MOTM May 2017 - Contest Thread

Ben_Misegades

Round 2, fight!

As per suggestion by @3dcad this month's contest is posted as a "question" to see if that works better with the format of the contest.

How to participate:

• The contest is open to any user, your level of subscription does not matter
• The age of the file does not matter. You are free to enter any existing project you may have, there is no need to create something specifically for the contest
• Despite the name of the contest being "model" of the month, things like Feature Scripts are also acceptable entries.
• Simply importing a model from another source into Onshape does not count! It must be clearly evident that Onshape was used to create or manipulate the document that you are entering!
• To enter, reply in this thread. Your post should include the following:

1. A link to the document you wish to enter. Be sure to make your document public!
2. A screenshot of the document. Please only one screenshot per entry.
3. A brief description of the project to help other users understand what complexities or difficulties may have been involved.

Voting:

• All users, whether you enter the contest yourself or not, may vote on submissions.
• Use the built-in forum features to "Vote Up" entries of your choosing. Please refrain from using the "Vote Down" as it goes against the spirit of the contest. Since the contest is posted as a "question" this time, this should hopefully work a little bit better than last month.
• At the end of the month the entry (or entries) with the highest number of "upvotes" will be declared winner
• A new thread will be created eventually to archive monthly winners

Discussion:

• Please only post in this thread with entries! For any feedback, questions, or discussion, please post in this thread:

https://forum.onshape.com/discussion/6384/motm-may-2017-discussion-thread/p1?new=1

Prizes:

• Since this contest is not organized by Onshape, no forum badges will be given out, sorry.
• An Amazon gift card in the value of $25 will be awarded to the winner
• Bragging rights 
• Last month's winner @john_mcclary was gracious enough to decline his prize and "pay it forward" to this month's winner, I would encourage people to thank him for that kindness!
  

This contest is open for entries immediately, and will remain open until May 30th. Voting on entries may begin immediately, as well. The winner will be announced on the 31st, so be sure to get all of your entries and votes in before then!

Rootentity

Tapped Horn subwoofer enclosure made from stacked plywood.  

    I plan to make a pair of these enclosures soon.  Frequency response is from 30hz to 80hz flat with equalization at 135db on 800w for the pair.  It is unique from other enclosure styles because it has two peaks in efficiency.  One resonating at the path length of the horn, and one resonating at double the path length of the horn, from the back side of the speaker cone to the throat and back. The back side of the cone also radiates directly at the mouth filling in the middle of the two peaks.  

    Cone excursion at the two peaks is mechanically limited to around 800w before something smashes together.  At around 60hz, between the two peaks the cone has almost no movement.  The cone first moves into the throat creating a pressure wave, as the cone moves back away from the throat the pressure wave travels through the horn, and meets the backside of the cone pushing against it.  This means that at the point between the two peaks the driver is purely electrically limited, and can take upwards of 1500w rms, or over 6000w in very short bursts before something melts.  What all this means is that it is capable of both sounding good (and loud) in everyday use, and holding it's own in SPL competitions reaching over 145db.



The Tapped Horn design is patented by Tom Danley of Danley Sound Labs.  He is a great guy and has been a huge help to the DIY community in both allowing people to use his designs for personal use, and in helping to understand them, however this design is NOT for commercial use or trade, and all rights to this design belong to Tom Danley.

https://cad.onshape.com/documents/58fd6d27b4b5be10cb41e989/w/61dee5932877eaed8e5ad0fe/e/6bb8829fbb6bf35148baae7b

brooks_talley

I'll play. Here's my set of modular cabinets and drawers. The product has a few requirements:

• Store a multitude of parts, ranging from M1.4 screws and washers up to solder rolls and stepper motors
• Be totally modular, allowing the addition of drawers and cabinets over time as my needs evolve and/or I learn how to make better parts
• Have a 9mm front face suitable for labeling with a Dymo or similar
• Be 3D printable -- every piece has to be able to lay flat on the print bed in some orientation where there are no overhangs > 45 degrees

The drawers are squares with sides matching the Fibonacci sequence, so when assembled the drawers will approximate the golden ratio. As larger and larger squares spiral outwards, they produce the golden spiral and just look nifty. Dovetail-style rails and notches around the sides would be evenly spaced so modules of any size can be mated and line up nicely.

The whole thing is as parametric/programmatic as possible. This allows every drawer to be unique in its height (also using the golden ratio), angle of its handle (simple geometric progression), and proportions of the parts containers inside (scaled using drawer height). The fact that sketch references are not resolved when patterned turned out to be a real challenge.

The result is a bit of a beast -- a linear pattern to produce the module frames, which also includes a linear pattern that creates the shelves, which in turn are used to produce the drawers, which then calculate handle angle, and so on. But you can indeed adjust the whole thing by just changing a few variables (try squareSize to get more/less, or a bit lower down, change how the desiredContainerSize variables are calculated to get more or less dense parts drawers).

Rootentity

Tapped Horn subwoofer enclosure made from stacked plywood.  

    I plan to make a pair of these enclosures soon.  Frequency response is from 30hz to 80hz flat with equalization at 135db on 800w for the pair.  It is unique from other enclosure styles because it has two peaks in efficiency.  One resonating at the path length of the horn, and one resonating at double the path length of the horn, from the back side of the speaker cone to the throat and back. The back side of the cone also radiates directly at the mouth filling in the middle of the two peaks.  

    Cone excursion at the two peaks is mechanically limited to around 800w before something smashes together.  At around 60hz, between the two peaks the cone has almost no movement.  The cone first moves into the throat creating a pressure wave, as the cone moves back away from the throat the pressure wave travels through the horn, and meets the backside of the cone pushing against it.  This means that at the point between the two peaks the driver is purely electrically limited, and can take upwards of 1500w rms, or over 6000w in very short bursts before something melts.  What all this means is that it is capable of both sounding good (and loud) in everyday use, and holding it's own in SPL competitions reaching over 145db.



The Tapped Horn design is patented by Tom Danley of Danley Sound Labs.  He is a great guy and has been a huge help to the DIY community in both allowing people to use his designs for personal use, and in helping to understand them, however this design is NOT for commercial use or trade, and all rights to this design belong to Tom Danley.

https://cad.onshape.com/documents/58fd6d27b4b5be10cb41e989/w/61dee5932877eaed8e5ad0fe/e/6bb8829fbb6bf35148baae7b

john_mcclary

This is my rifle, there are many like it....

It's far from complete, but I haven't had much motivation to finish it lately. Enjoy

https://cad.onshape.com/documents/c3e95f641b63d3f60afbee13/w/ad8f259166c4b0eb17d5bd81/e/864b7b377f31f939c6e021a4

tim_voght

This novel model steam engine uses a straight-line linkage (a Roberts Mechanism) in lieu of a crosshead. I drew it up in 2D CAD and built a model which runs on compressed air. The OnShape model was built after-the-fact as an exercise in learning 3D CAD.

https://cad.onshape.com/documents/576dae70e4b0cc2e7f468d75/w/b5ce5fc2ab3e5ffbb7388406/e/40632bab95d9aa5e4633ffad

Ben_Misegades

@Rootentity is the winner for May, congrats! I will get in touch with you shortly for your prize!

Though there were very few submissions this month, I have to say that I am quite impressed with what was entered!