Hozo ultrasonic knife

[Frank3k]

I posted this over at Whatif earlier

I've wanted to get an ultrasonic knife for a while, after seeing how easily they could cut through 3D printer supports, but I just couldn't quite justify the price of one.

Without an ultrasonic knife, support removal without damaging the part comes down to careful cutting and careful application of hot water. Supports connected to very thin or fragile parts can be troublesome to remove without damage and can take a lot of time.

I saw a review of the HOZO NeoBlade and it was both better built than the cheapest ones on Amazon, and cheaper. I got it last week and it's definitely a hefty, well designed tool:



It's fairly heavy, so it'll take some practice to get surgical precision out of it. The tool has two options - continuous operation and press to cut.  I used press to cut to remove the supports from a Spalah LAND-LGR4 Launcher. I had removed the cage and separated the print groups before I thought of taking pictures, but here's an example of where this tool really shines. This is the launcher, surrounded by supports. It's hard to see, but there are some fine details buried in there:



The tool doesn't make much sound as it cuts (unless it resonated against the surface it's cutting) and it can generate some very dust, so a mask is a good idea. It took a couple of minutes to remove all the supports from both parts:



There are some supports that will still have to be removed with a knife, but nothing broke off the part and there are no support craters to fill in.

I also have the Mikro-Mir Caproni B.72 near the top of the build pile, so I thought to try the tool out on plastic. The wing sections have thick attachment points and a thin, annoying layer of flash all along the edges. It took a second or two to remove the worst of the flash. You can see the cleaned section:



I also used it to remove the sprue attachment points:



The one on the left is flush with the surface, with no damage to the surrounding plastic. The tool does seem to slightly melt the plastic if I keep it over the area. It may be a combination of friction, cutting the plastic or both. It'll definitely make working with this kit easier. All of this took seconds, not many minutes.

I got several blade types with the kit and one looks like a chisel.  Overall, I'm pretty pleased with how this works. I nicked the plastic and resin in some spots, but that's just a matter of practice.

[GTX_Admin]

Does that go with the sonic screwdriver?

[Jeffry Fontaine]

A very interesting tool for sure.  Considering some of the acrobatics required for cutting parts away from the runners I can see where this device would be a winner. 

Also about damned time something like was made available to the hobby when you consider this type of device has been available to the woodworking industry for quite a long time. 

[apophenia]

A very cool-looking tool, Frank 

But am I the only one getting Olfa meets HK G11 vibes?

[Frank3k]

@Greg - I don't think this would work as a sonic screwdriver...or maybe it does - it won't cut metal, but it chatters into the audible range when placed parallel to a hard surface
@Jeff - I first saw these a couple of years ago when a pro was cutting the supports off of a large 3D print. I didn't know this was used in woodworking, although I think there's a ladies' depilatory tool that works on the same principle.

It would make an "interesting" bayonet for a G11. It says not to cut biological tissue, but I tried trimming a a tiny bit of fingernail and it cut through like it wasn't there...

[Jeffry Fontaine]

My neighbor introduced me to the woodworking version when he installed a new kitchen sink for me and used his cutter to whittle away some counter top that was in the way.  It was quick and efficient at getting into corners where a normal jigsaw or Skilsaw would never get into. 

[GTX_Admin]

@Greg - I don't think this would work as a sonic screwdriver...or maybe it does - it won't cut metal, but it chatters into the audible range when placed parallel to a hard surface

Missed Doctor Who reference...

[Kerick]

Would this work cutting plastic sheet? Especially the thicker stuff.

[Jeffry Fontaine]

Would this work cutting plastic sheet? Especially the thicker stuff.

It should have no problems cutting through thicker plastic card stock. 
The one safety feature of the vibrating cutters that my neighbor used was that it was unable to cut flesh unless you tried really, really hard and even then it would just leave a red mark from the pressure of pressing down on that spot with the device. 

Link: Amazon.com search results for oscillating saw/oscillating sander

[GTX_Admin]

The one safety feature of the vibrating cutters that my neighbor used was that it was unable to cut flesh unless you tried really, really hard and even then it would just leave a red mark from the pressure of pressing down on that spot with the device. 

Now where's the fun in that...?

[Frank3k]

Jeff, I think this ultrasonic knife is slightly different from the woodworking ones. I did manage to stab myself with the sharp end last night - although, surprisingly, it didn't bleed and the slice is already all but healed.

@Ken - I tried cutting some thin sytrene sheet and while it cut with barely any resistance (see above...) the friction from the blade vibrating so quickly melted furrows of plastic along the cut. I'll try with thicker plastic tonight. It also melts PLA when cutting - but that's not surprising since PLA has a lower melting point than styrene or ABS.

[Kerick]

I can live with little furrows along the cut. Using a regular knife produces some too and I’m used to removing them. As long as it cuts smoothly and accurately I’m impressed and will look into purchasing one. Maybe I’ll put it on my Christmas list.

[Frank3k]

Maybe another blade (other than the stabby one) would work better. You need to support the plastic, so you'll need something hard (or soft and disposable) under the plastic. Or just cut a groove and snap the part out.

[Kerick]

Cutting a straight line on thin sheet would be just as easy with a regular knife but sometimes I need to cut curved shapes or thick plastic. Clear PS is usually very brittle too. I wonder how it would work on that. Cutting something like a car body or a fuselage would be very useful.