This is 3-axis CNC plotter/engraver based on GRBL software and 2020 aluminum extrusions. Low-cost engraving and PCB manufacturing dual side.
Our prototype model is IoT-based thus providing it a scalable architecture to use it from practically anywhere with an internetconnection. This is a 350mm x 350mm CNC with a 250mm x 240mm work area, running on open source motion control software (GRBL). Even our hardware is also mostly open source and thus comes the major cost cutting. This machine is made wholly from locally purchased items and can machine on wood, plastics, hard rubber, hard resin, etc. Our primary target is low-cost PCB manufacturing.
The prospect of wood craving is also there.
We’re planning to add laser machining support too as part of our future project.
As the system can bepresently controlled from a local Intranet wirelessly, we want to scale itf urther to make a distributed model web application to make and connect anecosystem of multiple number of these kind of devices.
The possibilities are unlimited with our machine.
Our prototype model has its base frame made out of 2020 T-slotted aluminum extrusions and L-joints. The machine gives roughly about 80-85 Watts power with its 2000 rpm DC-controlled spindle. It has lead screw and threaded rod movement scheme with guiding smooth rods having radial groove snap fit ball bearings for smooth operations along all the 3 axes.
The minimum lead pitch is 0.8mm/revolution with a2000 steps/revolution we have a resolution of 1600 for all the axes. Our rough machine size is about 430x430x330mm and work area is about 270x170x65mm with 0.04mm positional accuracy. Our Z-axis gantry is 3D-printed from scratch with dual guiding rods.
The Z-axis travel 4.8 cm with spindle bit mounted. We’re using 45° V-bit cutting tool for PCB engraving purposes, it also supports 0.2mm to 1.8mm end mill bits. We’re using NEMA 23 Stepper motors with 3A maxcurrent for each axes main drive. The motors are driven by 2.5A A4988 drivers with 1/16th maximum micro-stepping resolution providing us theultimate machining precision at a very economic cost.
For the IoT part, we have made it possible to control the CNC router from a headless display like a mobile /tablet screen(acting as our HMI here) from anywhere with an Interne tconnection. We’re using a Raspberry Pi and a router (security) arrangement connected to the internet and running a web server to provide an interface for controlling our CNC wirelessly. We’re also planning to get hold of valuable machine part insights like real-time motor torque, current drawn, vibration, noise etc. and draw real time insights in a web platform for better collaboration. Which is perhaps called in the manufacturing sector as the Industrial IoT (INDUSTRY 4.0).
Source: DIY 3-Axis CNC VMC