New parts arrived and MMU Part 3

So today more of the parts arrived that I ordered for my built.

Finally I have the stepper motors. Pro Tip, whatch out for those with the lead screw as shaft, don't use the cheap ones with couplers. So I was about to finish the frame built today...

But I realized that the M3x10mm don't fit as the aluminium parts are not as thick as the original 3D printed Prusa parts and the screws don't fit far enought into the motors to be tight. So I ordered some M3x8mm as I don't have them in stock.

Then I got some of the MMU 2 parts today. I have not the stepper motors.

The MMU 2 electronic board came with cables. Also the 2x4mm orange PTFE(the usual PTFE tubing used for 3D printers has a smaller inner diameter than 2mm) with push fittings.
And the two shafts with brass tubes as bearings for the selector.

I am still waiting on the bearings and I need to get the 2 springs for the MMU 2. I could order them from Prusa, but the goal was to het everything as cloned parts. Then I still need to print the idler in PC. But printing PC is tough without enclosure.

I also got the 5x16mm shafts for the idler today.

I was so eager to put things together that I just started with the selector and put the electronics board into the chassis.

For the electronics board you just need 3 M3 nuts, 3 M3x6mm screws.

The nuts are pressfit into the 3D printed part. The electronics board is inserted. Watch out for the micro USB port and the switches. Then secure the board with the 3 screws. Don't tighten then too much, otherwise you night damage the board.

For the selector you need 6 M3x10 screws, 1 M3x18 screw, 6 M3 square nuts and 1 M3 nut.
And the front plate, the lead screw nut and the blade.

Prusa has a very good manual how to put it together.
Prusa MMU assembly

Once you are done, it should look like this. Be careful when you handle it as you can easily but yourself with the blade sticking out.

Raspberry Pi Zero W and Octoprint Part 1

One thing I really love about my Prusa MK3 and especially about the Einsy Rambo board is the ability to stack a Raspberry Pi Zero W on that board. No external power source or cabling required.

I have to admit that I used my original MK3 with the SD card for months until I did the Raspberry Pi Zero W upgrade. Now I don't want to miss it anymore. I am using the Telegram bot plugin, to receive messages from my printer and send commands with my smart phone.

And because I like it so much I also want to have this on my cloned MK3.

So what you need is the Raspberry Pi Zero W(for WLAN) itself.
A memory card, as priced dropped on black Friday and you never have enough I used a 16Gb card this time.
The 3D printed frame, that is available from Prusa.
And a 18mm GPIO header dual male strip. This is important as the "usual" ones are to short!
And maybe most important soldering equipment and skill!!

Then I would recommend printing a new case for the MK3 that allows you to get access to the Pi without the need to disassemble the whole printer every time. You can find plenty on Thingiverse or use the one from Prusa.
I am using this one Thingiverse MK3 case for Pi

I strongly recommend to follow this instructions from Prusa which are very good and also contain links to the Octoprint Image that is already prepared for the MK3, the Pi frame and the updated chassis for the electronics.

Manual Prusa MK3 Octoprint with Raspberry Pi Z W

And if you want to monitor and control your MK3 from your smartphone I recommend the Telegram plugin for Octoprint.
OctoPrint Telegram Plugin

But one thing I will mention as a warning. Be very careful touching the Pi with your hands, you might destroy the Pi with electrostatic charges. So I recommend to touch something grounded before.
Also be careful with the soldering. If not all pins have proper contact it will not work, your printer might noch even boot. Or worse, if you short the GPIOs then you might even damage the Einst Rambo board.

The Pi Zero does not have as much compute power as the Pi 3. This is why I would not make too much use of the streaming feature. Yes, you can attach a webcam or the Raspberry Pi cam to the Pi zero. You can use it to send you photos of the finished print or stream the whole print. But keep in mind, the Pi also sends the commands to the printer. If he is too busy doing other things this might have an impact on your print.
The other thing I would not recommend is to use the slicing feature in octoprint. Basically it allows you to send STL instead of GCODE to the Pi. You can install an older Cure version that will do the slicing job then. There is also a plugin for Slic3r.
I rather perform the slicing on my computer. It is faster and much more easy to change configuration and print settings as on the octoprint plugins.

The MMU 2 Part 2

Just a short update, was not sure if it is wort calling it part2. But you will need those things as well, so see this as a little help.

One thing I could not find on aliexpress was the brass threaded insert in the selector front plate.

