100W LED Torch Flash Light - Designing/3D Printing

I first came across the concept of making a very powerful torch (or flash light to our American cousins) from a YouTuber Matt aka DIY Perks. He re-purposed a CPU heat sink and a custom aluminium frame to make an insanely powerful hand held light. With the release of Instructables' 3D Printing contest, I thought that I would add my concept to the community.

My aim was to incorporate modern ergonomic techniques into a retro lantern like design using product design an engineering skills I have been learning about for my degree.

I would really appreciate your feedback on this as I feel it could be quite a good project to work on some more, it has very good real world usage and could be simple and cheap to make.

Simplicity and function were of course prioritised, closely followed by the juxtaposition of a retro shape and the very modern manufacturing technique of 3D printing.

Anyway let's get to it! If you think I've earned it please vote for my ible in the 3D Printing contest :)

Step 1: Inspiration

To get an idea of what I wanted to create, I had a look at vintage torches and kind of merged the handle shape of the wing light torch (pictured) and the old battery can style torch.

The boxy shape shape that I settled on also came from my love of old projectors. They are very simple shapes but are quite elegant and subtle.

Step 2: Initial Designing

As with the vast majority of my projects, I jumped into Autodesk Inventor. It is my go to program especially with a relatively simple design (not including the grip I will later work on) that doesn't require pre software sketches.

My design was based around the largest component that needed to be accommodated inside the case: a chunky aluminium heat sink which I salvaged form a fried VFD for my CNC machine.

I took down dimensions and created the initial frame of the light.

Next, to add to the retro aesthetic, a simple draft extrusion down to a smaller opening that would house the battery was created and hollowed out using a similar method.

Step 3: Handle Ergonomics

Ergonomics in product design is a huge deal and so for the sake of academic interest I wanted to take the design of the handle seriously and make it properly. I started using standard grip charts and hand dimension anthropometry to gather the necessary measurements from my own hand to build an understanding of the shape and size of the handle.

Once I had these dimensions (I won't go into much more detail on this, fairly boring really!) I could begin to sculpt the handle in Inventor.

Step 4: Designing the Handle

The basic shape of the handle was a rectangular profile, sweep extruded along a spline that matched the shape I was aiming for.

This gives a very rough handle shape from which I can work on by cutting bits away from it until it has suitable ergonomics for my hand. Of course a lot of it is guess work but you can use hand dimensions to decide where certain finger cut outs can be placed to maximise comfort. This is important as it will be a solid plastic handle with no padding so good design is essential to maximise comfort over extended periods of use (long walks in the evening), that is why I spent so long on this step.

Fillets were added on all sharp edges again to increase comfort. Once these fillets were in place then large chunks of material could be removed under the handle for the finger grip spaces. Referring to my measurements for guidance I used curves to remove material from where I saw fit.

The part where the handle joins to the main casing was also filleted for sleekness and also ease of 3D printing. For this same reason a flat was cut on the back of the handle so it would lie flat on the print bed.

Step 5: Switch Location and Vents

Next I designed the cut out for the switch I intended to use. This was a simple rectangular bodied rocker switch and the hole was cut into the handle within easy reach of where my thumb would rest.

A hole was extruded down into the case to allow wires from the switch to reach the electronics inside the case for the LED.

Vent holes were cut into the base of the model to allow the fan to draw up air and push it through the fins of the heatsink. I wanted al the openings to be underneath to aid with weather resistance. Having holes on the bottom and not on the sides or top reduces the amount of rain that could get into the case.

Step 6: Battery Door Design

This was another interesting design decision I had to make. Some method of keeping the battery door securely in place but allowing it to be easily opened for accessing the battery for charging. Not only this but I wanted to keep it as simple to print and as robust as possible! A tough task to accomplish with a latch or mechanism... So It thought more simply.

I thought of just having a flat panel with a slight raised inner rectangle as the battery door as you can see. I designed two sturdy lugs on either side of the case where the battery door goes (as you can see in the screenshots) to allow a strong loop of rubber to secure the battery lid in place. Unfortunately I wanted to use a loop of black ninja flex filament to match the black aesthetic for this but I had run out at the time. So to demonstrate the principal I have used a normal elastic band which is extremely secure. I can properly shake the torch a lot ant it doesn't move at all.

Of course this isn't necessarily the most elegant solution but it suited my design criteria for being simple (not only in function but print-ability) and effective.

I would love your feedback in the comments about this design choice!

Step 7: Beam Concentration Cone

This was the final printed part to design and it was fairly simple. I wanted to focus the beam of the LED quite a lot because without any focusing the LED puts out a near 180 degree light spread which is way to much. I settled for a light spread of 120 degrees and modelled a suitable cone shape to accomplish this. I attached said cone to a flat plate that could be mounted to the front of the case.

I think this a good solution a you could print different attachments of different angles to produce any angle of beam you wanted. You could even print a straight tube that could give you a spotlight effect. Furthermore, there is possibility of printing a mount for a lens that could aid in the uniformity of the light being produced as well as focusing it.

