FAQs for Buyers - Custom Spring Manufacturing Questions Answered

FAQs for Buyers

Real questions buyers ask before requesting a quote — answered from a manufacturing perspective.

Stock vs Custom 3 Quotation Readiness 4 MOQ & Samples 4 Design Changes 5 Tolerance 4 Tooling 3 Finishes 3 Shipping 3 Payment 3 Confidentiality 2

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Stock vs Custom

- No, we do not stock standard catalog parts. Every spring and wire form we produce is custom-made to your specifications.
- This means we manufacture based on your drawings or technical requirements, not from a pre-existing inventory.
- If you need modifications to a standard design or have unique dimensional requirements, we're equipped to handle that.
- Yes. All our production is custom, meaning we set up tooling and manufacturing processes specifically for your design.
- This approach allows maximum flexibility in materials, dimensions, tolerances, and finishing options.
- Lead time reflects setup and production time, not warehouse availability.
- Yes, we can measure and document an existing spring or wire form and create a technical drawing for production.
- This is common when the original supplier is no longer available or when drawings have been lost.
- We'll confirm critical dimensions, material type, and surface finish based on the sample you provide.
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Quotation Readiness

- A technical drawing with dimensions, tolerances, material specification, and surface finish requirements.
- Expected annual or per-order quantity, which affects tooling cost allocation and unit pricing.
- Application context (load requirements, environment, safety-critical status) helps us recommend suitable materials.
- Delivery destination and timeline expectations, so we can factor in logistics and production scheduling.
- Yes, but the quote will be preliminary and may need revision once missing details are clarified.
- We'll identify gaps in the drawing and request clarification before finalizing pricing and lead time.
- If the drawing is conceptual, we can work with you to develop a manufacturable specification.
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- Yes. Our engineering team reviews every drawing for manufacturability, material selection, and tolerance feasibility.
- If we identify potential issues (overly tight tolerances, unsuitable material for the application), we'll flag them in the quote.
- This review helps avoid costly surprises during production or after delivery.
- We document all assumptions explicitly in the quotation (e.g., "assuming material grade X," "assuming standard tolerance").
- You have the opportunity to review and correct these assumptions before order placement.
- Once confirmed, these assumptions become part of the production specification to avoid misalignment later.

MOQ, Samples & Prototyping

- MOQ varies by part complexity, material, and tooling requirements, typically ranging from 500 to 5,000 pieces per order.
- For high-complexity parts or specialized materials, MOQ may be higher to justify tooling and setup costs.
- We'll clearly state MOQ in the quotation so you can plan accordingly.
- Yes, we can produce samples for testing and validation before committing to full production quantities.
- Sample pricing reflects tooling setup and low-volume production but is credited toward future production orders.
- This approach allows you to validate fit, function, and quality before scaling up.
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Start with a prototype or trial order.
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- Yes, trial orders are possible and are common for new product development or when switching suppliers.
- Unit pricing will be higher for trial orders, but you avoid large upfront commitments while testing the process.
- Once you're satisfied, we can transition to volume pricing for subsequent orders.
- Yes, we offer expedited prototyping services with typical turnaround of 7-10 business days from order confirmation.
- Rapid prototyping is especially useful when you need to iterate on a design quickly or test multiple configurations.
- Prototypes are produced with the same equipment and processes as full production to ensure representativeness.

Design Changes & Cost Impact

- Wire diameter, mean coil diameter, number of active coils, and free length determine load characteristics and spring rate.
- Material type and grade affect strength, fatigue life, corrosion resistance, and temperature stability.
- End configurations (closed, open, ground) impact installation, load distribution, and overall spring behavior.
- Operating environment (temperature, corrosion exposure, vibration) drives surface finish and material selection.
- Increasing wire diameter dramatically increases spring stiffness (spring rate) and load capacity.
- Cost impact depends on wire availability—standard sizes are more economical than custom drawn wire.
- Changing wire size may also require tooling adjustments, impacting lead time for first production run.
- Spring stress changes approximately 2% for every 1% change in wire diameter (inverse relationship).
- Small changes accumulate quickly, so even minor adjustments can significantly impact fatigue life and reliability.
- We recommend validating stress calculations if you're making design adjustments to critical springs.
- Spring rate changes approximately 3% for every 1% change in mean coil diameter (inverse cubic relationship).
- Mean diameter adjustments are highly sensitive—small changes have large performance consequences.
- If you need to change mean diameter, we recommend recalculating the entire spring design to maintain performance.
- Spring rate is inversely proportional to the number of active coils—more coils = softer spring, fewer coils = stiffer spring.
- Changing coil count also affects free length, solid height, and the spring's ability to fit in the available space.
- This is one of the easiest adjustments to make if you need to fine-tune spring rate without changing wire or diameter.

