Laser engraver Air assist - V slot wheels, 500mm, RAMPS 1.6+ RE-Arm

thingiverse

Human: This revised design incorporates several modifications to accommodate 500mm aluminum pieces and switches from extruded aluminum and wheels to V-slot. The objective is to utilize readily available and cost-effective 500mm extruded aluminum, eliminating the need for cutting. The 5mmx500mm rod presented a challenge; I had to add a bumpout on the gantry for the bearing holder to ensure the rod's length was sufficient. Ultimately, it works well, with parts conforming to standard sizes. Since the wheels no longer match the original size, nearly every component underwent changes. I added endstops, belt tensioners, and air assist to enhance performance. Required hardware includes: 3 x 500mm V-slot 2040 2 x 500mm T-slot (or V-slot) 2040 1 x 500mm 5mm rod 1 x 16mm x 5mm and 5mm opening bearing 12 V-slot wheels, measuring 11mm in width, 25mm in diameter, and featuring a 5mm opening in the bearing. The gantry and air assist were designed for a 40mm x 40mm laser, with mine being 5500mW. I applied weather stripping to the inside of the air assist part near the lens to achieve a tighter seal for the air. The "tall leg" file can be mirrored for the opposing side. My controller is a Re-Arm RAMPS 1.6 with Trinamic drivers (TMC2100) and runs Marlin 2.0. It may be overkill, but I appreciate the quietness of Trinamic drivers, and my 3D printers both employ Re-arm RAMPS. The Mosfet switch was an eBay purchase; I removed bulky screw headers and soldered directly to the board. The air assist consists of a flexible 5mm OD hose approximately 36 inches (92cm) long connected to a 950 GPH, 32-watt air pump. I used a Vivosun pump purchased on eBay for about $45 CDN. The bed size for this setup is approximately 360 x 345, which isn't ideal but sufficient for 500mm parts. I mounted the endstops on the gantries for simplicity, with wires originating from two locations only. The belt tensioners are a remix that keeps the belt low in the V-slot, minimizing wear. Initially, I noticed the entire machine dancing on my desk during the first few attempts, resulting in distorted prints when it moved. To rectify this, I changed the legs, allowing me to screw the whole machine to a piece of wood and raise the workpiece without fear of further movement. To prevent the laser from turning on at startup, I utilized a Mosfet switch triggered by the stepper motor cooling fan output. This setup ensures the laser remains off during startup since the servo outputs (used to control PWM for the laser) are high during the boot sequence, making it quite hazardous. The Mosfet is connected between the laser power coming from the laser module and the laser itself. It activates for 600 seconds whenever any stepper motor moves. I use the "home" function to turn it on if I want to focus the laser before a print. I also adjusted Marlin settings, making the default laser power 1% rather than 100%, which makes setting the focus safer (although I always wear protective eyewear).