Thread and fastener profile inspection
A fastener silhouette can show visible thread interruptions, pitch features and selected outer dimensions when the part is correctly presented. Feature spacing must be measured from a stable reference.
Line solution
Test this on your samplesFastener inspection for bolts and turned parts
// Short answer
Fastener inspection with machine vision measures the silhouette of every bolt, pin or turned part as it passes single file between a collimated backlight and a camera with a telecentric lens, and rejects parts whose length, diameters or thread are outside the drawing. addaScan builds it on HIKROBOT cameras and HIKROBOT VisionMaster, and proves each feature with a gauge R&R study on your parts. An indicative installed budget for a typical application is R 270 000 – R 930 000 excluding VAT.
// At a glance
The station in three lines
- Faults caught
- Wrong length, diameter or head height; thread missing or short; mixed parts; burrs on the profile
- Configuration
- Mono camera with telecentric lens and collimated backlight, VC3000 controller with VisionMaster, air-jet reject
- Proof of capability
- Gauge R&R study per part and feature, on your master parts, before and after installation
// Fit & limits
What this station will not do, and what it needs
What it will not do
- Thread gauging: thread presence and length are checked; pitch diameter and fit stay with thread gauges.
- Hidden features: bores, internal threads and undercuts the camera cannot see in silhouette or end face are not measured.
- Surface and cracks: roundness, surface finish and cracks are not measured from a silhouette.
- A promised tolerance: no tolerance is promised before a gauge R&R study on your part and feature.
What makes it work
- Single-file parts: a feeder that presents one part at a time in a repeatable orientation.
- Clean parts: oil drips and swarf on the profile read as material.
- Drawing data: the features and limits that matter, per part number.
- Reference parts: master parts measured on a CMM or with calibrated gauges, for the study.
// On South African lines
Machined parts in South Africa, and why every part is measured
Machined parts are a large share of what South Africa’s component makers sell abroad: in 2025 engine parts were the second-largest automotive component export at R5 750m, and transmission shafts and cranks the fourth at R3 011m (naamsa, 2026). Behind those figures are turning, rolling and grinding lines making bolts, pins, studs and shafts to a customer drawing.
No South African regulation sets how a bolt or a shaft is checked; the requirement comes from the customer drawing, the fastener inspection standards it calls up and the supplier’s control plan. Where parts are checked by sampling with gauges and micrometers, a part made between two samples is not measured at all. A fastener inspection machine with a camera measures every part that passes, against the same limits, and keeps the values. As a fastener inspection system it adds a thread inspection camera to the measurement, so one station covers dimensions and thread presence.
Measurement claims are part-specific. A station’s capability on a feature is shown by a gauge R&R study on your parts, not by a camera’s pixel count, which is why this page quotes no tolerance. HIKROBOT’s lighting guide notes that a parallel backlight is usually used with a telecentric lens for high-precision dimension detection (HIKROBOT light catalogue, p.78). HIKROBOT’s telecentric lenses (HIKROBOT CN) and parallel lights (HIKROBOT CN) are listed on its Chinese site rather than its English product menu; addaScan supplies both for South African projects.
What the line and the quality team report, and what the station checks
| What the line reports | What a station checks | Where it stops |
|---|---|---|
| “A short bolt got mixed in with the long ones” | Overall length, head height and shank diameter from the silhouette of every part; parts that do not match the running part number are rejected. | Parts with the same silhouette but a different material or grade are not separated. |
| “Some parts came through without thread” | Thread present, and thread length, from the profile; deep-learning classification where the rolled thread shows as texture rather than an edge. | Pitch diameter and fit are a thread gauge’s job; a silhouette does not gauge them. |
| “We measure shafts with a micrometer, one in a batch” | Shaft measurement on every part: diameters, step lengths, shoulders and chamfers from the side profile, logged per part. | Only the outer profile is measured; roundness, run-out and surface finish are not. |
| “The customer wants proof that a critical diameter is checked on every part” | Each value is logged against its limits with time and result, and a gauge R&R study shows what the station can measure on that feature. | Capability is shown per part and per feature; no tolerance is promised before the study. |
| “Burrs and damaged heads are found at the customer” | Burrs and dents that change the profile show in the silhouette; the end-face view in the high case shows the head and drive recess. | Cracks and surface marks inside the outline are not seen in a silhouette; crack detection is a separate non-destructive test. |
// The complete solution
Fastener inspection station: optics, software and installation
The customer’s feeder presents parts single file on a guide. Each part passes between a collimated backlight and a camera with a telecentric lens, VisionMaster measures the silhouette against the drawing limits, and parts outside them are blown off the track by an air jet whose action is confirmed.
