CNC 3018 modular spring loaded engraving/paint tool

thingiverse

I want to explore various methods for creating PCBs on my 3018 CNC machine, but I found it challenging to find a spring-loaded engraver tool, especially one that fits a small shaft (5mm). So, I decided to design a module that enables regular tools to be spring-loaded. As I work with multiple 3D printers at home, I have a collection of spare parts - 8mm rods and linear bearings like LM8UU and LM8EUU, although they might be overkill for this purpose. DISCLAIMER: This project is still in the design phase and has not been tested yet. It may not work or function well, so please be aware that any part can be changed for various reasons. 1. Installing the adapter. You will need 2 linear bearings LM8UU or LM8EUU (if unsure, measure the outside diameter; LM8UU is 15mm and LM8EUU is 16mm) and print 2 equal pieces of adapter_LM8UU.stl or LM8EUU.stl accordingly. 2. Remove the spindle DC 775 motor and install 2 adapters with bearings inside. Note that the adapter is not symmetrical, so position it with the smaller side towards the CNC to avoid issues with the top plastic where the Z stepper is attached. Tighten them carefully but do not overtighten as you are working with plastic. 3. Print holder_motor_top.stl 4. Cut 8mm linear rods into two pieces around 70mm long, which will give a 5mm moving distance. If you want more, make them longer. 5. Place 2 3mm nuts in the vertical holes of the holder and attach springs to a 3mm bolt (14-20 mm long). Insert them, then insert the 8mm rods and tighten them with those 2 bolts. Again, do not overtighten. 6. Insert the rods into the adapter. Place 2 more 3mm bolts into holes on the adapter sides (self-tapping thread) to tighten springs. 7. Print holder_bottom (choose depending on the purpose). Insert 4 M3 nuts and tighten the motor and rods in place using 2 25mm long M3 bolts. Tighten 2 15-20mm M3 bolts to fix the 8mm rods. Again, this piece is still in design and testing, with more pieces and pictures to come. STL Files ======= * adapter_LM8UU.stl: Spindle adapter for LM8UU bearing. Print 2 of them. * adapter_LM8EUU.stl: Spindle adapter for LM8EUU bearing. Print 2 of them. Note that you do not need both, print 2 for the bearings you have and want to use. * holder_motor_top.stl: Top part holding 8mm rods by 2 M3 bolts (same bolts can be used for tension springs). You will need 2 M3 longer than 14mm bolts and 4 M3 nuts. Print 1. * holder_bottom_555p.stl: Bottom part to hold 555 DC motor with plates (thicker). You will need 2 20mm long M3 bolts and 2 M3 nuts. Print 1. * holder_bottom_555.stl: Bottom part to hold 555 DC motor bare (just motor). You will need 2 20mm long M3 bolts and 2 M3 nuts. Print 1. * holder_bottom_365.stl: Bottom part to hold 365 DC motor bare (just motor). You will need 2 20mm long M3 bolts and 2 M3 nuts. Print 1. Happy etching!