Case Study
Vision-Guided Tabletop Step Feeder Delivers Three Pin Sizes, Leading End Up, for Robotic Assembly
Three sizes of dual-pointed actuator pin, all the same diameter, each needing the tapered end leading. Standard orientation tooling could not tell the two ends apart.
The Challenge
A machine integrator approached Bellco with a parts-feeding problem most orientation tooling can't solve. Their robotic assembly cell needed to be fed three sizes of actuator pins — all the same diameter, all different lengths. So far, ordinary work for a parts feeder.
Here's where it got unusual: each pin had a tapered point on one end and a cylindrical point on the other. And the same end — the tapered end — always had to be leading when the robot picked it. The geometric difference between the two ends was real but subtle. Standard orientation tooling couldn't reliably tell them apart. A wrong-end-leading pin in the robot gripper meant a downstream failure, and even a small mis-orientation rate would stop the line.
The integrator needed a feeder that could distinguish two visually similar ends, present only correctly-oriented pins to the robot, and reject the rest — all in a tabletop footprint that fit their existing cell layout.
The Solution
Bellco's answer combined three of our core capabilities — step feeding, vision-guided orientation, and custom escapement design — into a single tabletop unit.
A tabletop step feeder elevates pins from a hopper to a 700mm vibratory linear track. As each pin travels down the track, a Keyence IV-series vision camera mounted overhead inspects it in flight, identifies which end is leading, and flags the pin as oriented or mis-oriented. A purge gate near the escapement diverts mis-oriented pins back to the hopper for recirculation. Correctly-oriented pins continue to the escapement zone.
The escapement is where the second piece of custom engineering happens. Rather than handing the pin to the robot lying flat, Bellco designed a custom rotary escapement that singulates each pin and rotates it from horizontal to vertical — presenting the leading end pointing straight up for the robot to pick. This eliminates a downstream re-orientation step and lets the robot pick parts in their final assembly orientation.
And because vision-guided feeding requires more than just a camera, Bellco supplied the complete control cabinet for the vision system — including the power supply, a mini PLC, and all the wiring and programming. The integrator received a turnkey vision-guided feeder, ready to drop into their cell.
Slow On Purpose
Throughput on this system is 3 parts per minute of correctly-oriented pins. By parts-feeding standards, that's slow — but it was exactly what the application required. The robot downstream worked at a deliberate cadence, and feeding faster than that meant nothing. What mattered was reliability: every pin that arrived at the pick point had to be oriented correctly, every time.
The vision-plus-rotary-escapement combination delivers that reliability. Pins that aren't presented correctly never reach the pick point — they're identified by the camera and purged back to recirculation. The robot only sees parts it can use. For a precision assembly application where a single misfeed costs more than five minutes of throughput, that trade-off is exactly right.
Full System Overview
- Tabletop step feeder — compact format designed for integration into the customer's existing cell
- Handles three sizes of dual-pointed actuator pins (same diameter, different lengths)
- Keyence IV-series vision camera, mounting and programming included
- Bellco-supplied vision control cabinet — power supply, mini PLC, full wiring
- Custom rotary escapement — rotates each pin horizontal-to-vertical for robot pick
- 700mm vibratory linear track (1107mm total feed length)
- Purge gate near the escapement for mis-oriented part rejection
- 38mm nickel-plated steel baseplate
- CUH variable-frequency digital controllers (PNP), housed in a lockable control box
- Keyence shortage sensor with full stopping function
- SMC pneumatics throughout, 110V or 220V power options
- Fully designed and modeled in SolidWorks — 3D model provided to customer for approval before build
- One-year warranty included
The Build
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