Multi-Material Road Sign (UK) Coasters

3D Printable Multi-Colour UK Road Signs

These are minature versions of real UK road signs, dervived from government provided vector graphics samples.

The generate.py Python script will use generate.scad to produce a configurable list of multi-material signs. If you want to add a new sign, modify generate.py and add one to the signs list. Latest sources all on github

To make rather fetching coasters/cup mats I've scaled the round signs to 9cm diameter, keeping the 4mm thickness, and added felt to the bottom with double sided tape. Printing them in PETG should mean they're fine for hot drinks.

Since I don't own a multi-material printer I've used a variation on a technique I found on a blog post that works with PrusaSlicer and my Prusa Mk3:

• I added a new printer to prusa slicer, and configured it with multiple extruders.
• I then added the custom G-code for "Tool change G-code" to be M600. This tells the printer to request the user to change the filament.
• When exporting gcode, I manually edit the file to remove the first M600 call - otherwise the printer asks you to change the filament immediately.
• Import all the STL files for the sign at once - it should ask you if you want to treat them as a single object. Say yes!
• I print the signs upside down, so the manual filament changes are over fairly quickly, and the rest of the sign can print without intervention.
• Using a wipe tower helps ensure there aren't any gaps or splurges in your print, but you can reduce the purge quantity a lot.
• When changing filament on the first layer, take special care to look for and remove any long stringing that PETG likes to do.
• When changing filament, grab the extruded waste with pliers, but don't tug it away until you've confirmed it's succeeded and the print head starts to move away! It will extrude a short lengthafter you've pressed the button to confirm.

Printing in PETG on the textured bed, with the 'front' of the sign facing down results in a very neat and tidy front surface. If you tweak the elephant's foot settings right (I found about 0.1mm worked for me) then there will be no gaps and very little colour blurring at the boundaries between colours.

Sign graphics are licenced under the Open Government Licence and available in their original vector format from here

Everything else licenced under GNU GPL-3.0-or-later.

Print Settings

Printer Brand:

Prusa

Printer:

I3 MK3S

Rafts:

No

Supports:

No

Resolution:

0.2

Infill:

15%

Filament: Amazon Basics (mostly) PETG

Misc

Notes:

See the summary for notes on how to use a non-multi-material printer to print these!