This guide covers 18 defect groups seen in custom American Mahjong projects. For each one, it identifies the visible symptom, likely control gap, prevention method, and inspection evidence a buyer can request.
Not every variation is automatically a defect. A finding becomes nonconforming when it violates the approved specification, reference sample, artwork, measurable tolerance, regulatory requirement, or documented appearance limit.
Defect Prevention Starts Before Production
Create one controlled inspection package containing:
- Product specification and revision
- Material and construction description
- Dimensioned tile drawing with tolerances
- Tile edge and surface requirements
- Face and back artwork index
- Color references
- Tile manifest
- Accessory bill of materials
- Retail packaging and master-carton specifications
- Approved physical samples
- Defect classifications and test methods
A beautiful reference photo is not a production standard. The factory needs to know which characteristics are required, how to measure them, and what happens when output differs.
1. Wrong Tile Material or Construction
What it looks like
Tiles use the wrong material family, transparency, layer count, color arrangement, thickness structure, or face/back construction. A project approved as two-tone bonded acrylic may arrive as a different visual or structural build.
Why it happens
- Quote says only “acrylic” or “plastic”
- Material samples were not coded or retained
- Construction changed to meet price or material availability
- Supplier interpreted a visual rendering as a manufacturing drawing
Prevention and inspection
Name the material, layer sequence, nominal thickness, transparency, colors, bonding direction, and approved sample in the specification. Require supplier approval before substitution. During inspection, compare the cross-section, material appearance, dimensions, weight reference if defined, and sample identification.
2. Material Color Variation
What it looks like
Tiles within one set or across cartons show different face, back, or layer colors. A reorder may not match earlier inventory.
Why it happens
- Different material lots are mixed
- Color target exists only on screen
- Supplier changed raw-material source
- Lighting and background were not controlled during approval
- Buyer expected different materials to reproduce color identically
Prevention and inspection
Approve physical color references where color is commercially important. Record supplier, material code, lot, and viewing conditions. Define whether different materials need one visual target or separate approved targets. Inspect samples across cartons and production positions, not just adjacent tiles from one tray.
3. Incorrect Tile Dimensions
What it looks like
Tiles are too long, wide, thick, or inconsistent. They may not fit the tray, racks, case, or replacement stock.
Why it happens
- Drawing lacks measurable tolerances
- Inspector measures over a chamfer instead of the main body
- Tool wear or process drift is not monitored
- Layer thickness changes after sample approval
- Packaging was designed from a nominal size with no allowance
Prevention and inspection
Use a dimensioned drawing with nominal values, tolerances, measurement points, and units. Confirm dimensions on representative pieces during first-article and in-process checks. Test actual tile rows in the approved tray and racks, not only individual measurements.
4. Inconsistent Edge, Chamfer, or Radius
What it looks like
Some tiles feel sharp while others are heavily rounded. Chamfers differ by side, corners are uneven, or the edge removes too much visible face area.
Why it happens
- Requirement says only “smooth edge”
- Tooling or polishing is inconsistent
- Edge geometry was changed without updating artwork clearances
- Manual finishing varies by operator
Prevention and inspection
Define edge geometry in a drawing and retain a physical limit sample. Specify which surfaces and corners are treated. Inspect profile, symmetry, edge damage, and how artwork sits relative to the finished edge.
5. Chips, Cracks, or Broken Corners
What it looks like
Visible material loss, hairline cracks, impact fractures, or broken corners appear after machining, assembly, packing, or transit.
Why it happens
- Cutting or drilling parameters damage the material
- Parts are dropped or collide during handling
- Bonding stress or incompatible construction creates weakness
- Tiles move inside the retail package
- Master-carton protection is insufficient
Prevention and inspection
Check parts after each high-risk process, protect surfaces during movement, and test the actual pack-out. Inspect under defined lighting and examine corners, edges, holes, and bonded interfaces. Separate process damage from transit damage using pre-shipment photos and carton-condition records.
6. Scratches, Haze, Scuffs, or Surface Marks
What it looks like
Polished surfaces show scratches, rubbing, cloudiness, fingerprints, adhesive residue, or handling marks.
Why it happens
- Protective film is removed too early
- Tiles rub together during kitting or shipping
- Dirty fixtures or work surfaces contact the tile
- Cleaning method damages the surface
- Cosmetic expectations were never defined
Prevention and inspection
Define graded surfaces, viewing distance, lighting, and limit samples. Use clean trays and handling controls. Ensure packaging restrains dense tiles without transferring abrasive marks. Inspect multiple cartons after the final cleaning and packing process.
7. Layer Misalignment, Gaps, or Bonding Marks
What it looks like
Two-tone or multilayer acrylic tiles show offset layers, uneven seams, bubbles, visible gaps, squeeze-out, or separation.
Why it happens
- Layer location lacks a drawing tolerance
- Bonding surfaces or fixtures are not controlled
- Material or adhesive behavior changes
- Machining after bonding exposes an uneven interface
- Sample approval focused only on front appearance
Prevention and inspection
Document the layer stack, interface location, acceptable seam appearance, alignment tolerance, and prohibited conditions. Inspect all sides and corners, not only the face. Include handling or conditioning tests only when the exact method and acceptance result are agreed.
