Sound reduction revolution: 3D printing with flexible filament

[Wodan]

I totally forgot that a while ago "flexible" rubber-like filament hit the market.

There is a thread on GH that reminded me of that:
https://geekhack.org/index.php?topic=84614.0

This guy came up with a great idea: 3d print perfectly custom fit noise dampeners for keycaps and keyboards in general. I immediately ordered a spool of the "softer" Ninjaflex filament and spent two days experimenting with it a little. The potential is incredible!

So far I focussed on mass-producing ultra thin dampening rings for Cherry profile caps and I get very good results making dampening rings that are just 0.5mm thick. That's not 0.5mm travel reduction but 0.5mm thickness! The travel reduction is hardly measurable but the noise reduction is very pleasant. The funny thing with 3d printing, 0.5mm isn't even very thin. At my current "safe" setting for mass production, 0.5mm means FIVE printed layers! A layer height of 0.1mm is still on the safe side!

When working on Topre dampening rings I am considering trying 0.06mm layers for a total thickness of 0.3mm!

This gives you the ability to reduce noise without affecting the characteristics of a keyboard as much. While I did enjoy the common 1.5mm O-rings on some keyboards, especially with OEM profile caps, I felt they made keyboards with Cherry profile caps feel very mushy. Especially the center R3 keys got far too much dampening for my taste.

This is over now, we can design our own dampening rings, experiment with width and thickness and size ...

Best part of it all .. even though the Ninjaflex filament is pretty expensive (50€ for 750gr) a set of 120 printed O-rings costs me ROUGHLY 50 cents in filament and about half an hour of print time:


Here's a picture of a ring fitted onto a GMK keycap:


Next on the list:
- Work in DSA/SA dampeners (like in the original GH thread)
- Work on ULTRA thin Topre dampening rings < 0.5mm thickness
- Print some rubber pads and anti-slip sleeves for keyboard feet to help stabilize them on the desk (HHKB!)

This Ninjaflex stuff is SO amazing ...

Oh yeah and here's the "magic" ... 15 sweaty minutes of CAD work:
https://www.tinkercad.com/things/7DFVac ... rings-05mm

[derzemel]

do you also have a sound sample so we can hear the difference?

[Wodan]

do you also have a sound sample so we can hear the difference?

The numpad and the arrow keys got some early prototype rings. Since the rings are very thin, they become ineffective when you hack on the keys to demonstrate something but if you press them with usual typing force the noise reduction is great.

Hope the videos caught the sound well.

Notice that these early rings were a little inconsistent and thus some keys are more silent than others, will equip a full board with the current revision I am printing soon for you

[zslane]

I am especially interested in rings for SA and DSA. But especially especially SA.

[lot_lizard]

Can you send one or two of these to me? I would consider as a replacement to this from our other project because of cost if it has similar durometer to 50 shore A silicon. Awesome work regardless.

[sinusoid]

Nice.

I'll drop you a few tips, maybe you can use some of that.

- Try giving it a go with a direct filament drive machine if you can. Ultimaker does pretty good Ninjaflex for a bowden machine, but results from a bowden vs a direct drive are night and day. I was printing a lot of NF with flashforges and old makerbots, they have pretty short distances between the drive and the heater, and the results were much better. Though I have to admit Ultimaker does a great job with NF for a bowden.

- Giving the washers some sort of structure may damp better. NF is hard, even in the soft variety. My suggestion is as follows (maybe with less incisions...):

washer.png (645.42 KiB) Viewed 6600 times

You may want to design it so that the radial incisions slice/print like this: (screenshot from the appropriate layer)

washer2.png (27.9 KiB) Viewed 6600 times

They should slice to a continuous line, if Cura prints it at a constant speed, they should come out OK. Takes some fiddling with dimensions to get it right, but it's doable.
You could probably fit that within 0.5mm, with 2x0.1 layer for the bottom plate, and 3x0.1 for the incisions.

NF is damn hard to tear, so it should work out OK. Don't overtension it while pulling it off the bed though, it likes to distort and lose flexibility. It sticks well to ANYTHING, and does so PERMANENTLY, so I was using dissolved PVA or PVA-based glue on the bed. Heating the bed up a bit softens pva, and you can pull off the NF without damaging stuff, then wash away the glue, it should peel off.

- Finally, there are ShoreOO-grade silicones (like Ecoflex 00-10A from Smooth-On), they have similar hardness to sorbothane. You can print a 10x10 mold with ABS or PLA and just pour it, you'll get a better product for a lower price and shorter turnover AFAIR these are platinum cured silicones, so get printer material specs - it mustn't contain sulfur.

Good luck!

[Wodan]

Awesome input, thanks so much

Printing with Ninjaflex on the Ultimaker did require some tweaking. Had to disable retraction and reduce the print speed to 40..mm/s ?

Oh yeah and I am using the 0.6mm nozzle for the ninjaflex which makes everything a little easier. Larger nozzle - less trouble. Didn't see any benefit in using a fine nozzle here. Had a really hard time getting good, consistent results with ABS until I upgraded to the Olsson block and used a 0.8mm nozzle. Never had issues since

[7bit]

You should do something useful and make rubber foam mats for model F keyboards!

