[ENHANCEMENT] better heatbreak

[SnickCH]

Printer: Mini /Mini+

Problem There is a reason why bondtech and others sell heatbreak upgrades for the Mini and Mini+. The actual heatbreak has a borehole that goes way to near to the nozzle. Another problem is the design, that is straight and has no cutout to minimize the heat travel. Therefore a lot of user experience a problem with the heat break.

• printing on high temperatures may defor the PTFE tube
• if the PTFE tube is replaces and not cut "perfectly" it has a gap that will easily filled with melted filament
• Other printing quality issues that are related to the heatbreak

A good overview and explanation is in this video: https://youtu.be/5CLnF0a9vwY

Solution Proposal There would the following things to improve it

1. The borehole shouldn't be so deep. Like other allmetal hotends (like the micro swiss for Creality printers).
2. A cut out just after the heatblock leaves the heatblock
3. Use titanium alloy that has better termic blocker

Points 1-2 is used by the bondtech upgrade that is sold for about 20 USD. This upgrade should nod cost much for if you produce it in your sclae. Points 1-3 is used by the brozzle upgrade that is sold for about 25 USD.

In the picture: Bondtech design (left), original (right). The credit for the picture (I took a printscreen at 6:55): https://www.youtube.com/watch?v=5CLnF0a9vwY