A Parent Found a Broken Needle Fragment Inside a Baby's Comfort Toy
Metal Detection and Needle Inspection Guide - Where Metal Contamination Comes From, Needle Detectors, Metal Detectors and X-ray Compared, Detection Sensitivity, Test Piece Checks and Broken Needle Control Standards, Spec Sheet Items, Stage-by-Stage Checks and a Checklist

Hello, this is StartMade.

A Korean baby brand produced 6,000 plush comfort toys at a stuffed toy factory in Dongguan, Guangdong. The pre-shipment inspection passed on stitching, stuffing and labels. Three months into sales, a parent wrote in that "something poked my child's mouth while chewing on the toy." When the toy was cut open, a broken sewing needle fragment a little over 2cm long was sitting in the stuffing. The brand had to stop selling that lot immediately and recall all remaining stock.

Tracing it back, the factory did have a needle detector. But it checked sensitivity only once a day, in the morning, and nobody knew that on the afternoon in question the detector had run for hours with reduced sensitivity. There was no procedure on the sewing line to record whether every piece of a broken needle had been found, and the inspector simply confirmed that a needle detector "existed" and moved on.

Metal contamination is almost impossible to find by visual inspection. It hides inside the product until it turns up in a consumer's hand or mouth, and by then it has become a recall and compensation problem. This article starts with where metal contamination comes from, then covers what needle detectors, metal detectors and X-ray each catch, how to set sensitivity and check frequency in numbers, and what to check in the spec sheet and at inspection.

A reply of "we have a needle detector" is not enough. Set detection sensitivity, test piece check frequency, the procedure for rejected items and broken needle records in numbers and forms, and collect the actual records during production. That is how you prevent metal contamination incidents.

1. Where Metal Contamination Comes From

Some metal arrives mixed into raw materials, but most metal contamination starts inside the factory. These are the causes that actually turn up in products from Chinese factories.

• Broken sewing needles: The most common cause in sewn products. When a needle breaks while stitching thick fabric or around a zipper, fragments fly into the fabric layers or the stuffing.
• Hand needles, pins and staples: Hand needles used for finishing, pins holding fabric in place, and staples fastening packaging can be left inside the product.
• Worn equipment fragments: Cutter blades, grinders, mixers and sieves wear or break and shed metal pieces. This is common in food and plastic raw material processing.
• Defective trims: Metal parts of buttons, snaps or zipper sliders crack, or burrs left inside them break off.
• Poor workplace control: Clips and bolts on workbenches, bits of steel wool, and workers' belongings such as hairpins get mixed in.

Because the causes sit inside the factory, they can be reduced through control. Metal detection is only the last line of defense; procedures for managing needles and tools have to come first. For safety requirements for children's products, see Episode 65, and for contamination control on the line, see Episode 126.

2. Inspection Equipment — What Catches What

Metal inspection equipment catches different metals depending on how it works. If you only ask the factory to "check for metal," it will run whatever equipment it has at its usual sensitivity, so decide on the right equipment and sensitivity for your product first.

Apparel Needle Detectors Do Not Catch Stainless Steel

Most needle detectors in sewing factories sense only magnetic ferrous metal. They catch sewing needles, but non-magnetic stainless steel or copper fragments pass straight through. Conversely, if buttons or zippers contain iron, even good products set off the detector every time and needle detection becomes impossible. For products that will be needle-detected, specify trims in non-ferrous "needle-detector-safe" materials.

Sensitivity Is Stated as a Test Piece Size

Detection sensitivity is expressed as "the diameter of metal sphere the detector can catch." For apparel and sewn goods a 1.2mm ferrous sphere is common, Japanese buyers often require 1.0mm, and baby products may require as fine as 0.8mm. Food metal detectors set separate levels by metal type, such as 1.5mm ferrous, 2.0mm non-ferrous and 2.5mm stainless steel. The smaller the number, the stricter the standard.

3. Control Standards — What to Set in Numbers

A needle detector is useless if it runs with reduced sensitivity or if workers put rejected items back on the line. Operating rules matter more than the equipment.

What happens when a check fails is especially important. If the test piece is not detected, the equipment stopped working properly at some point before that. Every product made since the last confirmed good check has effectively not been inspected. With an hourly check, the re-inspection scope is at most one hour of output.

4. Items to Put in the Spec Sheet

A single line saying "needle detection required" leaves each factory to set its own sensitivity and checking method. Put the items below in a table and attach it to the spec sheet or quality agreement. For how to write a spec sheet, see Episode 59.

Check the trim suppliers as well. Even if the sewing factory is thorough about needle detection, iron in zippers or snaps keeps setting off the detector on good products, and eventually the factory gives up and lowers the sensitivity or skips detection. Put a "must pass needle detection" condition into the trim purchase order from the start.

5. How to Check at Each Stage

Sample and Trim Stage

Once the trims are finalized, run actual samples through the factory's needle detector and confirm that good products are not flagged. If they are, change the trims; do not compromise by lowering the sensitivity at this stage. Also confirm the size and certification of the test pieces the factory will use.

Mass Production Stage

On the first day of production, get photos of the detection line and a video of the test piece check, then collect the check log for each lot. If every signature on a log is in the same handwriting and filled in at once, the checks were probably never done. Collect the broken needle log too; a log with no entries at all is a reason for suspicion, not comfort. Also confirm that these procedures went into the work instructions at the pre-production meeting. For how to run that meeting, see Episode 123.

