Union Jack - United Kingdom / Great Britain Flag

With 2012 being the year of the London Olympics and the Queen's Diamond Jubilee, the Union Jack seemed an appropriate project to try out some multicoloured printing on my RepRapPro - single extruder - Huxley.

RichRap's British Prusa Mendel, http://www.thingiverse.com/thing:12905 , was my inspiration for producing this thing, the idea being that it could be scaled as needed and stuck onto other things.

The design was produced with a piece of graph paper, an image downloaded from the internet and my somewhat distant memory of being taught at Cubs that the Union Jack is made up of three flags: the white diagonal cross on a blue background of St. Andrew (Scotland), the red diagonal cross on a white background of St. Patrick (Ireland) and the vertical red cross on a white background of St. George (England). The object is made up of three parts: a white base colour on top of which is a blue colour topped off with red.

The Union Jack by the way should always be displayed, hung, flown the correct way up (as shown in the photograph) as it is not symmetrical - those in the know should never fly it upside down!

Edit: My dad pointed out that the red St. Patrick cross is not as it should be. The two red stripes which form each of the diagonals should be offset and not continuous lines as I have drawn. Ho humm - thank you daddy!

Instructions

Slice and print the WHITE.STL file as normal using white plastic. This will give you a slab which is 0.6mm tall upon which the BLUE and then RED prints go. (On my RepRapPro Huxley sliced using Slic3r with a layer height of 0.3mm, Z goes from 0.3mm to 0.9mm)

BLUE.STL comes next. I used Slic3r to slice this file (again, 0.6mm tall) but took off the skirt and set the Z-offset to 0.9mm so that it would start on top of the white slab. This print will place the blue triangles on top of the white base as well as laying down the St. Patrick and St. George crosses. Use BLUE plastic for this file.

RED.STL finishes the job. Again, using Slic3r, I took off the skirt and set the Z-offset to start the job on top of the blue plastic This file will overlay RED plastic for the St. Patrick and St. George crosses on top of the blue which was printed earlier.

One little tip - starting a print with Z significantly higher than 'normal', (in my case 0.3mm), can give problems if your G-Code speed for raising the Z axis is too high for your particular printer. It may be a good idea to take a look at your BLUE and RED G-Code file and reduce the Z feederate for the initial height required by these two prints.

The flag can be printed from a single STL file (RedWhiteBlue.STL) but if you go down that route, you will need to split the file into three and change the filament when the Z height goes above the base colour (change from white to blue) and again when the printer has finished the blue section, (change from blue to red). Scropp gives some good instructions in his blog about how to split your G-Code: http://stephen.cropp.co.uk/2012/02/multi-colour-printing/

Category: Signs & Logos