have a more accurate prints at higher speeds. If we want to upgrade the hotend (like E3D-v6), bowden extruder is nearly a must. Although Nef Lopez have the solution to put the E3D-v6 hotend into the existing direct extruder, it is not an easy task. (Click here for details)

If you don't have another 3D printer that can print precise parts, you need to purchase the extruder set. Otherwise, you can print your own kit using the design from Dan Delaney (http://www.thingiverse.com/thing:2125375). I myself using the below kit

I tried to use the existing motor with the conversion mount but fail because the 28BYJ-48 don't have enough torque to drive the bowden setup and eventually a NEMA 17 take the place.

...

Stage 3 - 101spiderman Prequel

Before moving further to the extruder upgrade, I would like to give you more details on the electric and electronic parts using in 101hero.

1 x 12V 3A power supply, 1 x controller, 3 x stepper motors for the pylon (cable A B C) , 1 x stepper motor for the extruder (D), 1 x thermistor (E), 1 x cooling fan for the extruder (F), 1 x heater assemble (G), 3 x limit sensor switch (H I J)

The controller is Sanguinololu clone with ATmega1284P and 4 x Pololu A4988 stepper motor driver. The preset current limit for each motor is around 480-500mA

The 3 stepper motors for movement is a custom made 12V 28BYJ-48 with 1/32 reduction ratio. I believe the supplier does not use the normal 1/64 one is it cannot provide enough torgue even printing at 14mm/s. I will go deeper on this topic when talking about replacing the extruder stepper motor to NEMA 17.

The stepper motor for the extruder is the normal 12V 28BYJ-48 with 1/64 reduction ratio but longer shaft.


The thermistor is 100K ohm NTC 3950

The cooling fan is 12V 25mm 90mA fan

The heater is 15W and will draw 1250mA current.

The total power consumption of the 4 motor plus the heater is already need 3A that the existing power supply is merely able to support. So if you want to go further, you need to upgrade the power supply. 7A is the minimum requirement if you want to be the superhero.

Stage 2 - 101ironman

The structure of 101hero is built by plastic. It is not a problem, the structure of the pylon also very solid. The main issue is on the two triangle plates and the six diagonal push rods (arms). The material of the triangle plates is too thin and can easily bent. During printing, the whole printer will shake that make the pylon move and the arms also curved and loose the contact with the ball joint. The above two movement can make the nozzle out of its original position by 1-2mm that create wavy print. Even worse, it create missing step problem to the weak motor and create shifted layer. No matter you want to further evolve the 101hero, you should fix the structural problem.

Top and Bottom Plate

Andy Berger replaced the top and bottom plate with 2mm aluminum plate (https://www.facebook.com/groups/101herounofficial/permalink/1212951378782424/)

Some people just use superglue with wood bar.

My solution is insert 6 aluminum bar into the gap of the pylon. You can use any method you like, just to make sure the distance between the 3 pylon is fixed and will not move during printing. This upgrade cost me $0 as the aluminum bar is the remaining parts from my old curtain.

Diagonal Push Rods

Stefano Marcon replaced it with the carbon fiber arm.

Other people use elastic band or light weight springs to pull the arm to the ball join

Elastic band by Stefan-Gautsch - Spring by David Leeds

I am using the idea from David Leeds who glued a 2mm carbon fiber rod to the arm and attached weak springs to them. This upgrade cost me $4 for 4 x 1 meter carbon fiber rod and $1 for 8 springs. I just used one rod and still have 3 remain. This solution provide similar improvement as the carbon fiber arm but much less in cost.

For the remaining carbon fiber rod, you can also use them to strengthen the structure of the triangle plate as what David Leeds did (https://www.facebook.com/groups/101herounofficial/permalink/1225738600837035/)