Guide
What should a CNC machining or die-casting RFQ package include?
An RFQ package is the set of files and written requirements a buyer sends a supplier so a part can be priced without guessing: a 3D model, a toleranced 2D drawing, the material and finish called out by standard, the quantities to price, and the inspection documents needed at delivery.
By Saola Manufacturing engineering team · Published · Updated
This guide walks through each item in the order an estimator reads it, and names the public standard to cite for each one. It is written for engineers and sourcing managers sending drawings to an overseas machine shop or die caster, in Vietnam or anywhere else. The standards named here are the ones a supplier on any continent will recognize, so the same package works for every shop on your list. No figure on this page is a Saola capability claim; the quote states what applies to your part.
On this page
What files should a machining RFQ include?
Send a 3D model in a neutral format such as STEP, plus a PDF of the fully dimensioned 2D drawing. The model carries the geometry; the drawing carries the tolerances, threads, finish and notes that decide the price.
STEP (ISO 10303) is the safest 3D format because nearly every CAM and quoting system opens it without translation. IGES also works, but it loses solid-body information more often, so treat it as a fallback. Native CAD files are useful as an extra, never as the only file, because the supplier may run a different CAD version or none at all.
The PDF drawing is the document you will inspect against. State in the RFQ which file governs if the model and the drawing disagree; many buyers make the drawing the controlling document. Put the same revision letter on both files and in the file names, and send one folder or ZIP per part number so each quote line maps to one part.
On the Saola quote form, a STEP file plus a dimensioned PDF gets the fastest, most accurate quote. The form accepts STEP, STP, IGES, IGS, DWG, DXF, PDF, ZIP, PNG or JPG files.
How should tolerances and GD&T be called out?
Put a general tolerance note in the title block, then tolerance individually only the features that affect fit or function. Use one GD&T system and name it: ASME Y14.5-2018 for US-style drawings or ISO 1101:2017 for ISO drawings.
A general tolerance note such as “ISO 2768-mK” sets the default for every dimension that has no tolerance of its own, per ISO 2768-1:1989 for linear and angular sizes; ISO 2768-2 (geometry) has been withdrawn and replaced by ISO 22081:2021. ISO 2768-1 defines four classes: f (fine), m (medium), c (coarse) and v (very coarse). Pick the class that matches the process and the function, and write it once, instead of repeating the same tolerance on every dimension.
Tight tolerances cost cycle time, tooling and inspection, so reserve them for the features that need them. Define a datum reference frame that matches how the part locates in its assembly, and control position, flatness or runout against it rather than stacking plus-and-minus dimensions. Under ASME Y14.5 and ISO 1101, a feature control frame that refers to a datum the drawing never defines cannot be inspected the same way twice, so an estimator has to ask about it before pricing.
If a feature needs something tighter than routine work on turned features, flag it in the RFQ so it is reviewed on purpose rather than discovered after the quote.
How do you specify material so a Vietnam supplier quotes the right alloy?
Name the alloy and temper by its designation in a published standard, and name that standard. If the supplier buys to a different national standard, ask it to confirm the local equivalent in writing before it quotes, and check that chemistry against your standard.
A supplier in Vietnam may buy material to JIS (Japanese), ASTM or EN designations, so the same everyday alloy can carry three names. The table lists approximate equivalents for three alloys that come up in machining and die casting. They are a starting point for the conversation, not a substitution rule: grades across national standards overlap, but they rarely match element for element. Die-casting alloy ADC12 is the clearest case, because published EN cross-references for it differ.
| Alloy | JIS | ASTM / AA | EN | Caveat |
|---|---|---|---|---|
| 6061 wrought aluminum | A6061 (JIS H 4040) | 6061 (ANSI H35.1; bar per ASTM B211 or B221) | EN AW-6061 (EN 573-3) | Approximate equivalent; confirm chemistry against the cited standard |
| ADC12 die-casting aluminum | ADC12 (JIS H 5302) | Nearer 383 than A380 (Aluminum Association / ASTM B85) | Published cross-references differ (EN AC-46100 vs EN AC-46500, EN 1706) | Not identical to any of these; state the governing standard and confirm chemistry against it |
| 304 stainless steel | SUS304 (JIS G 4303) | 304, UNS S30400 (ASTM A276) | 1.4301 / X5CrNi18-10 (EN 10088-3) | Approximate equivalent; confirm chemistry against the cited standard |
Give the temper as well as the alloy, for example 6061-T6, and list any restricted-substance requirement such as RoHS. Say whether you need a material certificate for every lot. For cast parts, the alloy also shapes wall thickness and draft, which the die casting page covers in more detail.
How do you specify a finish?
Call the finish out by standard, type and class, not by a trade name or a color word alone. “Anodize per MIL-A-8625, Type II, Class 2, black” can be priced as written, while “black anodize” needs follow-up questions first.
For aluminum anodizing, MIL-A-8625 defines Type II (sulfuric acid) and Type III (hard coat), with Class 1 undyed and Class 2 dyed. Hard coat typically builds more thickness than Type II, so say whether drawing dimensions apply before or after coating, and mark threads and bores that must stay bare.
For zinc plating on steel, ASTM B633 sets the coating class, written as Fe/Zn followed by the minimum thickness, and the supplementary finish type. The current edition adds Types V and VI, non-chromate passivates, which matters when a finish must be free of hexavalent chromium for RoHS.
