Modified Segment R4 for MMU3 Buffer

Remixed from the Original Prusa segment-R4 for the MMU3 Buffer-R4.

Necessary as the smaller type of E3D collets that Prusa use are a) expensive and b) not readily available in the UK. The larger type was purchased from Amazon here -

https://www.amazon.co.uk/gp/product/B0CRTRLB7M

Note - this model is the Mk4 / MMU3 version of buffer cassette which is different to the Mk3S+ version.

R4 segment buffet modified to take the larger PTFE tube collets which fit in a 6mm hole, unlike the smaller E3D type which fit in a 5mm hole.