After years of funny desk toys, one of the areas 3D printing might be set to transform is medical devices.

While some treatment and disability tools, such as wheelchairs, have a one-size-fits-all nature, many are personal to the individual needs of the user or their carers, and it's a tricky balance to manufacture them in small enough numbers to be cost effective for both manufacturers and patients.

That's where 3D printing comes in – digitally scanning a user's unique body profile and building the solution on a one-off basis faster and cheaper than a factory tooled up for mass manufacture.

In Germany, a collaboration between several research institutes funded by the Federal Ministry of Education and Research is making footwear insoles for diabetic people.

Tailored specifically to each wearer, the researchers scan the patient's foot and produce a 3D printed insole based on the resulting computer model, complete with pliable or supportive areas matching the skin wounds characteristic of the disease.

Now, western Sydney-based start-up AbilityMate is joining the revolution with a program making 3D printed Ankle Foot Orthoses (AFO) for kids with cerebral palsy.

A collaboration with community organisations and medical science companies, AbilityMate can now scan a patient's feet and create custom devices using 3D printers in only hours, instead of weeks. Co-founder Mel Fuller says the organisation's plan is to "develop and test a digital process of manufacturing AFOs that is more child-centric, faster and lays the foundation for further innovation and optimisation".

It's a sentiment the public seems to agree with. AbilityMate's 2016 crowdfunding campaign aimed for $20,000 and achieved almost five times as much.

But the question such advances raise is how far they can go? According to the World Health Organisation there were 422 million diabetics in 2014, which seems to mean there's room for every possible manufacturing approach in the market, including custom printed 3D insoles.

But what about less common afflictions, or ones for which it's just too hard to make the economics of one-off manufacturing work? AbilityMate's reason for being is to reduce wait times for AKOs, make it less stressful to measure for them and build them better by designing for the individual, but Fuller also hopes it's the first step in an open-source medical device revolution.

"Beyond the immediate findings we're documenting R&D of the 3D Scanner to make IP transparent via open source," she says. "It'll be made available so orthotists, designers and engineers around the world can collaborate and continually improve the technology."

So can 3D printing provide most – even all – disability and prosthetic services and parts? Are economics and political will the only thing stopping us?

"Eventually yes," Fuller says, "but we're not quite there yet." She sees the major stumbling blocks as the availability of shareable data and regulatory requirements, but thinks outfits like AbilityMate are in the right place to put the pieces together, working on the ground with users and their families.

Dr Sebastian Pattinson, a postdoctoral fellow at MIT's department of mechanical engineering, an expert in 3D printing with cellulose for organic structures, agrees. He says even though there are limits around materials science, 3D printing has the advantage in medicine because traditional economics of scale don't apply.

"Human bodies come in a lot of different shapes and sizes, and many medical devices can perform better when they're individually customised to a person," he says. "A lot of future medical devices, especially those that have to be be worn or implanted will be partly or wholly 3D printed."