AQL, Tray Checks and What a QC Report Should Say
A US independent jewelers and Shopify sellers sent us a competitor's comparison in July with one question: why does this fail at prong geometry after a season. We measured it, rebuilt the spec around stone retention after a 40-cycle wear test and prong tip height within +/-0.10 mm, and shipped 240 comparisons that cleared inspection with zero rejects.
That rejection was avoidable at the drawing stage. prong geometry belongs on the spec sheet next to the stone size, not in the claim email three weeks after arrival. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
Our rebuild kept the buyer's retail price and changed four numbers on the bench. The next run cleared inspection because the specification traveled with the tray, not with a phone call. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
What American buyers Check Before They Sign
Most quotes describe the comparison and skip the part that determines the buyer's margin. Those four lines are listed below with the trade default beside our standard. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
| Spec point | Common trade output | HOLYCOME standard | Cost if missed |
|---|---|---|---|
| Prong Geometry on comparisons | Inspected visually at the tray | Gauntlet check on every piece, limit written in the spec | Returns inside 60 days of wear |
| Rhodium Burn Off on comparisons | Batch dependent, not logged | Thickness and tension logged per lot | Complaint after the second season |
| Size Step Drift on comparisons | Estimated from nominal | Gauged per size with go/no-go tools | Resize queue and reship cost |
| Tolerance stack-up on comparisons | Quote states nominal only | Worst-case band published per SKU | Freight and duty drift |
Write these four into the purchase order and the argument after delivery becomes arithmetic rather than recollection. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
Where USD 38-210 Per Piece Actually Goes
Buyers assume the stone dominates the cost of a comparison. At wholesale it is closer to a quarter, and the labor line is where two quotes for the same drawing diverge by double digits. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
| Cost line | Share | What moves it |
|---|---|---|
| Base metal or alloy for comparisons | 32% | Alloy choice and casting yield |
| Stone or melee for comparisons | 23% | Sieve range and lot batching |
| Setting and finishing labor for comparisons | 21% | Jig design and bench minutes |
| Plating, polish and QC for comparisons | 14% | Per-tray versus per-piece checks |
| Packaging and freight for comparisons | 10% | Box grade and DDP versus FOB |
The cheapest quote for comparisons usually hides its saving in the plating line and the stone grade. Both show up in the second season, not the first. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
The Three Failures We See Most in Incoming Samples
prong geometry
A prong that grips the girdle instead of the pavilion survives the showroom and fails the third ultrasonic clean. The seat has to be cut to the pavilion angle before the prongs close.
The commercial effect is a return shipment plus a resize labor claim, typically USD 9-14 per piece. Buyers who have seen it once put it in the purchase order; buyers who have not usually discover it on the first return.
rhodium burn-off
A 0.05 micron rhodium layer reads white in the tray and shows yellow at the shank in six months of daily wear. Thickness, not bath chemistry, is the variable that matters.
Our countermeasure is a gauge and a written limit. It adds about 22 seconds per piece and removes the defect from the run rather than from the carton.
size-step drift
A run gauged at size 6 and estimated elsewhere ships a size 8 that measures 7.75. The mismatch shows up as a resize queue two weeks after launch.
In a 240-piece run this typically shows on 8 of pieces. Catching it means measuring stone retention after a 40-cycle wear test at the tray level, not inspecting the finished carton.
AQL, Tray Checks and What a QC Report Should Say
On comparisons, the cheapest answer is rarely the cheapest outcome once the second season is counted.
The buyers who get the most out of rings treat the first order as a measurement, not as a purchase. They buy a small run, measure the four numbers that matter, and then commit.
We support it directly on comparisons: a 50-piece test run per design, the same gauge standard as a bulk order, and the same retained tray. Small does not have to mean loose.
How a Repeat Order Gets Built
The calendar below is what we quote on a 240-piece run of comparisons. It starts when the spec is signed, not when the deposit clears. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
- Spec sheet signed before casting: lost-wax cast, tolerances, plating thickness and packing format.
- Sample in 3-5 working days from stock components, or about 20 days if a new model is required.
- Production photos at three checkpoints: raw cast, post-polish, post-set, with buyer approval at each.
- Bulk in 15-20 days under 500 pieces; custom tooling runs 25-30 days.
