I've posted previously about my procurement process and elided a crucial detail: my part documentation for the past year has been pretty atrocious. Partly that's because I haven't been buying mostly 3D printed parts, which (when you buy from Shapeways et al) are documented only with STLs, but it's also because I haven't taken the time to set up my own drawing standards. Until yesterday.
This drawing is of the lid for The Public Radio. Depending on quantity it'll either be stamped or laser cut. I'd prefer stamped, but that's mostly because it'll be much less expensive at quantity - and I'd rather sell thousands of parts, not hundreds.
The details of the drawing itself are rather mundane, but the title block and drawing format involved a number of weighty decisions. A few points:
- I'm using an ISO A3 paper size. Because ISO is cool.
- I'm dimensioning in millimeters, and have default tolerances in millimeters too. This was a bit of a hurdle for me - I'm comfortable with metric dimensions but used to thinking of tolerances in thousandths of an inch - but I'm excited to be all (or mostly all) metric. Most of the tolerances here are three decimal places, which is basically the same at .13mm = .0051", is totally translatable for me.
- I'm using decimal points (instead of commas) between the ones column and the tenths column. Because Europe isn't right about everything.
- I don't have any "approved by" field. Fuck standard title blocks, right?
- "BREAK ALL SHARP EDGES." Yes.
- Note: As I'm looking at this, I'm realizing that I should probably relax a number of these tolerances. Which often happens, the more you look at a drawing.
- Revision tables. I start my drawings at "REV -", and then I increment alphabetically from there. This particular drawing was submitted to a few suppliers prior to this drawing standard, so I've incremented to "A" already... it's a little weird, but it works.
- I'm not a huge fan of "TYP" or "typical," but in some cases it makes sense.
- I'm using my part filename as a field in my title block. I considered separate boxes for part number and name, but I'm careful with filenames and this makes it easier.
- I'm using an ISO time string (but with decimal delimiters) throughout. Because ISO is cool.
- I'm a little flippant in my title block (the "info, documentation & jokes" thing), but it's better than having to list my phone number.
Changes I should probably make:
- I probably need a logo... or something. I don't know, a circle with a dot in it?
- Line weights are off.
- Do I really need to say what sheet it is? It's really only useful if you're documenting assemblies - at least with the simple parts I tend to design.
- I guess I should be marking zones of the drawing space, but I've never done so in the past and never felt like I was missing anything.
- I wish I could get rid of the file extension.
Overall I'm happy about this. Pretty fun.