Robotics Intern at Inkbit Designed and Printed a Robot Arm That Feels What It Touches
- Jeff Enslow
- 1 day ago
- 3 min read
A Worcester Polytechnic Institute (WPI) robotics intern spent eight weeks at Inkbit and left behind a working demo: a contact-sensitive skin and a pressure-sensing fingertip, each printed as a single part on Inkbit Vista.
Collaborative robots share space with people. That only works if the machine can tell when contact happens. Alexander Theofilou, an undergraduate robotics student at Worcester Polytechnic Institute, joined Inkbit for May and June of 2026 with one directive: build robotics demonstrations that show potential customers what Vista can do. He answered with a robot arm wrapped in printed skin that senses touch.
The mission brief from Inkbit
Alexander pitched three concepts to the team: a print-in-place unibody gripper, a harmonic drive, and a pressure-sensing finger. The finger drew the most interest, and the project grew from there. The final scope covered contact-sensitive sleeving for an entire robotic arm plus a sensing fingertip for its end effector - all printed on Vista system from Inkbit's Digital Factory.
A skin that senses contact
Each sleeving pad is a sealed air sack printed as one part: an outer skin, an internal gyroid lattice, and a hose port. The lattice was modeled as a solid body in CAD and specified in Inkbit Construct, turning the pad's internal volume into a structure that is compressible, energy absorbent, and load bearing at the same time. Press anywhere on the pad and the trapped air displaces. That displacement is the signal.
Inside corners were beveled to reduce stress concentration, and solid printed clips wrap the arm's sheet metal structure. The pad protects the hardware, cushions the impact, and reports the contact. One geometry, three jobs.
Five air sacks, one fingertip
The pressure-sensing finger slips over the arm's existing end effector with no tools or fasteners. Inside are five independent touch-sensitive air sacks fed by swept internal air channels. Two Vista capabilities made that geometry printable. Meltable support material let the internal channels curve and branch freely through the part, and a low-durometer elastomer gave the fingertip a soft-touch surface that conforms to whatever it grips.
No wires in the printed part
There are no electronics embedded in the sleeving or the finger. Tubing runs from each printed port to a barometer sensor, and a Raspberry Pi Pico 2W microcontroller reads the sensors and drives the arm's servos, with control handled from a web browser over a local network. The sensing element is the geometry itself.
That distinction matters on a factory floor. When the part is the sensor, a worn contact pad is not a rework order. It is the next print job.
Print, test, reprint
The demo reached working hardware through a full design-print-test-redesign loop inside the eight-week internship. Data from the first printed version fed directly into the second, which shipped with more sensitive padding. No tooling, no minimum order, no penalty for changing the design. The loop is the point.
"I could feel my design strategies changing to more closely align with the ideas in my head rather than the limitations of traditional manufacturing processes."
Alexander Theofilou, Robotics, Worcester Polytechnic Institute
Looking forward and how Inkbit provides solutions
Soft structures that sense. Compliant interfaces that protect hardware and the people working beside it. Sensing geometry printed directly into functional parts.
Discover how VCJ 3D printing technology changes what robotic systems can be, from tendon-driven hands to sensing skins.