injection_moulding — part_count (yolox-shot-count)
Physics
Section titled “Physics”A camera is aimed into the mould-open/ejection zone of an injection moulding machine and triggered once per shot by the machine’s mould-open signal (wired through the edge box’s digital input) rather than running free, since the ejection event itself is the only moment that matters and free-running capture would waste bandwidth and risk missing the brief ejection window. A yolox detection model counts the ejected parts visible in that triggered frame (or short burst of frames) per cavity, which catches double-shots, stuck parts left in the mould, or multi-cavity partial ejections that a single photo-eye below the mould would miscount as “one event, ambiguous part count.” The lens field-of-view is set to frame the full ejection/cavity area at the working distance clear of tie-bar and platen travel, and a strobed ring light fires in sync with the trigger to freeze any ejector-sled motion blur during the brief ejection window. For a mould cycling as fast as every 8 s, capturing a 5-frame burst at 60 fps starting at the trigger gives ~83 ms of coverage, enough margin over the ejector stroke’s travel time (~40-60 ms on typical machines) to always catch the fully-ejected frame regardless of small cycle-to-cycle timing jitter.
Sensor
Section titled “Sensor”- Spec: industrial GigE/PoE area-scan camera with fixed-focal C-mount lens and strobed LED ring light, triggered capture, global shutter
- Signal: counter ({count}), range n/a
Example parts
Section titled “Example parts”- Basler ace 2 a2A1920-51gcPRO GigE area-scan camera (1920x1200, global shutter, PoE, HW trigger input)
- Cognex In-Sight 2800 vision camera (integrated camera + strobed illumination, HW trigger)
- CCS Inc. LDR2-100SW2 strobed LED ring light with controller
Mounting
Section titled “Mounting”Mount the camera on a rigid stand or fixture clear of the mould’s platen travel and tie bars, framing the ejection/cavity area square-on to avoid perspective distortion of part counts across cavities. Mount the strobed ring light coaxially or at a shallow angle to avoid glare off moulded plastic, and verify neither camera nor light intrudes into the mould’s open/close envelope at any point in the cycle.
Wiring
Section titled “Wiring”Camera connects via PoE Ethernet to the edge box’s GigE Vision NIC; the machine’s mould-open proximity/limit switch signal is wired to the edge box’s digital trigger input, which fires the camera’s hardware trigger and the strobe light controller in sync; route trigger wiring away from the machine’s high-current heater-band and motor circuits to avoid induced noise on the trigger edge.
Validation
Section titled “Validation”run 50 shots at normal cycle time with a manual tally of ejected parts per shot (including any missed/stuck parts) and compare to the VisionEvent count per shot
Expected: shot-by-shot part counts within +/-0 (exact match) once score_threshold and trigger timing are tuned to the mould’s cavity count and ejector stroke
Safety notes
Section titled “Safety notes”- lock out/tag out the moulding machine (LOTO) before mounting the camera/light fixture near the platen, tie bars, or ejector mechanism
- verify the fixture cannot intrude into the mould’s open/close travel envelope at any point, including during maintenance strokes
- electrical safety for PoE camera cabling and strobe-light power wiring routed near the machine’s heater-band and high-current circuits
700–2500 USD, difficulty 4/5, ~90 min install downtime.