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Diamond hotend

Posted by frankvdh 
Diamond hotend
July 03, 2015 04:32PM
Anyone else bought a Diamond hotend? I have one, and am still building the printer for it to go on.

So looking to leech ideas until I have it running, at which point I'll be happy to share experiences.

Re: Diamond hotend
July 05, 2015 04:26AM

currently building more extruders...

I am still wondering about how to mount it... my I3 carriage has recessed nuts... the Diamond mount also has recessed nuts... something is backwards.

Adding an E2 to a ramps doesn’t look very hard... at the electronics level (I am concerned the MPU wont have enough power to do this)

Firmware... In theory simple colour swapping, setup 3 tools, no issues. tools has been supported in firmware for a while.
blending... stumped so far! needs concurrent extrusion

Duet has this function in firmware .... I'm not getting a duet just for this.

Teacup has 9 axis support, and could be forced to do it... but not nicely... post processing scripts to change g1 e0 to g1 w,u,v or what ever new axis's are.

no slicers support for blending at all that I’ve found.

But I knew most of this going into supporting a diamond. So soon the fun begins.

Edited 4 time(s). Last edit at 07/05/2015 06:11PM by Dust.
Re: Diamond hotend
July 06, 2015 03:27PM
I e-mailed reprap.me and asked them what they where using for mixing.

Here is the reply, very intersting.

"Repetier firmware supports color mixing, (if you will call what the hotend does mixing)

Here's the programmers explanation, I will comment more below:

Mixing extruder


A combination of exactly one nozzle with inputs 2 - 6 filaments driven by
their own filament driver build a mixing extruder. It is not required that this
combination in deed mixes the colors. It could also be used to put only one
of the colors through the nozzle.

This combination gives us one real extruder that can in theory print many
different color combinations. Through the M163 command, it is possible to
change the mixing ratio at any time. Since slicers do not support this,
the firmware also introduces the concept of virtual extruders. The mixing
extruders can simulate 16 extruders (reachable over T0 until T15) with a preset
mixing ratio. The current mixing ratio can be stored as a virtual extruder
with the M164 command.


Set NUM_EXTRUDER to the number of filament drives. In addition set
MIXING_EXTRUDER to 1 in your Configuration.h. Now the steps per mm and
heater control settings are taken from extruder 0. The corresponding
settings in higher extruder numbers are ignored.


All N extruders get a weight Wx and steps are executed to preserve the weights
in optimum number. Therefore each extruder has a error counter Ex which is
initalized with Wx and we also Compute the sum S of all weights.

Then for each extrusion step:
Make step with highest value and subtract S from that value, then add Wx to Ex
Extruders with weight 0 are not considered.

Example 1: 3 Extruders with weight 20 / 30 / 50

Step 1: E1 = 20, E2 = 30, E3 = 50 => E3
Step 2: E1 = 40, E2 = 60, E3 = 0 => E2
Step 3: E1 = 60, E2 = -10, E3 = 50 => E1
Step 4: E1 = -20, E2 = 20, E3 = 100 => E3
Step 5: E1 = 0, E2 = 50, E3 = 50 => E2
Step 6: E1 = 20, E2 = -20, E3 = 100 => E3
Step 7: E1 = 40, E2 = 10, E3 = 50 => E3
Step 8: E1 = 60, E2 = 40, E3 = 0 => E1
Step 9: E1 = -20, E2 = 70, E3 = 50 => E2
Step 10: E1 = 0, E2 = 0, E3 = 100 => E3

Result: E1 = 2 steps, E2 = 3 steps, E5 = 5 steps

Reverse stepping
Take the lowest error value of an extruder with weight > 0. Add S to that value.
Then subtract Wx to Ex for all.


M163 S P - Set weight for this mixing extruder drive

M164 S<0..15> - Save current mixing ratio as visrtual extruder S.

So as maybe you can see, there's different ways of doing this. Either pre-define up to 16 different mxing ratios (0-15) or change the mixing ratios on the fly using the M163 S P command.


All extruder 1:

M163 S0 P100
M163 S1 P0
M163 S2 P0

and 3/3 mix would be (even mixing)

M163 S0 P100
M163 S1 P100
M163 S2 P100
M163 S0 P5
M163 S1 P5
M163 S2 P5

And E0 off, E1 and E2 50%:

M163 S0 P0
M163 S1 P1
M163 S2 P1

And then to save this mixing ratio to virtual extruder 5, go

M164 S5

I hope this is clear, if not, ask smiling smiley


Michael Holm"

Edited 1 time(s). Last edit at 07/06/2015 03:32PM by Dust.
Re: Diamond hotend
July 09, 2015 03:44AM
The diamond hot end heats really fast due to it's low thermal mass. I used one successfully for ages on my rostock after I designed this as a proper fan cooled holder for it to also cool the PLA [www.thingiverse.com]
I changed though because the ceramic glue on the assembly made changing the nozzle a very risky process.

I now use a pretty standard heaterblock as sold by dx.com or robotdigg or geetech etc. My last order was from robotdigg, they have some crazy low pricing.
1.75mm is a more popular standard than 3mm or 2.85mm. I initially started with the diamondage filament but eventually switched to 1.75 because it was available from more places in better variety and pricing. Other than Diamond age, Ninjaflex also charges more by weight for 1.75mm but the vast majority of my printing is in PLA. Most places sell it for the same price by weight as 3mm filament.
steppersonline are great for steppermotor variety and pricing, I saw robotdigg is good for stepper motors too, good for lots of parts actually.

I have a printed nylon effector with a nylon cooling cowl and my hot end heat break stainless steel threaded tube screws into a custom aluminium water cooled block I made. This lets me print with pretty much any plastic but the biggest problem I have is thermal contraction as I don't have an enclosed chamber. taulman 910 specs look really good but I still haven't managed to get any yet.
Re: Diamond hotend
August 11, 2015 08:33PM
Step one: hardware, complete. Basicaly working for simple colour switching on layers.


Next. fix up the blockage issues and try some simple 2 and 3 colour prints

Sometime after that, play with blending!
Re: Diamond hotend
October 22, 2015 08:33PM
That sounds pretty awesome!

Would be keen to see the results : )
Re: Diamond hotend
October 23, 2015 01:08AM
Haven’t had a chance to do much with it...

It leaks like a sieve from the threads, once that runs down the hotend it catches on the print destroying it

I need to pull it apart and put some ptfe tape on the threads or some other method to stop the leaks.. Was also thinking of small soft copper washers.. but looks like I will have to make them.. probably going to do both... so its sealed on the base and the threads..

In the mean time I have had to put the normal hotend and extruder back on, so I could print some stuff.
Re: Diamond hotend
October 24, 2015 03:26PM
I am a big fan of soft copper washers for keeping PLA in.

I am tempted to make up my own diamond hotend but with only two extruders so I don't need to update my electronics too. My main machine has a separate second extruder and I only ever use it for printing either one filament or the other. Two colours is just too much hassle with mediocre results due to one hot end dribbling while the other one prints. Having two extruders connected to one nozzle would solve that. I don't know how this would work with say ABS and PLA hooked up at the same time. I suspect that extruding ABS would cause too much heat to go into the PLA and cause it to swell and block or melt and dribble thru the ABS. Probably best to have similar materials in each feed.

My Prusa Mendel i2 inspired Repstrap with welded steel frame: [youtu.be]
And my Smartrap derived Briefcase 3D printer: [youtu.be]
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