Bending Metal Machine & Spring Bending Machine: Full Guide

What Is a Bending Metal Machine and Why It Matters in Modern Fabrication

A bending metal machine is industrial equipment designed to deform metal workpieces — sheets, bars, tubes, or wire — into precise angles, curves, or complex three-dimensional shapes without cutting or welding. The core conclusion is straightforward: if your production line requires consistent, repeatable metal shapes at scale, a dedicated bending machine is not optional equipment — it is the backbone of your workflow. Manual bending introduces human error, inconsistent bend radii, and operator fatigue; mechanized bending eliminates all three.

Modern metal bending machines range from simple hydraulic press brakes capable of bending 3 mm mild steel plate to sophisticated CNC multi-axis systems that can execute 40 distinct bend sequences in a single automated cycle. A mid-range CNC press brake, for instance, can achieve angular repeatability of ±0.1°, which is essentially unattainable through manual operation. For automotive brackets, HVAC ductwork, furniture frames, electrical enclosures, and hundreds of other product categories, this level of precision is not a luxury — it is a manufacturing requirement.

The spring bending machine is a specialized subset of the broader bending machine family. While a general press brake focuses on sheet metal, a spring bending machine is engineered specifically to wind, coil, and form wire or rod stock into compression springs, extension springs, torsion springs, and custom wire forms. These two machine types often coexist in the same facility — and understanding how they complement each other is essential for any fabrication manager sourcing equipment.

Core Types of Bending Metal Machines and Their Applications

The term "bending metal machine" is an umbrella covering several distinct machine architectures. Choosing the wrong type for your application leads to poor part quality, excessive tooling wear, and unnecessary capital expenditure. Below is a structured breakdown of the main categories.

Press Brakes

The press brake is the most widely deployed sheet metal bending machine globally. It uses a punch and die set to apply localized force along a straight line, creating a single bend per stroke. Hydraulic press brakes dominate heavy-duty applications — bending steel plate up to 25 mm thick across bending lengths of 6 meters or more. Electric servo press brakes, increasingly popular since 2018, offer energy savings of 30–50% compared to hydraulic counterparts and provide faster cycle times for thin-gauge work (0.5–3 mm). CNC press brakes add programmable back-gauge positioning, automatic crowning compensation, and multi-step bend sequencing, reducing setup time from hours to minutes when switching between part programs.

Roll Bending Machines

Roll bending machines — also called plate rollers or section benders — use two or three driven rolls to continuously curve metal into arcs, rings, or cylinders. They are indispensable for pressure vessel manufacturing, pipe production, architectural steelwork, and tank fabrication. A three-roll symmetrical machine is the standard for producing large-diameter cylinders from flat plate. A four-roll machine adds a fourth roll that pre-bends the leading edge, eliminating the flat spot that is the classic limitation of three-roll designs. Bending radii from tight 150 mm curves to gentle arcs spanning several meters are achievable depending on machine tonnage and roll diameter.

Tube and Pipe Bending Machines

Tube bending machines bend hollow sections — round, square, or rectangular tubing — without collapsing the cross-section. Rotary draw bending, the most precise method, clamps the tube against a form die and rotates it around a fixed bend die, often with an internal mandrel preventing wall collapse. This method is standard in automotive exhaust systems, roll cages, bicycle frames, and aerospace hydraulic lines. CNC tube benders with multi-stack tooling heads can produce parts requiring multiple bends in different planes — a single automotive exhaust component may have 8 to 12 distinct bends programmed in sequence.

Wire and Spring Bending Machines

Wire bending machines and spring bending machines handle smaller-diameter stock — typically wire from 0.1 mm to 20 mm in diameter — and form it into complex two-dimensional or three-dimensional wire forms, clips, brackets, hooks, and springs. This category deserves dedicated discussion and is covered in depth in subsequent sections.

Spring Bending Machine: How It Works and What Sets It Apart

A spring bending machine — also referred to as a spring coiling machine, CNC spring former, or wire forming machine depending on configuration — is a highly specialized bending metal machine designed to process wire stock into springs and wire forms at high throughput. Understanding its operating principle helps clarify why it cannot simply be replaced by a general-purpose bending machine.

