A flashlight is one of those things you can’t be without. From household projects to fixing your car, it’s always there when you need it. That’s why it’s worth understanding how it’s made, step by step.

How does a flashlight come together? Why does it need batteries? Let’s shine a light on everything you need to know!

Look inside a flashlight and it might seem complicated. Wires, batteries, and switches all work together to make the light come on.

– Tammy Enz, author of Build Your Own Periscope, Flashlight, and Other Useful Stuff

What Are the Parts of a Flashlight?

Flashlights are made from many different parts. These include:

  • Switch
  • Case
  • Battery
  • Wiring
  • Reflector
  • Transparent lens
  • Lightbulb

The lightbulb and case give the flashlight its trademark look, but everything else works together to make it shine bright!

What Are Flashlights Made From?

Flashlights are made from some combination of plastic, metal, and glass, with low-cost polystyrene and aluminum being the most common for the cases.

The table below breaks down each part and the materials typically used to make it.

Case

Aluminum

Stainless Steel

Titanium

Plastic

Rubber

Translucent Lens
http://www.amazon.com

Glass

http://www.grainger.com

Plastic

Bulb
http://www.bhphotovideo.com

Glass

http://www.lampsplus.com

Plastic

http://www.lightingever.com

LED

Wires & Batteries
http://www.sjoow.com
http://www.squishycircuits.com

There’s a lot of variety in how a flashlight is made, but how well it works ultimately comes down to which lightbulb and type of battery are used. Every one works a little bit differently.

How Are Plastic Flashlights Made?

Plastic flashlights are super popular as they’re affordable and easy to carry. The process for making one involves seven steps that includes:

  • Step One: Plastic pellets are colored, heated, and injection molded.
  • Step Two: The molds are put under high pressure to ensure they are completely filled and held together.
  • Step Three: The molds are cooled down with water.
  • Step Four: The bulbs are wired and enclosed in a transparent glass cover.
  • Step Five: The cover and bulbs are vacuum sealed and heated.
  • Step Six: The final step is electrical circuity, which involves connecting the wires to a battery terminal.
  • Step Seven: The flashlight is packaged and ready to be sold.
  1. Step 1

    Injection Molding

    Plastic pellets that are dyed in the desired color of the flashlight are heated up and injected via a plunger directly into molds. This is ultimately what gives the flashlight case its shape and color.

  2. Step 2

    Putting Under High Pressure

    Next, the molds are subject to high pressures to ensure they are completely filled and held together. As much as 2,500 tons is pushed against the molds at extremely high speeds.

  3. Step 3

    Cooling Down

    Water is forced through open channels in the molds to cool down the molten plastic. This is necessary before the bulbs, batteries, reflector, switch, and lens can be added to the flashlight.

  4. Step 4

    Adding in the Light Bulbs

    Flashlights typically use LED, fluorescent, or incandescent bulbs. Each bulb has a metal filament inside, that when exposed to an electrical current, heats up and emits light in visible wavelengths. This filament is welded to two wires, connected to a cylindrical glass bead, and enclosed in a transparent glass cover.

  5. Step 5

    Vacuum Sealing and Heating

    The entire glass structure with the bulb inside is placed inside a vacuum chamber and sealed by heat. This causes the glass to soften and ensures the filament is properly aligned so the light beam is projected in the right direction.

  6. Step 6

    Connecting to a Switch

    Now’s the time for some electrical circuitry! Most flashlights rely on an off/on switch where the wires are connected to battery terminals. The switch typically slides up and down to work, and a battery may or may not be included.

  7. Step 7

    Packaging

    The flashlight is finally ready! The last step is getting it all packaged and ready to be sold.

The entire manufacturing process from start to finish is typically done on an assembly line. This allows for more flashlights to be created at a much faster rate.

How Are Metal Flashlights Made?

Metal flashlights follow a different process than plastic ones. These are usually made from aluminum and are created in eight steps that include:

  • Step One: Blades that run on a computer are used to shape metal rods into the flashlight’s case.
  • Step Two: A hole is drilled into the flashlight as a coolant is used to reduce the heat.
  • Step Three (Optional): A textured handle is created using a mechanized blade.
  • Step Four: The flashlight is either painted a different color or the metal is simply polished and buffed.
  • Step Five: Injection molding and pressure are used to form the lens.
  • Step Six: The bulbs are wired into the flashlight.
  • Step Seven: The batteries and lens are connected to the flashlight.
  • Step Eight: The flashlight is packaged and ready to be sold.
  1. Step 1

    Shaping

    A computerized machine trims down a metal rod via rotating blades. These blades shape the rod into a flashlight case.

  2. Step 2

    Drilling the Inside

    A drill hollows out the inside of the flashlight and a coolant is flushed over the top to prevent the metal from expanding as it’s heated up. At the same time, a blade cuts threads on the outside so a translucent lens can be added on later.

  3. Step 3

    Carving a Cross Weave (Optional)

    Some flashlights come with a textured handle that makes them easy to grip. This is done via a mechanized blade that slims down the back half of the flashlight and carves a cross weave pattern.

  4. Step 4

    Polishing

    At this stage, the flashlight is painted in its desired color or the metal is simply polished and buffed to remove any random discoloring or scuffs.

