Business Cards

3D Printed Business Cards with some useful scales and gauges.

Year: 2025

Problem

I dislike business cards from a design perspective. 

We have a unambiguous, unified, global standard for card size, but we don't use it for business cards!

 So they get crinkled in wallets, or pockets and never play nice with anything, and then not everyone uses the same business card dimensions.... and since business cards do not fit in wallets, I never have one on hand.

I also often need a small ruler on hand for engineering sketches, so I usually use a credit card. 

Design

A credit card sized business card to fit in wallets, with metric, imperial scales, a metric hole gauge, and a QR code on the obverse. Designed around the limitations of my venerable Prusa MK3S+, with no automatic filament changer and a 0.4mm nozzle. Designed with the fewest number of filament changes, and the fewest total number of layers possible to minimize print time and filament use, and to maintain credit card thickness. 

Because print detail is limited to ~0.3mm when using a 0.4mm diameter nozzle, to get the finest detail possible for the measurement scales, they are designed around negative space, as there is a much smaller minimum space between features. This also has the unintended effect of making them nicely tactile - like the engraved scales on old machine tools. 

Two chevrons on the face indicate on which side of the card the scales begin, as this isn't obvious without numerals. A binary or nonary dot system could be used to mark the scales, but I decided not to add it (yet)

A metric hole gauge is included for diameters from 10mm in steps of 1mm down to 2mm. The labels for 2mm, 3mm and 4mm holes are absent, but it is assumed that the user will see a pattern. 

The Weeds

Modeling a QR code is painful. I couldn't find an elegant solution to this, especially for linkedin qr codes which only export in png raster files. 

So, every dot is modeled. After making a array of nxn cubes, and scaling an overlaid QR code image, create a selection set to selectively merge some of those cubes with the card. Time consuming, but not very computationally intensive for the model itself.