Background:

Many many Shopbot users that I talked agreed that they would like to have a laser light dot or cross hair just like all laser printers do. Two of the most common uses of the laser light is to align the cutter to the part center, reference or origin points. and to follow the laser light to review the cutter path.

Compared to a laser cutter, Shopbot could use many cutter tool size and shape. It is inherently difficult to adapt a laser light on Shopbot.compared to laser printers.

Step 1: Innovative Idea

If we place a laser crosshair on the same bracket as the tool cutter, we could get the delta X and delta Y between tool cutter center point and laser center point. Delta X and delta Y between the two points could be obtained by placing a pointed center punch tool and glently push it down the surface to create a fine point, Reset the X & Y coordinates to zero. Gradually move the laser to the indented point. Record the new X & Y coordinate. Your delta X and delta Y would be your minus X and minus Y as displayed.

When positioning a new part, use the laser pointer to locate the intended target (center, reference or origin). Then assign current X and Y to zeroes (0.0). Press CTRL-K and enter delta X and delta Y. Confirm your target position is reached. Always recheck for data entry errors and confirm target is achieved.

Step 2: Materials & Assembly

Materials:

http://www.ebay.com/itm/DIY-5mw-650nm-3-5V-4-5V-9m...

$1.33 DIY 5mw 650nm 3.5V-4.5V 9mm Red Laser Module Head - Crosshair Cross Curve Line

http://www.harborfreight.com/catalogsearch/result?...

$3.49 27 LED Portable Worklight/Flashlight

$4.50 3D printed bracket.( Designed using Autodesk Inventor & Printed at TechShop Mojo 3D printer)

Power Source Hack:

I converted the flashlight into a 4.5v DC power source. I cutoff the lead to the 3 front LEDs and extended the wiring out of the side of the flashlight body.

Test:

Initially, I taped up crosshair laser to the bracket of the shopbot. I taped the power source as well. (see pictures)

Step 3: Crosshair Laser Holder

Assembly Note:

Attached are the 3D images of the Crosshair Laser Holder.

The cross hair laser light was slightly pushed in. It was powered to adjust the orientation of the cross hair axes.

Do not worry if you could not perfectly align the crosshair to the holder. The shopbot bracket could be slightly rotated before the screw is tighten. This coiuld be use for final alignment.
With this note in minde, always calibrate your laser dX and dY to assure.alignment and accuracy.
I used a table vise to slowly pressure push the laser light body. Keep the alignment and be careful not to damage the DC power wires. Luckily the cross hair came out aligned.

Step 4: Conclusion, Refinement and Feedbacks.

Conclusion:

We are able to achieve a giant step with cost of within $10. We could use the laser crosshair to align parts and locate center with ease. Preview tool path.is also greatly enhanced. I included both the stl file and the Autodesk Inventor file for all to review, enjoy and/or learn.

Future Refinement:

The 4.5v DC power source could be enhanced. But with the free Harbor Freight flashlight hack, we bypassed the need to assembly 3x AAA or 3x AA battery holder and latching switch. Note that the laser light might not withstand over 4.5v power for long. Subjecting it to higher voltage or reversed polarity would surely ruined it. So an error proofing to avoid these would help. Feedback: * One colleague wanted to use this invention to make surf boards. * I would use it to make sphere poles out of 3.5" square posts.

Feebacks:

* One techshop member think an expensive laser could further enhance the crosshair light resolution. This could help in project that require more precision. * Please send feedback on application that Thank you for all feedback and kudos from colleagues and TechShop DCs and friends.