Precision springs and metal components for respiratory drug delivery devices
How RPK Medical supports inhaler manufacturers, from prototype to full-scale production
10/05/2026
Inhaler manufacturers face a hard constraint: the metal parts inside a device must meet micron-level tolerances, pass biocompatibility requirements, and provide full batch traceability — every time, at scale. RPK Medical manufactures precision springs, stamped parts, and bent metal components specifically for MDI, DPI, and SMI respiratory devices. We work with you from the first design review through serial production.
MDI, DPI, and SMI: What Makes Each Device Different
Each inhaler platform puts different demands on its metal components.
A pressurized canister releases a fixed drug dose through a metering valve. The valve spring controls that release. New low-GWP propellants — HFO blends replacing HFA 134a — change internal pressure profiles, which means spring force specs need to be re-engineered, not simply carried over.
No propellant. The patient's breath drives drug delivery. Springs and stamped contact parts manage airflow resistance, dose consistency, and actuator feedback. Tolerances are tight because there's no propellant pressure to compensate for variation.
A calibrated spring drives a mechanical pump that atomizes the liquid formulation. Spring force directly determines droplet size — and droplet size determines where the drug deposits in the lung. Get the spring wrong and the therapy fails.
New Challenges Facing Inhaler Component Buyers
The regulatory and commercial environment is changing fast.
Critical Metal Components for Respiratory Devices
RPK Medical produces the metal parts that sit at the functional core of inhalers.
| Component | Application | Specifications |
|---|---|---|
| Valve springs | MDI metering valve dose release control | Compression & torsion. Tolerances ±0.02 mm wire diameter, ±0.5% spring rate. Materials: SS 302/304, Elgiloy, MP35N |
| Stamped parts & contact parts | Actuators, dose counters, locking mechanisms | Progressive die production with in-line vision inspection. Full dimensional traceability per batch |
| Bent metal components | Clips, retention brackets, guide features | Formed to customer drawings. Suitable for cleanroom-compatible alloys and surface finishes |
| All parts are deburred, cleaned, and inspection-documented before shipment — ready for direct integration into device assembly. | ||
Why RPK Medical
Cleanroom production
Metal forming and finishing take place in controlled environments designed for medical component manufacturing. Particulate control runs from stamping through final packaging.
Full traceability
Every batch ships with material certifications, dimensional inspection reports, and process records. Documentation aligns with ISO 13485 and FDA 21 CFR Part 820.
Design for manufacturability
RPK engineers engage early. We review drawings before tooling is cut, flag tolerance stack-up risks, and propose geometry changes that reduce cost without affecting function.
Volume flexibility
We run prototype quantities and 50M+ parts per year on the same quality system. Scaling up does not mean starting over.
Cross-sector process depth
RPK serves automotive, e-mobility, and industrial markets alongside medical. Process disciplines from high-volume automotive stamping transfer directly into medical production.
From design to production: how we work with you
1 | Feasibility review
Share your drawing or concept. We assess manufacturability, flag risks, and return written feedback. No commitment required.
2 | Prototype and validation
We produce the first articles, support PPAP documentation, and provide dimensional and functional data for your validation package.
3 | Serial production
Parts transfer to high-speed stamping lines with full SPC monitoring active. You get the same contact, the same quality records, and the same dimensional targets at volume.
One team handles all three phases. There is no handoff between an engineering group and a production group; the people who designed the process run it.
Frequently Asked Questions
What spring materials are compatible with new low-GWP propellants?
Stainless 302 and 304 perform well in most HFO environments. For aggressive formulations or elevated humidity, Elgiloy and MP35N offer better corrosion resistance and fatigue life. RPK will recommend the right alloy based on your specific propellant and pressure profile.
Do you produce parts under ISO 13485?
Yes. RPK Medical operates under a quality management system aligned with ISO 13485 and FDA 21 CFR Part 820. Full documentation is available on request.
Can you handle both prototype and mass production?
Yes, from single prototypes through tens of millions of parts per year, with the same traceability at every stage.
Let’s talk and turn concerns into certainties. Tell us!
Get in touch with our engineering and sales teams, we’ll listen to you carefully and find the best solution together.
Contact us now