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modification – CNC Maker Zone

Adding a shield to a CNC-mounted LASER module

My LASER is an attachment for my cheap Chinese 1610 CNC router so it isn’t tucked away inside a metal case with a tinted window. That means I have to wear LASER-safety glasses whenever it’s running, which can be annoying if I’ve got other things to do. So I designed this simple 3D printed shield with dark red windows (as the LASER is blue). It comprises a small frame that slips onto the LASER module (with a hole for a screw if needed to stop it sliding down) and a three-sided shield that slides onto the edge of the frame, as shown below.

3D view of the laser shield assembly

After 3D printing the front and two sides need to have dark red plastic glued in: I cut mine from a plastic square photography filter I picked up cheap on eBay. Then those three pieces need gluing together at the front corners to make the shield. If you want to add some rigidity then there’s also a bottom component you can stick below the three sides. The shield is then easily removed for when you want to focus the LASER or for removing cut materials. You can download the 3D printing files from Thingiverse by clicking here, and in case you need to make adjustments that includes the OpenSCAD file. The shield also works well with my LASER extractor project, localising the area it extracts air from, which is one reason why the bottom plate is included in the design.

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Improving lead-screw binding with a flexible coupler

CNC machines have plenty of moving parts and if we want our routing and LASER cutting to be as good as possible the movements need to be as smooth and unrestricted as possible. When I built my cheap Chinese CNC it came with rigid shaft couplers for connecting the threaded lead screws to the stepper motors. That meant that the motor spindle and lead screw couldn’t be adjusted to be perfectly in-line, just because of tolerances in parts and mountings. So, for part of a full rotation the lead-screw was binding (i.e. becoming hard to turn) and the rest of the turn was fine.

If you find you get the same problem, you could just do what I did: change the rigid couplers for slightly flexible ones. In the photo below I’ve shown the difference between the two. The bottom one is the original rigid one and changing to the new one involved no more than loosening the grub-screws, moving the lead-screw to the side, then inserting the new coupler, pushing in the end of the lead-screw, and tightening the grub-screws. For just a few minutes work it made X and Y axis motions so much smoother. And, for only a few pounds/dollars per coupler it was a cheap job too.

A flexible and rigid coupler

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