The Hot End Part 4 fan shroud and electrical connectors

In Part 3 I showed that the mounting kit from Chris Vahi I found on thingiverse did not properly fit on my Titan Aqua Klon from China and how I redesigned it. Chris left a comment and explained that his first design was like mine, but then he decided to lead out the water hoses sideways.

When I tried to mount the fan shroud I found other issues. First the fan shroud was tilted when I  tightened the screw. I could fix that by taking some material of from the edge that was pressing against the shroud. But then I realized that the position relatively to the nozzle is different from the position on the original Prusa design.
The corner of the fan shroud should line up with the middle of the nozzle and the lower end of the hexagonal part of the nozzle. But you seen see, it is some mm off.

This also leads to the problem that the fan shroud bumps into the cable of the temp sensor. But the alignment of the Y axis is fine.

So I imported Chris design into Fusion 360 and started by changing the orientation. Then I needed to cut the part in two pieces. The simple way to do this is, is using a construction plane.

Then I need to move the part that will be screwed to the Titan Aqua to the right position.

I joined them and cut of further pieces, extruded faces, cleaned up a lot of facets, rounded some edges and came up with this.

I also needed to flat the bottom surface that pushed against the fan shroud and added a fillet on the edge.

Now it was printing time. I used black PETG from Prusa and printed this in 0.15 mm layer height, 20% infill and supports from build plate only. The supports left some marks on the finished print, but this more important is the function.

Now this looks much more like the original design. I have made an update to my thing on thingiverse to include my version of the fan mount.


The wires that came with the Titan Aqua Klon kit do have connectors/couplers approximately 10 cm from the heater cartridge/temperature sensor, but not at the end. The connectors might become handy when you need to take apart the hot end and you don't want to unwrap the cables.
But the missing connectors at the end is a problem as you need them for the Einsy Rambo.

For the heater cartage you need some "AC 300V 10A 5.08mm Pitch 2 Pin Screw Pluggable Terminal Block". You can get them from brands like Phoenix Contact(best quality from Germany), Uxcell or cheap Chinese knock offs. With 24V and 40W for the heater cartrige you will load them with less than 2A unless you shorten something, but then the fuse will blow. It should be also safe to use the cheap ones as the connectors are rated with 10Amps.
The cables will be just screwed to the connectors that plug into the Einsy board.

I strongly recommend to use wire end sleeves for strands like this. Do NOT coat the ends with tin-solder! The tin-solder will get soft and deform, the resistance of connection might rise and create  heat to scorch the connectors. This can set your printer on fire! 

For the temperature sensor it is a little bit more complicated. The correct connector is a "Molex 5057-9402" connector with locking mechanism. It is not a "2.54mm Dupont Terminal" connector as it is used on RAMPS board. The look similar, but the Dupont connector does not have a locking mechanism. There are version with a locking mechanism, but they don't fit.

On Aliexpress I did find a complete kit with the connectors and some endstop switches with cables for a reasonable price. It seems from the picture 2 complete temp sensors are included.

1Set-EinsyRambo-Connectors-Cable-Wire-Complete-Kit-Molex-5057-9402-9403-9405-For-Prusa-i3-MK3  11,14€

If you want to connect any other temp sensor with Molex 5057-9402 connector, you can try to use some pliers to crimp the cables to the contacts. Usually there are special crimping pliers that costs a little fortune. So if you don't want to go into mass production you might find better ways to invest your money.
I am using this 4 pin connector as an example, the Prusa thermistor connector has only 2 pins.

Another thing that I find very annoying on the original Prusa design is the cable management on the x carriage. Besides the sharp kinks of the cables the cable holder goes straight to the back of the printer, but the cables have to bend then to go into the Einsy case from the top. 
Sometimes I print multiple parts, one by one, not layer by layer. This is called "Sequential Printing" in Slic3r. In Slic3r PE you cannot change the order of the objects to print. With the tilted print fan and the P.I.N.D.A probe the area you need to keep free for the hot end is quite big. But in addition you need to watch out not to hit anything with the cables sticking out in the back.
So I spent some time to create a new version that leads the cables in a 45° angle upwards.

But I still need to figure out the best orientation to print this, before I can test this.

Another modification I am thinking about is to change the lever design that Chris made for the Titan Aqua. Chris made a version with a housing for the filament sensor. But he reported in his comment that he disabled the sensor as he had many false alarms. It seems like a lot of people have the same problem and it depends very much on the filament (color and material) how good or bad the sensor is working. The sensor is sensitive to dirt as well. In the last versions of the firmware, Prusa added this new function to ask you if you want to disable it if the feedback from the sensor is poor.

