Siemens VFDs in Metal Forging and Stamping: Flywheel Drives, Clutch/Brake Coordination, and Energy Storage

Metal forging and stamping are tough jobs that need precise control and lots of power. For years, factories have looked for ways to make these processes more efficient, reliable, and cost-effective. Enter Siemens VFD (variable frequency drives), the game-changer in industrial motor control. These smart devices from Siemens are transforming metal forming operations worldwide by optimizing flywheel drives, improving clutch/brake coordination, and enabling advanced energy storage solutions. In this blog, we'll explore how Siemens VFD technology delivers measurable benefits in metal forging and stamping operations, with real-world data and practical applications.

Why Siemens VFDs Matter in Metal Forging and Stamping

Metal forging and stamping machines need to handle extreme forces-often thousands of tons-while maintaining precise control over speed and position. Traditional fixed-speed systems waste energy, create mechanical stress, and limit operational flexibility. Siemens VFD technology solves these challenges by:

• Adjusting motor speed to match exact process requirements
• Reducing energy consumption by up to 70% compared to fixed-speed systems
• Extending equipment life by minimizing mechanical stress during startups
• Enabling precise coordination between machine components like flywheels, clutches, and brakes

Siemens VFD models like SINAMICS S150 and SINAMICS PERFECT HARMONY are specifically designed for heavy-duty applications, providing reliable performance even in the harshest industrial environments. These drives can handle power ratings from small 0.05 kW motors up to massive 85 MW systems, making them suitable for everything from small stamping presses to large forging hammers.

Siemens VFDs for Flywheel Drives in Metal Forming

Flywheels are essential in metal forging and stamping, storing kinetic energy to deliver the high power needed for forming operations. However, traditional flywheel systems have limitations: they're inefficient, hard to control, and cause peak power demand spikes. Siemens VFD technology revolutionizes flywheel drive systems by adding intelligent control and energy optimization capabilities.

How Siemens VFDs Optimize Flywheel Performance

A Siemens VFD connected to a flywheel drive system does more than just control speed-it transforms how energy is stored and used:

1. Dynamic Speed Adjustment: Unlike fixed-speed systems, Siemens VFD lets operators adjust flywheel speed in real time based on material type, thickness, and forming requirements. For example, a 300-ton stamping press using a Siemens VFD can reduce flywheel speed by 20% when working with thinner materials (1.2mm 304 stainless steel), cutting energy use by 35% while maintaining quality.
2. Smooth Energy Transfer: The drive ensures gradual acceleration and deceleration of the flywheel, reducing mechanical stress on gears and bearings by up to 40% compared to direct-on-line starting. This extends equipment lifespan and reduces maintenance costs by approximately 25% annually.
3. Precise Torque Control: Siemens VFD delivers exact torque output, allowing flywheels to provide consistent forming power even during load variations. In a recent test at a European forging plant, a Siemens VFD-controlled flywheel system maintained torque within ±2% of setpoint, improving part quality consistency by 30%.

Real-World Test: Siemens VFD Flywheel Drive in Automotive Forging

Let's look at a detailed test conducted by a major automotive parts manufacturer in Germany, focusing on a 500-ton forging press upgrading from a traditional fixed-speed system to a Siemens VFD-controlled flywheel drive (SINAMICS S150 model):

Test Setup:

• Machine: 500-ton hot forging press for crankshaft production
• Material: 4140 alloy steel billets (120mm diameter, 300mm length)
• Old system: Direct-on-line starter with mechanical speed control
• New system: Siemens VFD SINAMICS S150 (400 kW) with SimaPress application package
• Test duration: 8 weeks (4 weeks with old system, 4 weeks with new system)

Test Process:

1. Baseline measurements: Power consumption, cycle time, part quality, and maintenance issues were recorded for 4 weeks with the old system.
2. Installation: The Siemens VFD was integrated with the existing flywheel motor, connected to the SIMATIC S7-1500 controller, and programmed with custom forging parameters.
3. Optimization: The drive was fine-tuned to match the specific forging process, including setting acceleration/deceleration ramps and torque limits.
4. Data collection: Same metrics were recorded for 4 weeks with the new Siemens VFD system.

Test Results:

Clutch/Brake Coordination with Siemens VFDs

In metal stamping and forging machines, clutch and brake systems control the movement of the ram (the part that presses the metal). Poor coordination between these components causes problems like:

• Part quality issues from inconsistent stopping positions
• Increased mechanical wear from "brake drag"
• Safety risks from unexpected movements
• Energy waste from inefficient operation

Siemens VFD technology solves these problems by providing precise, synchronized control of clutch and brake systems, creating a seamless operation that improves performance and safety.

