Very interesting ! I have a dual extruder project and I want to use it to print soluble support structures. I planed to do the same experiments once my dual extruder is functional. Does the ultrasonic pulses makes a lot of differences or a heated bath of sodium hydroxide is enough to dissolve the PLA ? Is the sodium hydroxide has to be laboratory grade ?by Petrus - General
Now, the temperature regulation electronics: The system is based on an Atmel atmega 324, the 8 thermocouple inputs are multiplexed by two 4052 circuits, so only one thermocouple amplifier is used. The 3 other boards are the power switching circuits, the big one will control the heated bed . The small one with the 2 big mos salvaged from a motherboard will control the extruder's heaters and the oby Petrus - Controllers
I installed the lighting system, 2 fluorescent tubes from scanners :by Petrus - General New Machines Topics
Here is the extruder switching electronics : A digital output is used to switch the step signal between the two extruder motor drivers, the circuit on the left do that job. My dual extruder design will use an RC servo to lift the unused extruder, the signal to drive the servo will be generated by a circuit based on a NE555, that's the one on the right.by Petrus - Controllers
I built my heavy Mendel with cable drive and 2:1 pulley system, it works perfectly, I can print, engrave circuit boards and cut polycarbonate sheets without any slip. The driving pulley is just a printed cylinder, way easier to print than a timed pulley. Other pulleys are also printed.by Petrus - Let's design something! (I've got an idea ...)
To power the the heavy mendel I am building a box with all the power supply and electronics it will need for current and future uses. The box will be equipped with : * 5V power supply * 12V power supply for the extruders and heated bed * 24V power supply for the stepper drivers * soft start circuit on the 12V and 24V * 6 stepper drivers (X,Y,Z,A axis and 2 extruders) * extruder switching circuitby Petrus - Controllers
I use EMC2 to drive my 3D printer/router combo, it's based on a real-time Linux kernel and outputs the step and dir signals directly to the parallel port. But parallel port is outdated and inputs/outputs are limited (12 outputs and 5 inputs). Mach3 (the closed source equivalent of EMC2) can work with dedicated USB adapters, I would be very interested by an USB adapter for EMC2.by Petrus - Controllers
J'ai gravé un circuit aujourd'hui, j'ai fait des photos à chaque étape : La gravure ne génère pas beaucoup de poussière, c'est le perçage et la découpe qui en fait le plus, mais elle reste a proximité de la plaque.by Petrus - RepRap Groupe d'Utilisateurs Francophone
Pas mal la gravure dans l'eau, la plaque est fixée par de l’adhésif double face ? EMC2 utilise le port parallèle du PC pour piloter directement les drivers des moteurs pas à pas, il n'y a pas de microcontroleur entre le PC et la fraiseuse. Dans la vidéo de Traumflug postée par DeuxVis, la même méthode est utilisée pour définir le zéro, donc ça doit être possible avec une gen7.by Petrus - RepRap Groupe d'Utilisateurs Francophone
Je grave aussi mes PCBs mécaniquement. Avant, j’utilisai le perchlo et tout le bazar. Avec la fraiseuse, c'est peut être plus long, mais tellement plus pratique, surtout pour le perçage. Je fixe le circuit sur la base avec des vis : C'est très important de mettre le circuit parfaitement à niveau, pour cela j'utilise le contact électrique entre la fraise à graver et la plaque de cuivre pour généby Petrus - RepRap Groupe d'Utilisateurs Francophone
Since you already have a CNC mill, you can cut the mechanical parts of the extruder yourself like I did for my first 3D printer. I built a light CNC mill then converted it to a 3D printer using itself to make the extruder parts : EMC2 can perfectly handle the extruder motor, just wire the extruder stepper driver on the A axis output and calibrate it to have 1° = 1mm of filament. With the alterby Petrus - Reprappers
I was also surprised by the low switching frequency, at first I put a 1nF capacitor and it was very noisy, then I changed it to a 470pF, the switching frequency is now above the human ear range, I will try lower values and check it it heats-up more. On the Electrical Characteristics table on the last line you can see that the frequency can vary from 60 to 200kHz with the standard 330pF capacitorby Petrus - Controllers
