16. Improvements

This steps are optional

Since I finished the Frankenstein Laser Engraver I did alot of engraving and made some improvements on the build. Or at least what I think could improve the whole machine.

1. Replaced working surface
The back of the picture frame looks nice and does not get burned to strong by the laser.
But fixing work pieces requires tape. Don’t get me wrong. I like tape. Especially duct tape 🙂 but there is a better solution.
I took the side panel of an old metal PC case and cut out a piece to fit on the scanner ground.
Using neodynium magnets helps fixing your work piece.
Especially harddrive magnets are usefull as they are strong and have a metal plate attached. I found some from old harddrives with 3mm and 4mm thick magents. Just perfect to hold different wood thicknesses.
However if your motors are not well shielded these magnets could cause interefences with them.

2. Shielded cables
I realized that when putting the cables from the motors and the laser to close together EMC troubles can occur.
Re-lay the cables in 90° to each other (motors / laser) minimizes these troubles. Anyway I stumbled over some old USB cables.
Those are often shielded (thick ones) and have 4 wires. The diameter of the cores are not perfect but should work okay.
In the picture where the pins are soldered to the wires I left out the shrinking tubes as it was too much of a hassle to solder the wires to the pins. I later on cut fitting shrinking tubes and sliced them on one side and slid them over the wires.

3. Case for the hardware
I found a site that offers a script to generate nice boxes that can be cut out and put together using box joints. This laser is by far to weak to cut wood but it can engrave it pretty good. I hammered in the dimensions of my desired box and got the pdf to download.
In Inkscape I realigned all the pieces to use the space more efficiently.
With a fine wood saw I sawed the vertical lines and used a jigsaw to do the horizantal lines.
I drilled some holes for ventilation and the cables and put a small PC (southbridge) fan on top of it.
One thing is important. The fan might cause interferences with the Easydrivers so they could loose steps or stop in the middle of the process. It is therefore important to place the fan in a secure distance to the motor drivers.

4. Laser diode replacement
Typically laser diodes found in DVD burners are Small Closed Can-Types. Those should not exceed a current of 300mA.
I have found some interesting threads over at Laserpointerforums.com that talk about cheap red laser diodes.
So a good alternative would be the LPC 826 red laser diode. It can be nicley driven at around 300mA. Combined with a glass lense which delivers more optical power to the work piece would be a great improvement.
Those laser diodes are 11$ / 8,50€ (free shipping) and might be worth it.
(eBay link to LPC 826 diodes)

 

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