Skip to main content

UV Lithography For Circuit Board Creation

In this multi part series on diy circuit board manufacturing/fabrication I'm going to cover my diy, vacuum pull down UV LED exposure box.

If you are looking for a description of the entire fab process click here

UV Exposure Rig

The photos bellow are of the  uv lithography exposure box I cobbled together. It also features vacuum pull down. 

The source:


A 4.1w High luminous efficiency 365nm UV LED. Sourced from digi key mid 2016. Model LZ1-00UV00

You might note the version I bought has a dome over the emitter. They did offer a dome less version which if I recall correctly is better for providing a collimated source. I was able to produce features at 8thou with out an issue with the domed Version. The dome less was something like $30 more expensive and out of stock at the time I ordered 

The heat sink was originally from an Intel core 2 CPU. in the picture above I had trimmed it around the edges to fit into a yellow lantern.

The Frame/box


Here's a close up of the heatsink(UV LED is mounted under the metal star) and mounting bracket. 

The mounting bracket was from a ceiling light. A can style light fixture. I wasn't sure exactly how much distance I would want or need so designing it this way allowed me to reposition The source on the fly. You can probably see the wing nuts that allow for height adjustments.


I found acrylic hinges for sale on ebay and employed them for the doors.

Vacuum Pull Down


Side view reviews the vacuum pump motor and some home Depot PVC too attach it to the three plexi glass sheet thick bottom. The middle is essentially hollow between the top and the bottom of the stack.

On the inside holes were drilled through the top of the bottom plate. I then drilled a hole out one side and was able to attach some easily sourced PVC up to the pump motor. It was done quick and dirty but it worked.
Plexiglass isn't very transmissive for uv so a sheet of low iron silica glass was placed on top of the weather stripping. This allowed the vacuum to pull the transparency against the pcb to be (copper clad) 


I utilized my lifx lights set to red while working with the uv sensitive acid resist film

Clyde liked to help...(only pic I can find of them set to red)

Printed CAD design (above)


I was able to obtain features down to 8 thou with out trouble. Double sided alignment wasn't bad either but I'll keep the precise nature of how I pulled that off to my self for now

The design above(board) is very basic. It was actually the first working pcb of my own design. I hadent yet realized the benefits of a power plane and I also wasn't confident in the tools ability to produce yet. 

Related:

Comments

Popular Content

Lawn Tractor Snow Plow Electric Upgrade

Do you have a lawn tractor you use to plow snow? Ever wondered if you could make a manual snow plow attachment into a push button? A friend of mine had a riding lawn mower and snow plow blade attachment. Every winter he used the riding lawn mower to plow the driveway. The plow was a kit that bolted on the front of the lawn tractor and it had a mechanicaly actuated adjustable snow plow blade. The issue and this project came about when the arm to adjust the snow plow blade broke. I had just bought a mig welder. I had also watched linear actuators capable of handling 300lbs of force drop to $25 on ebay.  Here's what I came up with for converting a riding lawn mower snow plow into an electricity adjusted lawn tractor plow. Repair  The lawn tractor snow plow kit had seen better days. The fork that attaches it had bent /deflected and spread. I used a map gas torch and a bench vise to squeeze the tongs back and then welded some L channel angle iron on the sides. Less Play I also tack weld

CD Resistance Spot Welder

This post is for anyone interested in owning or building a CD welder. I wanted a reliable Resistive spot welder for lithium ion pack construction and or repair. I didn't want to spend 3k or buy from china. I decided to design and fabricate my own. Bellow is my first crack at a Mosfet Switched capacitive discharge mcu controlled spot welder. This post is a work in progress. If you've stumbled across in hoping to build your own cd welder feel free to ask questions in the comments section.  I'll provide any help I can.  My CD Spot Welder  Here's pics of the first working version from 2018