My goals for this device were twofold: to allow me to *see* the coolant circulating thru my Laser Cutter, and observe its temperature in real time.
Many months ago I bought an off-the-shelf thermal module from Amazon.com, but I had always struggled with how to integrate it into my laser cutting setup. The 12″ cable for the thermistor was hugely limiting as it meant that the thermal module must be very close to the substance it measures.
By combining a $2 secondhand water bottle and a few tube fittings however, I was able to create a device solved that problem and more:
- Allows visual verification that coolant is flowing
- Allows real-time feedback on coolant temperature
- Can prevent laser from firing if coolant exceeds a programmed temperature
At a high level, the project is pretty straightforward: I epoxied a thermistor and two brass nipples into a bottle cap and gave it a little style.
Before the water bottle concept dawned on me, I played around with mounting the bare PCB thermal component on some 1/8″ birch. This excercise was useful to help figure out hole patters, but the design was ultimately not very useful.
Building The Visualizer
It wasn’t until the “inverted water bottle as visualization & measurement chamber” concept hit me that this project really came to life. By creating a sealed vessel thru which I pump the coolant, it gives me a quick window into my system, and an accessible point into which I can integrate the thermal sensor.
The steps here are super basic—drill a few holes and stick in some fittings. I happened to use 1/4″ID tubing and fittings, but this basic concept can be used with virtually any gauge of tubing you may have.
With the fittings snugly fit into the cap, I mixed up a small batch of 2-part quick-curing epoxy and sealed everything up.
Creating The Device Panel
I’d like to say I nailed this design on the first try, but it took me a lot of trial and error to land on a final design I liked.
Using my frankenstein $366 Chinese K40 Laser Cutter, I mocked up several versions of how this could work. Cut first, design later, right?!
Once I was satisfied with the cardboard mockups, I cut a version out of acrylic and began to assemble the final device.
|Water Bottle||$0.99||Thrift Store|
|Scrap Acrylic||$1.40/lb||Approx. 90¢ Used|
|Prototyping Chipboard & Corrugation||$5-ish||Chipboard / Cardboard|
|Surgical Hose – 10′||$16||Local Hardware|
|Studded Brass Nibs||$2.00||Local Hardware|
|M3x6mm Socket Head Cap Screws (x12)||$0.98||Amazon.com|
|M3 Brass Standoffs (x16)||$2.46||Amazon.com|
|M3 Brass Inserts (x8)||$0.25||Amazon.com|
|Wire & Connectors||<$3.00||Various Sources|
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