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Showing posts from January, 2011

Aixiz module finally arrived!

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After waiting for a month, I finally got the module from Aixiz. I had been very busy anyway, so the delay didn't really matter. Here it is: the 650nm 5mW Aixiz module! I also got an extra lens for it, made of glass. I'm sure it's better suited for a laser CNC than the plastic one the module came with. This module is needed for collimation and heat sinking. I will put the laser diode inside the module and focus the beam with the glass lens. Next up: how to insert the 250mW laser diode into the Aixiz module.

Sketching the CNC

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So, at this point, I have a scanner that I'm going to use as a base, with a stepper controlling the movement along one axis. This is the scanner I'm going to use as the base. I also have a stepper motor, a metal rail and a pulley system that will be used to move along the other axis. A stepper motor from an old printer. A metal rail & old printhead. I was thinking about the possibilities how to create the XY-controlled CNC from these parts, and came up with three sketches. I admit, I'm very bad at drawing, but anyway, I decided to share these sketches with you. My first idea on how to construct the CNC was not a very brilliant one: First idea of the CNC, a very shitty one. The laser points up. The surface to be engraved would be held upside down over the CNC byt something, and the beam is pointed upwards from the scanner. Well, you can imagine how this would make the whole set-up and engraving process a pain in the ass. Especially with heavier ite

Laser diode driver circuit

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Here's the schematic of an adjustable laser diode driver circuit. It's based on this post by nickname Daedalus on the Laser Pointer Forums . This post has gotten so popular that people are referring to the circuit as a 'DDL circuit' (DDL is Daedalus' signature in the forums). It's just a constant current driver, but Daedalus was the one who popularized the use of this in DIY laser scene. From various sources in the internet, the voltage of the red 16x DVD burner led is found to be 3.2V and it's said (in various sources in the 'net) to withstand 250mA current. The laser output power is said to be 250mW. That is the power of the light coming out of the diode. It's not needed for these calculations. The circuit, like this one , is using two 10 ohm resistors in parallel for the limiting resistor. So the total resistance is 5 ohms, and the resulting wattage is 2x the wattage of the resistors . 5 ohms results in a maximum output current of 250mA.