CNC Spring Former: Cam vs Camless, Key Ring Machine Specs

If you have ever stood in front of a production line wondering whether to spec a cam spring machine or a camless spring former, you are not alone. It is one of the most common questions we hear from buyers in Vietnam, Brazil, Indonesia, and Korea — and the answer is rarely "always cam" or "always camless." It depends on your wire diameter, part geometry, and tolerance budget. In this guide, I will walk you through the real numbers, share production-floor data from our customers, and give you a side-by-side spec table so you can match a machine to your actual application.

For the record, Dongzheng Spring Machine has been building CNC spring formers in Dongguan since 2004, with 150+ units running outside China across 15+ countries and a flagship HSM-CNC20 platform that alone has 100+ units in active production worldwide.

Why the Cam vs Camless Question Matters

The short version: cam machines are mechanical, camless machines are servo-driven with slide-by-slide programming. Cam machines tend to dominate in the 1.8–6.0 mm wire range where repeatability and tonnage matter. Camless spring machines tend to dominate in the 0.1–2.5 mm wire range where complex 3D geometry, fine pitch, and quick changeovers are the priority.

If you are running curtain rod springs — typically a heavier wire diameter, simple pitch, high volume — a cam spring machine is almost always the right answer. If you are running key ring making, torsion springs, or intricate wire forms, a camless spring machine gives you the axis count you need without retooling.

Real Customer Data, Not Brochure Talk

Numbers are where engineering decisions get made, so here is what we have actually seen on customer floors.

A curtain rod spring manufacturer in Vietnam purchased an HSM-CNC20 from us in 2010. After 8 months of operation, their daily output rose by 35%, and the pitch-to-pitch accuracy has held at ±0.01 mm without recalibration. The machine is still in production today.

A Brazilian customer bought two HSM-CNC20 units in 2022. The WeChat service group we set up for them has never been activated for a service request. Zero downtime incidents, zero warranty calls. They just keep producing.

In Shenzhen, a buyer took delivery of two HSM-CNC20 units and one HSM-CNC08 in 2026. The lead setup technician, who has used spring machines from multiple other brands in previous jobs, specifically asked for Dongzheng machines. His words to us: stable, durable, easy to set up. That kind of endorsement from a senior setup man carries more weight than any brochure claim.

In March 2026, another Vietnamese customer bought one HSM-CNC20 after seeing our machine run at a competitor's plant. He already owned machines from other brands and recognized the difference in stability immediately. The purchase decision took one site visit.

HSM Series Spec Comparison

Here is the full line at a glance. Wire diameter, axis count, and application fit are the three columns that matter most for a buyer.

Model	Wire Diameter	Type	Typical Application
HSM-CNC08	0.08 – 1.0 mm	Spring coiling	Micro springs, electronics, key ring making
HSM-CNC1008	0.1 – 1.0 mm	Camless spring machine	Fine wire forms, 3D geometry
HSM-CNC20	0.2 – 2.0 mm (up to 4.0 mm with select tooling)	Cam spring machine	Curtain rod springs, general compression springs
HSM-CNC1025	0.2 – 2.5 mm	Camless spring machine	Torsion springs, complex forms
HSM-CNC30	0.8 – 3.0 mm	Spring coiling machine	Medium wire compression springs
HSM-CNC40	1.8 – 4.5 mm	Cam spring machine	Heavy wire industrial springs
HSM-CNC1045	1.8 – 4.5 mm	Camless with wire rotary	Heavy wire 3D forms
HSM-CNC60	2.0 – 6.0 mm	Cam spring machine (with or without wire rotary)	Automotive springs, heavy industrial

When to Choose a CNC Spring Former for Curtain Rod Springs

For curtain rod springs specifically, the workload is almost always pitch-controlled compression springs in the 1.8–4.0 mm wire range, produced in long runs with minimal changeover. A cam spring machine wins here because:

• Mechanical cam control gives consistent pitch over millions of cycles.

• Servo-driven camless machines can match the tolerance, but the ROI math favors cam at this wire size and volume.

• The HSM-CNC20 is the platform most curtain rod producers in our customer base have standardized on — wire diameter 0.2–2.0 mm standard, 4.0 mm achievable with proper tooling setup.

The Brazil and Vietnam cases above are both curtain rod spring producers running HSM-CNC20. The 35% output gain in Vietnam is not a marketing figure; it is a before-and-after production log.

When to Choose a Key Ring Making Machine

Key ring making is a different problem. You are looking at fine wire, often 0.8–1.5 mm, with tight coiling tolerances and high output per shift. The HSM-CNC08 (0.08–1.0 mm) is a good fit for the smaller end of key ring production, while the HSM-CNC20 covers the 1.0–2.0 mm range that most commercial key ring producers run. If your key ring includes a twist or 3D shape — and many do — step up to a camless platform like the HSM-CNC1025 for the additional axis freedom.

Practical Buying Guidance

Three questions to settle before you contact any supplier:

1. What is your actual wire diameter range? Not your most common — your full range including edge cases.

2. How many axes do you need? Standard cam machines give you 2–3 axes. Camless platforms give you 4–5. If you are forming 3D parts, the axis count is non-negotiable.

3. What is your tolerance target? ±0.01 mm is achievable on the HSM-CNC20 and held in the field. If you need tighter, the conversation shifts to material handling and feed roll quality, not just the machine.

If you can answer those three questions with real numbers, the model selection becomes straightforward.

FAQ

What is the difference between a cam and camless spring machine?

A cam machine uses mechanical cams to control timing, which gives high repeatability at high speed for standard spring geometries. A camless spring machine uses independent servo axes controlled in software, which allows more complex 3D shapes and faster changeovers between part numbers.

What wire diameter range does the HSM-CNC20 cover?

Standard range is 0.2–2.0 mm. With proper tooling configuration, the machine can run up to 4.0 mm wire for specific applications such as curtain rod springs.

Which machine is best for key ring making?

For most commercial key rings in the 0.8–2.0 mm wire range, the HSM-CNC20 is the standard choice. For smaller key rings or more complex shapes, the HSM-CNC08 or HSM-CNC1025 camless platform may be a better fit.

Closing Thought

The cam vs camless decision is really a question about your part, your wire, and your production volume — not about which technology is "better." I am curious to hear from engineers running spring lines: what was the one spec that pushed you toward a camless platform, or kept you on cam? Drop your reasoning in the comments.

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