Face Shield Velcro Cutter

thingiverse

This is the mechanical components for construction of a device that extrudes and cuts reliable lengths of velcro strip. The least straightforward part of this design is the extruder wheel. To assemble: - Heat-set an M3 insert into the grub screw hole - Mount to the shaft of the stepper motor to make sure the insert was not pressed too far - Carefully superglue velcro to the outside of the wheel hook-side out so the seam is above the grub screw hole. I recommend wrapping the velcro tightly and then cutting with a sharp blade across two layers. This ensures the strip will align at the seam nicely. - Once the glue sets, jam a hex key into the velcro seam until you can actually turn the screw again - You may need two or three layers of velcro to build up enough thickness - the number of layers to apply depends on the thickness of the velcro strap and how many simultaneous strands are being run. Other notes - Pushing the blade into the cutter arm is dangerous and difficult. I recommend squeezing it in with a bench vice, and using a block of wood to ensure the blade is not damaged by the vice - The servo horn and linkage should be set up so that when the blade is firmly pressed into the "cut" position, the servo is at the bottom-dead-center of travel. This allows for a maximum mechanical advantage during the cutting action. - The "pretty box" case is unnecessary. It just helps prevent accidental cuts on the exposed cutter blade, and accidental pinching from the servo linkage. Required non-printed components - Box Cutter Blade - NEMA17 stepper motor - NEMA17 Mounting hardware (4x M3x8mm bolts) - 7x M3 heat-set Inserts - 4x M3x45mm bolts - 2x M3x14mm bolts - 1x M4x12mm bolts - 2x 608 skate bearings - High-Torque servo - 4x M3x12mm bolts for mounting servo - stiff Music wire for servo->cutter linkage - Velcro strip for gluing to extruder wheel - Electronics for running NEMA17 stepper and RC servo, Buttons, etc. for user interface A more in-depth assembly procedure and electronics design will be provided if more than one or two people wish to construct one of these. Onshape Project: https://cad.onshape.com/documents/740b532d7f68e974d6132f92/w/ad5aa8ce3bdc56bb445b1e83/e/ce3921381506a4ab4c506053 Arduino Code (Requires Arduino, stepper driver, and power supply) https://github.com/aseiger/Cutsruder_V2