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Injection Molded Parts Inspection
We go to your factory and check your molded parts before they ship. Dimensions against your drawing, the plastic against your PO, the looks against AQL. We're on site within 48 hours — and the full photo report is in your inbox within 24.
Book an Inspectioninquiry@utsinspection.com
Independent since 2006
CNAS-accredited to ISO/IEC 17020
ISO 9001:2015 quality system
On-site within 48 hours
PDF report within 24 hours
The Defects That Slip Through Uninspected Molding Runs
The sample was perfect. Then production starts, the machines get pushed faster, and small things begin to slip. These are the defects our engineers grade on every molded-parts job — caught at the factory, not in your warehouse.
Flash
Extra plastic on the edges and around ejector pins. Parts stop sitting flat and housings won't close cleanly.
Sink Marks
Small dents above ribs and thick spots. On any visible face, that's a reject.
Short Shots
The mold didn't fill completely — missing corners, thin walls, parts that fail assembly outright.
Warpage
Parts bow or twist as they cool. Snap-fits won't close and the part wobbles on a flat table.
Weld Lines
Lines where two plastic flows meet. It looks bad — and it's the first place the part cracks.
Splay & Silver Streaks
Streaks from wet or degraded plastic. Your customer will spot them before you do.
Burn Marks
Trapped air scorches the plastic near gates and thin walls. Ugly, and the material is weaker there.
Voids & Bubbles
Hidden holes inside thick sections. You can't see them — until the part breaks in someone's hands.
Color Streaks & Black Specks
Dirty material or poor mixing. The part fails the side-by-side check against your approved sample.
Molded Parts We Inspect Every Week
If it comes out of an injection mold, we've probably stood in front of a machine checking it.
Housings & Enclosures
Electronics boxes, appliance shells, power-tool bodies — checked for fit, finish and assembly.
Houseware & Kitchen Plastics
Cups, kettles, storage boxes, bathroom fittings — the everyday items your customers handle most.
Toys & Childcare Plastics
Toy shells and parts for children's products — with the extra safety checks that come with them.
Bottles, Caps & Closures
Bottles, jars, caps and seals that have to close tight — on every unit, not just the sample.
What We Check on Your Molded Parts
- Appearance & WorkmanshipSurface, gate trim, flash, sink, warp, short shots — every piece graded against the agreed limit, not a quick glance.
- DimensionsThe sizes you marked as critical on your 2D drawing, measured with calibrated calipers, gauges and projectors.
- MaterialThe plastic grade and filler content checked against your PO and the supplier's material certificates.
- Color & FinishHeld next to your approved sample — color, texture and gloss have to match.
- Assembly & FunctionTrial fit with mating parts, snap-fits, screw torque, moving parts, and a drop test where your spec asks for one.
- Quantity, Packing & LabelingPiece count per SKU, assortment, inner protection, carton strength, an ISTA 1A drop test and 100% barcode scanning.
Sampling That Gives You a Defensible Decision
We don't eyeball a few pieces and call it done. We pull random samples the ANSI/ASQ Z1.4 way (ISO 2859-1), and every defect gets a grade — Critical, Major or Minor. The result stops being a matter of opinion, so the factory can't argue with it.
0.0Critical defects accepted
2.5AQL for major defects
4.0AQL for minor defects
Critical
Sharp edges, cracked housings, the wrong plastic, a failed safety function. One of these and the whole lot stops.
Major
Short shots, warping out of tolerance, sink marks on visible faces, color that doesn't match your sample, parts that won't assemble.
Minor
Light flow lines in places nobody sees, slight gate marks within the agreed limit.
Dimensions and Resin — Where Molding Orders Usually Go Wrong
- Real numbers, not tick boxesEvery critical size is written down as an actual measurement against your tolerance — so you see drift before it turns into rejects.
- First-off disciplineOn a new mold we check the first parts off the machine against your drawing, before the same mistake comes out of every cavity, every shift.
- The plastic vs your POMaterial certificates get checked against the physical parts. The two swaps we see most: a cheaper grade, and more regrind than agreed.
- Compliance screeningUL94 flame ratings, REACH, RoHS and TSCA declarations checked against the rules of the market you're selling into.
Why the Bulk Order Never Quite Matches the Sample
Ask anyone who has bought molded parts for a few years. The golden sample was made with care — the container was made on a deadline. Here's what usually changes in between.
The plastic gets stretched
Regrind ratio creeps up, or a cheaper grade quietly replaces the quoted one. The parts look fine and fail six months later.