Tolerance & Drawing Notes

- Standard tolerances follow DIN 2095 or similar industry standards and are included in base pricing.
- Tighter tolerances than standard are achievable but require additional inspection, fixturing, and potentially rework.
- We'll flag unrealistic tolerances during quotation review to avoid setting unachievable expectations.
- Yes. Tighter tolerances require additional quality control steps, secondary operations, and may reduce yield.
- Lead time may increase by 1-2 weeks if parts require sorting, grinding, or other secondary finishing operations.
- We'll estimate cost and lead time impacts during quotation so you can make informed tolerance decisions.
- We interpret this as requiring tumbling, grinding, or manual deburring to eliminate sharp edges that could cause handling injuries or assembly issues.
- If there's a specific burr height or edge radius requirement, please specify it on the drawing to avoid ambiguity.
- Deburring adds a secondary operation and will be reflected in cost and lead time if not already included.
- Yes, heat treatment can cause minor dimensional changes (typically ±0.5-1% in length and diameter).
- We account for these changes during tooling and production setup so final dimensions meet your specifications.
- Heat treatment is standard for most springs to relieve forming stresses and improve fatigue performance.

Tooling & Manufacturing Control

- Yes, all tooling is designed and manufactured in-house, giving us full control over quality and lead time.
- This also means we can quickly adjust tooling if design modifications are needed during development.
- Tooling ownership remains with us, ensuring consistency and availability for future repeat orders.
- Yes. Tooling and process parameters are documented and archived for every part number.
- Repeat orders use the same setup, which reduces lead time and ensures dimensional consistency batch-to-batch.
- If tooling wears or requires maintenance, we replace it to maintain original specifications.
- We use statistical process control (SPC) to monitor dimensional variation during production runs.
- First-article inspection and in-process checks ensure parts remain within specification throughout the run.
- Final inspection includes dimensional verification, load testing, and visual examination before packaging.

Finishes & Surface Treatment

- Common finishes include zinc plating, powder coating, electropolishing, passivation, and black oxide.
- For high-corrosion environments, we recommend stainless steel material with passivation rather than plated carbon steel.
- Finish selection depends on your corrosion resistance needs, appearance requirements, and operating environment.
- Surface treatments add 3-7 days to lead time depending on the process and whether it's done in-house or outsourced.
- Cost impact varies—basic zinc plating is relatively inexpensive, while specialized coatings like PTFE can double unit cost.
- We'll provide finish options with cost and lead time implications in the quotation so you can make informed choices.
- Yes. If you describe the operating environment (humidity, temperature, chemical exposure), we can recommend suitable finishes.
- For outdoor marine environments, we'd recommend stainless steel with passivation rather than zinc-plated carbon steel.
- Our recommendations balance performance, cost, and manufacturability for your specific application.

Packaging & Shipping

- We use compartmentalized packaging, layered trays, or individual bagging to prevent tangling and physical damage.
- For long extension springs or torsion springs with extended legs, we pack them vertically to prevent bending.
- Packaging approach is selected based on spring geometry, finish, and whether you'll use automated handling.
- Yes, we can package in reels, tube feeders, or custom trays designed for vibratory bowls or pick-and-place systems.
- Custom packaging typically requires tooling or setup costs but can significantly reduce your assembly labor.
- Share your automation setup details during quotation so we can propose the most suitable packaging format.
- We offer door-to-door logistics including export documentation, freight forwarding, customs brokerage, and final delivery.
- You receive a single tracking number and one point of contact, eliminating the need to coordinate multiple logistics providers.
- Alternatively, you can arrange your own freight forwarder—we'll prepare all necessary export documentation.

Payment & Trade Terms

- Standard terms are 30% deposit, 70% balance before shipment for new customers.
- For established relationships, we can discuss net 30 or net 60 payment terms.
- We accept wire transfer (T/T), letter of credit (L/C), and for smaller orders, credit card or PayPal.
- We support FOB, CIF, DDP, and other standard Incoterms depending on your preference and destination.
- DDP (Delivered Duty Paid) is our most popular option for buyers who want hassle-free door-to-door delivery.
- We'll explain cost and responsibility differences between Incoterms during the quotation process.
- If a defect is confirmed to be our manufacturing error, we'll replace the parts at no cost or issue a credit.
- We ask that you document the issue with photos and dimensional measurements so we can investigate root cause.
- Our goal is to resolve quality issues quickly and transparently to maintain your production schedule.

Confidentiality & IP Protection

- All technical drawings and specifications are treated as confidential by default and are not shared outside our organization.
- We maintain strict internal access controls—only personnel directly involved in your project can view your designs.
- We never manufacture your parts for other customers without explicit written authorization.
- Yes, we routinely sign mutual or one-way NDAs before receiving proprietary technical information.
- You can send your NDA template, or we can provide our standard confidentiality agreement for your review.
- NDA execution typically adds 1-2 business days to the quotation process but provides formal legal protection.
All files are confidential by default. NDA available.
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