8. Engraving Too Shallow, Deep, or Inconsistent
What it looks like
Lines appear faint, excessively recessed, rough, incomplete, or uneven across faces. Fine details may disappear while broad areas look over-machined.
Why it happens
- Artwork is unsuitable for the selected process
- Engraving parameters are not locked by design type
- Material surface or thickness varies
- Tools wear during production
- Buyer approved a digital proof but no physical process sample
Prevention and inspection
Prepare production-ready vector artwork with minimum-feature guidance from the factory. Approve representative fine lines, solid areas, text, and dense faces physically. Record process references and inspect output from early, middle, and later production stages.
9. Incomplete, Overflowing, or Contaminated Color Fill
What it looks like
Engraved areas contain gaps, bubbles, thin coverage, paint outside the recess, mixed colors, dust, or residue on the tile surface.
Why it happens
- Engraving does not support clean filling
- Fill viscosity or curing is inconsistent
- Cleaning removes fill or leaves residue
- Multiple colors are handled without separation controls
- Inspection is conducted before the finish stabilizes
Prevention and inspection
Approve the engraving-and-fill combination, not each process in isolation. Define whether slight recess, flush fill, texture, or gloss differences are acceptable. Inspect full and fine details under repeatable lighting and include gentle cleaning simulation only if an agreed method exists.
10. Printing Misregistration or Missing Ink
What it looks like
UV-printed or otherwise printed artwork is shifted, blurred, doubled, clipped, incomplete, or inconsistent in opacity.
Why it happens
- Fixture location is unstable
- Print file size or origin point is wrong
- Artwork lies too close to a chamfer
- Surface preparation varies
- White underbase or color layers are misaligned
Prevention and inspection
Define a print reference point, artwork safe area, face orientation, and registration tolerance. Approve representative colors and dense/fine details. Inspect the relationship between print, tile edges, layers, and any engraved features.
11. Print or Fill Adhesion Failure
What it looks like
Color flakes, lifts, rubs away, scratches too easily, or transfers to packaging.
Why it happens
- Surface preparation and process chemistry are incompatible
- Curing is incomplete
- Product is packed before the finish is ready
- Buyer and supplier use different informal rub tests
- Cleaning or handling exposure was not considered
Prevention and inspection
Develop a repeatable test suitable for the actual process and intended use. State conditioning time, tool, force, cycles, contact material, and acceptance result. Avoid improvised destructive tests at final inspection that were never correlated with approved samples.
12. Wrong Face Artwork, Mirrored Symbol, or Orientation
What it looks like
A face uses the wrong symbol, outdated logo, mirrored artwork, incorrect number, or an upside-down relationship to a directional back.
Why it happens
- Artwork files do not use stable face codes
- Revisions are sent through several channels
- Production program maps the wrong file to a tile position
- Back orientation is not marked in proofs
- Repeated artboards were edited separately
Prevention and inspection
Link each manifest face code to one approved artwork file or artboard. Freeze the artwork index and include face/back orientation diagrams. Inspect every unique face against the proof during setup, then sample mappings throughout production.
13. Artwork Scale or Position Drift
What it looks like
Symbols sit too high, low, left, or right, or vary in size between related faces. Geometrically centered art may look visually unbalanced.
Why it happens
- No origin point or safe area is defined
- Factory adjusts files individually
- Bounding boxes include invisible objects
- Different faces use inconsistent artboard sizes
- Visual centering expectations are not documented
Prevention and inspection
Use consistent artboard dimensions, named layers, outlined fonts, and a documented alignment method. Create an overview proof showing every face at actual relative scale. Inspect groups side by side rather than approving isolated close-ups.
14. Missing, Duplicated, or Incorrect Tiles
What it looks like
A finished set has the approved total count but contains one duplicated face and one missing face, or the total itself is wrong.
Why it happens
- Purchase order lists only 152, 160, or 166 tiles
- Kitting relies on gross count or weight
- Similar faces are stored together without codes
- Rework returns tiles to the wrong bin
- Packing change was not reflected in the manifest
Prevention and inspection
Use a face-by-face manifest, stable bin labels, controlled tray positions, and set-level verification. The factory process should check every set to the approved composition. Third-party inspection can independently open randomly selected sets, but sampled checks do not replace full kitting control.
15. Wrong or Missing Accessories
What it looks like
Racks, pushers, dice, indicators, chips, bags, or inserts are missing, mismatched, damaged, or supplied in the wrong quantity.
Why it happens
- Accessories appear only in a marketing image
- Bill of materials is incomplete
- Several vendors deliver components without final reconciliation
- Packaging positions are not labeled
- Substitute accessories are used without approval
Prevention and inspection
Create one bill of materials with code, quantity, material, dimensions, color, artwork, supplier, and packing position for every component. Approve substitutions in writing. Inspect accessory function and condition as well as count.