The Wire Feed and Forming Mechanism

Wire is drawn from a spool or straightened from a coil and fed through precision guide rollers into the forming zone. The feed mechanism — typically a servo-driven pinch roll system — controls the length of wire dispensed to an accuracy of ±0.05 mm. In the forming zone, a coiling point or forming tool deflects the wire to create the coil diameter. The pitch tool simultaneously controls the axial advance of the coil, determining the spring's free length and pitch. A cutting mechanism — either a rotary cutter or a cam-driven cam knife — severs the finished spring from the wire at the programmed point.

On CNC spring bending machines, every axis — feed length, coiling point position, pitch tool angle, and cut timing — is independently servo-controlled and synchronized through a central motion controller. High-end machines from manufacturers such as Wafios, Itaya, or Bamatec can produce compression springs at rates exceeding 200 pieces per minute for small-diameter wire (under 1 mm), with dimensional repeatability that manual spring winding cannot approach.

Types of Springs Produced

• Compression springs: Helical coils that resist compressive force. The most common spring type, used in everything from ballpoint pens to automotive valve trains.
• Extension springs: Closely wound coils with hooks at each end, designed to resist stretching. Hook geometry is programmed into the CNC cycle.
• Torsion springs: Wire wound into a coil with straight legs that store energy when twisted. Door hinges, clothespins, and garage door mechanisms rely on torsion springs.
• Wire forms: Custom bent wire shapes — clips, brackets, handles, rings, and hooks — produced on multi-axis CNC wire bending machines that can bend wire in 3D space.
• Conical and barrel springs: Variable-diameter springs requiring coordinated adjustment of the coiling point during the forming cycle — a capability unique to CNC spring bending machines.

The Role of Springback in Spring Bending

Springback — the elastic recovery of metal after bending — is the central challenge in all metal bending operations, but it is especially critical in spring manufacturing. Because the spring's functional performance depends on precise geometric dimensions (free length, coil diameter, pitch), any springback that causes dimensional deviation directly translates to a spring that fails load specification. CNC spring bending machines compensate for springback algorithmically: the control software overbends the wire by a calculated amount so that after elastic recovery, the finished spring lands on the target dimension. This overbend value varies with wire material, diameter, temper condition, and bend radius, and modern machines store these values in material libraries for rapid job changeover.

Key Technical Specifications to Evaluate When Buying a Bending Metal Machine

Purchasing a bending metal machine — whether a press brake, spring bending machine, or tube bender — requires evaluating a set of technical parameters that determine whether the machine can actually produce your parts. Relying on a salesperson's description without verifying these figures against your part requirements is how companies end up with machines that cannot do the job.

For Press Brakes and Sheet Metal Bending Machines

• Tonnage: The maximum bending force the machine can apply, expressed in tons or kilonewtons. Undersized tonnage causes incomplete bends; oversized tonnage wastes capital and energy. Calculate required tonnage using the formula: T = (575 × t² × L) / V, where t is material thickness in mm, L is bend length in mm, and V is die opening width.
• Bending length: The maximum length of a single straight bend, typically 1.25 m to 6 m. Ensure this exceeds your longest part dimension.
• Back-gauge travel and precision: The back-gauge positions the material before each bend. A CNC back-gauge with ±0.01 mm positioning accuracy is the standard for precision work.
• Open height and stroke: Determines how deep a box or channel can be bent without the part striking the machine frame.
• Crowning system: Larger machines deflect under load, causing the center of the bend to be shallower than the edges. An active crowning system compensates for this deflection automatically.

For Spring Bending Machines

• Wire diameter range: Each machine is rated for a specific wire diameter range — for example, 0.3–3.5 mm or 1–8 mm. Operating outside this range degrades quality and risks machine damage.
• Number of CNC axes: Entry-level spring coiling machines may have 4 axes; advanced multi-slide wire forming machines can have 8 to 16 independent servo axes, enabling complex 3D wire forms in a single cycle.
• Production speed: Measured in pieces per minute. Speed varies enormously by wire diameter and spring geometry — a machine producing 200 ppm on 0.5 mm wire may only produce 30 ppm on 3 mm wire.
• Coil diameter range: The minimum and maximum outside diameter of springs the machine can produce, determined by the range of coiling point adjustment.
• Control system and programming interface: Modern spring bending machines use proprietary CNC controllers with graphical programming interfaces. Some manufacturers offer simulation software that previews the spring geometry before running wire, significantly reducing setup scrap.
• Feed straightener: A multi-roll wire straightener upstream of the forming zone removes the residual curvature from coiled wire stock. Inadequate straightening is a leading cause of inconsistent spring geometry.

