PiBot.com releases new Spring loaded extruder for 3D printers. The new metal extruder offers a significantly higher torque with compact design. All metal parts are anodized with comfortable texture. Extruder reliability is increased and its filament could be processed with high speed. This design incorporates a spring-loaded arm to squeeze the filament between the drive gear and a bearing with a constant amount of pressure. Minimizing the chance of skips due to variance in filament thickness.A simple spring height adjustment part is included to easily increase the spring rate if needed. With this piece, you will avoid loosening and tightening the screws of the extruder every time you change your printer filament .One-Handed Operation makes inserting new plastic filament to the extruder easier. The mounting support is designed for hot ends with a diameter of 6mm and could be assembled on most 3D printers. Due to its compact design, it is also suitable to be mounted as a dual extruder. you can see more in reprap.org it is opernsource or pibot.com i don't know if the files in .dwg can upload? i make it sample ,easy to use