[Schematic]Plan view, not to scale
Swipe sideways to see the whole drawing →
[1]: Fires the camera as each part enters the field of view.
[2]: Collimated light behind the part gives a sharp silhouette edge.
[3]: A mono camera with a telecentric lens images the side profile.
[4]: Blows parts outside the limits off the track.
[5]: Confirms the rejected part left the track.
Hardware
| Component | HIKROBOT example | Role in this station |
|---|---|---|
| Camera | HIKROBOT MV-CS060-10GM 6 MP mono GigE camera (low); two MV-CS200-10GM 20 MP mono cameras for side profile and end face (high) | Images the silhouette at the resolution the tightest feature needs |
| Telecentric lens | HIKROBOT MVL-MY series telecentric lens (MVL-MY-02-140; MVL-MY-0188-167 for long parts), supplied by addaScan | Keeps the image size constant when the part sits nearer to or further from the lens |
| Backlight | HIKROBOT MV-LBPS parallel flat light, supplied by addaScan, or a telecentric backlight illuminator (the budget is priced on a third-party telecentric backlight) | Collimated light gives a sharp edge on round and chamfered parts |
| Processing | HIKROBOT MV-VC3302P-128G60 vision controller running HIKROBOT VisionMaster | Runs the measurement recipe, logs every value and signals the reject |
| Reject (high case) | Not HIKROBOT: stainless air knife with a fast-switching solenoid valve, plus a confirmation sensor | Blows failed parts off the track and proves they left |
| Guide and fixture | Local supply: precision guide or fixture on your feeder output, rigid plate for camera and backlight, calibration artefacts | Puts each part in the same place in the field of view and keeps the optics aligned |
Software and vision tools
| Tool or software | What it does here |
|---|---|
| HIKROBOT VisionMaster measurement tools | Find edges on the silhouette and measure diameters, lengths, shoulder positions and chamfers in calibrated units. |
| Calibration to a reference artefact | Converts pixels to millimetres with a reference pin or setting master of known size, checked at every shift start. |
| VisionMaster deep-learning classification | Thread present or not where the thread shows as texture, as in HIKROBOT’s case on machined holes and threads on its Chinese site. |
| Recipe per part number | Nominal sizes and limits from your drawing for each part number, selected by the PLC at changeover. |
| Measurement log | Every value per part with time and result, exported for SPC and for the gauge R&R study. |
Installation and integration
01
Mounting and enclosure
Camera, lens and backlight on one rigid plate so their alignment cannot drift; a cover keeps oil mist and swarf off the glass.
02
Lighting and shrouding
A collimated backlight behind the part and a shroud against plant light; the silhouette is the measurement, so the backlight window is kept clean.
03
Trigger and tracking
A part sensor fires the camera as each part crosses the field of view; the controller times the reject from the same signal.
04
PLC link
Pass, fail and reject reason by digital I/O from the VC3000 controller to the machine PLC; measured values to a PC or MES over Ethernet.
05
Reject and confirmation
Air-jet reject with a sensor that proves the part left the track; a part that was not measured, or a vision system that is not ready, means reject or stop, never pass.
06
Recipes and operator screen
A recipe per part number with drawing nominals and limits, chosen at changeover; the screen shows each value against its limits and the calibration status.
// Indicative cost in South Africa
What this station costs, excluding VAT
Indicative budget for a typical application of this kind. Every project involves custom requirements (your products, line speed, layout, PLC and acceptance criteria), so the final price differs from case to case. A firm price follows the sample test.