  5. Step 5

    Forming the Lens

    Hot plastic is injected into a mold and compressed with a ton of pressure. This is used to create the lens that will fit at the top of the flashlight.

  6. Step 6

    Wiring

    If the bulb is LED, the lights are soldered onto a circuit board and trimmed with snippers. The bigger the flashlight, the more bulbs are placed on the circuit board. Incandescent and fluorescent bulbs, on the other hand, are connected directly to the battery terminals.

  7. Step 7

    Loading in the Batteries

    Springs are inserted into the metal flashlights to hold the batteries in place. The bulb assembly is put into the flashlight at this stage as well and the lens is secured onto the top.

  8. Step 8

    Packaging

    The flashlight is packaged and ready to be bought by the consumer!

Do you want to learn more about making plastic and metal flashlights? Check out this video!

What Kind of Batteries Are Used in Flashlights?

Almost every flashlight, whether it’s made from plastic or metal, relies on batteries to work. Typically, it takes either standard alkaline or lithium batteries.

Lithium batteries tend to last longer, while alkaline are much affordable to buy. There are many different types of each you can find on the market:

Alkaline

9V

A 9-volt battery was used for early transistor radios. It has a prism shape, works with LED bulbs, and lasts a long time when used in a flashlight.

AA

AA batteries are bigger in size than AAAs and carry more power. Many flashlights are powered using AA batteries as they’re easily accessible.

AAA

While AAAs may not carry as much charge as AAs, they’re still awesome for flashlights. You may need to use more batteries for your light to last longer.

C Cell

The C Cell battery is often found in what’s called “medium-drain” applications. This refers to items, like flashlights, that take a moderate level of power to operate.

D Cell

D Cell batteries have a high amount of voltage. They can be found in large, high-powered flashlights that are used by the military, first responders, and in other emergency situations.

Lithium

Lithium-Ion

A lithium-ion battery is fully rechargeable and stores a lot of energy. It’s great for not only flashlights, but also cell phones, laptops, and MP3 players.

Non-Rechargeable Lithium

Most convenience stores carry this type of battery. It’s long-lasting, which makes it great for higher-end flashlights and digital cameras.

The type of battery is an important part of how long the flashlight will last. Some are replaceable while others require charging to function. You should understand the distinction when choosing your next flashlight.

How Are Flashlights Customized with a Design?

Custom flashlights are sometimes ordered by companies as giveaways at trade shows or fundraisers. They may even be branded with a logo and sold exclusively at stores or online shops.

Either way, these custom flashlights receive their design via any of the following printing processes:

Screen Printing

Screen printing is the most common method for decorating customized items. Ink is pushed through a mesh stencil and thick green goo called emulsion is spread over the stencil to create a specific design.

Stamp Printing

This process is sometimes referred to as pad printing or ink transfer. A giant stamp is covered in ink and then pressed down on the flashlight to provide the customized design.

Full Color Transfer

A full color transfer, or digital printing, is the most economical choice if you have to print many colors. An Inkjet printer digitally transfers your design onto the flashlight.

Laser Engraving

Flashlights that are made from metal may be customized via laser engraving. A concentrated beam of light etches the design directly onto the flashlight.

No matter how the design is added, a custom flashlight is a great way to boost brand awareness. It’s an item that’s useful for all businesses, no matter what the size!

The Bottom Line

Now you don’t have to stumble around in the dark about how flashlights are made! Whether you get your next one from the store, make it right at home, or order branded ones for your next event, it’s worth knowing all about this fascinating process.

References

How Products Are Made. (2019). Flashlight. Retrieved June 26, 2019, from
http://www.madehow.com/Volume-6/Flashlight.html

Energizer. (2019). How Do Flashlights Work? Retrieved July 1, 2019, from
https://www.energizer.com/about-flashlights/how-does-a-flashlight-work

How Its Made. (2015, January 4). How Its Made – 368 Flashlights. Retrieved July 1, 2019, from
https://www.youtube.com/watch?v=GxWB826yVC4

LED Watcher. (2017, May 31). What Are Light Bulbs Made Of? Retrieved July 1, 2019, from
https://www.ledwatcher.com/what-are-light-bulbs-made-of/

Chet, H. (2015, July 26). Informational: What Are the Different Flashlight Battery Types? Retrieved July 1, 2019, from
https://www.taklite.com/blogs/news/38972993-informational-what-are-the-different-flashlight-battery-types

Woodford, C. (2019, April 26). Batteries. Retrieved July 1, 2019, from
https://www.explainthatstuff.com/batteries.html

Medic Batteries. (2019). Alkaline vs. Lithium Batteries. Retrieved July 2, 2019, from
https://www.medicbatteries.com/alkaline-batteries-vs-lithium-batteries-compare-alkaline-lithium-alkaline-compared-to-lithium

Difference Between. (2019). Difference Between AA and AAA. Retrieved July 2, 2019, from
http://www.differencebetween.net/object/difference-between-aa-and-aaa/

About the author

Alyssa Mertes

Alyssa is a promo expert with over three years of experience in the industry. Her passion for writing has led to a BA in English & Communications from Aurora University and work published for the Advertising Specialty Institute and The Bolingbrook Sun Times.