There is a new idea to have an indirect measurement by using a small ball bearing that is moved by the filament. So the sensor will monitor the motion of the bearing, not the filament itself. I have found plenty similar designs and remixes on Thingiverse. But the version from CARLOS BASAURI aka RaavHimself seems to ne most appealing to me. He also made a version for the usage with the MMU2 upgrade.

So my plan is to change the lever design that Chris made for the Titan Aqua and adopt the idea of the indirect sensor for the filament. So stay tuned to see how this works.

Don't buy from Dave 3D TECH Store on Aliexpress!!

Today I want to warn you about the "Dave 3D TECH Store" on Aliexpress.com.

On the sale on 11.11 I bought a 1Set Prusa i3 MK3 Aluminium alloy metal frame with Profile and smooth rods kit 6mm thickness Prusa i3 MK3 Frame Fast Ship for €104,79 from this seller.
In the description of the item he states "Package: includes 1full kit frame like first image show" in big red letters and in the headline description he explicit mentions "with Profile and smooth rods".

As you can read and see the steel rods and the aluminium extrusions are included. After 4 weeks of waiting I received the package(fast shipping??). To my surprise he only send the frame parts, but neither the alu extrusion profiles nor the steel rods.

So I opened a dispute on Aliexpress and demanded a refund. He did not respond until the short before the deadline from Aliexpress expired and made me a ridiculous offer to refund 30€, but only if I close the dispute.
So he did not send even half of the parts, that would me costs about another €60 to order them, any want to give only €30 back. And in addition he wants to blackmail me to close my dispute and trust that he will pay me anything back.

Don't buy anything from this thief and liar! There are plenty of other good sellers on Aliexpress. You can get the same kit from "Funssor Official Store" on Aliepxress. I bought already other items from them and had no issues.

Funssor Official Store 1Set Prusa i3 MK3 Aluminium alloy metal frame with Profile and smooth rods kit 6mm thickness Prusa i3 MK3 Frame Fast Shipangen-kit-6mm

The Power Supply Part1

When I ordered my first parts the naked PS that should fit to the Prusa MK3 should costs about 40€. Again, just the PS with no enclosure, Power Fail circut board or cables.

So you can order a prebuilt MK3 power supply with all features for about 40€. Given the costs for the PS itself, the power fail board, switch and the effort to design and 3D print the parts I would rather go with the complete PS for this price.

So I went for a 9.99€ PS from ebay with the same specs. 24V 250W(240W has the original).

First I wanted to have a more beefy PS(320W/12.5A or 360W/15A), that I could use to power the water cooling and some LED strips as well. But the common cheap PS over 10A usually have a fan installed, a cheap noisy fan to be precise. Also I would have to step down the 24V to 12V for the "silent" water pump I picked.

Nothing on this power supply matched to the one that Prusa uses, except for the Voltage and Amps specs.
The outer diameter is bigger, the holes for the screws, nothing fits.

Not even the holes that are used to mount the PS to the frame. Which is important for a usual MK3 as this makes the frame more sturdy. But in my case, I wanted to mount the PS outside of the Ikea enclosure anyway. So this was the only point that was not a problem.

So I started to import the original Prusa STL files in Fusion 360 measured the dimension and looked for a good spot to cut the part in two.

Then I move the parts apart until the dimensions matched with my cheap power supply. Then I simply extruded the cut surface about the same distance and joint both parts together again.

Next I need to sticht the holes for the screws that clamp the PS to the 3D printed parts. Once that was done I removed the strengthening on the backside.
Then I extruded the back wall to the point where the screw holes on my PS are covered. I added some new strengthening and the holes that fit to my PS.

The advantage of doing it this way was the I did not had to change any more complex parts from the original design.

To put this together you need some M3x10mm counter sunk screws and some round headed M3x8mm screws that go into the PS. Be careful, do not use M3x10mm or longer as the screws might damage the inner circut board or create a shortcut.

As you can see there is plenty of room for the cabling inside.

One part I needed was the power switch. I wanted to have a switch that has two ways and switches both connections, as in most countries you don´t know which cable is phase and neutral when you plug it into the wall.

And it also needed to fit into the gap in the printed part. So this snap in version just did fine.

But to mount it to the Ikea Lack table you need another part that Prusa provides with the files for the Ikea Lack enclosure. But this bracket needed to be modified as well to fit to my PS.

Same process as above. Measure the dimensions, cut and extend on 2 axis. To make it look good I removed the side wall and created a new one once the part had the new size.

