Case Studies · Robotics & UAS hardware
A printed gripper finger that holds the part still
Gripper fingers are machined per-part. We made a printed pair an engineered, stiffness-validated product — and proved the part stays located to 21 µm.
The result at a glance
Problem → built result
What we solved
Every parallel-gripper application needs fingers shaped to its part, so fingers are machined bespoke at $100–400 each. A printed pair is far cheaper and faster — but a gripper finger has one job, and it's not looking pretty: it has to hold the part still.…
What we built
Treat the finger as the cantilever it is: bolted to the jaw at one end, gripping at the other. Cradle round stock in a self-centering 90° V-groove, pick CF-Nylon for stiffness, and compute the tip deflection under the clamp load — that's the grip stiffness.…
How we proved it
The engineering behind the result.
Grip stiffness is the spec
The finger grips at 1.9 N/µm. Under the full 220 N clamp the tip splays 117 µm — but both fingers move symmetrically, so the part stays centered. What matters for precision is disturbance rejection: a 40 N process side-load shifts the part just 21 µm, 4.7× inside a 0.1 mm budget.…
Caught and fixed in simulation
The first cut put the V-groove 11 mm deep into a 12 mm finger — nearly severing the tip. The FEA flagged it immediately: a non-physical 898 µm splay and a factor of safety below 1.…
Two independent checks
The FEA tip deflection agrees with a textbook cantilever hand-calc to 15% — the residual is real V-groove and shear compliance the simple beam ignores. And the reactions balance the clamp load to 0.00%, which is the finite-element mesh validating itself.…
Delivered result
Evidence a buyer can use.
A printed gripper-finger pair that ships sized to the customer's gripper and part, with the FEA proving the part stays located to 21 µm under load — for a fraction of a machined finger's cost. The honest gates travel with it: stiffness scales with geometry so it's re-solved per setup, and an optional TPU liner adds no-mar grip at a small stiffness cost.
Application notes
Under the full clamp the tip splays 117 µm — disclosed — but both fingers move symmetrically so the part stays centered; the meaningful number is the 21 µm disturbance shift. Grip stiffness scales with finger thickness and reach, so it's re-solved per gripper and part.…
Bring us your version
Configure the Custom Gripper Fingers / Jaws.
Send the part, drawing, sample, or operating requirements. We’ll quote the engineering and build together.