Materials Processed by Bending Metal Machines

The material being bent determines tooling selection, tonnage requirements, springback compensation, and achievable bend radius. Not all metals bend equally, and a bending metal machine optimized for mild steel may produce entirely different results — or fail outright — when attempting to bend hardened spring steel or titanium.

Mild Steel and Low-Carbon Steel

The default reference material for bending metal machines. Mild steel (yield strength approximately 250 MPa) is forgiving, bends cleanly, and has moderate springback. It is the material used in machine tonnage ratings and die opening recommendations. Grade S235 or A36 mild steel bends reliably to a minimum inside bend radius of 0.5× material thickness without cracking.

High-Strength and Advanced High-Strength Steel

HSLA steel (yield strength 350–700 MPa) and AHSS grades used in automotive body structures require significantly more tonnage to bend — often 2 to 3 times the tonnage required for equivalent mild steel thickness. Springback is also proportionally higher: a 90° bend in HSLA steel may require programming the punch to 84–87° to achieve 90° after springback recovery. Die opening must also be wider to prevent cracking at the bend line.

Stainless Steel

Austenitic stainless steels (304, 316) work-harden during bending, which increases resistance as bending progresses. They require approximately 50% more tonnage than mild steel of the same thickness and exhibit pronounced springback. Tool surfaces must be kept clean to prevent stainless steel from picking up contamination, which causes corrosion in service.

Aluminum Alloys

Aluminum requires less tonnage than steel but is more prone to surface marking and cracking if bent across the grain direction of the sheet. Temper condition is critical: 5052-H32 bends readily to a 1× thickness radius, while 6061-T6 in the same thickness may crack unless the bend radius is increased to 3–4× thickness. Spring bending machines processing aluminum wire for the electrical or packaging industries must use polished guides and forming tools to prevent surface damage.

Spring Steel and Hard-Drawn Wire

Spring steel — typically high-carbon steel (0.6–1.0% carbon) or alloy spring steel such as 51CrV4 — is the primary material for spring bending machines. These materials have yield strengths of 1,000–2,000 MPa and extremely high springback. A spring bending machine must be capable of applying forming forces that exceed the wire's yield strength while precisely controlling the plastic deformation that determines the spring's final geometry. Music wire (ASTM A228) is the most common spring wire grade — over 70% of precision compression springs are wound from music wire or hard-drawn wire because of their consistent tensile strength and surface quality.

CNC vs. Hydraulic vs. Manual: Choosing the Right Control System

Every bending metal machine falls into one of three control tiers: manual, hydraulic/mechanical with basic controls, or full CNC. Each tier has a distinct cost-to-capability profile, and the right choice depends on production volume, part complexity, and available operator skill.

Manual Bending Machines

Manual folder brakes, hand-operated box and pan brakes, and manually adjusted spring coiling machines are appropriate for prototype work, very low volume production (fewer than 50 parts per run), or situations where part variety is extremely high and setups change constantly. Their capital cost is low — a manual folder brake capable of bending 1.2 mm steel across 1 m can be purchased for $500–$3,000. The tradeoff is operator-dependent quality, slow throughput, and significant physical effort for heavier gauges. In a spring manufacturing context, manual spring winding lathes are still used for prototyping and custom single-piece orders where CNC programming time would exceed the value of the parts.

Hydraulic Machines with Basic Controls

Hydraulic press brakes with a simple depth stop and manually set back-gauge represent the workhorse of small and medium fabrication shops worldwide. These machines are rugged, relatively straightforward to maintain, and capable of heavy-duty work. A 100-ton, 2.5 m hydraulic press brake with a basic 2-axis back-gauge typically costs $15,000–$40,000 depending on brand and origin. They are well-suited for medium-volume runs of simple parts — straight flanges, channels, and angles in mild steel or aluminum where one or two bends per part are required.

CNC Bending Machines

Full CNC control transforms a bending machine into a programmable manufacturing cell. A CNC press brake stores hundreds of part programs, each defining bend sequence, back-gauge positions, punch travel depth, crowning correction, and material parameters. Operators select a program, load the part, and the machine executes the entire bend sequence automatically. Setup time for a repeat job drops from 45–90 minutes (on a manually set machine) to under 5 minutes. For a factory running 20–30 different part numbers per day, this reduction in non-productive time is worth more annually than the price premium of the CNC system.

