Try these techniques and tools when working with tiny parts for prototypes
It is helpful to have a work mat with edge walls to keep parts from falling if they move by accident. Having a table-top vise is a must.
BY JEREMY LOSAW
I have always been fascinated by miniature versions of things.
As a kid, I built scale model cars and played with Hot Wheels and Micro Machines. I never drove a full-scale race car but was obsessed with racing 1/10th scale R/C cars.
Fast-forward to the present day and I love watching the Tiny Kitchen videos on YouTube, in which a voiceless and faceless person makes tiny but edible versions of common dishes like pizza and pho.
In prototyping, building small things is fun but requires some special tools and techniques. As a consumer product designer, I work on products that are often between the size of a loaf of bread and a baseball—a manageable size for constructing prototype parts.
So, what do you do when you need to make really small devices or tiny parts that go into a bigger device? Consider these tools and techniques you can use to build tiny parts for your next prototype.
Before doing any work on small parts, it is important to have a workspace that is amenable to the challenges of manipulating tiny parts.
Small parts can move around easily from vibration or just breathing, so it is helpful to have a work mat with edge walls to keep parts from falling if they move by accident. You can make one out of wood or plastic, but silicone versions have molded-in trays that are great, too.
Holding onto small parts can be a challenge; having a table-top vise is a must. They can usually be found for less than $20 and often come with a suction cup base so you can keep them locked down to your workspace. I also like keeping a ball of clay around on my work mat to help keep parts steady or a temporary place to put spare parts.
One of the big problems with processing small parts is doing it gently enough. Cordless drills and standard-size tools do not provide the fidelity of motion or force that are required for detailed work.
Fortunately, there is a whole suite of tools to support the watch and jewelry makers that can be leveraged.
Many people have a kit of eyeglass screwdrivers around the house, and these are a good start. They are perfect for dealing with small screws. It is helpful to add some small hex drivers to your toolbox as well.
For drilling, a pin vise is a must-have. It is about the size of a pen with a small collet to hold drill bits.
You make a hole by twisting the shaft by hand. This gives you the force feedback to keep from bending or breaking fragile and thin parts. Jeweler’s saws are great for cutting small pieces of raw material because they have ultra-small blades and teeth to cut detailed parts.
This is a great way to produce miniature parts, and the technology is accessible to inventors. Although FDM printers (the ones that require rolls of plastic filament) are limited in resolution, stereolithography or light-cured 3D printers can make small parts with high fidelity.
Formlabs is one of the best producers of desktop stereolithography machines. Its Form 3 boasts a resolution of 25 microns and layer height of 25-300 microns, which is perfect for making small and detailed parts. The Form 3 system starts at $3,500 and material cartridges are $150 per liter, which makes it a slightly high-end but reasonable tool for a garage shop.
If DIY stereolithography is out of your price range or expertise, a number of service bureaus can print high-fidelity parts for you.
Shapeways and Xometry are websites that allow you to upload parts and order directly. They offer many different materials and printing processes to support the creation of small parts. If you are confused about material choice, sales representatives can help guide you to suitable offering.
Some small parts are too complex to be made by hand, but fortunately there are some specialized equipment and processes to help.
For 2-dimensional parts, micro water jetting is a great option. This is a refined version of standard waterjetting, using a micro abrasive that can produce parts with an accuracy of .01mm. The equipment is not readily available but can be sourced out from websites such as microwaterjet.com.
Wire EDM is a great tool for making small high-precision 3D parts. EDM is short for electrical discharge machining—a process in which material is burned away by passing high current between the tool electrode and the workpiece.
This only works for materials that are electrically conductive, like metals, but it is a non-contact technique that can yield tolerances in the .0002-inch range that also have a great surface finish. Wire EDM shops are all over the country and can typically be found with a quick internet search.
Tools and techniques are helpful, but it also takes the right mind-set to work on small prototypes and devices. Small parts can be lost or broken easily, so it is important to be patient while you work. Just a little too much force with a pair of pliers can crush hours of work.
Make sure you have the physical and mental space to work effectively. Keep a meticulously clean work area so as not to lose parts and think through the consequences of each action before you make a move. Being deliberate, patient and slow reaps dividends when working at small scale.