It is the ultimate tool for soldering and prying in the very small range. But over time I found that I do not have enough light on my work when using this tool. Actually all the benefits you would expect from having a magnifying glass for easy reach are over shadowed by the shadow cast by the rim.
And honestly I haven't managed to position my desk lamp in such a way that I was able to conveniently light my tiny work.
So I decided it is time for some upgrades.
As usual you will find all G-code and other files included so you can reproduce this easy on your own CNC machine
Step 1: Materials & equipment
PCB prototype board unstructured (rs-components)
Resin cored solder
PCB LED's warm white 40pcs (old LED tube light)
Old 12V DC transformer (anything with more then 3W will do fine)
E-wire (some scraps)
Double sided tape (carpet tape)
Some Acrylic sheet scraps
CNC mill + computer
45deg engraving too or 0.5mm flat end mill
2mm centercutting flat end mill
Some crocodile clamps
Hot melt gun
Extra hands with magnifying glass
Step 2: Design
I would like a nice uniform light source around the magnifying glass of my extra hands.
Low voltage, compatible with common power sources (12V)
Low power consumption
The outer diameter of my magnifying glass is 62mm
An LED is approximately 5mm long
An LED is approximately 3.5mm wide
An LED has 0,75mm wide contacts on its underside over the width of the LED
Each LED needs 3V
Knowing this I will put 4 LED's in series. To minimize human mistakes I will make sure all LEDs can be mounted in the same orientation.
To get a nice even distribution of light I divided the ring in 40 segments leaving each led with plenty of space so I can poke around it with my soldering iron. This gives one LED every 9 degrees.
To connect them there will be a 1mm conductive path on the inside of the ring and one on the outside. Within these rings I will fit the series groups. (see picture)
Between the series groups and the main power rings there will be 1mm space (for the convenience of my thick fingers)
After finishing the design in Sketchup I exported it to DWG format to convert it to G-code
Step 3: Mounting and aligning
I found that the trick is to apply a nice smooth surface of tape to sick your workpiece to. Covering the entire surface will prevent any warping of the prototype board.
Next I clamped it down on my milling table.
All programs are aligned to the centre of the ring
Load the 2nd code file for the 2mm flat end mill to check the clearance.
Load the first program named 1ringlight engrave.nc
Insert a 45degree engraving stylus or a 0.5mm centercutting flat end mill, touch off the top of the stock as z0
set a spindle speed of 5000rpm and a feed speed of 300mm min
in my case I used an engraving stylus so I set the plunge rate also at 300mm/min
After running the first program
Change tools, insert a centercutting 2mm flat end mill
touch off the top of the stock as z0
Spindle speed 5000rpm
feed speed 300mm/min
plunge rate 300mm/min
After running the programs it is time to dust everything off and unstick your ring.
Note that all programs have a higher feed rate, I have used these programs at 50% of the feed speed.
Step 4: Solder
I use a lead core solder with rosin, altough not most environmentally friendly this is a faily easy solder to work with at a low temperature.
Set your soldering iron at 260 deg Centigrade
Next I have applied a small dot of solder to each contact
After this I soldered on the LED's (thats what the tweezers are for)
Every small LED had a tiney tiney marking as if one of the corners is missing (look for it in the picture)
This marks the polarity of the LED, I have made sure all leds where oriented with the marking nearest the outer ring.
I also applied a dot of solder to the big contact pads so I can make easy contact with some crocodile clamps or solder wires to.
Tada your done.......
Well I did not manage the first try...
The LEDs are so tiny that it is very hard to align them properly and solder them correctly with my big ass needle solder tip, compared to this tiny LED its huge any way.
Step 5: Mounting the ring
And stick it to the frame of the magnifying glass.
Be sure to leave it cool and done
I soldered two wires to the main contacts for easy access. I use an old charger which emits 12V with a crocodile clip to each wire.
I find it very handy to have a easy 12V powersource laying around which can also be used to power the ring.