Introduction
A lot of assembly RFQs arrive with one drawing and a short message: “Please quote this product.”
For a simple machined part, that may be enough to start a discussion. For an assembly project, it usually is not. The factory needs to know every custom part, purchased component, finish, label, package and test requirement before the quotation means much.
A weak BOM slows quotation, but the bigger problem is hidden assumptions. Those assumptions often become expensive during sampling or mass production.
Quick Answer
For an OEM assembly RFQ, send a BOM with part names, drawings, material grades, quantity per assembly, purchased part specifications, approved brands, surface finishes, inspection points, testing requirements, packaging details, target quantity, annual demand and delivery requirements.
1. Start With the Assembly Structure
The BOM should show how the product is built. A factory needs to know which parts are made in-house, which parts are standard purchased items, which parts may need outside sourcing and which items are only packaging accessories.
If possible, provide an exploded drawing or product photo. This helps the engineering and assembly teams understand part relationships before quotation.
Nbfeiyu’s Assembly & Supply Chain work connects these steps: drawings and BOM review, custom part manufacturing, standard part sourcing, outsourced part coordination, incoming inspection, warehouse control, kitting, assembly, testing and export packaging.
2. Define Custom Parts Separately
For custom metal parts, the BOM should not stop at the part name. It should include material grade, process route if known, finish, tolerance notes, quantity per product and any critical dimensions.
If a part needs CNC machining, casting, stamping, welding, surface treatment or assembly preparation, the factory needs to know early. A missing finish note or tolerance can change both cost and lead time.
Useful related capability pages include CNC Machining, Surface Treatment and Quality Control.
3. Do Not Leave Purchased Parts Vague
Purchased parts are a common source of assembly trouble. A BOM line that only says “bearing” or “screw” is not enough.
Define size, grade, material, standard, finish, brand requirement, approved alternative, quantity per assembly and any document requirement. For bearings, springs, bushings, rubber seals, cables, motors or electronics, a small substitution can change fit or function.
If the buyer allows alternatives, say so clearly. If only one brand or standard is acceptable, that also needs to be clear.
4. Add Testing and Inspection Requirements
Many assembly products need more than a visual check. The BOM or RFQ package should say whether the finished product needs torque verification, fit test, movement test, load test, leak test, electrical check or a final appearance standard.
Without this information, the supplier may quote basic assembly only. If testing is added later, the price and lead time may change.
5. Include Packaging From the Beginning
Packaging should not be left until the end. If the product is heavy, visible, painted, plated, assembled with accessories or shipped internationally, packaging can affect cost and after-sales risk.
Define inner protection, bagging, labels, carton size, carton marks, pallet or wooden crate requirements and any retail packaging needs. Then the factory can check whether packaging materials should be sourced together with the components.
For assembly work, quantity affects fixtures, work instructions, inspection frequency, purchasing plan and production scheduling.
A one-time trial order may use a simpler setup. A repeat annual program may justify dedicated fixtures, gauges or more formal records. Share target order quantity and expected annual demand so the factory can plan realistically.
Better BOM, Better Quotation
A strong BOM does not need to look fancy. It needs to be clear. It should help the factory understand what is being made, what is being bought, what needs inspection, how the product is assembled and how it should leave the factory.
When a buyer sends a complete BOM, the supplier can respond with fewer assumptions and more useful risk comments. That saves time on both sides.
CTA: Preparing an assembly RFQ? Send Nbfeiyu the BOM, drawings, purchased part specs, testing requirements and packaging plan through the Contact page. We can review the missing points before the project moves into sampling.