Locating a straight edge on stacked timber
Timber localisation should identify the physical edge of the intended top board over a usable length. Do not use it as the physical datum.
Industry // Building materials
Request an assessmentTile inspection, brick and board inspection with machine vision
Tile quality inspection and camera checks for boards, bricks, blocks, roofing sheets and pipes.
Technical review: Frank GuoReviewed
// Short answer
Tile inspection with machine vision finds visible surface defects such as cracks, chips, blisters and glaze faults, measures length, width and squareness, and can sort units into grades or shade classes; the same checks apply to boards, bricks and blocks. Continuous or large products such as board, sheet and pipe are usually imaged with line-scan cameras. Dust, heat and vibration decide how the station is built. Strength, density and internal cracks are not visible to a camera.
// Where it fits
Inspection points from forming to stacking
A generic sequence; each product skips or adds steps.
[Schematic]Process flow · not to scale
Swipe sideways to see the whole drawing →
[1] Continuous surface: board, sheet or pipe imaged by line-scan before cutting.
[2] Dimensions: length, width and squareness of cut units.
[3] Cracks & chips: after drying, firing or curing.
[4] Surface & shade: finish and colour, combined into a grade for sorting.
// Defect risks
What goes wrong at each step
Visible faults by step, and the application that checks for them.
| Production step | Typical visible faults | Inspection |
|---|---|---|
| Forming, pressing, extruding | Blisters, paper tears and streaks on board; marks on sheet and pipe | Web & line-scan inspection Surface defect detection |
| Cutting | Wrong length or width, out-of-square corners, chipped edges | Dimensional measurement |
| Drying, firing, curing | Cracks, chipped corners and colour change between kiln or dryer zones | Surface defect detection |
| Glazing, printing, coating | Pinholes, glaze drips, missing or smeared print, coating scratches | Surface defect detection |
| Sorting and stacking | Grades or shades mixed in one box or pallet | Grading (below) |
// Inspections
Checks that apply to building materials
Surface and dimension checks can often share one station.
Surface defect detection
Cracks, chips, blisters, pinholes and glaze faults.
At: after firing, curing or finishing
Dimensional measurement
Length, width, squareness and edge straightness of cut units.
At: after cutting
Web & line-scan inspection
Continuous board, sheet or pipe imaged line by line as it moves.
At: after forming, before cutting
// Grading
Sorting units into classes
Several checks combine into one decision per unit.
01
Define the classes on samples
Each grade or shade class is set by physical reference units agreed with your quality team.
02
Hold the image stable
Shade needs constant lighting and colour settings, checked regularly against a reference.
03
Combine and signal
Surface, dimension and shade results form one grade, sent to the sorter or stacker.
// Application map
Building materials inspection scenarios by product
Typical products from South African building materials plants, what a camera checks on each, and the application page with the detail. The method in each row is a starting point, confirmed on your own product. Strength, water absorption, density and internal cracks remain laboratory tests.
| Product / line position | What is inspected | Typical fault caught | Inspection method | Related application |
|---|---|---|---|---|
| Ceramic floor tilesafter the kiln, before the sorting line | Glazed face, edges, size and shade | Cracks, chipped corners, pinholes, glaze drops, a shade outside the batch | Diffuse and low-angle light; colour camera for shade | Surface defect detection |
| Inkjet-printed wall tilesafter the digital printer or kiln | Printed decor across the face | Streaks from blocked print-head nozzles, missing decor, smudges | Colour line-scan or area camera with even light | Surface defect detection |
| Gypsum board (plasterboard)on the board line after the dryer | Paper face and bound edges | Paper tears, blisters, stains and damaged edges | Line-scan across the width with a line light and encoder | Web & line-scan inspection |
| Fibre-cement sheets and ceiling boardsafter curing and trimming | Face, edges, length, width and squareness | Cracked or broken corners, edge delamination visible at the cut, out-of-square sheets | Overhead cameras or line-scan with the sheet presented flat | Dimensional measurement |
| Concrete blocks and paverson the production board after the block machine | Top face and edges of each unit on the board | Broken corners, cracks, missing or incomplete units | Overhead camera triggered once per board, low-angle light | Surface defect detection |
| Clay face bricksafter the kiln or at the setting machine | Face colour, texture and arrises | Chipped arrises, cracks, colour outside the agreed range | Colour camera with low-angle light | Surface defect detection |
| Concrete roof tilesafter curing and colour coating | Nibs, interlocks and coating cover | Broken nib, cracked interlock, bare patches in the coating | Camera over the tile with diffuse and low-angle light | Surface defect detection |
| IBR and corrugated roof sheetingafter the roll former | Coated surface along the moving sheet | Coating scratches, dents, roll marks and colour change. Profile height needs a laser profile sensor | Line-scan camera paced by an encoder | Web & line-scan inspection |
| PVC pipesafter the extruder, at the marking printer and saw | Printed marking along the pipe, outer surface, cut end | Missing or unreadable marking, streaks, a ragged cut | Cameras around the pipe; OCR/OCV on the marking | OCR/OCV & code inspection |
| Melamine-faced boardsafter the short-cycle press | Decor surface | Scratches, press marks, dry spots, the wrong decor | Colour line-scan with even light across the board | Web & line-scan inspection |
| Insulation rollsafter roll wrapping | Wrap intact and the right label for the product | Torn wrap, missing or wrong label | Camera beside the conveyor with diffuse light | Label & print inspection |
| Cement bagsat the rotary packer discharge | Printed cement class and date code on the valve bag | The wrong class printed after a silo change, missing code, burst bag | Camera over the bag face; OCR/OCV on the code | OCR/OCV & code inspection |
| Strapped cubes of bricks or blocksat the stacker and strapping station | Cube label present and matching the product; layers complete | Missing or wrong cube label, a gap in a layer | Camera or code reader at the strapping station | Carton & pallet verification |
// Environment
Conditions specific to building materials plants
Dust, heat and vibration are designed for from the start.
