Mechanical servo metal stamping presses use high-torque brushless motors to produce complicated stampings at fast speeds. But the type of motors used—traditional geared, chain drive system, or direct drive—can dramatically affect the final product.
Modern stamping machines are highly sophisticated devices and can be a large capital investment. They give metal formers the ability to create precise, often complex forms while meeting the need for high throughput and production. But that high throughput and production can pose a challenge: A higher production volume means it’s more difficult to inspect every piece and spot defects.
For nonappearance parts such as metal cans or automotive components, the finish on the product is secondary to its function. But for finished parts such as decorative metal trim on appliances, control panels, and door covers, the stamping press needs to produce parts free from any errors.
In a progressive die press system, the mechanical limitations of a traditional motor and gearbox system create vibration, which affects the final finish on the product. Traditional applications use oversized servos and gearboxes to match the inertia of large rolls. This is costly to maintain, limits index times and throughput, and has a low power density, and accuracy can suffer.
Using a direct-drive motor in next-generation stamping presses can increase speed and stroke optimization while requiring fewer parts and producing much less vibration throughout the process.
Fewer Parts, Less Vibration with Direct Drive
Direct-drive motors allow machine builders to use small motors with a high-resolution feedback design that couples directly to the load. This eliminates the need for mechanical transmission, such as the use of a gearbox, which is what typically introduces vibration into the production process. This creates a quiet and dynamic operation with a very long system lifetime.
A direct-drive motor also can protect the system against excessive reaction torque. It can reduce system inertia by removing the gearbox and related transmission elements, Again, this helps to minimize vibration and disruptions which could cause imperfections in appearance parts—and accelerates production.
Reducing vibration in the stamping process is the principal reason for selecting a direct-drive motor, but there are other complementary advantages: reliability, size, power, speed, and ROI.