16. Retail Packaging Damage or Poor Product Restraint
What it looks like
Cases arrive dented, trays crack, box corners crush, tiles shift, accessories rub against tile surfaces, or closures do not work.
Why it happens
- Packaging is designed for appearance without product weight
- Tray tolerance does not fit production tiles
- Dense components concentrate load
- Void space allows movement
- Transit tests use empty or substitute contents
Prevention and inspection
Test the final production-equivalent pack-out with all tiles and accessories. Define product orientation, dividers, restraints, wraps, closures, and acceptable packaging cosmetics. Inspect units from top, middle, and bottom positions in master cartons.
17. Wrong Labels, Barcodes, or Carton Marks
What it looks like
The package carries an incorrect SKU, unreadable barcode, old brand name, wrong country-of-origin statement, mismatched quantity, or destination mark.
Why it happens
- Label data is approved separately from packaging art
- Barcode image is scaled or redrawn
- Old files remain at the packing station
- Carton marks are typed manually
- Legal and retailer requirements are reviewed too late
Prevention and inspection
Control label and carton files by SKU and revision. Verify human-readable data and scan production barcodes using an agreed method. Check marks against the purchase order, packing list, destination, and current compliance review.
18. Master-Carton Failure and Shipment Damage
What it looks like
Cartons split, deform, become wet, lose seals, or allow heavy Mahjong sets to shift and damage retail packaging.
Why it happens
- Carton strength and gross weight are mismatched
- Sets are packed with unused space
- Tape or closure is inadequate
- Pallets overhang or stack poorly
- Container or warehouse conditions expose cartons to moisture or compression
Prevention and inspection
Define carton material, dimensions, set count, maximum gross weight, internal arrangement, sealing, labels, and pallet pattern where used. Confirm carton condition before loading and record container or truck condition. Any transit-test protocol should reflect the actual pack-out and distribution route.
Turn Defects Into a Control Plan
Use a table that connects each risk to prevention and evidence.
| Characteristic | Requirement | Process control | Inspection method | Frequency/sample | Defect class | Record |
|---|---|---|---|---|---|---|
| Tile count | Approved manifest | Controlled kitting | Face-by-face check | Factory-defined complete control | Buyer-defined | Kitting record |
| Tile dimensions | Drawing/tolerance | Tool and first-piece check | Caliper at stated points | Agreed plan | Buyer-defined | Measurement sheet |
| Face mapping | Artwork index | Program verification | Proof comparison | Every unique face plus production sample | Buyer-defined | First-piece approval |
| Packaging | Approved pack-out | Packing work instruction | Open-set and carton check | Agreed plan | Buyer-defined | Packing QC record |
Do not leave frequency as “random.” State the sampling plan, process interval, carton selection, or complete-check requirement.
How to Write Better Defect Criteria
Replace vague instructions:
- “No scratches” becomes a defined surface, lighting, distance, size, quantity, and limit sample.
- “Correct color” becomes a physical target, approved range, material/process reference, and viewing method.
- “Smooth edge” becomes a dimensioned chamfer or radius plus a physical sample.
- “Strong print” becomes a named adhesion or wear test with method and acceptance result.
- “Complete set” becomes a face-coded manifest and set-level verification record.
The goal is not to make the document long. It is to make pass and fail decisions reproducible.
What to Do When a Defect Appears
Use a disciplined response:
- Stop or contain affected production.
- Identify when and where the problem began.
- Determine which batches, machines, operators, materials, or artwork revisions are affected.
- Separate conforming, suspect, and nonconforming goods.
- Approve a rework or sorting method.
- Verify repaired output against the original requirement.
- Record root cause and preventive action.
- Decide whether resampling or broader inspection is required.
Replacing the inspector's failed sample does not establish that the rest of the lot is conforming.
Frequently Asked Questions
What is the most serious common Mahjong quality problem?
Severity depends on the product and buyer requirements, but missing, duplicated, or incorrect tile faces can make a set unusable even when its total piece count appears correct.
Can an approved sample prevent all defects?
No. A sample establishes a reference but must be connected to controlled materials, process settings, revision documents, inspection methods, and bulk-production checks.
Should transparent acrylic use the same cosmetic standard as opaque acrylic?
Not automatically. Transparency can reveal inclusions, bonding interfaces, dust, and surface marks differently. Define appearance limits for each construction and surface.
Is a cosmetic variation always a defect?
Only when it falls outside the agreed requirement or limit. Natural or process variation should be reviewed during development and translated into documented acceptance criteria.
Can final inspection solve a factory process problem?
Final inspection can detect evidence of a problem and support a lot decision. Correcting recurring defects requires containment, root-cause analysis, process action, and verification.
Build a Custom Mahjong QC Checklist
Send Lucky Mahjong your tile construction, artwork, packaging, accessories, target market, and quality priorities. We can help convert those requirements into a production specification and inspection reference before sampling or bulk manufacture.
Discuss a Custom Mahjong Project or email [email protected] with the subject line Custom Mahjong QC Checklist.