Improving Cheap Laser Engravers For PCB Fabrication

A few months ago, [Marco] picked up a cheap, cheap, cheap laser engraver from one of the familiar Chinese resellers. It’s a simple affair with aluminum extrusions, a diode laser, and a control board that seems like it was taken from a 3D printer controller designed five years ago. Now, [Marko] is building some upgrades for this engraver and his PCB production skills have gone through the roof.

The laser engraver [Marko] picked up is called the EleksMaker, and lucky for him there are quite a few upgrades available on Thingiverse. He found two 3D printable parts, one that keeps the belt parallel to the aluminum extrusion, and another that provides adjustable x-axis tightness on the belt. With these two mods combined, [Marko] actually has a nice, smooth motion platform that’s more precise and makes better engravings.

These upgrades weren’t all 3D-printable; [Marko] also got his hands on a few Trinamic TMC2130 stepper motor drivers. These stepper drivers are the new hotness in 3D printing and other desktop CNC machines, and looking at the waveform in an oscilloscope, it’s easy to see why. These drivers produce a perfectly smooth waveform via interpreted microstepping, and they’re almost silent in operation. That’s terrible if you want to build a CNC chiptune player, but great if you want smooth engraving on a piece of copper clad board.

This project has come a long way since the last time we took a look at it a few months ago, and the results just keep getting better. [Marko] is making real PCBs with a laser engraver that cost less than $200, and the upgrades he’s already put into it don’t add up to much, either. You can take a look at [Marko]’s progress in the video below.

Thanks [dechemist] for the tip.

24 thoughts on “Improving Cheap Laser Engravers For PCB Fabrication

    1. He’s using copper with a layer of spray paint as the resist and using the laser to ablate the paint away, then etching in acid. It’s really nice because you get the tidiness of photosensitive resist without the cost of pre-sensitized boards.

      1. Don’t expect miracles. On the X and Y axis the stepper is very directly coupled to the axis, allowing it to move fast. Therefore when it hit an obstruction the forces are much more easily “seen” in the motor current. The Z-axis does not need to move fast and mostly has a very high gear ration between motor and axis. Therefore when the motor hits an obstruction (the bed) it will take longer for it to be detected, simply because of the gear ratio you have more torque, therefore you are able to jam the nozzle deeper into the bed before it will be detected as an obstruction.

        Homing X and Y would be OK, as it does not matter when you have an error. Nobody cares if your print is a mm more to the left or the right of your printbed. Absolute positioning is not relevant. But for the Z-axis it is, because you will notice the difference between a nozzle at perfect height above your bed or the nozzle being 0.1mm too high (or too low….. resulting in sounds like SQRRRRRRRRRGGGGGGGGGGGGGG when printing the first layer)
        Sounds may differ depending on your machine.

        However, this doesn’t mean that the feature is worthless, it’s a great feature, but it must be used for the right things. Saving a limit switch could help reduce cost (no wires, no IO-pin, no switch, no special mechanical requirements). Though I wonder if this detection is automatic or if it is an extra IO-pin/flag signal that can be ignored when not desired. Because sometimes you want the mechanism to continue to move even after hitting an obstruction, though I would not be surprised if this is a setting/configurable. Basically it’s just current sensing and/or EMF measurement. A very useful feature on a stepper motor controller.

      2. I was thinking exactly the same thing for my Delta. I’ve ordered the Panucatt SD2224 drivers for my Azteeg X5 Mini with hopes of removing the force sensitive resistors on my bed for leveling and limit switches for homing. What would be really interesting is being able to detect magnetic ball link failure.

  1. I’ve been doing this with a k40. Works great with some practice. I found that you must let the spray paint dry at least overnight, then you can hold the smallest traces. Otherwise they scrub off. I’m using the cheapest flat black from ace hardware. Also, cut isolation outlines in vector mode, not raster. I’ve been running 3-5 passes with a 0.1mm offset each time to get a wider isolation. In LaserWeb software I use the “Laser Cut Outside” operation. Scale your holes down in the artwork, and the multiple passes will clear the hole center and make a very nice alignment point for your drill. I just etched a FFC connector with .012 traces and spacing. Similar to toner transfer, it’s nice because if the detail doesn’t hold you can clean it off with acetone and try again.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s