- Low
- R 270 000
- one silhouette view
- High
- R 930 000
- two views with air-jet reject
- Basis
- Typical application of this kind, indicative
- South African rand, excluding VAT
- Prices as at 2 October 2026
- Travel (Gauteng): outside Gauteng quoted separately
// Included and excluded
The low figure is one camera with a telecentric lens and backlight measuring the side silhouette of parts presented single file by your feeder, with a gauge R&R study. The high figure adds an end-face view, a large telecentric backlight for long parts, an air-jet reject with confirmation, a measurement system analysis and calibration artefacts. Telecentric measurement sits outside the standard ranges on the cost guide and is therefore priced here separately. Your feeder or bowl, part handling, utilities and VAT are excluded.
Hardware is priced from public list prices converted at the ECB reference rate, plus freight, clearance and margin; engineering at R 900 – R 1 300 per hour. How these ranges are built →
Swipe the table sideways to see the high figure and the basis →
| Cost block | Low | High | Basis |
|---|---|---|---|
| Vision hardware (landed, with margin) | R 91 600 | R 299 900 | Low: one 6 MP mono camera, telecentric lens, small telecentric backlight, VC3000 controller. High: two 20 MP cameras with large-field telecentric lenses, large and small telecentric backlights, controller, air knife and fast valve |
| Software licence | R 33 800 | R 40 100 | HIKROBOT VisionMaster standard licence |
| Local materials and reject | R 30 000 | R 120 000 | Low: rigid mount, light source for the backlight, cabling. High: precision guide or fixture, reject with confirmation, calibration artefacts, panel |
| Engineering (recipes, PLC link) | R 72 000 | R 260 000 | 80 h at R 900 to 200 h at R 1 300 |
| Installation, FAT, SAT, training, documents | R 28 800 | R 104 000 | 32 h to 80 h, including the gauge R&R study |
| Project management | R 14 400 | R 52 000 | 16 h to 40 h |
| Travel (Gauteng) | R 3 000 | R 6 000 | Outside Gauteng quoted separately |
| Total (rounded) | R 270 000 | R 930 000 | Low: one silhouette view. High: two views with air-jet reject |
// Related technology
Which technologies this scenario uses, and why
The technologies behind this station, how much each matters here, and where each is explained in depth.
| Technology | Role | Why it matters in this scenario | Read more |
|---|---|---|---|
| 2D measurement (backlight, telecentric optics) | Core | The job is dimensions from a silhouette: a telecentric lens and collimated backlight give an edge that does not move with part position. | Dimensional inspection |
| Lighting technique | Core | On round and chamfered parts the backlight decides where the edge is; a parallel backlight gives a sharper edge than a diffuse one. | Machine vision lighting |
| Area scan cameras with a vision controller | Supporting | A mono camera on a controller gives the resolution and the per-part measurement log that a vision sensor does not. | Camera and lens selection |
| Deep learning (classification, segmentation, DL OCR) | Supporting | Thread presence is a texture, not an edge; classification separates threaded from unthreaded parts. | Rule-based vs deep learning |
| PLC link and reject with confirmation | Supporting | Small parts need an air-jet reject, timed from the trigger, and a confirmation that the part actually left the track. | PLC and reject integration |
// Acceptance
How the station is proven before handover
Every station is accepted on your products, against numbers agreed in writing before the build. How we deliver →
01
Sample test
Your master parts and parts outside the limits, imaged with the proposed camera, telecentric lens and backlight; the report shows which features can be measured and how repeatable the values are.
02
FAT with gauge R&R
Before delivery, a gauge R&R study on your parts (several parts measured repeatedly by the station under the agreed conditions), plus challenge parts outside each limit that must all be rejected.
03
SAT on the line
On your feeder, at production rate, the challenge parts are run again, false rejects and escapes are counted over an agreed run, and the study is repeated where line conditions differ from FAT.
Shafts and turned parts: define each measured feature
For single-file shafts, pins and turned parts, create a characteristic list from the drawing before selecting the lens. A silhouette can expose a shoulder, groove or chamfer, but it is not a complete assessment of every functional surface.
| Decision or event | Check or action | Acceptance boundary |
|---|---|---|
| Shoulder and groove | Locate from the specified datum and measure accessible edges | Rounded edges and burrs can shift the apparent boundary. |
| End orientation | Identify the distinctive end before applying dimensional regions | Symmetric silhouettes need another visible feature or identifier. |
| Thread outline | Check the agreed visible thread features | Retain the prescribed functional thread gauge and hidden-feature checks. |
| Reloading | Repeat feeding and presentation on reference parts | A study on the same stationary image omits handling variation. |
Keep the original result when a part is routed to reference measurement. Define reinspection and acceptance near tolerance boundaries before production release.
