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Universal Does a 3D printed slingshot can hold?

Discussion in 'Homemade Slingshots' started by Bat, Nov 18, 2020.

By Bat on Nov 18, 2020 at 1:38 PM
  1. Bat

    Bat New Member

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    For those of you that want to know if a 3D printed slingshot is safe to use, I made this video months ago, but I just added english subtitles.

    In the video i´m testing a frame printed in PLA, I have been shooting it since over a year now with no issues (And no fork hits). I measured the strength that different bands wield on the forks, one frame printed with horizontal layers and one with vertical layers, also did a destructive test with 8mm and 3/8 steel balls:



    Recently I printed some frames in PETG, with a little beefy forks, and added band clips, working great so far, I´m using 0.75 Precise bands 1 cm straight cut with 8 mm steels, I just need to make the same test to this forks:

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    Cheers!
     
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Comments

Discussion in 'Homemade Slingshots' started by Bat, Nov 18, 2020.

    1. AppalachiaFlipShooter

      AppalachiaFlipShooter Member

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      I wanna buy one with clips

      Sent from my SM-N986U using Tapatalk
       
    2. Palmettoflyer

      Palmettoflyer Well-Known Member

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      Interesting frame and a great video. Very interesting and good to see your tests. Thank you for taking the time to share your results with us. It would be interesting to test the static pull in a more dynamic manner to simulate the repetitive motion of the band pull and release.

      Your fork hits did better than I would have expected, but would like to see more hits with shooting within the distance of the band pull. Fork hits happen within the first 1/2 meter of flight, not 1 or 2 meters down range.

      I'm a big fan of 3D printing and have a few that I have made. Are you planning to make your frame available to us in anyway? There are a few STL designs here on the forum and I'm always happy to share my work.
       
    3. Bat

      Bat New Member

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      Thanks Palmettoflyer, glad you find this video useful (it really takes time to make videos)

      First I wanted to see how much force does the bands really put on the fork tips.
      Since the stronguets bandset I measured delivers 20.5 pounds of force, and the forktips can take up to 74 pounds, I really don´t think you need more test´s to confirm that the forks can handle a heavy bandset, as the force is applying when you are drawing the bands and aiming, I don´t think the release force is equal or greater than the drawing force.

      As for the forktips, I also did not was hoping a lot either, I was surprised to see how they perform.

      As for the distance of the shots, I also don´t think theres much of a diference on the impact force between 80 cm (My draw) and 4 meters, this because I used 8 mm steels and 3/8 steels, so you can take the 3/8 steels shot at 4 meters as if they where 8 mm at 80 cm.
      Also I did the shots at a safe distance because I dont whant to shoot my eye out!

      As for my frame design, the plan is to sell it, so for the moment I´m not sharing this, because behind it is a lot of design work and 3D printed tests.

      Cheers!

       
    4. Palmettoflyer

      Palmettoflyer Well-Known Member

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      Bat, thank you for your reply. Not being critical at all, just know that there are other influences in the mechanical strength of a frame beyond what you measured. Your results are good, but there are other tests. Your point is clear and I do agree that your design is quite strong.

      I have printed many frames and shared them with less experienced shooters. I have personally seen what a 3/8 ball does to PLA and PETG after one strike. It may appear to be still in good condition but its structure is compromised to the point that it should be retired.

      Good luck with your sales and wish you well. Many that have tired selling 3D frames don't do so for long. The customer expects G10 quality from 3D printing and it just isn't there. 3D printing is great for prototyping and proof of concepts, Just no value in plastic frames. I understand the long hours, hard work, and wanting something in return. The gratification and joy of sharing is a really good payment system and pays great dividends.
       
    5. Bat

      Bat New Member

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      No worries! Did not took it as a negative critic! thanks for your opinions! Also my answer is just what I think about your comments, good vibe!.

      I´m aware that there are more mechanical strengths to measure, I just measured the ones that I think are more critical. and the ones that I could measure with the digital scale. I have been shooting with a PLA frame for almost a year for target shooting with no issues, of course, I´m using 0.75 precise, 1 cm straight cut, with 8 mm steels, so not much strees for the frame, also I have 0 forkhits on that frame.

      What you mention about less experienced shooters is the reason I made this tests, and the reason i´m not selling my frame desing yet. Here in México almost all shooters like to use very heavy bands, with big ammo, so a 3D printed frame is not safe to use with this heavy setups.

      And you are right, with just 1 fork hit, you sure damage the fork event if it looks ok on the outside, could present damage on the inside.

      I printed the PETG ones with 4 walls, and less infill, but I don´t think they can take a forkhit with a 3/8 steel, even with 5 or 6 walls printed with vertical layers (More strong)

      And about the sales, I think is about telling the costumer the limits of the frame before selling it, (Hence the video) I agree with you that 3D printing does not have the quality / strength of HDPE, nor think about G10, but is something that can be used taking proper precautions and understanding the limits of 3D printing.

      Also, I think you need to have experience with additive manufacturing and understand this procces to get the best settings (Layer height, speed, number of walls, infill, temperatures, type of filament, etc) to be able to print the strongest and safest frame you can, I have more than 1 year gathering info, testing profiles, settings, filaments, and printing tests of my frame design, apart from the time I have designing and making slingshots.

      Cheers!



       

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      Last edited: Nov 19, 2020
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