Dust
Clay, cement and gypsum dust
Dust coats optics and can look like a defect on product. Sealed housings, air purge and cleaning keep the image usable.
We askDust sources near the line
Heat
Kilns and dryers
Radiant heat affects electronics. The check sits after cooling, or the housing is cooled.
We askProduct temperature at the check
Vibration
Presses, saws and conveyors
Vibration blurs images and shifts measurements. Cameras mount on rigid, isolated frames.
We askWhere the station could be mounted
Size
Large and continuous product
Board and sheet are imaged by line-scan cameras paced by an encoder; wide product may need several.
We askProduct width and how speed is measured
Texture
Rough faces and patterns
Textured and printed surfaces vary naturally. Samples show where texture ends and a defect starts; brick and block lines add tight dimensional consistency.
We askDesigns and finishes that run
// Limits
What a camera cannot tell you about building materials
We agree these boundaries before a project starts.
Needs another method
- Internal cracks and laminations. Need methods such as acoustic or ultrasonic testing.
- Strength and absorption. Strength, water absorption and density are laboratory tests.
- Hidden faces. The underside needs another view; the inside of a pipe may not be visible.
- Height. Flatness, warp and thickness need 3D or profile measurement.
Works reliably when
- Product is presented consistently. Flat, spaced, with an encoder on continuous lines.
- Optics are protected. Housings, air purge and cleaning are part of the design.
- Classes are defined on samples. Physical reference units for every grade and shade.
// Samples & acceptance
What to send for a sample test
We test your own products before proposing a station. The same samples later define acceptance.
Sample preparation guideGood product
Units from normal production, for each size, colour and finish.
Defect samples
Cracks, chips, blisters and out-of-size units, each marked.
Grade references
Units that mark the boundary between grades or shades.
Acceptance
False rejects, missed defects and grading agreement with your inspectors; levels agreed per project.
// Manual inspection
Why manual inspection struggles on these lines
Conditions on building materials lines that make checking by eye unreliable over a full shift.
- Dust. Clay, cement and gypsum dust coats product and hangs in the air, hiding fine cracks and chips.
- Heat. Product leaving kilns and dryers is too hot to inspect up close, so checks move to after cooling or are skipped.
- Size and weight. Large tiles, boards and blocks are heavy to turn, so undersides and edges are often not looked at.
- Glare, texture and shade. Glazed and textured faces reflect light differently, and grading shade by eye varies between inspectors and with the light.
- Shift fatigue. Noise, vibration and long runs of near-identical units make the occasional defect easy to miss.
These are reasons to automate the checks that are defined and visible, and to keep people for judgement and for fixing causes. The guide to manual or automated camera inspection compares the two.
// Line solutions
Line solutions for building materials
Complete stations for lines in this industry, each with the HIKROBOT hardware, installation and an indicative installed budget for a typical application in rand, excluding VAT. All line solutions →
| Line solution | Faults it catches | HIKROBOT configuration | Indicative budget (excl. VAT) |
|---|---|---|---|
| Cement bag inspection | Missing or illegible packing code, wrong pre-printed bag, bag count per order | Vision sensor or 2 cameras in purged housings, reject flap | R 140 000 – R 840 000 |
| Pipe print inspection | Missing, smeared or wrong marking text; metre count out of sequence | Vision sensor or 3 cameras around the product, encoder, alarm | R 110 000 – R 650 000 |
| Aluminium extrusion inspection | Scratches, dents, die lines and pick-up on visible faces | 1 or 3 line-scan cameras, encoder, deep learning, marker | R 360 000 – R 1 340 000 |
Basis of the budget column: an indicative installed budget for a typical application, in rand excluding VAT, as at 2 October 2026, the price date used on the line-solution pages. Projects involve custom requirements, so the firm price follows the sample test. Each row links to the line-solution page that shows the cost breakdown.