Fixtured housings and multi-feature parts · Vision, CMM and gauges
// FAQ
Questions about fastener inspection
What does a bolt inspection machine with a camera check?
It measures the silhouette of every bolt as it passes: overall length, head height and diameter, shank diameter, thread length and whether thread is present, and chamfers and burrs that change the outline. A second view adds the head face and drive recess. Each value is compared with the limits from your drawing, failed parts are blown off the track, and the values are logged per part.
How much does fastener inspection with vision cost in South Africa?
An indicative installed budget is R 270 000 – R 930 000 excluding VAT, at 2 October 2026 prices. The low figure is one telecentric silhouette view on parts from your feeder, with a gauge R&R study; the high figure adds an end-face view, a large backlight for long parts, an air-jet reject with confirmation and calibration artefacts. Both include engineering, installation, FAT and SAT in Gauteng. A firm price follows a sample test on your parts. This is a typical application: every project involves custom requirements, so the final price depends on your products, line and acceptance criteria.
Can a camera inspect threads on bolts and studs?
Partly. Of the usual thread inspection methods, gauges, thread measurement and visual checks, a camera covers the visual part. Thread inspection with vision system tools covers what the silhouette shows: a camera sees whether thread is present, where it starts and ends, and the outer diameter over the thread; deep-learning classification helps where the thread shows as texture. It does not gauge pitch diameter or fit, which stay with thread ring and plug gauges, and it does not see internal threads in a nut or bore from the side. So this station works as an automated thread inspection machine for presence and position of external thread, such as bolt thread inspection before packing, not as a replacement for the gauge check.
How accurate is shaft measurement with a camera?
It depends on the part, the field of view, the optics and how the part is presented, so we do not quote a figure in advance. The capability on each feature is shown by a gauge R&R study on your parts, first at FAT and again on the line. For tight features on long shafts, the field of view and resolution may call for more than one view.
Is this inline fastener inspection or a sampling check?
Inline fastener inspection: every part is measured as it passes from the feeder or conveyor, and parts outside the limits are rejected. Your micrometer or gauge checks on samples stay as the reference.
Why use a telecentric lens instead of a normal lens?
With a normal lens a part looks bigger when it is closer to the camera, so a part sitting slightly off the guide measures wrong. A telecentric lens keeps the image size the same over its working range, and with a collimated backlight it gives a sharp edge on round and chamfered parts. addaScan supplies HIKROBOT telecentric lenses for South African projects.
Does it suit the inspection of machined parts other than fasteners?
Yes, where the features are on the outer profile or the end face: pins, studs, bushes, shafts and turned parts presented single file. Features inside the part, bores and internal threads, and surfaces such as finish and roundness need other methods. Large or heavy parts that cannot be fed single file need a fixture and a different handling design.
Sources
- naamsa Automotive Trade Manual 2026 (component export ranking: engine parts, transmission shafts and cranks) (industry report, checked 2026-10-02)
- HIKROBOT MVL-LBT-039-238-F bi-telecentric lens (telecentric lens category on the Chinese site) (vendor product page (Chinese site), checked 2026-10-02)
- HIKROBOT MV-LBPS-27-27-W parallel flat light (Chinese site) (vendor product page (Chinese site), checked 2026-10-02)
- HIKROBOT Light Source Catalog 2025Q3, p.78: parallel backlight used with a telecentric lens for dimension detection (vendor catalogue, checked 2026-10-02)
- HIKROBOT Light Source Catalog 2025Q3, p.38: MV-LBSS-H flat lights for workpiece size and contour measurement (vendor catalogue, checked 2026-10-02)
- HIKROBOT automotive industry cases on the Chinese site (deep learning for holes, threads and machined faces) (vendor case list (Chinese site), checked 2026-10-02)
Related:
// Next step
Send us master parts and the ones that got through
Describe the line, the products and the fault. We test on your good and faulty samples and reply with a feasibility note and a budget.