CNC spring bending machines deliver analogous benefits: once a spring program is written and qualified, every subsequent production run starts from a known good baseline. Parameter changes — coil diameter, free length, pitch — require only software edits rather than mechanical adjustments. Leading CNC spring machine controllers from Wafios (Germany) and Itaya (Japan) include real-time dimensional feedback: an integrated measuring system checks every spring against the programmed specification, rejecting out-of-tolerance parts automatically. First-article qualification time drops by 60–80% compared to manually set coiling machines.

Tooling for Bending Metal Machines: Selection, Maintenance, and Cost

The bending machine is only as capable as its tooling. For press brakes, the punch and die set determines the minimum bend radius, achievable bend angle, and maximum material thickness. For spring bending machines, the coiling tools, pitch tools, and cutting tools define the spring geometries that can be produced. Tooling is a recurring cost that must be factored into the total cost of ownership calculation.

Press Brake Tooling

Standard European-style (Trumpf/Wila compatible) press brake tooling has become the de facto global standard, with tooling from one manufacturer fitting machines from dozens of others. Punch profiles range from acute angle punches (30°) for tight flanges to gooseneck punches for deep box bending to hemming punches for zero-radius folds. V-die openings are selected based on material thickness: the industry rule of thumb is V-opening = 6–10× material thickness for air bending. Hardened tool steel punches and dies in standard configurations last 500,000 to 1,000,000 strokes before requiring reconditioning. Specialty tooling — roller followers for radius bending, offset punches for narrow flanges — adds versatility but increases tooling inventory cost.

Spring Bending Machine Tooling

Tooling for a spring bending machine is more application-specific than press brake tooling. Coiling points are typically tungsten carbide tipped to withstand the continuous abrasion of high-tensile wire at high speed. A coiling point may last 50–200 million cycles before replacement, but this varies significantly with wire surface condition and lubrication. Pitch tools, guide tubes, and cut-off tools are similarly subject to wear and must be checked at regular intervals. Maintaining a stock of tooling consumables — particularly for high-volume production springs — prevents costly unplanned downtime. The cost of a complete tooling set for a new spring profile on a CNC spring bending machine ranges from $200 to $2,000 depending on complexity, which is modest compared to the cost of press brake tooling for unusual part geometries.

Tooling Maintenance Practices

• Inspect press brake punch tips for chipping or deformation every 50,000 strokes; a chipped punch creates a stress riser in the bent part that can cause premature fatigue failure in service.
• Keep V-die surfaces clean of metal debris; embedded particles cause surface marking on the workpiece underside.
• Apply appropriate wire lubricant (typically a water-soluble drawing oil) to spring bending machine wire feeds; inadequate lubrication increases coiling tool wear by a factor of 3–5×.
• Store press brake tooling in dedicated racks that prevent contact between cutting edges; tool-to-tool contact causes micro-chipping that shortens service life dramatically.
• Log tooling usage cycles and establish replacement intervals based on measured wear, not visual inspection alone — wear-related dimensional drift in spring dimensions often precedes visible tool damage.

Common Quality Problems in Metal Bending and How to Fix Them

Every bending metal machine operation encounters recurring quality issues. Identifying the root cause — machine, tooling, material, or programming — is the prerequisite for fixing the problem. The following are the most common defects encountered in press brake and spring bending operations, with their causes and corrections.

Angle Inconsistency Across the Bend Length

Symptom: A 90° bend measures 90° at the center but 92° at the ends, or vice versa. Cause on a press brake: machine frame deflection (bowing) under load, causing the center of the bed to deflect more than the ends. Correction: activate the crowning system; if the machine lacks crowning, use a segmented die with thicker sections at the center, or reduce the bend length to stay within the machine's rated straight-bend capacity. On a spring bending machine, pitch variation along the spring length suggests a worn pitch tool or inconsistent wire straightening.