[Shihatsu]

Wodan why the hell are you always killing me? Again, unbelievable work and idea. I am left with 3 questions, maybe 4:
1. When can we participate in your GB?
2. Which keyboard is used in the video?
3. Where did you get this awesome keycapset?
(4. How much for everything? )
Honestly, only questions 1 and 2 are to be taken seriously... Great work!

[Wodan]

@7bit: Will play a little with that the next time I refurbish a Model-F

@Shihatsu: Aw very charming but most of the credit goes to MajorKoos from GH (his thread linked in the OP)
1. I don't think there will be a GB, I might offer them on a regular basis until I get bored. It's very simple to make these "on the side" while I'm at home it's not much of an effort for me.
2. That's my brand new TX-CP (https://geekhack.org/index.php?topic=83572.0) and basically flawless!
3. It's Skidata keycaps from "vintage" Skidata keyboards and then some nice orange caps from the Skidata+ GB. I wish I got more from those orange mods!

[the_marsbar]

Very cool

[Wodan]

Printed some sneakers for my HHKB

The flipout feet of the HHKB were one of it's biggest flaws to me, with these little "rubber" shoes, it stands MUCH more stable.

Still havent found the perfect angle for the feet! Printed about 30 different versions and still in the process of finding the perfect fit! Will publish the CAD files when done for non commercial use.

Oh and if you're curious, the rubber feet add 1mm length to the feet.

[lot_lizard]

Love this... Assuming this is out of the same Ninjaflex filament, and how does it effect the traction? Some "rubber" parts I had printed in the past actually had less grip as an end result.

[Wodan]

Love this... Assuming this is out of the same Ninjaflex filament, and how does it effect the traction? Some "rubber" parts I had printed in the past actually had less grip as an end result.

Pretty well! En par with any other rubber-like material I can think of. Great stuff for keyboard feet or sneakers

No long term experience yet though... maybe it gets slippery like a girl on a prom date after a few weeks ...

[zslane]

I think the mistake is yours, not the HHKB's. Why are you putting a mech keyboard on a bare surface? It should be resting comfortably on a soft keyboard-shaped pad, itself on a large fabric desk pad. Not only will the keyboard not slide around, it will have extra layers of noise dampening!

[Wodan]

Here's the design files for the HHKB Sneakers:
https://www.tinkercad.com/things/gweGTV ... kb-sneaker

Have fun tweaking them!

In face I might try and get their fit tight enough to stay on the feet when flipped in

[duynguyenle]

Wodan showing off his new keyboard

Could you do some more videos? Maybe with typing a few short phrases? On stabilised keys as well?

[kekstee]

I was gifted a couple of HHKB slippers and MX o-rings at Mechanicon.

While none of these parts look great, as is to be expected from a common 3d printer, they are actually surprisingly useful.

HHKB feet
I've been using my HHKB with its feet out for the past week and it's just rock steady. In fact the completely flat undersides of these feet are so sticky on my table that I was happy for some dust to collect. And since I don't see the feet while I'm using my keyboard they may stay on. :)

o-rings
I compared them against WASD rings (I guess 40A?) on different switches.

• light linear switches: I almost couldn't tell the difference. Both reduce the bottom out sound, the real orings might dampen a bit more overall, but it's difficult to tell. Switch feeling was almost not affected since there isn't much force behind bottoming out.
• 67g Zealio: I'm using these without orings. The reduced travel doesn't mesh so well with their tactile bump and cushioning. Also their bottom out force is heavy enough to notice the rings, plus their upstroke is so loud that it's nice to 'balance' it a bit.
  As noted earlier these rings are almost as good as o-rings in reducing sound. And their smaller effect on key travel and key feeling becomes noticeable. I'd probably use them over regular rings if I wanted to dampen the board.
  It also revealed a downside though. Their tolerances are failry high and if they happen to be tight enough to bulge around the stem they will add some kind of gritty feeling when carefully bottoming out. I can't really tell if it's due to them acting like a tiny disc spring, or just some lip of material on the stem getting caught first. It's not very prominent or even always the case since they are so soft, but still weird.

[Wodan]

Thank you very much for taking the time to give such nice and detailed feedback kekstee, very valuable to me!

Regarding the bulging of the O-rings, I had the same problem but used a pen to push every ring all the way up the stem to prevent that from happening. I just looked at all the pens I had laying around, unscrewed them und checked how well a Cherry MX keycap stem fits into the pen tube. One pen gave me an almost perfect fit and is since my o-ring placement tool

Spoiler:

[Shihatsu]

Groupbuy of these pens? :D:D

[Wodan]

After Novatouching my JP Type-S, this is me typing on a non silence HHKB/Topre board and it's pretty pathetic. I couldn't have loved my HHKBs as much if they came like that ...

Will try printing some Topre rings this week, very curious.

Anyone got 2-3 Hypersphere rings left over? Would love to compare my results with Type-S and Hypersphere and bareback of course.