Michigan Technological University professor Joshua Pearce has released a project of a homemade grinder to the public. The goal is to enable the artisanal production of expensive compression augers used in 3D printers for printing with plastic granules.
A couple of years ago, Professor Pearce, a well-known advocate for 3D printing technology and open source design, already laid out a project for a homemade Recyclebot filament extruder capable of recycling plastic waste into consumable material for FDM / FFF 3D printers. Alternatively, to reduce the cost of 3D printing, you can use an extruder that feeds not filament to the hot end, but cheaper granulate or crushed secondary raw materials. In any case, both filament extruder assembly and pellet extruder assembly will require a screw of the right size and shape, and in order not to struggle with finding a key component and not overpay, Pierce offers a tool for making handicraft customized screws. At the same time, the problem with the granule size, which is often too large for commercially available micro-screws, can be solved.
The device makes it possible to manufacture screws of different diameters and lengths, with different depths and thicknesses of grooves, directions, and angles of turns. The pilot machine has been successfully tested on three grades of steel — 1045, 1144, and 416. The design is inspired by conventional lathes, but for the sake of saving on components, the main component is a grinder with a grinding disc, installed at the required angle, and moved along the part using a 3D-printed carriage-slide … The workpiece is mounted in a chuck whose rotation is synchronized by the belt drive with the movement of the carriage. You can use a screwdriver, socket wrench, or a homemade handle as a drive for the positioning system.
In its current form, the equipment is capable of processing workpieces up to 110 mm long and 4 to 16 mm in diameter. One of the main problems is disc wear, so it is recommended to replace it with a new one before finishing the grooves.