diy - DIY & Electronics

I'll share my experience first.
I've started 3d printing a bit more than one year ago
My printer is a prusa-mendel i2 ( http://reprap.org/wiki/Prusa_Mendel_%28iteration_2%29 ), the extruder is a wade geared extruder and the hot-end is a plastic j-head, only partially cooled. Right now, they work in direct feed configuration (meaning that the extruder, which is the part that pushes the filament into the hotend, is directly above the hot end and moves with the carriage) but now that my hotend broke I'm switching to a bowden style (the extruder is fixed and pushes the filament in the hot end by guiding it with a bowden tube).
For the electronics, it's a ramps kit (1.4 I think) with a big screen (there are versions with 2 lines screen, but the big one was just $10 more and it's totally worth in my opinion), the motor drivers are based on the Allegro A4988 and they're not cooled (no fins, no fans). The base board is a standard arduino mega 2560, branded sainsmart. Power comes from a 500w pc psu, which barely does its job and should be replaced with a decent 12V power supply.
The only other electronic parts are the motors (generic nema 17, bought along with the rest of the electronics), two fans (one partially cools the and the part, the other is supposed to cool the part but none of them work very well since I am too lazy to do it properly), the heater units (a 40w resistor for the hotend, a 120w heated bed), two 100kohm thermistors to read bed and hotend temperature, and the endstops, which are mechanical based on makerbot design.
The frame is made out of m8 threaded rods and plastic parts, it uses 8mm smooth stainless steel guides for the carriages.
Firmaware is a marlin, I don't recall the version.

I suppose that's enough boring informations.
I print mainly with pla, because I work in my room which is small and poorly ventilated and ABS smells like death, if you have ever burned some electronic appliance you know the smell I'm talking about. It doesn't smell that bad, but it's pretty close.
The smallest part I've ever printed is probably a 7t 1.25mm pitch (iirc) gear, done using a 0.5mm nozzle, which worked, but it was a pretty poor print. (pic related the gear mounted, on a 2mm shaft).
The biggest part I've printed is a big cilinder, part of a frame, it wasn't really hard to print but was hard to fit in the 20x20 cm^2 buildplate.
The longest print I've made is a 10x10 cm^2 hollow cube with 5mm thick walls, which took 7h to print, not having a battery pack I was pretty tense because if the power goes out you can say goodnight to all your plastic.
You can actually recycle the plastic at home, but I still haven't tried it, despite having quite some scrap plastic saved up by now.

Speaking about slicing softwares (the program that create the path for the printer head), I've used slic3r and Cura. Both have pros and cons, I like cura because it's easy (well, before the version 16) but slic3r gives you far more control and it's a good thing on tricky prints. But it also requires more skill, which I lack for the most part.

Right now my jhead is broken, I can still print but it leaks plastic and it's not nice, but hopefully it shouldn't catch fire.

>>1320
My RepRap Kossel Mini kit just arrived, forget to buy filament...

>>1320
I want to get started in 3D printing but have absolutely no idea on how to get started. Hypothetically, say I buy a 3D printer and its stuff. Then what?

>>1386
start modeling in 3dsmax or something

>>1386
Why do you want to get started?
If just because you think it's cool, then you can go on sites like Thingiverse and download what other people make and try to print it.
If you want to make your own things, as the other lainon said either get a 3d modeling software or a cad (depending on what kind of things you want to make) to make your own models, and then print them.

Even just printing is fun or frustrating but making your own parts is more interesting and gives you better understanding about how the development of a part that needs to be printed goes like using adjusted clearances, sticking to proper dimensions and always thinking about "how ill I print this?".

After you have the hardware (let's assume you'll buy a commercial printer already built and set up) you will have to get used to the slicing software, some prints are tricky and you need to know how to set it up to obtain a good Gcode for that print.
There is nothing like first hand experience, but some times you might not understand why something is not going well so you might want to ask questions on the reprap forums or places like that.

On an unrelated topic this week my new parts will be delivered, I'll make sure to post some more photos of the new setup. I really hope that the bowden will give me even better prints.