The 470uF was just a guess but actually it is justified, the example on the datasheet show a 47uF capacitor on Vmot with an Fosc of 400kHz, with a current set at 1A/phase. With Cosc = 470pF I get a switching frequency around 30kHz (measured with an oscilloscope) and I will use the driver at 3A/phase. Big capacitors can also absorb more energy from back EMF during direction changes, and I will haby Petrus - Controllers
The Vmot delay and soft start will be handled by a dedicated circuit, I already put the schematic on an other thread : /!\ wrong schematic/! It still needs to be tested. The problem with a relay is the current surge due to the capacitors, I don't think a relay will last very long without a soft start circuit.by Petrus - Controllers
I did not see the AKA47 design before. The schematic is the same, except for additional pull-down resistors I put just in case and the reset RC circuit. What I don't like in this design as well as other design I found is that there are components on the rear of the TB6560 so you can't put a thick heat sink on it. The one I put on the prototype would fit on AKA47 design too, but it get very hot aby Petrus - Controllers
To improve the performances of my heavy Mendel I need powerful steppers drivers, so I designed a driver board based on the TB6560AHQ driver circuit : Instead of expensive and hard to find power resistors, I use several 1ohm small resistors in parallel, each resistor adds 500mA to the driving current. Current, excitation mode and decay mode can be adjusted using jumpers. The circuit is singleby Petrus - Controllers
I've uploaded the files on thingiverse : Main/Frame : X Axis : Y Axis : Z Axis : Linear bearing : I've also put the files on the wiki :by Petrus - General New Machines Topics
I installed my repstrap's extruder on the heavy Mendel temporarily. The speed is twice as fast as my last printer (60mm/s instead of 30mm/s) I plan to improve the speed again using more powerful stepper drivers and maybe a bigger Y stepper motor. I don't have backlash problems, as you can see, rounds are round.by Petrus - General New Machines Topics
EM483, pas de problème, c'est bien un moteur bipolaire au format nema17 j'en ai aussi récupérés. Les bobines sont connectées sur les fils 1-3 et 2-4, la résistance d'une bobine est de 3 Ohms.by Petrus - RepRap Groupe d'Utilisateurs Francophone
Did you try with ABS juice (ABS dissolved in acetone) on glass ? The part is printed in clear PLA left : without ABS juice right : with ABS juiceby Petrus - General
There are several turns around the driving pulley, here is a close-up picture of the system : On the picture it was 0,75mm 7 strands steel wire but it was too rigid and broke during the reliability test. The driving pulley is printed in ABS.by Petrus - General
Y axis upgrade, now with 4 smooth rods :by Petrus - General New Machines Topics
I use 0.5mm stainless steel cable on my current project, it's not finished yet but I already tested the X axis : The video show 4 test cycles, with 100 cycles the result is the same.by Petrus - General
X axis test :by Petrus - General New Machines Topics
mad-e on the forum has the same drivers :by Petrus - CNC Routers, Mills, and Hybrid RepRapping
Je serait présent. D'ici là, ma Heavy Mendel ne sera certainement pas finie, mais elle sera au mois opérationnelle avec un seul extrudeur, je l’emmènerait pour faire une démo.by Petrus - RepRap Groupe d'Utilisateurs Francophone
You will need to export the model to a .stl file. Blender can do that. You will need to print support structures for this model, skeinforge can create them automatically. The surfaces in contact to the support structures will not be very clean. Do not expect perfect surfaces with an fdm printer. I printed a warhammer soldier to see what my printer can do : The printing time will depend of theby Petrus - Reprappers
last advancements : The opto end stops are salvaged from printers, I designed a support to clip them in :by Petrus - General New Machines Topics
I will also use TB6560 to drive my heavy mendel, for power switching I firstly, I thought about using a relay powered by the logic supply, but switching the power of 5 drivers with a 470µF cap on each is not a good idea. So I designed this delay/soft-start circuit : I didn't tested it yet, but the simulation works.by Petrus - Controllers
I wired an epson printer board with A2917SEB drivers to test some steppers :by Petrus - General New Machines Topics