Again let me know in the comments if you have any suggestions for this, I would love to develop this design more!

Step 8: Finished Design Rendering

Just for fun I dropped all the models into an assembly and did a quick local render! (I could have done a lot better job if I cloud rendered it using a proper material library..)

Step 9: Slicing + Settings

Before printing everything I had to slice everything in slic3r. If you buy an original Prusa i3 they provide a copy of slic3r with all the settings programmed in which is awesome! I have only had to tweak a few things from stock such as the cooling which I have shown in the pictures above.

Slic3r is what generates the g-code and tells the 3d printer where and how to move, and when to move. The printer builds models layer by layer and the slicing software takes the model and turns it into thin predetermined thickness layers.

Step 10: The Printing!

This was the nerve racking part... this print took about 15 hours to complete as you can see in the photo. Even though I used PLA I had a bit of warping caused by too high a bed temperature and forgetting to put new hair spray on the glass bed (both accidents). By the time I realised it was warping I was too far through to start again, what a waste of filament it would have been!!

It's about the biggest thing I have and probably will print on my little Prusa i3!

The printer coped fine with most of the features, it didn't like he vent holes as you can see in the video but this was partly because of the warping I suspect. It scraped the nozzle a bit as it moved around the layer.

The battery plate cover thing printed perfectly as did the focus cone. I originally printed the battery cover in white but then re printed it in black to give a nicer overall aesthetic.

For the record I use a heated bed with a glass print surface. I use extra strength hair spray that I re apply every 5 small prints and every large print I do gets a fresh coat. MY nozzle temp for PLA is 210 degrees Celsius and the bed is at 50 degrees Celsius. I typically have no warping with this set up for PLA (I have yet to fully master printing large objects with ABS).

Step 11: Building Up the Heatsink and Components

As I mentioned before, the heatsink that I am using for this came from a Variable Frequency Drive for my CNC machine that blew up for some reason?! I salvaged a lot of useful parts from it including this big beefy heatsink.

The fist thing I did was to mount the LED itself to the heatsink. I drilled and tapped 4 holes into the aluminium of the heatsink and mounted the LED with thermal paste and then screwed it down. Next I did the same with the DC-DC boost converter which steps up the 12v from the lithium battery to 32v for the LED. I soldered some 5 amp rated wires from the output of the boost converter to the LED and I used 10 amp wire on the input of the boost converter.

Next I soldered he wires from a 12v pc fan to the input of the boost converter as this will be in parallel with the converter so it will receive 12v from the battery.

The fan was attached to the back of the heatsink with some 3m super strong double sided foam tape.

The whole assembly could then be dropped into the front of the case. It is held in place with a friction fit as I designed it this way. No glue required!

Step 12: Beefy Little Switch

The battery will be putting out around 8 amps to boost the voltage up to 32v and 3 amps for the LED so I needed a hefty switch to power on and off the device. I found a switch rated for 240v at 10 amps in my collection of salvage parts so I used this.

I fed wires up into the cut-out for the switch in the main case. I put heat shrink around the wires and then soldered them to the terminals of the switch and used a heat gun on the heat shrink to shrink it and help prevent possible short circuits.

The switch could then be pushed into its mount and it went in perfectly and held with a friction fit, no glue required!

Step 13: Battery and Battery Door.

I mad a lithium ion battery pack out of an old laptop battery. I took the whole thing apart and then used tabbing wire to connect them up to form a compact 12.6v (3s) 5000mah battery pack. I then soldered some 3.5mm bullet connectors to the positive and negative poles of the pack. This is so it can be easily disconnected and connected to the torch.

As you can see I first printed the battery door in white and then changed it to black to match the beam focus cone.

The battery is attached to this printed cover using 3m double sided foam tape so it won't come off. The battery can then be connected to the lamp with the bullet connectors and the cover can be closed. A strong elastic band was then used to hold it securely using the lugs that I talked about earlier that are designed into the side of the case.

It is not the most elegant solution but it is simple, effective and durable. A complicated latch would have meant that if it breaks you would have to reprint everything. with this you just need to replace the elastic band. I am going to make a more professional elastic strap out of some ninja flex filament when I get some more.

Step 14: Focus Cone

The focus cone can then be attached to the front. Again it is a friction fit but as an added measure I used some heat resistant glue. This is because as the heatsink heats up (it gets a little warm after extensive use) it could weaken a bond made with super glue and also cause the PLA case to expand. So some glue was a bit of added insurance.

Step 15: All Done!! Final Thoughts!

So that's it complete! I hope yo liked this little project and if you did please vote for me in the 3D Printer contest!

I would like to conclude with some thoughts on what I think I could improve on and what I could do differently:

The battery door could do with some work perhaps. The elastic ban is very effective and gives it some what of a DIY aesthetic but I would maybe make some kind of latch based on a retro metal wire clasp design... i'm gonna think on this.

I would like to make a modern version and try to make it as compact, tough and sleak as possible. Perhaps the complete opposite of what I tried to achieve here? A modern version?

Let me know if you have any ideas! they are always appreciated!