A complete metal fabrication RFQ helps manufacturers evaluate technical requirements, identify production risks and prepare a more accurate quotation. Missing information often leads to repeated clarification, assumptions in pricing or changes after an order has already been placed.
For custom components and assemblies, buyers should define not only what must be manufactured, but also how conformity will be evaluated and what documentation must accompany the shipment.
1. Part Drawings and 3D Models
The technical drawing should be the primary reference for quotation and manufacturing. It should include:
- Part name and drawing number;
- Drawing revision;
- Overall and functional dimensions;
- Hole locations and connection interfaces;
- Weld symbols and joint details;
- Machined surfaces;
- Critical characteristics;
- Applicable tolerances;
- Surface treatment requirements.
If a 3D model is provided, the buyer should state whether the model or the 2D drawing takes precedence if differences are found.
Welding symbols should follow a recognized system agreed by both parties. ISO 2553, for example, establishes rules for the symbolic representation of welded joints on technical drawings. Clear symbols reduce the risk of uncertainty about weld type, location, size and extent. ISO 2553:2019
All files should carry a consistent revision. Sending a revised model with an outdated drawing can result in quotation errors and unnecessary engineering clarification.
2. Material Specification
The RFQ should identify the required material by a recognized grade and standard, rather than using a broad description such as “carbon steel” or “stainless steel.”
Useful information includes:
- Material grade;
- Applicable ASTM, EN, JIS, ISO or other specification;
- Plate, pipe, tube, bar or section dimensions;
- Required condition or heat treatment;
- Corrosion, temperature or wear requirements;
- Whether material substitution is permitted.
If an equivalent grade may be considered, buyers should request the proposed alternative for approval. Materials with similar commercial descriptions are not necessarily equivalent in chemical composition, mechanical properties, weldability or service performance.
The RFQ should also state whether a material certificate is required. EN 10204 defines different types of inspection documents for metallic products, but the required document type must be specified before material procurement. BS EN 10204:2004
3. Dimensions, Tolerances and Acceptance Criteria
A dimension without a tolerance may be interpreted differently by the buyer and manufacturer. The RFQ should distinguish between:
- Critical dimensions;
- General fabrication tolerances;
- Machining tolerances;
- Geometric tolerances;
- Weld profile or distortion limits;
- Assembly and interface requirements.
Buyers should avoid applying unnecessarily tight tolerances to every feature. Tighter tolerances may require additional machining, fixtures, measurement time and production controls, increasing both cost and lead time.
Where general tolerances are used, the applicable standard and tolerance class should be stated explicitly. The buyer should also identify dimensions requiring an inspection report.
4. Welding Requirements
For welded components, include the base material, joint configuration, weld size and any applicable welding code or customer specification.
The RFQ should clarify whether the project requires:
- Specific welding processes;
- Approved welding procedures;
- Qualified welders;
- Visual inspection;
- Penetrant, magnetic particle, ultrasonic or radiographic testing;
- Specified weld acceptance criteria;
- Weld maps or inspection records.
NDT should not be requested simply as “full NDT.” The method, coverage, acceptance standard, personnel requirements and reporting format should be defined. ISO 9712 specifies qualification and certification requirements for personnel performing several industrial NDT methods. ISO 9712:2021
5. Quantity and Order Pattern
The manufacturer needs to know whether the RFQ covers:
- One prototype;
- A first production batch;
- A repeat order;
- Annual demand;
- A blanket order with scheduled releases.
Pricing for one prototype can differ significantly from repeat production because programming, tooling, fixtures and process preparation may be distributed across different quantities.
Buyers should provide the requested quotation quantity and, where possible, estimated future volumes. However, manufacturers should not be expected to price mass production solely on an unconfirmed forecast.
6. Inspection and Documentation
The RFQ should define how the product will be accepted. Depending on the project, the documentation package may include:
- Dimensional inspection report;
- Material certificate;
- Welding records;
- NDT report;
- Surface treatment certificate;
- First Article Inspection report;
- Certificate of Conformity;
- Packing list and product identification;
- Factory Acceptance Test report.
The buyer should also identify any hold points, witness points or third-party inspection requirements. These activities affect planning, cost and delivery time and should therefore be agreed before order confirmation.
7. Surface Treatment, Packaging and Delivery
Specify the required coating system, colour, finish, surface preparation and any thickness or testing requirements. Terms such as “industrial paint” are usually insufficient for products exposed to outdoor, marine, chemical or high-temperature environments.
Packaging instructions should cover lifting points, preservation, moisture protection, export packing, identification marks and any dimensional or weight restrictions.
Finally, the RFQ should include the requested delivery date, delivery location, Incoterms® rule and any document submission deadlines.
A Better RFQ Creates a Better Manufacturing Start
TOMECO SI manufactures custom metal components, fabricated structures and mechanical assemblies based on customer drawings and technical requirements. Its manufacturing scope may support prototypes, individual parts and repeat production, depending on the product and agreed project requirements.
Providing complete RFQ information enables TOMECO SI to review manufacturability, clarify technical issues and prepare a quotation based on a clearly defined scope.
