Rotary tattoo machine pioneers swisstattoomachine came to us with an idea for a cordless device — we worked with professional artists to develop the “unchained”.

Building on the tried-and-trusted motor design of the extremely popular “Heidi” model, we were tasked with developing the very first tattoo machine on the market that could be operated without a power cable. One of the challenges we faced with the project was that the device had to stay light and balanced, despite the extra weight of the battery pack — and any serious product would also have to meet the same specs as medical technology.

Video still from our use analysis

We started by sitting in on several tattoo sessions, quizzing artists and watching their fingers to get a precise sense for what they needed when using their machines. Our observations allowed us to optimize and double-check performance parameters, components, layout, build and ergonomics with a series of refined functional prototypes. We eventually constructed a mass-producible device featuring two AAA rechargeable batteries, a precision maxon RE 13 motor and a chassis machined from sections of extruded aluminum and injection-molded parts that weighs only 20g more than its power-corded predecessor. In creating a look appropriate for such an innovation, our design stands in stark contrast to the ornamental retro styling of the competition: the unchained’s design evokes high-end motorcycles and futuristic jets — stealth aircraft design for cutting-edge technology.

Identifying the forces in the drive kinematics to optimize dimensioning of the components.
Hands-on tests to lay out the components
Joint ideation by sketching on the projected CAD concept model
Concept sketch: Version with top-mounted control panel and battery compartment from the rear (implemented)
Handling test at Tribecraft to check ergonomics and weight distribution using a 3D printed mock-up.
Ready-to-use enhancement of the mock-up for functional tests
Stealth Design moodboard as basis for the appearance
Sketch rendering of the design concept
Testing the drive in the aluminum extrusion housing
Control panel definitions
Assembling a near-series prototype with a SLS chassis
“I have so much more room to maneuver.”
Alena Lizier, tattoo artist and owner Howy's Tattoo Shop

Market launch:


Our contribution:

Use analysis
Styling concept
Product design
Mechanical engineering

Discover more!

Case: Bosch sabre saw

Breaking things down intuitively

Tradesmen and firefighters often have to improvise in their work. Thanks to the rock-solid approach of its developers, the newly made-over Bosch reciprocating saw is ready for anything you throw at it.
Breaking things down intuitively


A safe car ride for pet dogs combined with the convenience of a stylish tote.


radically reduced transport trailer for Veloplus