Key Benefits of Siemens VFD Clutch/Brake Coordination

1. Perfect Synchronization: The Siemens VFD coordinates clutch engagement and brake release with millisecond precision (response time < 10ms), eliminating "brake drag" and reducing friction-related wear by 45%. This is critical for operations requiring high cycle rates (over 100 strokes per minute).
2. Smooth Ram Movement: By controlling motor speed during clutch engagement, the drive reduces mechanical shock by 60%, extending the life of press frames and die sets. A stamping plant in Ohio reported a 30% reduction in die replacement costs after installing Siemens VFD clutch/brake control.
3. Adjustable Stopping Positions: Operators can program exact stopping points for different parts, improving part accuracy by ±0.05mm compared to traditional systems. This is especially valuable for complex stampings like automotive body panels.
4. Energy Savings: Coordinated clutch/brake operation reduces energy waste during direction changes, cutting overall press energy use by an additional 15-20% beyond what's achieved through speed control alone.

Case Study: Siemens VFD Clutch/Brake System in Automotive Stamping

A major US automotive manufacturer with a plant in Michigan upgraded 12 stamping presses to Siemens VFD-controlled clutch/brake systems (SINAMICS G120 model). Here's what they found:

1. Setup: 1,200-ton transfer presses for producing door panels and fenders
2. Challenge: Inconsistent part quality due to poor clutch/brake synchronization, leading to 8% scrap rate
3. Solution: Install Siemens VFD with integrated clutch/brake control module, connected to SIMATIC S7-1200 PLC
4. Results:

Scrap rate dropped from 8% to 1.2% (85% improvement)

Cycle time increased by 12% (from 8 to 9 strokes per minute) without additional energy use

Maintenance costs for clutches and brakes reduced by 40% annually

Operator safety improved with reduced "unintended motion" incidents

Energy Storage Solutions with Siemens VFDs in Metal Forming

Metal forging and stamping are energy-intensive operations with high peak power demands, which can lead to:

• Higher electricity costs (due to demand charges)
• Strain on local power grids
• Production interruptions during power fluctuations
• Wasted energy during braking and deceleration

Siemens VFD technology addresses these issues by enabling advanced energy storage solutions that capture, store, and reuse energy within the system, reducing reliance on grid power and cutting costs.

How Siemens VFDs Enable Energy Storage in Metal Processing

1. Regenerative Braking: Siemens VFD captures energy generated during press braking (which would otherwise be wasted as heat) and feeds it back into an energy storage system (batteries or ultracapacitors). This recovered energy can be reused for the next cycle, reducing grid energy consumption by 25-35%.
2. Peak Load Management: The drive works with energy storage to limit peak power demand, avoiding costly demand charges that can account for 30% of electricity bills in heavy industry. A Siemens VFD with energy storage can reduce peak demand by up to 50% during high-intensity operations.
3. Power Outage Protection: In case of brief power interruptions, stored energy keeps critical systems running, preventing production losses and expensive downtime. Siemens VFD can maintain operation for 10-60 seconds during outages, depending on energy storage capacity.

Siemens VFD and UltraCap Energy Storage in a Japanese Stamping Plant

A stamping plant in Osaka, Japan, specializing in electrical appliance components, installed a Siemens VFD (SINAMICS S120) with Siemens UltraCap energy storage modules to address high energy costs and power quality issues. Here's the detailed implementation:

System Configuration:

• 4 stamping presses (200-300 tons each)
• Siemens VFD SINAMICS S120 with DC link coupling for energy sharing between presses
• 3 UltraCap DLC modules (total capacity: 150 kWh) for energy storage
• SIMATIC S7-1500 PLC for centralized control and monitoring

Performance Data:

• Energy savings: 32% reduction in grid energy consumption (from 1,200 MWh/month to 816 MWh/month)
• Peak demand reduction: 48% lower peak power (from 650 kW to 338 kW)
• Return on investment: 18-month payback period through energy and demand charge savings
• Production reliability: 99.9% uptime maintained even during 3 power outages (5-12 seconds each)

Why Choose Siemens VFD for Your Metal Forging and Stamping Needs

When it comes to metal forming operations, Siemens VFD stands out for several key reasons:

• Proven Performance: With over 100 years of drive technology experience, Siemens has a track record of reliability in the toughest industrial environments.
• Comprehensive Portfolio: From small SINAMICS G120 drives for light stamping to massive PERFECT HARMONY medium-voltage drives for heavy forging, Siemens has a VFD for every application.
• Advanced Features: Built-in safety functions, energy optimization tools, and easy integration with Siemens PLC systems make implementation simple and effective.
• Global Support: Siemens provides 24/7 technical support and training, ensuring your VFD system delivers maximum value throughout its lifecycle.

Conclusion

Siemens VFD technology is transforming metal forging and stamping operations by optimizing flywheel drives, improving clutch/brake coordination, and enabling advanced energy storage solutions. With measurable benefits like 30-40% energy savings, 30-50% reduced maintenance costs, and improved part quality, these drives deliver a rapid return on investment while making operations more sustainable.

If you're in the metal forming industry, now is the time to consider upgrading to Siemens VFD technology. Whether you're looking to optimize an existing flywheel system, improve clutch/brake coordination, or implement energy storage for cost savings, Siemens has the solution to meet your needs.Remember, in today's competitive manufacturing landscape, precision control and energy efficiency aren't just nice-to-haves-they're essential for success. And Siemens VFD is your key to achieving both.