The part is cheap, the defect is small, and the line is fast.
A pre-rolled cone is a high-volume, low-value consumable, and the defects that matter are cosmetic and structural — a contamination speck, a tip that did not form, a loose filter fold, an out-of-round base. The line has to feed, image, decide, reject, verify and pack with no one in the loop, at a rate a person could not sustain.
DomainIndustrial AI, optical inspection and sorting
PlatformsFaststream Vision, Connected Edge
ScopeFeasibility to installed line and handover
Binding constraintThroughput at cost — a small defect on a cheap part
DisclosureProperty level; customer not named
CONTEXT
Where this started.
Pre-rolled cones are produced in enormous volume and were inspected, historically, by eye. Manual inspection is inconsistent and does not scale, and the defects are small: a dark contamination speck on a pale paper body, a tip that did not form cleanly, a filter crutch whose rolled fold is loose or irregular, and a base opening that is not round.
The economics invert the usual inspection trade. The unit is cheap and the volume is high, so the inspection cost per unit has to be almost nothing — which means throughput, not per-image cleverness, is the constraint. The line inspects several cones in a single image so the cost per unit stays near zero, and it runs at many cones a second.
And it had to be a line, not a camera. Feeding, conveying, imaging, rejecting, verifying and packing all had to run as one automated flow, because an inspection step that produces a verdict but leaves a person to act on it saves nothing at this volume.
CHALLENGES
4 problems, named.
The ones that decide whether the line pays for itself, stated before any of them had an answer.
01
Small defect, cheap part
A sub-millimetre speck decides a reject on a low-value, high-volume unit. Imaging has to resolve the defect while the inspection cost per unit stays close to zero.
02
Throughput is the specification
At many cones a second the whole line — capture, inference, decision and actuation — has to hold the rate, not just the model. The beat is shared.
03
Feeding a light, awkward part
Cones are light, tapered and nest together. Singulating them reliably from a stack without jams is harder than inspecting them, and it sets the line rate.
04
Verdict to actuator, in time
The vision result has to reach a pneumatic reject at the right cone, over PLC IO, before that cone has moved past the bin. A correct verdict applied late is a defect shipped.
ARCHITECTURE
How the line is built.
The imaging and inference blocks are marked because the line’s economics live there — the defect has to be visible and the verdict has to land in a fraction of a second. The verification block is marked because it is a second, independent check that a rejected cone actually left the line.
CONTRIBUTION
What Faststream did.
The scope of the build, from feasibility to an installed line, rather than a capability list.
Line architecture — the six-stage flow from feeder to packaging, and the takt budget that ties camera, GPU, PLC and actuators to one rate.
Feeding and singulation — a rotating loader with a suction gripper and single-cone gravity drop onto a transparent conveyor.
Imaging design — high-resolution cameras with diffuse lighting, arranged so contamination, tip, filter and base defects are all visible in one frame.
Inference — a model on a single GPU processing several cones per image, sized to the line rate rather than to a benchmark.
Controls integration — the camera-to-inference-to-controller path, with the controller driving pneumatic reject actuators over IO.
Reject and verification — gravity-drop rejection into a bin, with an independent scan confirming the reject actually happened.
Stacking and packaging — actuated stacking through channel tubes onto a box-packaging conveyor.
Build and handover — hardware assembly and firmware, then on-site trials, commissioning and quality support through to handover.
WHAT WAS HARD
The parts that consumed the schedule.
Rarely the subsystem that sounds difficult. Written out because a reader facing the same line gets more from this than from a list of what went well.
01
Feeding, not inspection
Singulating light, tapered, nesting cones from a stack without jams took more iteration than the vision did. The feeder sets the line rate, so its availability — not its speed — is the number that matters.
02
Throughput as a system property
A fast per-image number is only useful if capture, transfer, inference, decision and actuation all fit the same beat. The tail of each stage, not its average, is what drops cones.
03
Small defect, cheap part
Resolving a sub-millimetre speck while keeping per-unit cost near zero drove the imaging, and the decision to inspect several cones in one frame rather than one at a time.
04
Timing the reject
A verdict is only useful if it reaches the pneumatic actuator at the right cone. Tracking each cone from camera to reject bin had to be exact at line speed.
05
A second, independent check
An independent scan after the sort verifies a rejected cone actually left, because a reject that does not physically drop is a defect that ships. The check is deliberately independent of the camera that made the verdict.
OUTCOME
What resulted.
A line, not a camera
Feed, convey, inspect, sort, verify and pack running as one automated flow, from a manually loaded stack to a packed box.
Sized to the rate
Several cones per image on a single GPU — a design sized to run at many cones a second rather than to a benchmark.
Defects caught by class
Contamination specks, tip formation, filter-fold quality and base roundness — the classes manual inspection caught only inconsistently.
Verified rejection
An independent scan confirms the sort, so the line’s promise is that a rejected cone has actually left it rather than merely been flagged.
Confidentiality
Customer projects are presented at property, capability, outcome and integration level. Customer names, internal architecture, confidential deliverables and commercial terms are not disclosed. Where a figure would identify a customer, it is omitted rather than approximated. More detail is available under a non-disclosure agreement, within the limits the customer has agreed.
PRODUCTS AND CAPABILITY USED
What this was built from.
Every item links to its own page, with characteristics, applications and maturity stated honestly for that item.
Why inspect several cones in one image instead of one at a time?
Because the part is cheap and the volume is high, so the inspection cost per unit has to be almost nothing. Imaging several cones per frame and processing the frame in a fraction of a second on a single GPU is what makes the per-unit cost small enough, at many cones a second.
02
What defects does it catch?
Cosmetic and structural classes: contamination specks on the pale paper body, tips that did not form cleanly, loose or irregular filter folds, and out-of-round base openings — the defects manual inspection caught only inconsistently.
03
Why a second scan after the reject?
As an independent check that a rejected cone actually left the line. A pneumatic reject that does not physically drop the cone would otherwise let a known defect through, so an independent scan verifies the sort happened rather than assuming it.
04
What was the hardest part?
Feeding, not inspection. Singulating light, tapered, nesting cones from a stack without jams set the line rate and took more iteration than the vision model did.