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3D printing and laser cutting blades - the physics of blades
https://ooakforum.com/viewtopic.php?f=58&t=30263		 Page 3 of 3
Author:  Musicfreak0 [ 02 Sep 2016, 06:22 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
iskandar taib wrote:
Hmmm... Send $20 to these folk and get four sheets of rubber in about three weeks:
http://www.aliexpress.com/item/RITC-729 ... 13352.html
No muss, no fuss. :lol:
Iskandar


Cheers, Iskandar, but I've already ordered 4 sheets Reactor Corbor off Aliexpress - I don't reckon it'll be too long before they arrive.

kim biceps wrote:
One way to eliminate human error, probably let robo pong hit the bat stationery? Just a suggestion


Thanks Kim, I'm doing that anyway - I set the robot up and measure the angle & velocity of the rebound.

I'll have different speed/power tests, I'll do one set with a rubber on, and one without. One lot of tests will be done with the blade handle in a clamp, allowing the blade to flex a little on impact, while another will be done with the blade mounted against some timber, which will isolate the hardness variable. I'll then set the robot to different speeds and measure the rebound speed: hopefully I'll get a nice graph to show how the blade reacts at different speeds.

The spin test will also be done with and without a backing (timber), and I will measure the throw angle (which I figure out by subtracting the angle of incidence from the angle of reflection), and that will determine the spin result.
Author:  kim biceps [ 02 Sep 2016, 08:00 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
Well you're doing important works for us mere tt players!!
Author:  Musicfreak0 [ 02 Sep 2016, 15:13 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
kim biceps wrote:
Well you're doing important works for us mere tt players!!

Glad to know I'm not wasting my time! :D
Author:  iskandar taib [ 02 Sep 2016, 17:44 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
Just had another thought. Maybe the laser cutter can cut the rubber as well! :lol:

Might smell some, though... :lol:

Iskandar
Author:  Musicfreak0 [ 02 Sep 2016, 17:48 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
iskandar taib wrote:
Just had another thought. Maybe the laser cutter can cut the rubber as well! :lol:

Might smell some, though... :lol:

Iskandar


Ha! Some of my mates suggested this because I cut the pips so roughly! :lol:
I've got a hold of some carbon fibre, too... I'll have to update about that next Friday when I've got class next.
Author:  Musicfreak0 [ 06 Sep 2016, 06:35 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
UPDATE: Inverted rubbers (4x Reactor Corbor) have arrived! I will get them in class on Friday, and I can start doing the proper scientific tests! :party:
Author:  BeGo [ 06 Sep 2016, 19:23 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
Musicfreak0 wrote:
UPDATE: Inverted rubbers (4x Reactor Corbor) have arrived! I will get them in class on Friday, and I can start doing the proper sceintific tests! :party:

my suggestion,

place those rubber,

2 for your printed blade,
other 2 rubber on your trusted blade

;)

Sent from my T1X Plus using Tapatalk
Author:  Musicfreak0 [ 06 Sep 2016, 22:04 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
BeGo wrote:
Musicfreak0 wrote:
UPDATE: Inverted rubbers (4x Reactor Corbor) have arrived! I will get them in class on Friday, and I can start doing the proper scientific tests! :party:

my suggestion,

place those rubber,

2 for your printed blade,
other 2 rubber on your trusted blade

;)

Sent from my T1X Plus using Tapatalk


:lol: :lol: :lol:

Good idea, but I couldn't do it! I doubt the Corbor is reliable enough to use, anyway!
Author:  BeGo [ 07 Sep 2016, 06:12 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
Musicfreak0 wrote:
BeGo wrote:
Musicfreak0 wrote:
UPDATE: Inverted rubbers (4x Reactor Corbor) have arrived! I will get them in class on Friday, and I can start doing the proper scientific tests! :party:

my suggestion,

place those rubber,

2 for your printed blade,
other 2 rubber on your trusted blade

;)

Sent from my T1X Plus using Tapatalk


:lol: :lol: :lol:

Good idea, but I couldn't do it! I doubt the Corbor is reliable enough to use, anyway!

Well,

This to make sure that your assessment is only for blades, so we must make sure no effect of rubber on it. :D ;)

Sent from my S5G using Tapatalk
Author:  111Iceman111 [ 07 Sep 2016, 06:38 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
nice little project you have there mate, looking forward for results...

i always had problems understanding the difference between hardness and flex/stiffness, but you summarized it so even i could understand :clap: :rock: :lol:
Author:  Musicfreak0 [ 07 Sep 2016, 06:47 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
111Iceman111 wrote:
nice little project you have there mate, looking forward for results...

i always had problems understanding the difference between hardness and flex/stiffness, but you summarized it so even i could understand :clap: :rock: :lol:

Thanks, Iceman! Glad to know I'm helping people out! :up:
Author:  Musicfreak0 [ 27 Sep 2016, 13:10 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
Okay, here's a link to a thread which shows me playing with blade 2, but it's not exactly a review of the blade - just an example showing that it can be used! viewtopic.php?f=39&p=325153#p325153

As far as the experiment itself goes, I've got my hands on some different materials, which I will show in my next post. I've also tried combining the 3-ply with an acrylic (2mm) ply, and I will have to write a bit about it - all I really remember at the moment is that the blade itself weighs around 150 grams (around 240 with rubbers, I think), anyway, it's stupidly heavy, and seems fairly fast.
Author:  Musicfreak0 [ 27 Sep 2016, 14:09 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
Materials that I've gotten my hands on:
1. 12mm thick 5-ply. Density: 0.840479786g /cm2. Blade mass (assuming 20g handles): 220g.
Image Image

2. ~1mm carbon fibre. Density: To be measured. Blade mass: TBM.
ImageImage

3. Some metal (I need to investigate!) - around 1mm thick (not measured). Density: TBM. Blade Mass: TBM.
ImageImage

4. 5-ply. Can't remember the thickness. I think it was ~8mm. Probably wrong, though. Needs to be flattened. Density: TBM. Blade mass: TBM.
ImageImage

5. Another 5-ply. I think this was ~6mm from memory - again, probably wrong. Density: TBM. Blade Mass: TBM.
ImageImage

6. Yet another 5-ply. Same thickness as the one above - very similar in appearance. Density: TBM. Blade Mass: TBM.
ImageImage

7. ~1mm Acrylic (will only be a layer - probably not strong enough to use by itself). Density: TBM. Blade Mass: TBM.
ImageImage

8. Thicker acrylic (can't remember the thickness). I've got 2 different thicknesses of the thick acrylic - probably stiff enough to be usable by itself (though not ITTF-legal). Density: TBM. Blade mass: TBM, but surely very heavy! :lol:
ImageImage
9. The other acrylic... no photos at the moment. I think it's a little thicker than the one shown above.
Author:  iskandar taib [ 04 Jun 2017, 14:53 ]
Post subject:  Re: 3D printing and laser cutting blades - the physics of bl
Now I've actually had a 3D printer for about a month, I now know a lot more about 3D printing (or at least, about the inexpensive hobbyist melted filament deposition type of 3D printing) than I did previously.

I was suggesting that you print blades entirely out of ABS or PLA (it turns out PLA would be a great deal easier to deal with... :lol: besides, it's stiffer and I think would make better blades..), with solid surfaces and a honeycomb-like core. Turns out it's very, very easy to do this - you only need make one 3D model of a blade (with the tang but without the handle pieces). In the 3D modeling software (this would be the equivalent of a CAD package - the commonly used ones are 123D Design, and Fusion360, though there are many others, including TinkerCAD, which is entirely web-based) you'd draw the outline of the blade and extrude it to the desired thickness (probably 6mm or so). And then you use this model to print any number of blades by varying parameters in the slicer software (most people use Cura - version 2.5 is awesome in the amount of control you have). In the slicer software, you can specify the thickness of the top and bottom layers, all the way down to maybe 0.2mm. You can also specify how much "infill" you want (this is the honeycomb-like structure in the middle of the object) - this is in terms of percentage. 100% will give you an entirely solid object. You can also specify the infill pattern, and there are many options to choose from. The most interesting are the interlocking tetrahedral, and the interlocking cubes. There's even an option for the interlocking cubes to be smaller near the edges of the object and larger towards the middle.

The main obstacle to printing a blade is the size of your print bed - mine's a little too small (8 inches square). There are larger printers that don't cost very much (the TIVO Tarantula is under $300, and has a 8"x10" print bed option).

You can download Autodesk Fusion360 for free, and if you register as a "hobbyist" (or are a student or an educator) you can continue to use it for free. This is a professional tool, there's a bit of a learning curve, but you'll find a huge number of tutorials on YouTube. 123D Design was easier to use but Autodesk discontinued it in April. I was able to download it before they disabled the downloads and still use it. Cura 2.5 is also free. Even if you don't have a printer, it's fun to learn to use these things, you can even send your parts off to be printed professionally.

Printer filament (and printers!) has become quite cheap. $20 a kilogram or less is common. There's an interesting variety available these days, too - there's "wood" and "metal" filament (wood and metal particles embedded in PLA), even "carbon fiber" filament (little short strand embedded in PLA). The "carbon fiber" filament is stronger and stiffer than normal PLA but the parts would be nowhere as strong as properly laid-up carbon fiber. Still, I've seen quadcopter frames printed out of it.

Printers? The one I bought retails for about USD400 in the US, there are many that cost a lot less than that but are every bit as good. The only drawback is you have to assemble them (shouldn't be too hard, but I chose not to go that route).

Iskandar
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