Kitting and assembly is the work a warehouse does before an order arrives: taking several stocked items and combining them into one new item that is stocked, picked and sold as a unit. A subscription box, a starter bundle, a display pack of twelve, a product with its manual and cable in a branded carton are all kits. It is a value-added service on the 3PL's rate card, charged per kit or per labor hour, and it is also an inventory event, because the component SKUs go down and the kit SKU goes up. This page covers both halves from the operator's side: how the job is specified and written up, and how the record stays true when a kit is built.
The bill of materials is the SOP
Every kit needs a written bill of materials: the component SKUs and quantities, the packaging, the inserts, the label and the finished kit's own SKU and barcode. That document is the kitting SOP in all but name, and the assembly steps follow it in order. A client who changes an insert has changed the kit, so the bill of materials carries a version and a date the same way a receiving SOP does. The warehouse SOP template worksheet on this site counts the procedures a client account needs, and kitting is one more process with a variant per kit.
The inventory move that people forget
Building 500 kits consumes 500 of each component and creates 500 of the kit SKU. If the WMS is not told, the component count is wrong on the next cycle count and the kit shows as unavailable when the orders come. The work order for the kitting job is the record: components issued, kits completed, shortages noted, all confirmed by scan or count at the end of the job. In a barcode WMS the kit is received into a location like any other SKU, which is what makes it pickable by the same path as everything else.
Pricing assembly and kitting services
Charge by the kit where the kit is standard and the time is predictable, by the labor hour where the client's kits vary or the specification changes often. Either way the floor is measured time: a kit that takes four minutes of one person's time at a loaded rate is priced from that, plus packaging at cost and a margin. Time the first batch, write the time into the bill of materials and re-time it when the spec changes. Pickpathly Pro keeps the kit specification, the timings and the completed work orders against the client so the price and the operation stay in agreement.
Questions people ask about kitting and assembly
What is the difference between kitting and assembly?
Kitting gathers several finished items into one unit, typically without changing them; assembly may involve fitting parts together or light finishing. In a 3PL both are value-added work done before an order, charged per unit or per hour.
How does kitting affect inventory?
Components are consumed and a new kit SKU is created. The kitting work order records what was issued and completed, and the WMS is updated by scan so the component count and the kit count are both right at the next count.
Should a small 3PL offer kitting and assembly?
If it can write the bill of materials, time the job and update the record, yes; it is well-paid work that uses the same team and floor. If the specification lives in an email thread, the job will cost more than it earns.