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Projects/laserengraver

From 757Labs

Contents 1 Retrofit of Meistergram Laser Engraver 2 Overview 3 Current status 4 Need to do 4.1 New Control Board Features 5 Other research needed 5.1 Laser 5.2 Cabinet

[edit] Retrofit of Meistergram Laser Engraver

[edit] Overview

The lab was given a Meistergram laser engraver that is from the late 80's or early 90's. The unit features a 25W CO₂ laser and approximately 12" x 18" of engraving area.

The control electronics on the unit are troublesome, and the control software was MS-DOS based. The company sold off their laser engraver business some time ago, but Ethan believes the company still continues to make embroidering machines.

The goal is low cost modification to retrofit the unit to be directly driven by EMC2 software running on Linux. Chris is currently finishing up a replacement controller which features a rotary encoder knob for laser intensity adjustment, a fancy character LCD, and toggled output based on state of EMC2 for starting and stopping the laser.

EMC2 has some support for pulse width modulation of the laser, and it appears there are other, better, methods of controlling the laser pulse with EMC2. Will have to research this.

[edit] Current status

As of 4/16/11, The laser engraver is operational and is parsing G code

Tested Materials:

• Scrap wood lying around the lab
• Circuit board - terrible
• CD-Rs - interesting effect, disc not usable afterwards
• Plastic encasing a Zip drive - flawless
• Mousepad - also flawless

[edit] Need to do

• Build enclosure for engraving unit
• Set up safety systems for the engraver
  • indicator lights
  • enclosure for laser path
  • easily-accessible kill switch

[edit] New Control Board Features

• Small ATtiny2313 microcontroller
  • Sends PWM tickle pulse to idle laser
  • Upon getting a TTL signal logic-high, fires laser at specified intensity
  • Stops firing laser when TTL signal goes logic-low
• LCD screen on microcontroller
  • Allows adjustment of pulse width to drive laser (change power)
  • Rotary encoder increments or decrements intensity
  • Emergency stop button

[edit] Other research needed

[edit] Laser

• Datasheet for the Synrad laser series.
• Information on alignment in hobbyist lasers.

[edit] Cabinet

We have to build a cabinet for it. What do we use as a safe window for the top.

A material such as Persplex (Methyl Methacrylate) will be effective as a safe window. It does well blocking 10.6 um waves as do most acrylics.