Simple, yet effective Top-Down Design approach


Every product on the market always starts with one thing in common---a problem in need of a solution. Yesterday I had a problem that I was in dire need of a solution. A little bit of background on myself lately; I have been going to the gym trying to lose a few lbs (down 18 lbs in two months), as being a drafter seems to make you fat from sitting all day. It was suggested that I start taking creatine supplement to boost my muscle gain, so I went to the store to pick some up. To my dismay, I went to mix the powdery substance per the directions of "1 rounded teaspoon" and there was no "scooper" to measure that out. I was at the gym and had no idea of knowing if I had just poured out a rounded teaspoon or not!

So I done what any normal person would do, I went and bought a teasp........I mean I designed one in Solid Edge and 3D printed it on a $26,000 Stratasys printer.


To do this easy project, I used a Top-Down design technique in Solid Edge ST8. The first thing I done was to model a representation of the interior volume of the scooper. I needed to be exactly 1 teaspoon. I knew I wanted the I.D of the cutout to be around 0.75". Mathematically I could figure out what the height needed to be to equal 1 teaspoon, but I wanted to use a feature I LOVE in Solid Edge called Goal Seek. I modeled a cylinder that was Ø0.75 by 1" tall and saved it; the 1" just being a placeholder. Then I gave the model some random material because in order for Goal Seek to work, a material HAS to be assigned.

Then on the Inspect Tab, I chose Goal seek and got a tool bar like so:


I chose "Volume: as my goal. I then converted 1 teaspoon to in³ which is approx 0.301 in³. I then set the target for that value. For the Variable, I set that to the height of the cylinder. Once I clicked the green check, the cylinder transformed right before my eyes and adjusted itself to a height that satisfied Goal Seek to a volume of 0.301 in³. I then saved that part. I only need this part for one reason in my next step.


For my next step in the process, I started a new part. I then used the feature Part Copy. This can be found on the Home Tab>Clipboard Panel. Using Part Copy, I browsed to the part I just modeled that represented the volume. I inserted it as Construction Body so that is would not be considered geometry. I just needed it as a reference.


You can see the options I chose above and the outcome to the right. Next I started my scooper with Revolve and created the main body to the scooper. The cool thing about the sketch for that was the only dimensions for it was the wall thickness. I used the Construction Body as a reference. In doing this you create a "link" between the two files. If the file that contains the cylinder ever changes, it affects this part file. So in theory, I could change the volume of the cylinder to whatever I see fit, and the scooper file will update with it.


I then proceeded to add a handle to the the scooper and finish it out to end up with what you seen in the first picture above. I saved an STL file in fine resolution and printed it out. I used it today when I went to the gym.

The point of all of this is tho show you two features that I LOVE in Solid Edge---Goal Seek and Part Copy as well as to show you a Top Down design method. Had I done it Bottom-Up, I would have found out the size of the internal volume cylinder and just modeled that into my revolve. However, I feel like anytime you can put a part copy into something and reference off of that, then DO IT. Bear in mind this system will not work good in an assembly or a part that is used in many different models or products as it will have "links" to other parts that may not be in that assembly or what have you. Cheers!

#solidedge #CAD #howto #Drafter #design

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© 2019 by Scott Lester Drafting & Design

Mount Airy, North Carolina

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