Sourcing springs from a supplier in another country adds distance, a second language and often a different set of default assumptions. What it does not have to add is weeks of back-and-forth. A good share of spring enquiries can be quoted within two days. The rest come back with a list of questions, and the exchange that follows can drag on for up to three weeks before ending in a conditional quote. The gap between the two groups has little to do with how difficult the part is. It comes down to how complete the information was at the start.
A quote rebuilds whatever the enquiry left out
When an RFQ is incomplete, the supplier has to make assumptions: which accuracy grade, which material, which coating, what batch size. Every one of those assumptions moves the price, and some of them move it several times over.
The buyer then receives an offer that cannot be compared with the competition, because each supplier guessed differently. Filling in the data up front removes that problem on both sides of the table.
Drawing or functional requirement – both routes work
A technical drawing with a full parameter table is the most convenient input, but it is not the only one. A part described by its function can be quoted just as well. For example: the spring must resist with a force of 45 N when deflected to 28 mm, work inside an 18 mm bore, survive around 500,000 cycles and operate at temperatures up to 60 °C with periodic moisture.
That second form is sometimes the better one, because it leaves the supplier free to choose the geometry from the available range of wire sizes. A spring designed around 1.85 mm wire and one designed around 1.8 mm wire can do the same job with slightly adjusted geometry. The difference between the two will show up in material availability – and therefore in the price of the part itself.
One thing a description cannot replace is a 3D model for shaped and bent parts. There the spatial geometry is the requirement, and a STEP file saves both sides several iterations.
Volume and schedule – the item most often missing
This is the information with the strongest effect on price, and it appears in fewer than half of all enquiries.
Three numbers matter: annual demand, the size of a single delivery and the expected lifetime of the project. The same part at 2,000 pieces a year and at 200,000 means a different technology, different tooling and a different inspection method. Without that information the supplier quotes the safest option, which is usually the most expensive one.
Then there is timing. If the first delivery is needed in six weeks, some manufacturing routes are ruled out regardless of budget – and it is better to know that at the quotation stage than after the order has been placed.
Material: state the requirement, not the solution
The best specification names the grade together with its standard – for instance EN 10270-1 SH for patented carbon steel wire, or 1.4310 to EN 10270-3 for stainless. Writing just “spring steel” or “stainless” leaves far too much room for interpretation.
If the grade is not dictated by the end customer, list the operating conditions instead: temperature, environment, contact with chemicals, a non-magnetic requirement. The supplier can then propose the material that meets the requirement at the lowest cost, and will flag it if the grade chosen earlier turns out to be over-specified.
Tolerances: name the governing parameter
For cold-coiled compression springs, quality requirements are set out in EN 15800, with three accuracy grades: grade 1 has the narrowest tolerance band, grade 3 the widest. Extension springs are covered by DIN 2097, torsion springs by DIN 2194.
As a default, the middle grade is a sensible starting point, tightened only where the application calls for it. Tightening the grade on every dimension at once raises the price without any functional gain, and in some cases creates requirements that contradict each other.
Separately, the RFQ has to say which value takes priority: force or dimension. A spring that must deliver a set force in a mechanism is toleranced on force. A spring that must fit a tight seat is toleranced on geometry. Holding both within narrow bands at the same time is usually very difficult and sometimes impossible. Where a compromise can be found, it raises the part price significantly.
Quality requirements and inspection documents
If the part needs an inspection document, specify its type according to EN 10204. The standard defines, among others, the type 2.1 declaration of compliance with the order, the type 2.2 test report based on inspection that confirms conformity with the order, and the 3.1 and 3.2 inspection certificates carrying actual test results for the specific batch. A 3.2 certificate also requires confirmation by an independent party.
State as well whether the project falls under the end customer’s system requirements. In automotive that normally means IATF 16949 with full product approval documentation; in other sectors, ISO 9001. The product approval process has its own schedule and its own cost, so leaving it out of the enquiry changes the entire calculation.
Describe the coating by requirement, not by name
“Zinc plated” is not a technical requirement. It covers solutions whose durability differs by an order of magnitude, and it says nothing about acceptable appearance or process risk.
A useful specification contains three things: the corrosivity category of the operating environment as defined in EN ISO 12944-2, the required number of hours before corrosion appears in a neutral salt spray test to EN ISO 9227, and whether the part is visible after assembly.
High-strength springs bring one more question: hydrogen embrittlement. Electroplated coatings need de-embrittlement baking carried out promptly after plating. For heavily loaded parts, the alternative is a coating applied without an electrolytic process. This decision is better made at the quotation stage than after the first batch.
Packaging and logistics – the details that are not details
Packaging is often skipped, yet for parts fed automatically it decides whether the assembly line runs without stoppages. Springs packed loose can tangle. Bent parts with sharp edges damage each other in transit.
Add to the enquiry: unit pack size, the required presentation at the line, pack labelling, delivery location and delivery terms. For cross-border supply, include the Incoterms rule too. It changes the price, not only the paperwork.
Why offers for the same part can differ so much
When several quotes for one enquiry differ by tens of percent, the cause almost never lies in the margin. It lies in the fact that each supplier read the enquiry differently.
The most common sources of divergence are three: the accuracy grade assumed, the scope of inspection and the way tooling is charged. One supplier includes the tool in the unit price at an assumed volume; another lists it separately. Compare them without that breakdown and the winner is whoever hid the cost in the piece price. The difference only surfaces when the volume changes.
So ask for the breakdown explicitly in the RFQ: unit price at two or three volume levels, tooling cost shown separately, scope of inspection, and the accuracy grade stated in the offer. The comparison then takes far less time instead of stretching over several meetings.
Prototype, pilot batch, reference sample
For a part launched for the first time, the sensible path is a pilot batch with the load characteristic measured before production starts. Adjusting the number of coils or the bending compensation at that stage is relatively cheap. The same correction after a production batch costs many times more, because it often means reworking or replacing dedicated tooling.
For parts with three-dimensional geometry, agree on a physical reference sample as well: an approved piece from the first batch that settles doubts faster than any dimensional note.
Changing supplier or adding a second source
A separate case is a part already in production, where the buyer is looking for a second source or a replacement. Beyond the documentation, send samples of the part currently in use together with information about any problems that have occurred – complaints, fractures, loss of force.
That last piece of information is often the most valuable. A part copied one-to-one in dimensions will also copy the cause of the problem if that cause was in the design rather than in the manufacture.
Checklist before you send the RFQ
- Drawing or 3D model, or a full description of the working condition: force, stroke, installation space, number of cycles
- Operating temperature and environment, including contact with chemicals or washing
- Material grade with its standard, or the requirements on which it should be selected
- Accuracy grade and the governing parameter: force or dimension
- Corrosion requirement expressed in test hours, not as a coating name
- Annual volume, batch size, project lifetime and date of first delivery
- Required inspection document to EN 10204 and any system requirements of the end customer
- Packaging method, delivery location and delivery terms
What you get back
With a complete enquiry, the reply contains unit prices for the volumes given, tooling cost shown separately, lead times for the pilot and production batches and – where we see the opportunity – a proposed change that lowers cost without changing the function of the part.
We quote technical spring manufacturing as well as bent wire parts and steel strip components, in runs from prototype to high volume. Our customers include the automotive industry, where stable supply and repeatability over long project cycles matter most.
Have the documentation ready and want a quote within days? Send us your enquiry with a drawing or 3D model and your planned annual volume – we will reply with a unit price and a date for the pilot batch.