>>1392
It's because 3D printing would be really fun, yes, but I can probably also make little things around the house for myself. Why buy things when I can just make them? /diy/ in a nutshell. Instead of buying phone covers, I'll make one. Etc.

>>1393
It's not a replacement for cheap mass produced goods yet, because most of them are cheaper bought than made with plastic.
It's more like "oh, I'd really like to have a thing like this but nobody around here sells for a decent price it so I'm going to make it myself", and for replacement parts since most companies don't sell tiny parts or price them ridiculous amounts.
That said, you can do almost anything with 3d printing and post processing, and it is less messy than working with wood for example, if you have the money go for it.
Plus is fun and pla smells very nice.

>>1368
Oh, I must have missed this.
Nice, the kossel looks very sexy imo!
Have any photos? Did you already get the hang of it (if it is your first printer)?

Parts are here, everything's alright except that I'm disappointed about the connection part inside the hotend because it doesn't have PTFE lining. I can cut a little piece out of the bowden cable but I'm still buttmad about it since it's an easy task for them to machine little pieces but not for me. Will get more in detail about this tonight, with more random photos about the changes I'll make.

>>1410
>Will get more in detail about this tonight, with more random photos about the changes I'll make

Sweet! I will be looking forward to that.

Just finished assembling/converting to bowden the extruder.
You can divide the extruder in two parts, the part that pushes, and the part that melts.
The part that pushes is the one with the motor, can be geared or not and can be mounted directly on the hot part, in a direct feed setup, or connected to it with a bowden cable, in a bowden setup.

Right now I'm converting to a bowden setup from a direct feed, you can see in the image the bowden cables (they're PTFE, teflon is a commercial name of PTFE based parts), both for 3mm and 1.75mm filament.

In the image you can see things as they will be assembled, the push fit connectors are connected to the bowden (I won't use the top ones because I'm using ones that fit the Wade geared extruder, which is my current motor part of the extruder), then as we go down we have the hot-end body, which is the part that is connected to the carriage and must cool down the filament to avoid clogging, then the connection part, and finally the heater and the nozzles.

This particular hot-end has a shroud and a fan to allow better cooling, which is important to avoid clogging especially when using small nozzles.

Other parts in the image are the Z axis coupler which are the parts that connect the threaded rods of the Z axis to the stepper motors, I was using printed ones but these are springy and they're better because they correct little unalignment, which means you can run your motors at lower Amps without losing steps even if the thing is not perfectly aligned.

There are also some extra thermistors (you always want to have some spare especially if you have to buy them on the internet) and a support part, which I'm not entirely sure how it's supposed to work but I'll figure out something worst case scenario, there is always duct tape.



The other image is what I was complaining before. You can see how the 1.75mm connector has no PTFE lining inside, and this is something you definitely want to avoid because it WILL clog. Technically you'd want that PTFE layer to be as thin as possible because it's insulating and reduces the cooling capabilities, but I hope it will be okay the way I made it.

Next post will be the installation of the lining.

This is the creation of the lining. Despite what I said earlier, that part is pretty hot so even if you skip this you will probably be fine. But cleaning a clogged extruder is one of the most boring things ever, so better avoid that.

I used part of the PTFE bowden tube. It is obviously too big to fit inside there, so I had to sand it a bit. The hard part about it is that you have to keep it the most round possible, to ensure good connection (thus heat exchange) with the outside metal part. I used a drill (aka tiny handheld lathe) to make it spin, using a 2mm drill bit butt put inside to keep the thing steady.
Another thing you want to know about PTFE is that it is extremely slippery. So it will slip away at the first chance or stop, better not apply too much force with the abrasive tool. The abrasive tool I'm using is just a cheap knockoff dremel.
After some tries I made it fit, and now you can see how both have a ptfe lining.

Again, this was probably unnecessary but I'll never tire of complaining about how damn boring is to clean an extruder

Do not forget to check if your filament can pass without effort through it, because hard to push filament means hotter motor and possibly clogs.

