Unlike most advents, CADvent will celebrate the 25 days until kickoff by sending out CAD challenges daily. I created CADvent for my team last year to help prepare my team for the season, and because of its success, I’ve decided to share it here as well. The CADvents will increase in difficulty as we get closer to kickoff and will vary between flat, solid, and sheet metal, along with a few other types of parts. As today is Day 0 I have included a simple version of a standard CADvent drawing. Feel free to share CADvent with your teams as it is a good way to prepare for the season.
I’m human (I think), and I may have missed some dimensions on some drawings. If you see a missing dimension please let me know so I can update the drawings accordingly. I designed most of the parts that will be used in CADvent, although there are a few that I did not design but was a member of the team that designed it.
Assumptions for all drawings:
If it looks like it should be colinear, concentric, parallel, vertical, horizontal, tangent, or equal in size, it probably is unless otherwise stated.
CADvent will officially start tomorrow so I look forward to seeing you all then!
Great work! We’re everyone on our CAD/design team do them every day, and take it another step to see who can complete each CAD challenge most efficiently. Also, on the dimensions in the day 0 drawing I’m assuming it’s inches, but just a heads up that it says mm down there in the drawing specs. Great work and my team is excited for the next 25 days of CADmas!
Welcome to the first official day of CADvent!
I hope you all are as excited about the upcoming season as I am.
Today’s CADvent is a fairly simple piece that I designed as an elevator bracket over the summer. As always, please let me know if there is a problem with the drawing.
I have a question on how you would expect a part to be CADed.
I would read the 0.13 dimension to mean the edges of the diagonal struts are equidistant from the diagonal line connecting the opposite circles. Since the strut is 1/4" thick, halfway across would be 1/8" or 0.125. To preserve machining precision, this number is rounded to 0.13 - or at least that’s my assumption.
When a student makes the CAD based on this drawing, would you expect the entered dimension to be 0.13 as shown, or 0.125 as (likely) intended?
As an engineering teacher, I’m interested in how things like this are handled in industry, and how far the professionals are allowed to design to intent rather than follow the prints directly.
I would say, in industry, typically the designer is not modeling off of a drawing, but rather they are the input to the design, and thus this situation wouldn’t really arise.
Alternatively you can use other drawing techniques, like C.L. (centerline) callouts or setting up good GD&T Datums to capture design intent without actual dimensions.
Lastly, at least at my work, we only put dimensions on critical features we want inspected in a vendor’s First Article Inspection or by our Receiving Inspection Quality Control team. Undimensioned features would only be controlled by an overall part Surface Profile GD&T callout, and often not fully inspected.
So the drawing would feature fewer dimensions and the 3D model we send to the shop captures the ultimate design intent that they put into CAM software.
I also couldn’t really tell what was being indicated, but I assumed it was because I’m fairly new to CAD.
My interpretation was that the construction line wasn’t the exact center line for the cross braces.
I appreciate that, but I’m still interested in an answer to my earlier questions. Should team members CAD to dimensions given, or are they given the leniency to, say, dimension to 5/8" (0.625) rather than the 0.63 as shown?
I hope you don’t take my inquiries as critical to the drawings you’ve made. I’m just looking for relevant understanding, since I wasn’t formally trained.
Most of the dimensions in CADvent are “nice fractions” (1/8, 3/16, 5/8, etc), so if a dimension is a rounded version of one of those (.13, .19, .63, etc), I would say go ahead and use the fraction. I will also try and add more decimal places to dimensions that need them in the future to limit confusion.
Today’s CADvent was designed for my team’s 2018 intake. It is a semi-simple part that mainly uses extrudes and extruded cuts along with a few linear patterns. 2018_intake_finger.PDF (57.2 KB)
Please note, I slightly changed the format for the drawings. From now on, part thickness for most flat/sheet metal parts will be found under the material section.
TBH, I’m not sure. I mainly designed the elevator in 2018, but from what I remember we needed the intake to have very specific dimensions to avoid having the cubes jam in the intake, so that may have been the reasoning.
Today’s CADvent was designed for my team’s 2019 HP grabber. If you want a fun challenge, try doing this CADvent with as few extrudes/extruded cuts as possible (it is possible to do in one). 2019_hp_grabber.pdf (55.1 KB)