Springback Variation Between Parts

Symptom: Parts bent to the same program come out with slightly different angles — within a single batch or between batches. Cause: material property variation between coils or sheets. Even certified material to the same grade can vary by ±5–10% in yield strength between production heats. Correction: bottom bending (coining) instead of air bending eliminates springback variation at the cost of higher tonnage — the material is fully plastically deformed through its thickness. For spring bending, this manifests as free length scatter and is corrected by tightening wire supplier specifications (tensile strength range), improving wire straightening, and using closed-loop feedback measurement to adjust forming parameters in real time.

Cracking at the Bend Line

Symptom: The outer surface of the bend develops micro-cracks or visible fractures. Causes: bend radius too tight for the material, bending against the material's grain direction (rolling direction), or using hardened material that has insufficient ductility. Correction: increase the inside bend radius (minimum 1× material thickness for most steels in the transverse direction, 2× in the longitudinal direction for harder alloys). For sheet metal, orient parts so the bend line is perpendicular to the rolling direction. For spring wire, cracking indicates wire surface defects or a coiling radius below the minimum for that wire diameter and temper.

Spring Free Length Drift During a Production Run

Symptom: Spring free length starts at nominal and gradually increases or decreases over the course of a production run without program changes. Cause: thermal expansion of the machine's feed rollers or forming tools as the machine warms up from cold start, or progressive wear of the coiling point changing the effective coiling radius. Correction: allow a 15–20 minute warm-up period before production measurement; monitor and log free length on a statistical process control chart throughout the run; establish tool change intervals based on measured length drift rather than arbitrary time intervals.

Industry Applications: Where Bending Metal Machines and Spring Bending Machines Are Indispensable

Understanding which industries depend most heavily on bending metal machines helps contextualize the scale of this equipment category and the stakes involved in machine selection and maintenance.

Automotive Manufacturing

A single passenger vehicle contains an estimated 100 to 200 individual spring components — valve springs, suspension springs, seat springs, brake return springs, clutch springs, and dozens of wire clips and retainers. Every one of these is produced on a spring bending machine. Sheet metal bending machines produce body reinforcements, brackets, heat shields, and structural members. The automotive industry's tolerance requirements — combined with production volumes measured in millions of units annually — make CNC bending machines with in-process measurement and statistical process control essential.

Aerospace and Defense

Aerospace applications demand traceability and certification at every production step. CNC bending machines in aerospace facilities must maintain complete audit trails — recording which program was used, what the machine parameters were, and what the measured dimensions of each part were. Titanium, Inconel, and aluminum-lithium alloys present extreme bending challenges: titanium's springback is approximately twice that of steel at equivalent thickness, requiring sophisticated overbend compensation. Spring bending machines in aerospace produce landing gear springs, ejector seat springs, and control cable return springs to precise load specifications verified by mandatory load testing.

Electronics and Electrical Equipment

The electronics industry uses spring bending machines to produce contact springs for connectors, battery contacts, switch springs, and wire form retainers in materials ranging from phosphor bronze and beryllium copper to stainless steel. These parts are often extremely small — wire diameters of 0.1–0.5 mm are common — and require production rates of several hundred pieces per minute with dimensional tolerances of ±0.02 mm. Sheet metal bending machines produce enclosures, chassis, and heat sink brackets for electronic equipment in aluminum and steel.

Construction and HVAC

Press brakes and folder brakes dominate construction and HVAC metal fabrication, producing ductwork, flashing, fascia panels, structural brackets, lintel angles, and equipment enclosures from galvanized steel, aluminum, and stainless steel sheet. A sheet metal shop serving the HVAC trade may operate 3–8 press brakes of various capacities to handle different gauge materials and part sizes. Productivity in these shops is measured by linear meters of bent profile per shift — a well-run CNC press brake operation can produce 2,000 to 4,000 linear meters of bent product per 8-hour shift, depending on part complexity and material.

Medical Device Manufacturing

Medical springs and wire forms — catheter guide wires, surgical clip springs, implant fixation springs, and diagnostic equipment components — are produced on precision spring bending machines to biomedical-grade specifications. Materials in this sector include 316L stainless steel, nitinol (nickel-titanium shape memory alloy), and titanium. Nitinol wire forming on a spring bending machine is particularly challenging: the material's superelastic behavior means standard springback models do not apply, and tool paths must be developed empirically for each part geometry.

Buying Guide: What to Look for When Sourcing a Spring Bending Machine or Press Brake

Sourcing a bending metal machine — particularly a spring bending machine — requires more due diligence than most capital equipment purchases because the machine's capability is highly application-specific and the performance differences between suppliers are significant. The following checklist applies regardless of whether you are buying new, refurbished, or used.