Now I'll take a break and then either disassemble the Z axis or post some photos of the hot-end body and assembly.

I am not looking forward trying to take down the backlash remover. I used springs that are too strong and compressing them was a pain. Now I have to remove them with the thing half installed (I am sure as hell not taking it down and redoing all the alignment).
So well, here are some more photos, this time it's the hot end.

So, in the first image you see how you want it to be assembled.
There MUST be a small gap between the heatsink and the heater, because that allows to have only that tiny bridge of metal as transition. It makes a real difference and you will most probably clog the extruder if you do otherwise. I believe that they're too close but I don't want to get the screw out more, because it will have too little part inside the heater and I also prefer it to be fastened tightly on the other side (the one with the fins), because it will make it easier to clean if it clogs (although it shouldn't).
The second image is the example of how you do NOT want to do it.
The little scheme on the side is an explanation of how the temperature must be inside of the hot-end.
As you see, the hot part is only the one down, I am not sure but I think the best thing would be if the connection part and the nozzle were connected without that buffer chamber in the middle, but my things are a little short and anyway there is really hot so it doesn't matter for clogging. If the heat goes up in the zone where it is supposed to be cooling, the filament will start to melt there, and when finally reaches the part where it should be cold, it creates a puddle in the connecting part and as soon as it cools, your hot end will be clogged.

In the third photo there is a closeup of the heater part, the red wired thing is the resistor, that should be 40w, there are also smaller ones at 3W for smaller printers I think. You can also see how I put the white PTFE tape on the threads. That is a thing you have to do if you use J-head style hot ends, because it might leak otherwise. I'm not sure if it's needed there but better safe than sorry.
I've also added a bit of threadlock hoping that it will prevent the thing from unfastening.
It shouldn't happen at that point (because it would have to take away all the damn wires) but then again, better safe than sorry because that part vibrates a lot and it heats up. Once the resistor retainer screw on my j-head unfastened and it dropped on the plate and the print caught fire. That's when I started putting nail polish on that screw, then letting it cook up the first time so it would make some sort of poorman's threadlock.


Another kinda important thing, that black cap thing is the best kind of push fit connector, because it allows the PTFE tube to go through all the way, while the other kinds stop the tube at the connector and leave a small part where the filament is unsupported. If that space is big enough, the filament will bend and make a mess, again clogging your extruder (this is easier to clean though). I think this is a problem only with the 1.75mm filament, but I had it fuarking crumple up for being unsupported for less than 1cm.

Couldn't push them to unlock them easily, had to damn unscrew them for the whole length. I've been turning those damn things for the last 30 minutes. At least it's done now.

Will not write much now, just dumping some photos of the old extruder.
It is a J-head model (because it looks like a J I suppose) and it is made of plastic (I don't remember what kind, but it softens at 245°C).
It was seriously abused, and even when it broke I kept printing the adapters for the bowden (although with poor results because I didn't compensate in extra flow for the part that I was losing on the sides).
The "burned" color is because of those leaks I was talking about earlier. if the plastic leaks down, it will burn on the heater and give you that color. It won't go away.

Maybe I should spoiler them. Watch out plastic gore ahead (or behind, by now).

By the way it is a pretty easy extruder to operate, it doesn't clog much (at least with 0.5 nozzle) even though I didn't have a dedicate fan. And if it clogged it was supereasy to disassemble, then just drop the whole thing in boiling water and you're set. At least with pla. But even ABS softens a bit at that temperatures, making cleaning really easy.
You can look online for the cutaways, but basically the black part is a tube and has a ptfe tube inside that drives the filament till the head, the nozzle is attached to the heater, they're just a single block of aluminum. The lining has a cap on the top that keeps it in place, is just a hollow very short allen screw.