For powder coating, give a color reference (a RAL number or a physical sample), a gloss level, and the dry film thickness range your design allows, measured per ASTM D7091. Mark cosmetic surfaces and surfaces to mask. Saola manages surface finishing through partner plants, including anodizing, zinc plating and powder coating, and the quote names where each step is done.
What quantities should you ask quotes for?
Ask for two or three quantity breaks that you choose, based on your real annual volume and release size. Add the annual volume and how often you expect to order, so setup and tooling are spread the way your program will actually run.
A single quantity hides how the price moves. Setup, fixturing and first-piece inspection are paid once per lot, and a die-casting die or a stamping tool is a one-time cost spread over the program. Ask for tooling as a separate line from the piece price, so different suppliers can be compared on the same basis.
Keep sample or prototype quantities separate from production quantities, because the route for a handful of samples can differ from the production route. Saola quotes are tiered by annual quantity and show tooling separately from the piece price.
What inspection documents should you request?
List the documents you need at the RFQ stage, because each one adds work that belongs in the price. The usual set is a first article inspection report, material certificates, and a dimensional report on agreed characteristics.
A first article inspection (FAI) report compares every characteristic on the drawing with a measured value on the first production parts. SAE AS9102 is a widely used FAI format, and many buyers outside the industry it was written for ask for it by name. A material certificate traces the lot back to its mill or foundry; EN 10204 type 3.1 is the common inspection-certificate level to request.
For ongoing lots, balloon the critical characteristics on the drawing and ask for a dimensional report on those, with the sampling plan you expect. These are documents to ask of any supplier you evaluate. Saola’s ISO 9001 certification is in progress, not held, so if a signed certificate is a gate for your approved-vendor list, say so in the RFQ.
Which drawing mistakes delay a quote?
Quotes usually stall on missing information, not on hard geometry. The common gaps are a cast part with no draft callout, an unspecified finish, a thread without a class, and no datum scheme.
- No draft callout on a die-cast part. Cast walls need draft to release from the die. Per NADCA product specification standards, say where draft is allowed and which faces are machined flat afterward.
- Finish missing or given only as a color. Use the standard, type and class described in the finish section above.
- Threads without a class. Write 1/4-20 UNC-2B per ASME B1.1, or M6x1-6H per ISO 965-1. For tapered pipe threads, name NPT per ASME B1.20.1.
- No datum scheme. Without datums, position and profile tolerances cannot be measured the same way twice.
- Model and drawing on different revisions. The estimator has to ask which one is current before pricing either.
- Surface roughness missing where it matters. Give an Ra value per ASME B46.1 or ISO 21920 on sealing and bearing surfaces, and let the general note cover the rest.
- Cast-and-machined parts drawn in one state. Mark the machined surfaces clearly, and cite casting tolerances per ISO 8062-3 for the faces left as cast.
RFQ checklist
Send this with every drawing package. Each line names the standard a supplier will expect to see on the drawing or in the RFQ notes.
| Item | What to send | Standard to cite |
|---|---|---|
| 3D model | STEP file on the same revision as the drawing | ISO 10303 (STEP) |
| 2D drawing | Dimensioned PDF with title block, revision and general tolerance note | ASME Y14.5-2018 or ISO 1101:2017 |
| General tolerances | Default class for dimensions without their own tolerance | ISO 2768-1:1989 (geometry: ISO 22081:2021; ISO 2768-2 withdrawn) |
| Threads | Size, pitch and class on every thread | ASME B1.1, ISO 965-1, ASME B1.20.1 (NPT) |
| Surface roughness | Ra only where the function needs it | ASME B46.1 or ISO 21920 |
| Material | Alloy, temper and the governing standard | JIS, ASTM or EN designation |
| Finish | Process, type, class, color and masking | MIL-A-8625, ASTM B633, ASTM D7091 |
| Casting features | Draft, parting line and as-cast tolerances | NADCA standards, ISO 8062-3 |
| Quantities | Two or three breaks you choose, plus annual volume and order frequency | Buyer’s own figures |
| Documents | FAI report, material certificate, dimensional report | SAE AS9102, EN 10204 type 3.1 |
| Confidentiality | Ask for an NDA before sharing drawings, if you need one | Your own NDA or the supplier’s |
Frequently asked
Can I get an NDA signed before I send drawings?
Need an NDA first? Email rfq@saolamfg.com or WhatsApp +84 86 501 7914 and we will sign yours, or send ours, before you share a drawing.
Which file formats can I send?
The quote form accepts STEP, STP, IGES, IGS, DWG, DXF, PDF, ZIP, PNG or JPG files. A STEP file plus a dimensioned PDF gets the fastest, most accurate quote.
Can I send a 3D model only?
A 3D model lets a supplier start reviewing; toleranced features, threads and finish still need a 2D drawing or written notes.
Which processes run at Saola’s lead plant and which go to partner plants?
CNC turning and CNC milling run at Saola’s lead CNC plant. Die casting, stamping and surface finishing go through partner plants Saola manages, as do sand casting, aluminum extrusion, injection molding, sheet metal and laser cutting, waterjet cutting, and rotational molding. For a partner process, Saola holds the drawing, the purchase order and the inspection, and the quote names the production site and origin.
Sources
- ASME Y14.5-2018, Dimensioning and Tolerancing, ASME, 2018
- ISO 1101:2017, Geometrical tolerancing — tolerances of form, orientation, location and run-out, ISO, 2017 (reviewed and confirmed 2022)
- ISO 2768-1:1989, General tolerances — Part 1, ISO, 1989 (reviewed and confirmed 2022)
- ASTM B633, Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel, ASTM International, 2023 edition