Define Your Part Requirements Before Contacting Suppliers

• For press brakes: maximum material thickness, maximum bend length, minimum inside bend radius, angular tolerance, and annual production volume by part family.
• For spring bending machines: wire material and diameter range, spring types (compression, extension, torsion, wire form), minimum and maximum coil diameter, free length range, load specification tolerance, and required production rate in pieces per minute.
• Identify your 5 highest-volume part numbers and your 3 most geometrically complex part numbers — the machine must handle both the volume leaders and the difficult parts.

Evaluate Suppliers on Application Expertise, Not Just Machine Specs

A supplier who can run your actual sample parts on their demonstration machine and show you the first-article inspection results is infinitely more valuable than one who provides only specification sheets. Insist on a machine demonstration with your wire or sheet material before committing to a purchase. Ask for references from customers in your industry and contact them. Ask specifically about accuracy over time (not just out-of-box performance), spare parts availability, and technical support responsiveness when the machine goes down during production.

Total Cost of Ownership Over 10 Years

The purchase price of a bending metal machine is typically 40–60% of its total cost of ownership over a 10-year operating life. The balance comprises tooling ($5,000–$50,000 over the life of the machine for a press brake), maintenance and spare parts (budget 2–4% of purchase price annually), energy consumption (an 80-ton hydraulic press brake consumes approximately 7.5 kW; an equivalent electric servo machine consumes 1.5–2 kW on average), and operator training. For a spring bending machine, add wire scrap cost during setup — a poorly programmed spring forming job on a CNC machine can consume 5–15 kg of wire before a good sample is achieved, which at $3–$8/kg for music wire represents $15–$120 in raw material loss per setup.

Used and Refurbished Machines: Opportunity and Risk

A used press brake from a reputable manufacturer — AMADA, Trumpf, Bystronic, LVD — can deliver 80–90% of new machine capability at 30–50% of the purchase price, provided the machine has been properly maintained and the CNC controller and hydraulic system are in good condition. Key inspection points include ram parallelism (check with a precision level across the ram at multiple positions), back-gauge positioning accuracy (verify with a test program running 20 consecutive positioning cycles and measuring variation), and hydraulic oil condition and system pressure stability. For used spring bending machines, inspect coiling tool wear, feed roller condition, and verify the control system can communicate with current programming software — obsolete proprietary controllers can make a machine effectively unusable if the software is no longer supported.

Safety Requirements for Operating Bending Metal Machines

Press brakes and spring bending machines are among the most injury-prone machine tools in metal fabrication. The press brake in particular has a long history of hand and finger injuries caused by the fast-closing punch and die. Modern safety standards have significantly reduced injury rates, but compliance requires understanding the specific safety systems involved.

Press Brake Safety Systems

• Laser safety guarding (e.g., SICK PSENvip, Lazer Safe): A laser curtain mounted just ahead of the punch monitors the mute point — the point at which the punch is close enough to the material that protecting fingers from the closing zone is no longer possible. Above the mute point, if an obstruction is detected, the ram stops. This is the current safety standard for new press brakes sold in the EU and most other regulated markets.
• Two-hand control: Requires both hands to be on control buttons simultaneously to initiate the bending cycle, preventing one hand from being in the die area during ram descent.
• Safe speed monitoring: The ram descends at low speed (typically ≤10 mm/s) in the muting zone — the last few millimeters before contact with the material — even if safety guarding is active, as a secondary protection layer.
• Emergency stop circuits: Foot pedal emergency stop and frame-mounted emergency stop buttons must meet Category 3 or Category 4 safety circuit requirements per ISO 13849, providing redundant stop channels.

Spring Bending Machine Safety

Spring bending machines present a different injury profile: the primary hazard is flying wire ends during coiling, particularly when a wire break or mis-feed occurs at high production speed. Wire ends at 150–200 m/min can cause severe lacerations. Enclosed guarding around the forming zone, mandatory PPE (safety glasses and cut-resistant gloves), and automatic stop systems triggered by wire break sensors are the minimum safety requirements. Spring bending machines should never be operated with guards removed, even during setup and adjustment — a practice that dramatically increases injury risk and is a leading cause of the injuries that do occur in spring manufacturing facilities.