Bagged and Sorted Molded Parts Kitting Service with Lot Traceability

An assembly line does not want moulded parts; it wants counted bags that arrive in the sequence the line consumes them. The gap between the moulding machine and the assembly bench is where programmes lose margin: parts that arrive bulk get counted twice, sorted twice, and mixed once, and the mixed lot is the one that stops the line. Kitting closes that gap, and it is quoted as a service rather than as a part price, because the value is in the handling, not the moulding.

We bag, sort and kit injection moulded components with lot-level traceability for assembly programmes.

What kitting actually includes

Kitting is four operations that are usually quoted as one service but priced separately: degating and trimming, colour and variant sorting, counting into bags with a stated count, and labelling with a lot card that ties the bag back to the moulding lot. Programmes that take only some of the four take the corresponding price reduction, and the quote lists each operation so the buyer can see what is being paid for. The operation most often dropped is sorting, and it is the one whose absence causes the line stop.

Counting: weigh-count versus piece-count

Small parts are counted by weight against a sampled piece weight, and the accuracy of a weigh-count depends on the uniformity of the part more than on the scale. A part with a 2 percent weight spread counts to plus or minus 1 percent at best, and a programme that needs an exact count per bag pays for piece-count on the parts that matter. We state the count accuracy on the quote rather than implying an exact count, because an assembly line that plans for a weigh-count accuracy never stops for a short bag.

Specification

Traceability that means something

A lot card is only useful if the line can act on it, which means the card has to carry the moulding lot number, not just the packing date. We print the moulding lot on every bag and hold the mapping for the retention period the programme specifies, so a field failure can be traced to a cavity and a shift rather than to a month. Programmes that run PPAP or an equivalent process get the same mapping in the format their system reads, which is usually the difference between a traceability claim and a traceability capability.

Colour and variant sorting

Multi-colour programmes are where unsorted parts hurt most, because a red part in a blue assembly is invisible until the finished product is on the shelf. Sorting is done under a stated light source with a physical master per colour, and the reject stream is quarantined rather than returned to the good parts, because a re-run part is a different lot and mixing it back in breaks the traceability the card promises. Where the programme uses vision inspection, the reject criteria are agreed with the buyer before the first lot rather than tuned afterwards.

Compliance and the audit document

Kitted parts carry the same compound declaration as bulk parts, and the declaration is filed against the moulding lot that the bag card references. Programmes that need a certificate per shipment take the declaration pack with the lot map attached, and programmes that test per lot take the sample pulled at the packing stage, which is the sample that represents what the line actually receives.

Related reading

Our unassembled components programme covers the bulk supply route, and the moulded parts category lists the full range.