Custom Metal Printed Hotend!
by JGJMatt in Workshop > 3D Printing
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Custom Metal Printed Hotend!
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Hello fellow makers,
In this Instructable we will be making use of all the 3D printing technology currently available SLM, SLS and SLA to create a brand new custom hotend for an FDM printer.
My hand built 3D printer has been through a lot of iterations and while I'm mostly satisfied with the quality of prints I struggle printing with lower temperature filaments such as PLA since building it into an enclosure, even when printing with the door open I still get heat creep and eventual clogging which requires complete disassembly of the hotend.
To try and solve the issue I upgraded the fan from the standard 30mm to a 40mm and while this helped in cooler weather I still get heat creep during our South African summers.
Let's get making...
Supplies
To replicate this hotend you will need the following:
- 3D printed components attached
- 2x 4010 Blower fans
- Ender 3/5 CR-10 Heater block
- Ender CR-10 Heat break (all metal or PTFE lined)
- Ender 3 100k Thermistor
- Thermal grease
- 4x 3mm X 15mm bolts
- 2x 3mm X8mm bolts
- 3mm Thread tap
- 7mm Drill bit
Optional:
- BMG Extruder
*As an Amazon Associate I receive a small percentage from sales made through provided links at no cost to you, this helps fund future projects.
The Old Setup:
The setup I used up until now was a V6 e3d cooling tower with cooling provided by the 40mm fan version of the Fang part cooler and while I can definitely highly recommend the part cooler the 40mm fan just didn't give enough airflow.
This all is direct driven by my trusty BMG extruder.
Designing the New Cooling Tower:
Using Fusion 360 I started designing a new hotend from scratch.
A few design inspirations I had was:
- More compact than the current setup
- Squirrel cage fans for improved airflow
- Has to fit the BMG extruder
- Follow the design restrictions of SLM printing
- Ender style heater block
- Affordability of parts
- Accessibility of parts
As we will be using SLM printing technology to print the metal cooling tower there are certain design rules we have to abide to ensure we get a successful print, most importantly qall thickness >1.2mm, thinnest part ≥0.8mm, hole size ≥1.5mm.
The tower was printed in 316L Stainless steel, I tried to get the weight down as much as possible while still having enough cooling ability. As you can see in the photos the fins of the cooling tower have waves and are swept slightly upwards to improve cooling and redirect the air away from the built plate.
Features like this would have been nearly impossible with other manufacturing processes...WHAT A TIME TO BE ALIVE!
Thanks to SLS technology we can print our part cooling components out of 3201PA-F Nylon which gives us unbelievably strong parts and is heatproof up to 147 degrees celcius which allows us to design the cooling duct snug to the heater block.
Printing of All the New Parts:
Thanks to JLCPCB I was able to get all of the components needed for the hotend printed together.
I received a lot of feedback from them during developing and they were kind enough to let one of the engineers assess my SLM file for any problems before printing which saved me from having to reprint is as there was faults with my first iteration.
I received my parts about a week after ordering and they looked very good, the parts have already been post processed so you get parts that looks like it is production ready and the dimensional accuracy is spot on.
The price breakdown for the printed parts at the time of writing is:
SLM - 316L Stainless steel - Cooling tower - $23.36
SLS - 3201PA-F Nylon - Cooling tower fan - $2.42
SLS - 3201PA-F Nylon - Part cooling fan - $1.23
SLA - 8228 Resin - Fan coupling - $1.23
Total - $28.24
Considering the E3D V6 cooling tower costs around $40 I think getting a custom designed cooling tower to fit your needs for $29 is a bargain!
Preparation for Assembly:
Before we can start assembling our hotend there are a few modifications we need to make to some parts.
I used a heat break from a Ender CR-10 and because our new hotend is so compact we need to shorten the heat break slightly. Using a diamond cutoff wheel in a Dremel I shortened the heat break by 4mm. In the future I will be modifying the design to compensate for the extra length.
Next I tapped the four mounting holes of the fans in the cooling tower with a 3mm tap, originally the fans take a 2mm bolt but I don't have a 2mm tap and I just know I'll end up breaking that small of a tap a few times!
Then using a 7mm drill bit I drilled out the mounting hole of the heat break, this gave me a very tight fit that needs some hammering to insert the heat break...perfect.
Finally I used a 3mm drill bit to just enlarge all eight mounting holes on the two fans.
Installing the Heat Break:
Now that the heat break is shortened we can insert it into the cooling tower.
I start by smearing some thermal grease onto the barrel of the heat break as well as inside the cooling tower, then using a small dead blow hammer I tapped the heat break into the cooling tower until it bottomed out.
Note that the depth of the heat break will determine the position of the part cooling, so if the two are too close together you can shorten the heat break a little more.
The Heater Block:
Time to install the heater block.
The heater block I chose to base the design around is the Ender 3/5, CR-10 as I like how they mount to the cooling tower with two 3mm bolts which makes changing the nozzle so much easier.
The heater block is mounted with two 3mm x 15mm V head bolts.
The Cooling Tower Fan:
The 4010 cooling tower fan simply slots into place in the fan shroud and is fastened with two 3mm x 8mm bolts.
The cooling shroud with the fan then simply clips over the cooling tower, the shroud is securely held in place by long clip in slots as well as the extruded pieces that clips around the back.
The Part Cooler:
As you can see from the photos the 4010 part cooling fan slots into the cooling duct perfectly.
To assemble I first slot the fan into the part cooling duct and push through the screws to hold everything in place, then place the assembly onto the cooling tower making sure the screws align with the holes and tighten it down.
The Fan Coupling:
The last piece was originally just aesthetic but ended up being a very useful part.
Apply a strip of thin very high bond double sided tape (usually used in cellphone repairs) onto the back of the resin piece then slot it into place. The posts on the back of the resin piece goes through the top mounting holes of both fans.
This piece ended up stiffening the whole hotend and keeps it totally vibration free.
Wiring:
To organise the wiring a bit I simply slipped over a piece of heat shrink tubing.
Later on I will be designing a PCB that has the sensors, fans and heater connections on to make connecting and disconnecting easier.
PTFE Insert:
This will depend on the type of heat break you have as well as your extruder.
I chose a PTFE lined heat break which requires a longer piece of tubing compared to the all metal version.
Also my extruder requires an extra 5mm or so of tubing that goes inside the extruder body.
Having used a few different brands I can highly recommend Capricorn PTFE tubing as they last longer and are much slippier than the no name brands.
Test It Out:
It's finally time to hook up your new custom hotend to your printer and test it out!
I hope you guys found this Instructable helpful and if you have any questions please feel free to leave me a comment bellow.