And this is the printed result.

Now I had to wire everything together.

IMPORTANT! This is main voltage. Leave this to an expert, you can risk you life and the life from others by electric shock or fire if you don't know what you are doing!

Mistakes I made and how I straightened them out

When I started this project, not all parts came in the at the right time. So I could not strictly follow the  order of the assembly instructions that Prusa provides. One thing that was missing was the "white lithium grease". Prusa recommends only this for lubrication of the bearings.

This is the one I ordered from Amazon. Don't get confused by the brand WD40. They usually make alight oil with the same name, and this is what you should not use!

So when I got it finally, I was to lazy to take everything apart again. But today I discovered a much bigger mistake, a real stupid one.

When I got the stepper motors I did not unwrap all the cables. The ones for the z-axis where obvious by the lead screw which id also the motor shaft. But I assumed all other 3 would be exactly the same.
It turned out they are not.
I cannot tell you if the motor parameters are different, but the cable length is.
And I used the one with the shortest cable as extruder motor and the one with the longest for the Y-axis.
I had to swap them out or try to extend the stepper motor cable for the extruder.

I decided that this is the opportunity to take apart all axis and use the lithium grease to lubricate all bearings.
BTW: just applying it on the steel rods does not help so much as the gaskets wipe of most of it before it reaches the inner bearings.

Another thing that annoyed me was the crap design of the idlers in the X-axis end and the belt tensioner for the Y-axis.
I had ordered new ones from Aliexpress already:
2x Idler with two bearings 3,63€

As you can see, the ones that where used on the CNC alu parts are poorly designed. Not only the have only 1 bearing on one side, the inner diameter of the bearing is too big. So they wobbled around on the M3 screw.
The new ones on the right site have 2 bearings, one per site and the inner diameter fits properly on a M3 screw.
The other alternative would have been to use ones with teeth. Some people think they would be better as they would not flatten the teeth of the belts over time. Not sure, I usually do not put too much tension on the belts, not more than is required. So I never had that problem.

But the biggest pain was to disassembly the complete Titan Aqua hot end again. The way it is designed, you cannot easily swap out the extruder motor as everything is screwed to it.
Luckily I had enough thermal compound to assemble it properly with the new motor.

BTW: The thermal compound and also the lithium grease are both not very healthy. Make sure you wipe of the residue everywhere except where it belongs and wash you hands!

The Hot End Part 3

When you have followed my previous post, you know that the CNC machined aluminum mount for the Titan Extruder did not work for my Titan Aqua Klon as the Titan Aqua is quite different from the Titan Extruder or Titan Aero Hot End.

By accident I stumbled across a mount on thingiverse from Chris Vahi from Vancouver . He did an awesome job in designing and testing a mount for the Titan Aqua that can be screwed on to the original Prusa MK3 x-carriage. So a big THANK YOU from my side to this guy.

But he did not only design the Parts you need, he also described which parameters you have to change in the Prusa Firmware to get this to work. Including the right offset for the position of the nozzle. Make sure you grab his latest design, where the P.I.N.D.A. Probe is at the same position as with the original hot end.

So I began to print all parts, including a new lever that can hold the filament sensor. Everything is printed with PETG from Prusa(not Prusament) in black. I was able to print everything without support, I just needed to adjust the orientaion when I imported the STL files in Slic3r PE.
There is the mount, the angled mount for the print cooling fan(just like in the new Prusa versions), the new lever with top cover for the filament sensor.

On the left is the original lever that came with my Titan Aqua Klon and the on the right side the the 3D printed version from Chris design. The big top is the housing for the filament sensor.

As the original lever use a ball bearing to press the filament to the drive gear. In Chis design he make use of the bond tech gear from the original MK3 hot end. I had a set of bond tech klon gears ordered from aliexpress that I use here.

Basically like in the Prusa design the gear is held in place by the shaft that is pushed thru the holes in the 3D printed part.

You just need this part from the set, not the one that usually goes on to the stepper motor shaft. Chis explains in his instructions in Thingiverse why you cannot easily use the other gear, as you would have to modify the shaft of the original gears that come with the Titan Aqua.

So I don't see what sense it makes to use the bond tech gear on the other side if it is not driven by the other gear. I don't see why this is better then the ball bearing. But that is my opinion, not even having tested it yet. Maybe the silhouette of the bond tech helps to align the filament better than the flat bearing surface.

Before you start I strongly recommend watching the assembly instruction video from Triangel Lab(my Klon was from D Force) and the original E3D instructions. I will give you some additional tips below as the video from Triangle Labs does only have music and they don't mention some important things.