So I did some research to figure out what exactly this is and what it is called. The correct name is "Multi Micro Insert" and is designed to be press fitted into plastic parts.
It comes in different sizes with threads from M2 to M10. I was able to finde 2 manufactors in Europe that sell those things. The one used in the Prusa MMU 2 has a M5 thread.

Unfortunately not to end customers and not in small quantities. I was able to get some, but now I have much more than I will ever need. And as I struggled to get those I thought I sell them on ebay for anybody else who might need them.
Ebay Link to the threaded insert

So if you plan to build your own MMU 2 or just need them as replacement you have now an easy way to get them.

The other item that you probably not order from Aliexpress is the cutter blade. Most break off blades come in 18mm, but what you need is 9mm.

You can find them in the home improvement store or just order them on Amazon like I did. Break off 2 blades and they fit right in the selector.

The steel rods with brass tubes for the selector is something I ordered as a kit from Aliexpress, same as the PTFE tubing. You need to watch out for the right PTFE tubing. The inner diameter is bigger then the other PFTE tubing you get for 3D printers with 1.75mm filament.
For the MMU 2 you need 4x2mm, so 4mm outer and 2mm inner diameter. On Aliexpress you can even buy them in the orange cooler that Prusa uses for the original MMU 2.

Some more parts and Frame Part 1

The mounts for the steel rods of the y-carriage arrived today. They are made of aluminium and black anodized. The steel rods are heat in place by some set screw instead of zip ties. If this is better? Well, time will tell.
To mount them you need M3x10 screws. Only problem I found is that the holes for the screws are either not tapped properly or during the anodizing process they messed it up.

And as I have most of the parts now, I decided to mount the frame today. So what you need is the frame parts and 32 M5x16mm screws.

And do not forget the T-nuts for the power supply and the rubber feet, before you attach the front and rear plates.

The most important thing about the frame is to get it square. I strongly recommend to follow the instructions from Prusa. They are very detailed and very good.
Prusa MK3 assembly instructions

And this is the result, my cloned Prusa MK3 frame.

As you can see the frame is not really black. The frame parts seem to be powder coated, not anodized like the extrusion parts. This coating is thick and has some metallic effect.
But the holes did fit, some where a little tight because of the coating.

The LCD Display

I printed the plastic parts for the LCD display in original Prusa orange PETG.
But not without tweaking the files a little bit to reflect that this is not an original Prusa.

For the assembling you need :

LCD-Controller with SD card reader  € 6,67
2 M3x10mm Screws
Allen wrench that fits the M3 screws
Plastic parts that Prusa shares as STL, STEP and SCAD files on GitHub

The 2 supports slide from the side over the LCD circuit board, which is then secured by a notch and the 3 M3 screws in the plastic part.

Then you need to attach the cables. Both red marks have to be on the side of the smart card reader.

Then the knob is attached and you have your LCD assembled.

This is a part that makes me wonder about the pricing politics from Prusa. If you order the LCD board from Prusa as a replacement part they will charge you 57,32 € for it, plus shipping. So 10 times more as if you buy it from a Chinese seller. 

Maybe Prusa does some testing to ensure every LCD is properly working and that would justify a price that 2 double the price of the part. But 10x more?

The MMU 2 Part 1

I already printed most of the plastic parts for the MMU 2 in PETG. I want to printer the idler in polycarbonate. Meanwhile the polycarbonate filament from Hobbyking arrived, but my first attempts to print the idler failed due to extreme warping.
I have tried my print milk, a 1 to 1 mixture of wood glue with water, but that was not strung enough to keep the first layer on the bed.
It seems like others had success with PET foil, yes PET, not PEI as the standard MK3 coating for the spine steel. I have ordered a PET foil with some iron particles, that is usually used as a whiteboard that can hold magnets. Let's see if this will work with the magnetic heat bed of the MK3.
I was also thinking of printing a raft with PETG and then the other layers in PC. Maybe I will give it a try too.
But I guess the key is the enclosure to prevent the part from cooling down too fast. But that is not ready yet. Unfortunately I did ran out of the nice Prusa orange PETG and it is not in stock in the Prusa shop right now.

But I thought I give you the list of parts I ordered from aliexpress for my MMU 2.

