Diamond Nozzles, and the aftermath

For whatever reason, USSupply. who has been manufacturing industrial diamond products for decades, has a Kickstarter campaign for their "Diamondback" 3D printer nozzles. They certainly don't need the minor funding, but, what the hey, I signed up and I'm expecting my 0.4mm diamond nozzle in November. It's cheaper than an Olsen Ruby, and unlike an Olsen the diamond itself seems to have been manufactured, dimensioned, and polished specifically for filament extrusion.

Why diamond?:
1) It's hard. It will never wear out, unless you try to print diamond impregnated filament.
2) It has phenomenal thermal conductivity, much better than pure copper or even silver, and way better than ruby, brass, or steel. Or anything else. It should get the heat to the filament better than any other material.

The company seems to know what they are doing from a technical standpoint, and appear to have all of the details figured out. We'll see.

Having now scratched diamond nozzles off of my to-do list because someone else is doing it, I'm a bit more comfortable ordering some fine silver to cast, and then machine, the ultimate heat block. Pure silver conducts heat better and more rapidly than any other metal. In conjunction with my tri-metal (G5 titanium, 316SS, OFHC copper) heat break, and the VDE-100 extruder, I'll be interested to see the effects, foibles, benefits, or drawbacks.

I wonder how they manage the difference in thermal expansion coefficients of the diamond and brass that it's mounted in...

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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the_digital_dentist
I wonder how they manage the difference in thermal expansion coefficients of the diamond and brass that it's mounted in...

The kickstarter page mentions that the nozzles should not be used above 300C-- assuming they install the tips to an interference fit by heating the brass, perhaps this is the point at which the diamond is at risk of coming loose?

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the_digital_dentist
I wonder how they manage the difference in thermal expansion coefficients of the diamond and brass that it's mounted in...

I don't know. From their images, it appears that the diamond itself is conical, and fits a conical recess in the brass. There doesn't appear to be a retaining ring of any kind. It may actually be brazed in place (which might explain the temperature limit?). I have heard several reports of the ruby in an Olsen going missing. That, and the poor thermal conductivity of aluminum oxide, steered me away from the Olsen. That, and the price. I know from watch repair that a very large ruby watch bearing costs about $0.50 in single pieces.

When I started research into a possible diamond nozzle, I was surprised to find that the actual diamond part of a water jet nozzle is quite inexpensive, even in single crystal form. It's the meticulously machined stainless steel housing that you pay for at 90,000 pounds per square inch.

The Diamondback nozzle is sintered from synthetic diamond particles, and then polished. The theory is that it will be much less prone to cleaving or cracking that a single diamond crystal. The tradeoff appears to be that the thermal conductivity is about 25% that of a single crystal, but still about 20X better than single crystal aluminum oxide (ruby).

Edited 2 time(s). Last edit at 08/06/2021 05:10PM by rq3.

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NathanaelXYZ

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the_digital_dentist
I wonder how they manage the difference in thermal expansion coefficients of the diamond and brass that it's mounted in...

The kickstarter page mentions that the nozzles should not be used above 300C-- assuming they install the tips to an interference fit by heating the brass, perhaps this is the point at which the diamond is at risk of coming loose?

Beats me. A quick back-of-the-napkin shows a 2mm diameter nozzle insert is held in at about 200 pounds per square inch with just a one pound extrusion force from the molten plastic. Of course, if the plastic gets between the ruby or diamond and the brass, then all hell breaks loose!

But, from experience, I know that a well lapped tapered glass stopper can be damn near impossible to remove from its mating glass labware, unless well lubricated.

I emailed them about the nozzles- here's what they said:


Great questions and observations. We’ll try to answer your questions with as much information as we’re comfortable sharing.

Questions 1 & 2: To retain the diamond, the brass body housing was deformed around the polycrystalline diamond tip. We have patents pending on the detailed method that addresses your retention question and the thermal expansion management of the two different materials. Obviously, the parts are small, so the thermal expansion is small. Although the thermal expansion coefficients are about a magnitude apart, the total displacement of both materials is relatively small at the interface—but we did have to account for that in our design.

Question 3: Yes, our plan is to continue to add additional designs, and the volcano style will be included in our evaluation. We’re hopeful that our current nozzle design will gain some visibility and traction in the 3D printing community. This will help us have the confidence to move forward with additional designs. Any information on new designs will be announced and added to DiamondBackNozzles.com.

If you haven’t seen our Kickstarter, we’d invite you to visit that page. We’ve had some good conversations there.

Thanks,

The DiamondBack Team

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]