Now it was time to prepare the rest of the parts. Mine came partially pre assembled, but I need to take  it apart to install it the proper way. The shaft of the gear is secured with a spring washer. Don't take this apart, it is not necessary. 

I started to screw in the pneumatic connectors to the thin aluminum plate. Use only moderate force to tighten them, when you ruin the threads, your hot end will leak. Make sure you remove the protection foil from both side of the gasket. Mine was hard to spot as they are all transparent.

First put the drive gear on the stepper motor shaft and make sure the side with the set screw is closer to the motor. Otherwise the set screw will block the gear afterwards.

Then put the part together without any thermal compound to test if you can move the gears and the set screw is not blocking and to see that the gears are flush.

Now we need the thermal compound that came with the kit. There is enough of this for the assembly if you don't waste anything.

The next step is to apply a bit of the thermal compound to the surface. Don't use too much, this is only to cool down the extruder motor as well. You need more of this stuff on more important parts.

Also check the surface of you stepper motor, my cheap blurolls motors have some gap in the surface that will not touch the aluminum parts, so they don't need the thermal compound either.

  Then put it together and secure the aluminum part with the short screw to the motor.

In the next step we need to make sure we use enough thermal compound, because this is the surface between the part with the water cooling and the part where the heat brake gets screwed in. It is essential to have a good thermal conduction here. But leave something for the heat break later.

And make sure you have the assembled new lever ready now to attach it to the stepper motor shaft. 

Now we need to put the two parts together and secure them with the mid length screw on the right side to the other aluminum part and with the 2 long screws on the left side to the stepper motor.
Then you screw in the adjustment screw with the spring. Not a bad idea too test again that the gears are still working fine.

I also checked the alignment of the bond tech klon gear with the drive gear.

For the next step you need to prepare a piece of the PTFE tube that is 7mm long. I used a digital caliper and a sharp knife for masking tape.

I will not use the heat brake that came with the Titan Aqua klon, they are full metal ones and seem to be ok. But I bought some Titanium alloy heat breaks from aliexpress some time ago. How I know it is no fake? Well, I tested them with a magnet to make sure it is not steel, then I measured the weight with a precise scale and they are lighter than the steel ones I have. So there is a good chance it is some Titanium alloy. All the other methods I found are destructive, so I did not do it.

My heat block came pre assembled with heater cartridge, NTC sensor and nozzle. It disassembled them as I wanted to have my cables on the other side and it made the assembly of the heat break and the heat block easier.
IMPORTANT! Not you need to apply some of the thermal compound as well on the heat break. BUT ONLY on the upper part, the longer threads. Stay away with the thermal compound from the lower part!
You want to increase the thermal conductivity from the heat break to the heat sink, to help to cool it down. You don't want to help transfer more heat from the heat block into the heat break!

Screw in the heat break into the Titan Aqua alu part. Then it is a good time to use a paper towel to wipe of all the excess thermal compound of the part and wash your hands. This stuff is not very healthy!

Screw on the heat block and counter it with the nozzle. Once than is done you can insert the NTC and the heater cartridge again.

Mine looks like this, as I wanted to have the heater block orientation exactly the same as on my original MK3 hot end.

Now it was time to attach the mount that Chris designed and I found out that it did not fit. As you can see the arm of the mount is to thick as pushes on the pneumatic connectors. This is not good, either the threads get damaged or the thin aluminium plate get bended. In both cases the hot end will leak.

So back to the drawing board, or better Fusion 360. I imported the files from Chris and started to modify them. First I cut out a space for the pneumatic connectors.

Then I beefed up the other side a bit to compensate for the loss of rigidity with the cut out.

Finally I just added some fillets to make it more appealing.

I have uploaded my remixed files to Thingiverse if someone else needs them.

Here you can see the difference between my remixed version and the original version from Chris Vahi.

The part fits perfectly now, so it was time to press in the 3 M3 nuts and 1 M3 square nut.

To mount the Titan Aqua to the mount you need 3 M4x12mm screws and 1 M4x16 for the fan mount. Of course I have don't have the right size here, as you can see. So I have to order them and replace them later.
To attach the mount then to the Prusa x-carriage you need 1 M3x10mm and 2 M3x16mm screws.

The pneumatic connectors have sufficient room now. As you can see the filament sensor is not yet installed.

The mount for the part cooling fan will be screwed to the remaining corner of the Titan Aqua.

It has the same angle as the new design from Prusa, and there is the hole to mount the fan shroud as well.