Translate the product specification into inspection points
South Africa’s Concrete Manufacturers Association represents the precast concrete industry and describes its cooperation with SABS on standards. Its site also distinguishes association membership from product certification. That distinction matters when buying inspection: an image-based grading station does not certify concrete strength, water absorption or conformity with an entire product standard. (Concrete Manufacturers Association: precast industry and standards)
| Production point | Visible check | Failure consequence and containment |
|---|---|---|
| After cooling or curing | Chips, incomplete edges, surface cracks visible in the selected views | Segregate before costly finishing; retain strength tests separately |
| After cutting or trimming | Length, edge position, broken corners and missing features | Prevent incorrectly sized units entering a mixed stack |
| After glazing or coating | Surface blemishes and appearance against agreed grade references | Avoid mixing cosmetic grades; do not infer coating adhesion |
| Before pallet wrapping | Product identity, count where visible and pack marking | Hold the stack when identity is inconsistent; reconcile rework |
Choose inspection after a surface has stabilised enough to compare, but before handling hides it. A wet face and a dry face can appear different without either being defective. Separate recipes or controlled conditioning may therefore be more valuable than a more complex classifier. For a textured tile, establish which pits are permitted texture and which are chips; for a pipe, define whether the requirement is an external silhouette, a socket feature or an internal condition that this view cannot see.
A hypothetical pallet-release decision illustrates the boundary: an otherwise acceptable tile with a visibly broken corner is held as a cosmetic or dimensional failure under the agreed product specification. A tile with a clean image still follows the separate material-testing programme. The example is an inspection policy, not a project result or a claim that every crack is optically detectable.
Commission with references covering the grade boundaries and with dust on the protective window at the agreed maintenance limit. HIKROBOT’s lighting glossary explains how directional illumination reveals relief while diffuse illumination changes the appearance of reflective faces. (HIKROBOT Light Source Catalog, 2025 Q3, glossary) Where a dimensional check decides a grade, compare repeated reloads with reference measurements following a defined measurement-system study. (NIST e-Handbook, 2.4 Gauge R&R studies) Count unnecessary downgrades separately from defects released; their costs arise from lost selling grade, handling and customer replacement, so the business case should use the plant’s own records.
// FAQ
Building materials inspection questions
Can tile inspection and brick inspection find cracks and chips?
In tile and brick inspection, usually yes, when lighting makes the crack or chip stand out; low-angle light shows relief. Fine cracks on rough or patterned faces are harder, so we test your products first.
Can a camera do tile surface inspection on the line?
Yes, for visible faults. Ceramic tile defect detection finds cracks, chips, and glaze and print faults on the top face, with lighting chosen for the glaze and line-scan cameras on wide or fast lines. Board surface inspection works the same way. Shade grading and dimensions are separate checks, described here too.
Can a camera grade tiles by shade?
It can sort units into shade groups when lighting and camera colour are stable and classes are defined on physical reference tiles. Random patterns are harder.
How are boards or roofing sheets inspected while they move?
With line-scan cameras that build the image line by line as the product passes, paced by an encoder. Defect positions can be passed on so the right piece is rejected after cutting.
Can vision check length, width, squareness and flatness?
Length, width and squareness can be measured from a top view when the product is presented consistently. Flatness, warp and thickness need height information, usually from a 3D or laser-profile method.
Will dust and heat stop a camera working?
Not if they are designed for. Sealed housings, filtered air and regular cleaning keep dust off the optics. Near kilns, the station sits where the product has cooled, or the housing is cooled.
Can vision replace strength or water absorption testing?
No. A camera sees surface and shape. Strength, water absorption, density and internal cracks need laboratory or other test methods.
Can concrete blocks and pavers be checked on the production board?
Yes, for visible faults. An overhead camera triggered by the block machine images each board and flags broken corners, cracks and missing or incomplete units. Compressive strength, density and faults below the top face need sampling and laboratory tests.
Sources
- Concrete Manufacturers Association: precast industry and standards (South African precast sector and SABS standards cooperation; read 2026-10-27)
- HIKROBOT Light Source Catalog, 2025 Q3, glossary (vendor lighting geometry; archived source checked 2026-10-27)
- NIST e-Handbook, 2.4 Gauge R&R studies (measurement study design; read 2026-10-27)
Related:
Line solutions using this:
Common in these industries:
Typically built with:
// Building materials
Request an assessment for your line
Tell us the products, finishes, grades and conditions around the line. We will say which checks apply and what a sample test needs.