The machines get pushed
Cycle times are squeezed to hit the delivery date. Cooling time drops — and out comes warpage, sink and short shots.
The mold wears down
Parting lines and ejector pins wear with every shot. Flash and rough edges appear halfway through the run.
The color batch changes
New material lot, new masterbatch — suddenly the red is a different red. Nobody at the factory held it next to your sample.
None of this is visible on a video call. It's visible on the factory floor — which is where we stand.
Three Points in Production Where an Inspection Pays
Initial Production Inspection
At 5–10% of the run. We confirm the mold setup, the material and the first-off dimensions — before the same mistake comes out of every cavity.
How IPI worksDuring Production Inspection
At 30–50% finished. Drift in size, color or cycle time gets caught while the rest of the order can still be saved.
How DPI worksFinal Random Inspection
At 100% finished and 80% packed. The ship-or-stop decision — pass, fail or hold — with photos to back it.
How FRI worksThis Is What an Inspection Actually Looks Like
What Happens on Inspection Day
You book
Send your PO, drawing and packing details. We assign an engineer and build the checklist from your documents — not a generic template.
We show up
On site within 48 hours of your booking. GPS check-in from the factory floor, so you know exactly who stood at your machine.
Samples get pulled
Random samples, the ANSI/ASQ Z1.4 way. Our engineer picks the cartons and the parts — not the factory.
Every check runs
Looks, dimensions, material, color, assembly, function and packing — all against your approved sample and drawing.
Defects get documented
Every defect is photographed, measured and graded on the spot. You hear the provisional result the same day.
You decide
The full PDF report lands within 24 hours — pass, fail or hold. Forward it straight to your supplier if you need to.
A Report You Can Forward Straight to Your Supplier
- Photo evidenceEvery defect photographed and graded Critical, Major or Minor — no vague remarks like "workmanship not good".
- Real measurementsActual sizes against your drawing's tolerances, instrument by instrument.
- The verdictSample size, defects found, and one clear word: pass, fail or hold.
- Packing proofCartons, labels, barcodes and assortment photographed exactly as we found them.
- In English, in 24 hoursWritten for the person who has to deal with the supplier — you.
The Numbers Buyers Actually Book Us For
2006Independent since
48hEngineer on site
24hPDF report delivered
13+13Chinese provinces & Asian countries covered
When This Inspection Pays for Itself
New mold, first run
A first-off check plus an early inspection catches setup mistakes before ten thousand parts repeat them.
New supplier
Make sure their machines, material and packing actually match the sample you approved — before your deposit becomes inventory.
Repeat order, quality slipping
Faster cycles and extra regrind show up first in size and color. A mid-production check catches it while there's still time.
Before the balance payment
A failed inspection is your leverage to demand rework. A passed one is your green light to pay and ship.
Before goods go to Amazon
FNSKU labels, polybag warnings and carton drop get checked with the product — so a warehouse rejection never happens.
What an Inspection Costs
Priced per man-day
One inspection day covers the sampling, all the checks and the report for one product at one factory. Most molded-parts orders fit in a single day.
Quoted on your order
The price depends on your product, your quantity and the factory city. Send your PO and drawing, and we come back with one all-in number — no hourly surprises.
Nothing hidden
No travel fees in covered cities. No weekend surcharges. The 24-hour PDF report is part of the price — there's no separate "reporting fee".
If it fails
A re-inspection after the factory fixes things is booked at the same day rate — enforcing your standard never costs extra.
Where We Inspect
- 13 provinces across ChinaOur own engineers, based where the molding factories are — Guangdong, Zhejiang, Jiangsu and beyond.
- 13 countries across AsiaVietnam, India, Thailand, Malaysia, Indonesia, Pakistan, Cambodia, the Philippines and more. If your order moves countries, your QC moves with it.
- One standard everywhereThe same checklist, the same sampling method and the same report format at every factory we walk into.
Why Buyers Trust the Verdict
- Independent since 2006We're a third-party inspection company. We work for you — never for the factory.
- Accredited, not self-declaredCNAS-accredited to ISO/IEC 17020 for inspection bodies, with an ISO 9001:2015 certified quality system behind it.
- Our own engineersFull-time, university-educated UTS engineers run your inspection — no freelancers hired the night before.
- Proof we were thereGPS check-in on every visit, so you know exactly who was on your factory floor, and when.
- Your spec is the standardThe checklist comes from your drawing and your approved sample — the factory argues with your document, not with us.
What to Send Us Before the Visit
- Your POQuantities per SKU and the delivery date, so the sampling matches your real lot.
