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ApexDesign

Ultimaker Hot end redesign

by ApexDesign Apr 1, 2012
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I like your design. I'd love to test it out, but I don't have access to those machine shop tools. Any chance you'll start selling this print head to Ultimaker owners? I'd buy just to have an alternative to the Ultimaker plug-o-matic print head.

my comment on this design would be that it introduces too many new parts, and that the mass to be heated is also larger, making it more energy inefficient (too much radiant surface area), and also slower to react to changes, and slower to heat up. additionally, I think there is too much heat transferred to the PEEK, where other designs try to create a gap to limit the heat transfer, and this design maximizes the heat transfer to the PEEK.

I know it looks like a larger heated mass, but that factor was

prominent in my mind during design. I didn't write down the numbers,

nor do I remember them, but my aluminum mass is the same or only

slightly larger than the stock designs' combined brass and aluminum.

I think the stock design conducts more heat to the peak (and thereby

to the large aluminum heat sink) because the brass goes nearly all the

way thru. For the reasons you state I did not want to vary the heated

mass by much if at all. I am still running the stock marlin PID

settings for the nozzle and my temperature is very stable. I never

timed the heat up on a stock hot end or on mine but I did not notice

an increased time after I installed the revision.

I recognize that minus the heater and thermistor all the parts are
different. It could be argued that the heater block is more complex,
but the machining is still done from only two axes (2 set-ups on 3
axis CNC mill or one on manual lathe and one on drill press/mill). On
total part count, I hav
e 2 less including the blue clip. One less if
you count the extra printing orifice. I have only a single connection
between the bowden tube and the nozzle proper.

I have not seen a single drawback since I started using it. The
targeted problems (plugging and popping) were fixed, and I have an
in
creased flexibility. I have no 'brown stuff' or PLA leaking.

I am not sure why I should care enough about this to feel even
slightly defensive about it. I am confident my hot end and bowden
problems have been solved and I am offering to share my success. Over
a career of designing machines, and
correcting bad designs, I have
found that sometimes stop-gap measures are sufficient, and sometimes
they are not. In this case I decided to abandon most of the offending
mechanism and go back to what I thought would be a good set of design
tenets. Doing this adds unconstrains a design solution. T
he added
freedom in this case allowed a quick change tip.

I am willing to make up a couple sets of the unique hardware for
others to test. That would be a nozzle, heater block, PEEK, and
bowden tube. I can't provide the heater or thermistor. I would
request that the beneficiary share their exper
ience.

Matt

Update.

I have been printing sucessfully with both .8mm and .4mm nozzles without any problems. Takes about a minute to change over sizes.

I no longer see the PEEK insulator as a weekness in an nozzle design. Never did really, but in the past others did..

I just noticed that my threads in my model don't all match. I think 2 parts show an M12, and the other a 1/2-20. Either will work as long as they are all the same. I think finer is better. I used 1/2-20 because its easier with my lathe.

You haven't included any files. A solidworks assembly file just contains the mating arrangement of the files in the assembly - it doesn't contain the parts itself. Can you upload all the parts? You can use File-
&
gt;Pack and Go to ensure you got them all.

Also saving the assembly as STEP and IGES will be helpful for people who don't have solidworks. As a last resort an STL file doesn't hurt either, but it won't help people who need dimensions for machining. Actually, for machined parts, a PDF drawing is best anyway. I can make one if you aren't sur
e how to do that (once you upload the parts, of course).

I added some better files so someone can try this out if they like. I forgot when I uploaded the .sldasm that it didn't include the parts. All the .sldprt's are there and now if you do have SW2010 or higher you can open the assembly. Otherwise I uploaded an .igs and .stp of the assembly, and a zip file of the 4 parts as *.stls.

My prototype is not built exactly as the models shown, but the same design intent was followed. It was built to 95% of the dimensions of the model. If your meking your own things, you can adjust as you go to accomodate errors or tooling limitations.

If you want to duplicate the 60deg hole botto
m, use a #1 center drill. One thing I will do differently on the next pass is make the nozzle bore (the .4mm part) as short as possible to help flow or pressure drop.

Hope that helps.

Matt

Awesome, thanks. Yeah I've got 2012 so I'll check it out. I'm having some issues with my hot end so I may decide to make this!

.spk for google sketchup

.scad for openscad

Or if possible an stl file will do!

Thx

sry .skp for sketchup

Solidworks doesn't export to either of those. An STL file is pretty much your only option.

STL is a terrible option, as all curves and flat planes get lost. Solidworks exports many formats (but not spk or scad, which aren't in the realm of engineering files). I typically export STEP and IGES alongside my solidworks files. IGES can be imported almost anywhere, as can STEP.

Where do you get your PEEK insulators?

I made all the parts in my garage

any chance to get it scad or sketchup?

I added a zip file of the *.stl's for my nozzle prototype. See my notes above to tlalexander

What file formats would those be? If SW will export them sure.