Pre-Shipment Inspection Stage

Have the inspector bring their own test pieces and verify the factory detector's sensitivity on site. Place the test piece inside the product, at the edges and in the thickest part, run each through, and pass some sample products through the detector again. Have the inspector photograph the quarantine box and check logs as well. For pre-shipment inspection, see Episode 100.

6. Example Request Wording for the Factory

Putting the wording below into the purchase order or quality agreement takes sensitivity and checking methods out of the factory's discretion, and makes it easier to assign responsibility if a metal contamination incident occurs.

"所有成品须在最终包装前100%通过输送带式检针机检测，检测灵敏度为铁球φ1.0mm。检针机须在每天开工时、每隔1小时、收工时及调整设定后用测试卡检测并记录。测试卡未被检出时，须对上一次合格检测之后生产的全部产品重新检针。被检出的产品须放入上锁的隔离箱，查明原因并记录，不得重新过机后当作合格品。断针须找齐全部碎片，贴在断针记录表上并由主管签字；找不齐时，相关产品须隔离。拉链、四合扣、纽扣等辅料须使用可过检针的非铁材料。包装区禁止使用大头针和订书钉。每批货须提供检针记录、断针记录表和检出品处理记录。"
(All finished products must pass 100% through a conveyor needle detector before final packing, at a sensitivity of a φ1.0mm ferrous sphere. The detector must be checked with a test card and recorded at the start of each working day, every hour, at the end of work and after any setting change. If the test card is not detected, all products made since the last passed check must be needle-detected again. Detected products must be placed in a locked quarantine box, with the cause investigated and recorded, and must not be run through again and treated as good. All fragments of a broken needle must be found, taped to the broken needle log and signed by a supervisor; if they cannot all be found, the related products must be quarantined. Trims such as zippers, snaps and buttons must be made of non-ferrous materials that pass needle detection. Pins and staples are prohibited in the packing area. Needle detection records, broken needle logs and reject handling records must be provided for every lot.)

7. Three Real Cases

These are anonymized versions of patterns we often see in consultations. Amounts and figures are examples.

Case 1 — Baby Comfort Toys

This is the case from the opening. The brand recalled the lot and had a Korean contractor re-inspect every unit with handheld needle detectors, finding two more toys with needle fragments inside. Recall and re-inspection costs, customer compensation and lost sales added up to about KRW 30 million. From the next order, the brand set sensitivity at a 1.0mm ferrous sphere and required hourly check records and broken needle logs for every lot. Product liability and recall response are covered in Episode 53.

Case 2 — Children's Wear for Japan

A company making children's wear at a factory in Jiangsu for a Japanese buyer was told that the buyer's warehouse needle detection had flagged the goods. It was not a metal fragment: the factory had switched to cheaper snap buttons that contained iron. The factory's own detector had alarmed too, but workers passed the goods anyway, saying "it's just the snaps." In the end every snap had to be replaced and the goods re-inspected. After that, trim changes required written approval, and every trim change triggered a new needle detection pass test. For change management, see Episode 119.

Case 3 — Nut Snacks

A company importing small packs of nut snacks received a report that a customer had found a piece of wire. The factory had a metal detector, but its test piece check log had been blank for weeks. The cause was the sieve used to screen raw materials: wire had broken off from a torn sieve. After that, the factory checked sieve condition daily, and the importer collected metal detector check records for every lot. For processed food import requirements, see Episode 86.

8. Common Mistakes

• Confirming that a needle detector exists without checking its sensitivity or check records
• Using trims that contain iron, so good products keep getting flagged
• Failing a test piece check without re-inspecting the output made in between
• Running a flagged product through again and treating it as good if it does not alarm
• Not recording whether all fragments of a broken needle were found
• Assuming an apparel needle detector also catches stainless steel and non-ferrous metal

9. Metal Contamination Control Checklist

Spec and Trim Stage

• Chose inspection equipment and detection sensitivity suited to the product
• Wrote check frequency and re-inspection scope for failed checks into the spec sheet
• Specified non-ferrous trims and ran a needle detection pass test
• Set rules for managing needles, pins and staples

Mass Production Stage

• Received a video of the test piece check and check logs for each lot
• Received broken needle logs
• Checked the quarantine box and reject handling records

Pre-Shipment Inspection Stage

• Verified detector sensitivity with test pieces brought by the inspector
• Ran sample products through the detector again
• Cross-checked the check logs against the actual production schedule

Wrapping Up - Verifying "We Have a Detector" with Records

Metal contamination rarely shows up at the factory or at inspection; it is found in the consumer's hands. By then, a sales halt, recall, compensation and lost brand trust all arrive at once. Writing sensitivity and check frequency into the spec sheet in numbers and collecting check records and broken needle logs does not cost much.

There is something you can do right now. Ask the factory currently producing for you to send photos of last week's needle detector check log and broken needle log. If there are no records, or the detector was checked only once a day, build a metal contamination control requirements sheet and send it before your next order.

StartMade supports you on the ground with spec sheets covering detection sensitivity and check procedures, needle detection pass tests for trims, review of check records during production, and test piece inspection before shipment. If you have already received a metal contamination report, we start with finding the cause and re-inspection. If you are preparing a new product, we start with the control requirements sheet.