Preparing an RFQ for Custom Castings and CNC-Machined Parts

Created on 08.04

A quotation can be prepared quickly. A useful quotation takes a little more context.

For custom castings and CNC-machined parts, price depends on more than the shape shown on a drawing. Material, supply condition, machining scope, quantity, inspection requirements and delivery expectations can all affect the manufacturing route.

The good news is that you do not need a perfect RFQ package before contacting a supplier.

"Please quote" is a perfectly reasonable starting point—but it is rarely the whole conversation.

A practical RFQ should help both sides understand three things: what the part needs to do, what the supplier is expected to deliver and which points still need to be confirmed.

Quick RFQ Checklist

For an initial review, the following information is usually the most helpful:

2D drawing, 3D model, sample or available photographs
Part name, application and working conditions
Material grade, standard or required performance
Required supply condition: raw, semi-machined or fully machined
Critical dimensions, tolerances and machined surfaces
Trial quantity and estimated annual demand
Surface treatment, inspection and documentation requirements
Target timing and delivery destination, when available

Not every project requires every item at the first stage. Start with what is already available, and use the review to identify the remaining questions.

Start with What You Already Have

A complete 2D drawing, together with a 3D model when available, normally provides the clearest starting point. These files help the supplier review the structure, dimensions, tolerances, machining areas and possible manufacturing risks.

However, an existing sample, older drawing, photographs, preliminary model or incomplete specification can still support an initial review. If the material grade is undecided, the application and required performance may be enough to begin. If annual demand is uncertain, an estimated range is useful.

The first review does not need to settle every detail. It only needs to show:

what is already clear;
what may affect the quotation; and
what can be confirmed before tooling or production.

When information is incomplete, the aim is not to fill the gaps with assumptions. It is to identify which gaps matter now.

2D drawing, 3D model, physical sample and technical information prepared for a custom casting RFQ review.

Three Groups of Information That Shape the Quotation

Most RFQ information can be organised into three practical groups: product information, manufacturing requirements and commercial information.

Product Information

The supplier first needs to understand what the part is and what it is expected to do.

Useful information may include:

product name and application;
2D drawing, 3D model, sample or photographs;
material grade and applicable standard;
service medium;
operating temperature and pressure;
corrosion, wear or strength requirements.

Not every item applies to every part. A simple support bracket may not require the same service information as a pressure-containing housing or a part exposed to corrosive media.

When operating conditions influence material selection, wall thickness, heat treatment, coating or testing, they should be discussed early.

Manufacturing Requirements

The next question is what the supplier is expected to deliver.

The same part may be quoted as:

raw or cleaned casting;
semi-machined part;
fully CNC-machined part;
finished part ready for assembly, with surface treatment when required.

Raw, semi-machined and fully CNC-machined supply conditions for the same custom casting.

This distinction is essential. A raw casting quotation may cover tooling, casting, cleaning and basic inspection. A fully machined quotation may also require fixtures, datum planning, CNC operations, threads, surface-finish control and dimensional inspection.

Critical features should be identified whenever possible. These may include bearing bores, sealing faces, mounting surfaces, locating features, threaded areas, hole patterns, coaxial relationships and surface-roughness requirements.

Not every dimension needs the same level of attention. Highlighting the features that affect assembly or function helps the supplier focus the manufacturing and inspection plan on the right risks.

Surface treatment, heat treatment, pressure testing, non-destructive testing and special documentation should also be stated when required. The objective is not to add every possible inspection item, but to confirm the checks that matter for the part.

Commercial Information

Technical information defines how the part may be produced. Commercial information helps determine which production route is practical.

The most useful details normally include:

prototype or sample quantity;
trial-order quantity;
expected batch quantity;
estimated annual demand;
target delivery schedule;
delivery destination;
preferred trade terms, when already known.

Quantity does more than influence unit price. It may affect tooling, moulding, fixtures, machining arrangements, inspection frequency and packing.

An estimated annual range is usually enough at the early stage. It does not need to be a fixed purchasing commitment, but it helps the supplier evaluate the project in the right context.

Which Details Most Often Change Price or Lead Time?

Some points have a greater influence on quotation accuracy than others:

Material grade: A specific alloy or standard may change material cost, casting process, heat treatment and testing.
Machining scope: A raw casting price cannot automatically include finished bores, threads, sealing faces or tight geometric tolerances.
Critical tolerances: Tighter tolerances may require different fixtures, machining operations or inspection methods.
Quantity: Trial quantities and repeat-production volumes may need different tooling and production arrangements.
Inspection and documentation: CMM reports, material certificates, pressure testing, NDT, PPAP, special packing or third-party inspection may affect cost and lead time when required.

Confirming these points early reduces the risk that two parties are discussing different supply scopes under the same part number.

Drawing review and dimensional inspection of a custom casting before quotation and production planning.

What Happens After You Send the RFQ?

The quotation process should not feel like a black box.

After receiving the available information, the supplier should normally:

review the drawing, model or sample;
understand the application and required supply condition;
check the material, quantity and manufacturing scope;
identify necessary technical questions;
clarify critical machining and inspection requirements;
define what is included in the quotation;
prepare the price and preliminary lead time.

A few focused questions at the beginning can make the quotation clearer and reduce avoidable changes later.

If the project moves forward, the next stage may involve sample development, tooling, drawing approval or more detailed process planning.

A Simple RFQ Format You Can Copy

Part name / application: 

Drawing, 3D model or sample available: 

Material grade or required performance: 

Required supply condition: Raw casting / Semi-machined / Fully machined 

Critical dimensions, tolerances or machined areas: 

Trial quantity: 

Estimated annual quantity: 

Surface treatment or heat treatment requirements: 

Inspection and documentation requirements: 

Delivery destination: 

Target timing: 

Other information or open questions:

You do not need to complete every line before making contact. Send what is currently available, and use the review process to clarify the rest.

A Clear Scope Makes a More Useful Quotation

A good RFQ is not necessarily the longest one. It is the one that helps both sides understand the part, the required supply scope and the conditions behind the quotation.

Clear information at the beginning can reduce repeated questions, make quotations easier to compare and create a more reliable basis for sample development and production.

At Unna Metal, we review custom casting and CNC-machining enquiries based on the information available. We identify important open points, clarify the manufacturing scope and avoid filling technical gaps with assumptions.

Send us your drawing, model, sample or current project information. We will review what is available and help identify what should be confirmed for the quotation and what can be addressed at the next stage.

💡