Today I accidentally broke the glass printbed. They're pretty cheap because I just get 21x20 photo frames and get the glass. I also get some MDF wood, which is pretty useless but you might use it sometimes. It's just 2€, spending 10€ for the borosilicate kind is not worth it in my opinion. at least to print pla and ABS. I never had problems heating it up to 100°C, but if you want to use a particularly hot bed, then you might choose the borosilicate.
On the other hand, the photoframe glass is very thin, so when you go put it on the bed it warps a lot (my bed is about 0.15mm higher at the center, and that is A LOT for printing purposes) if you use clips, rendering bed leveling impossible. You can still print obviously, but you either choose to only print at the center and accept that the borders my detach, or set it almost touching at the center so that the borders stick better. You have to find the right compromise.
Now I'll try to not use the clips anymore, I've read that people keep it in position with just tape, I want to try that.
Or maybe buy thicker glass, if I wasn't a dumb fag I could have scavenged the glass from a window that broke some time ago, that would have been cost effective.
This glass is 1.65mm thick.

Today's topic is actually the motor part of the extruder. I thought that I never showed you how the direct feed extruder was set up, so the first photo is a complete photo of the X axis carriage, the part on the top is the one that pushes the filament (which comes from a reel) and it is a Wade's geared extruder, the hot end is attached to the rest of the extruder with those two screws on the front just below the big screw with the bearing.

On the second photo you can just see how the bottom of the extruder without the hot-end looks, that hole is where the filament comes in and it enters the hot-end right away.

The third photo is more interesting, that is the inner part of the extruder and it shows how it works.
Starting from the beginning, the gears are the stepper transmission.
The big gear is connected to that screw, that is called hobbed bolt and it is the part that pulls the filament. Not all the extruders use a bolt, some use a proper gear, but it always does the same thing. It grabs the filament and it pushes it, and that's achieved thanks to the middle part which has all those little teeth.
You can buy one, but if you have tools you can easily make one yourself, I made mine using a press drill, an angle grinder and a tap (I used one of those conical counterclockwise taps that are used to remove broken bolts.


Now that you know about the hobbed bolt, the only remaining thing is the tensioner, which is just an idler bearing that presses the filament on the bolt thanks to those two springs (you can only see the head in the photo but look at the first and you'll see them in ready position).
That is a pretty important part, because depending on the filament you have to regulate it in order to have a good grip and to not eat through it. PLA is pretty resilient, so as long as it doesn't clog it won't eat it, but abs is more delicate and needs lower force. You don't want it "tight as Satan's sphincter" as some people on the internet would describe it but neither too loose, it's just something that you'll learn in the first week.


This turned out to be pretty long, I hope people like reading even tho I'm not that good at explaining things, in case just look at the images.
Next up will be the conversion I think, but not tonight since I want to get more work done, I have to rewire the carriage.
Had to delete the part about how to make a hobbed bolt, will add the next time maybe.

I don't really feel like working too much today so I'll just talk about the bowden adapter for the Wade's extruder.

Baically, it's just the top part of a J-head style hot end, and it has a clamp for the tube inside.
Remember that if you have a universal extruder (1.75/3 mm) you'll have to run the PTFE tube up to the hobbed bolt. My extruder is only 1.75 so it didn't matter.
In the photo you can see the adapter disassembled, and you can notice a broken teeth on the clamp.
That's because the print quality was really bad (irl you can see all the parts where the extrusion was too low) and I was wondering how strong it was.
Answer: not enough.
But it doesn't matter, it works anyway.

Many times, especially when you are starting or when something breaks, you can't afford to be too picky. Just patch things up until you are up and running, then modify. Second pic very related to this concept. Since the support was not good for a bowden (I suspected it but I still wanted to try it) I had to patch it up with a small plastic sheet cut off one of those blister packs. Is it an optimal solution? hell no, but it works.

By the way, printer is now up and running, but now I need to draw and print most of the supports for the hot end and the extruder motor, which right now are just staying up thanks to mysterious forces or maybe thanks to cheap plastic and metal wire

I still need to find a satisfying fan. I tried the circular ones and they're pretty cool, I also bought a lot of blowers for them but it's damn hard to make one that won't hit the plate. Since I have to draw the mount for the extruder anyway I could attach it there.