10 x 625ZZ bearings for the idler €1,51
100 locating pins 5x16 mm as shafts for the idler (just need 5) €5,27
Prusa i3 MMU 2 bord, motors, power and signal kabel kit €103,72
120mm smooth rods and brass tube 5x6x25mm kit €7,96
pneumatic fittings and 2*4mm PTFE orange bowden tube €6,03
(this one is for the connection from the MMU to the extruder)
5pcs Drivee Gear with groove for MK8 extruder  €2,33
Another set of P.I.N.D.A v2 probe and filament sensor with cable  €14,58
(just need the P.I.N.D.A probe for the MMU, the filament sensor with be spare)

I ordered those parts among with others for the printer itself on the 11.11 sale and expect to get them begin of December.

I need also this multi micro brass insert that is pressed into the printed part. Those are not so easy to come by. I have found manufactures in UK and Austria, but both only sell to dealers.
So I have decided to buy some more and sell them in my ebay store.

I also need some more PTFE tubing in 2x4mm to reduce the friction for the filament and the set of springs for the idler tensioner.

More parts arrived...

So on Wednesday some more parts arrived for my build. All this stuff was ordered on 26th October and arrived at 14th November, not bad for a shipment from China.

Finally the rest of the frame is here now. So I guess I will make the first video on the weekend how I put together the frame. Just need to check that I got the right screws. The aluminum extrusions have an extra layer of foil for protection. The linear rods have a nice chamfer the the end.

The part I was most exited about was the mount for the Titan Aero hot end. I can only hope it fits for the Titan Aqua as well. But that did not arrive yet.
It did come without linear bearings. This time the bearings are secure with a locking spring instead of a set screw. It is well made and looks top quality.

As my goal was to have all features formt the original MK3, I also ordered this board for the power fail. It comes with a power inlet and seems to have an opto coupler to separate the board logic from main voltage. It is the little IC that bridges the 2 parts of the board.

Then we have the stand offs for the heat bed. Nothing special, comes with screws and a cheap allen wrench.

Then we have the filament sensor with cable. Looks exactly as the original part from Prusa.

For the automatic bed leveling I ordered this P.I.N.D.A V2 probe. A proximity switch with built in thermal sensor to compensate the influence of temperature to the measurement.

And I ordered 2 sets of those rubber feet. One for this project and the other for my original Prusa. It is so annoying that the original feet fall off every time you move the printer. They come with T-nuts, screws and a cheap allen wrench.

Next we have the textil sleeve for the cables that Prusa now recommends over the spiral sleeve. They say the spiral sleeve might be to stiff and grind on your cables.

The idler pulleys with bearings. Not so sure if I need them anymore.

Then the U bolts for the linear bearings on the Y carriage. Unfortunately only 2 of those bolts, one is missing. The seller promised to send the missing one right away. Let's see how long this will take as this will delay my little project.

I had also ordered a pair of radial fans in 5V. They did not come with the nice shroud as show in the picture on aliexpress and even advertised as a MK3 part, the cable is not long enough and needs to be extended to fit the MK3.

This is the timing belt. 5 meter, should be more than enough.

I also ordered a NTC element for the hot end, just as a replacement part.

I ordered a set of those heat sinks for stepper motors. One was damaged on arrival, not much, but you now I am picky. The reason I ordered them is that on my original Prusa the stepper motor gets real hot while printing. The stepper did not break so far, but makes me feel uncomfortable.

Now that I have most of the parts I can start with the build soon.

Most of the aluminium parts

Today most of the aluminium parts arrived. The mount for the Titan Hot End is still missing, but I ordered it from a different dealer.
Again I am impressed how quickly the order arrived, ordered on 27th October and arrived today 13th November. Less than 3 weeks. Wow!

Those parts look good and seem to be made well. Also the black anodizing was done properly. Of course I would have preferred to get them in Prusa orange, but you tale what you get.
I even thought about an all black printer, but I have a to admit that I really like the Prusa orange/black color scheme.

The z-axis motor mounts come with little bearings in the top parts. There are little set screws that hold those bearings and the linear rods in place.

The mount for the timing belt under the build plate is actually made of 3 parts. But still looks nice and I guess there is no other way to machine those teeth that grab into the timing belt.

The x carriage was a little surprise as they did come with linear bearings installed. I think I need to remove them as all bearing ball from both bearings as in line, but should be 45° offset from each other. There is a little set screw that holds them in place.

The holes for the z-lead crew nuts look not so nice as the rest. Also You can see that one pair of holes per part are drilled for a bigger diameter than the other two. I can only guess that they try to accommodate for different types of nuts and hope it is not a mistake.

Then we have the mount for the y-axis motor and the idler pulley, which I will not use I guess.

And this adjustable idler pulley mount is the reason I might not use the other one. I have to test how well this works, and maybe upgrade my original MK3 as well.