- The 2D drawingCritical sizes and tolerances marked — this is what our calipers answer to.
- The approved sampleA master sample, or clear reference photos for color, texture and finish.
- The material specPlastic grade, filler percentage, flame rating where it applies.
- The packing filesLabels, barcodes, carton marks and the assortment plan.
With these on file, the checklist matches your spec — and the factory can't argue about what "acceptable" means.
Multi-Cavity Molds and Mixed Orders
Two things make molded-parts orders tricky to judge from a distance: one mold can have many cavities, and one order can have many SKUs. We handle both the same careful way.
Every cavity gets sampled
Tell us the cavity count and we pull parts across cavities — so a worn insert in cavity 7 doesn't hide behind good parts from the rest.
Every SKU gets counted
Mixed orders are checked SKU by SKU: quantities, colors, assortment per carton. A shortage of one color doesn't get averaged away.
Family molds get split verdicts
When several different parts come from one tool, each part gets its own measurements and its own defect count in the report.
Running a mixed order? Read how we handle quality inspection for multi-SKU orders.
Services Molded-Parts Buyers Also Book
Initial Production Inspection
First-off sizes, tooling and material confirmed at 5–10% of the run.
Read more
During Production Inspection
Drift caught at 30–50% finished, while the rest can still be fixed.
Read more
Final Random Inspection
The ship-or-stop check when goods are finished and 80% packed.
Read more
Sample Evaluation
Your golden sample verified in detail before you approve production.
Read more
Container Loading Supervision
Right cartons, right count, loaded without damage — sealed in front of us.
Read more
Amazon Compliance Inspection
FNSKU, polybag warnings and carton rules checked before FBA sees them.
Read moreWorth Reading Before You Book
First Article Inspection Before Mass Production
BOM audits, material verification and dimensional validation before the run launches.
Read the article
Product Testing Before Mass Production
Sample review, material checks and acceptance criteria that hold up in production.
Read the article
How to Prepare for a Final Random Inspection
Specifications, AQL setup and the packing files that make the visit decisive.
Read the articleQuestions Buyers Ask Before Booking
What AQL do you use for injection molded parts?
We sample to ANSI/ASQ Z1.4 (ISO 2859-1), normally at General Inspection Level II, with acceptance limits of Critical 0.0, Major 2.5 and Minor 4.0 unless you set your own. The sample size comes from your lot quantity, and the verdict is a clear pass, fail or hold.
How fast can you inspect?
An engineer can be on the factory floor within 48 hours of a confirmed booking, and the full PDF report follows within 24 hours of the inspection.
Which defects do you check on molded parts?
Appearance defects such as flash, sink marks, short shots, warpage, weld lines, splay, burn marks, voids and color streaks — plus dimensions against your drawing, resin against your PO, assembly fit, function, packing and labeling.
Can you measure dimensions against our 2D drawing?
Yes. Send the drawing with critical dimensions and tolerances marked, and our engineers record actual measured values with calibrated calipers and gauges. The report shows numbers, not tick-box OKs.
Do you verify the plastic material?
We check resin grade and filler content against your PO and the supplier's material certificates, and we screen declarations against REACH, RoHS and TSCA requirements for your destination market. Suspected grade swaps or excess regrind are flagged in the report.
What happens if the inspection fails?
You receive a fail verdict with photo evidence and measured values, so you can require the factory to rework, sort or reproduce before shipment. A re-inspection after rework is booked at the same day rate.
Where do you cover?
Our own engineers cover 13 provinces across China and 13 countries in Asia, including the main molding regions of Guangdong, Zhejiang and Jiangsu.
My mold has many cavities — do you check them all?
Tell us the cavity count and we pull samples across cavities. That way a worn insert in one cavity can't hide behind good parts from the rest — the findings show the pattern.
What if I don't have a drawing or a full spec?
We inspect against your approved sample and your PO instead, and we still record actual measurements for the key sizes. We'll also tell you honestly which checks can't run without a spec — so you can decide before booking.
How much does an inspection cost?
Pricing is per man-day and depends on your product, your quantity and the factory city. Send your PO and drawing to inquiry@utsinspection.com and we come back with one all-in number — no travel fees in covered cities, no weekend surcharges.
Ship Molded Parts You're Sure Of
Send your PO and drawing today. An engineer is at the factory within 48 hours — and within 24 hours of the visit, the report is in your inbox, every defect photographed and graded.
Book an InspectionEmail Your PO & Drawinginquiry@utsinspection.com · +86 757-86783812 · +86 571-87423201