- Pre-shipment QC report with per-tray counts and a retained reference tray for disputes.
MOQ is 50 pieces per design, low enough to test a category and high enough to keep the casting line accountable. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
Alloy, Karat and the Cost of a Color Change
Buyers ask it in the first call about comparisons and rarely get a number they can put in a spreadsheet.
Buyers who get this wrong on rings usually get it wrong in the first order and correct it in the second. The cost of that correction is rarely the money; it is the four to six weeks of shelf time lost while a replacement run of rings is scheduled behind other orders.
Our approach is to write the rule into the comparisons spec sheet before casting, then test it on the first tray. A rule that only exists in an email is not a rule, and a rule that is not tested is a hope.
The Sample Approval That Survives Production
Nobody quotes it for comparisons until something goes wrong, which is exactly why it belongs in the first email.
The commercial version of this question for rings is simple: what does a failure cost the buyer, and who pays it. In our terms the answer is a replacement inside the same order cycle, with the retained reference tray as the arbiter.
That clause matters more than a discount on rings. A 4% lower unit price disappears on the first rejected tray; a written responsibility clause does not.
What the Quote Actually Covers
The short version for comparisons: it is arithmetic, not relationship. The long version is below.
In the American bridal market terms, this is the difference between a landed cost the buyer can plan against and a number that moves after the container ships. For rings, we publish the figure per SKU and hold it for the order window rather than for the calendar year.
Practically, it shows up in three places for rings: the proforma, the QC sheet and the credit note if something goes wrong. All three should quote the same number. When they do not, the argument is about paperwork, not about the product.
What This Means for a First Order
The point of a small first run is not the margin. It is finding out whether the supplier's paperwork survives contact with the actual goods. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
The first order is the cheapest inspection a buyer will ever run, because the volume is small enough to check every tray by hand. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
Freight, Duty and the Arrival Check
Sea freight costs roughly a third of air and takes three times the transit, which only makes sense for an SKU already selling in the American bridal market. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
FOB is the default and DDP is the option. Buyers new to the American bridal market usually take DDP once and then switch after they see the breakdown. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
The arrival check is three steps: count cartons against the packing list, weigh a sample tray, and measure ten pieces against stone retention after a 40-cycle wear test and prong tip height within +/-0.10 mm. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
Frequently Asked Questions
What is the minimum order for comparisons?
50 pieces per comparison. Designs mix inside one shipment, so a first order of three designs at 50 pieces each is normal for a new US account. Below 50 we cannot keep the gauge check independent of the shift, which is the part buyers actually pay for on comparisons.
How long does a reorder of the same comparison take?
12-15 days for comparisons, because the model, the gauge set and the signed spec stay in our system. A first run is longer: 3-5 days for a stock-component sample, about 20 days if a new model is needed, then 15-20 days for bulk under 500 pieces.
Do you supply certificates for comparisons?
IGI or GRA above 0.50 ct for comparisons. Below that threshold we supply a batch report plus per-piece measurement of stone retention after a 40-cycle wear test, which is what most resellers need at the counter.
What finish do you use on comparisons, and how thick is it?
Rhodium at 0.20 micron minimum on white comparisons, with a palladium strike layer so wear-through reads white rather than yellow. Thickness is logged per lot and appears on the QC sheet, not only in the brochure.
How do you handle a rejected tray of comparisons?
We replace or credit inside the same order cycle. The retained reference tray decides: if prong geometry shows on our retained comparison we own it, and if it appeared in transit we split the assay cost and file with the carrier. A typical exposure on comparisons is a return shipment plus a resize labor claim, typically USD 9-14 per piece.
Next Step
Send one drawing or one competitor sample with your target landed cost. We answer with a tolerance sheet, a cost breakdown and a production calendar in two business days. For comparisons in this band the rule is the same on every tray of the run, not only on the first.
HOLYCOME runs this line from Wuzhou, Guangxi, through Wuzhou HengliLai Jewelry Co., Ltd. Output is about 60,000 pieces a month across comparisons and adjacent categories. service@holycome.com or WhatsApp +86 18078079070.
Related reading: Care & Cleaning Manufacturer: Carton Cube, Duty and the Freight Line That Surprises B - HOLYCOME Trends & Styles Manufacturer: The Sample Approval That Survives Production - HOLYCOME
