CNC Precision Segmented Multi-V Dies | High-Accuracy Bending Blocks for Universal Machines

CNC Precision Segmented Multi-V Dies: Engineered for High-Accuracy Air Bending

The ALAS CNC Precision Segmented Multi-V Die system is purpose-built for high-tolerance sheet metal fabrication and advanced CNC press brakes. By combining the versatile multi-slot capability of traditional multi-V blocks with precision CNC grinding and standardized segment splitting, this tooling setup eliminates standard alignment cumulative errors, drastically reduces changeover downtime, and handles complex box and enclosed sheet metal profiles effortlessly.

Key Technical Advantages

• High-Precision CNC Ground Finishing: Full-length precision grinding guarantees center alignment accuracy within ≤0.02mm, ensuring consistent bending angles along long workpieces without localized angle deviation.

• Standardized Modular Segmenting: Fully segmented into modular block lengths, allowing rapid combination setups for complex 4-sided boxes, channel profiles, and localized bending without tool interference.

• Heavy-Duty 42CrMo Steel Construction: Forged from premium 42CrMo alloy steel and subject to full-body deep vacuum heat treatment, reaching a working hardness of 47 ±2 HRC for exceptional fatigue resistance.

• Multi-Gauge Versatility: Engineered with multi-V slot geometries to accommodate varying sheet thicknesses (0.8mm to 8.0mm) on a single lower block using standard quick-clamping tables.

Industrial Material Standards: Premium 42CrMo Alloy Steel

Tool longevity and deflection resistance depend heavily on raw material metallurgy. ALAS utilizes strictly controlled high-alloy steel with deep vacuum quenching to extend tooling service life up to 8–10 years under heavy daily operation.

Engineering Selection Guide: The V-Opening & Force Calculation

To achieve high-accuracy air bending without overloading your CNC machine or damaging the die shoulders, selecting the optimal V-opening (V) based on sheet thickness (T) is critical.

1. The Standard V-Opening Rule (6T to 8T Benchmark)

For standard mild steel and stainless steel processing, the recommended lower die V-opening width (V) is calculated as follows:

2. Tonnage Requirement Calculation Formula

Calculate the required press brake bending force (P, in Tons) for air bending mild steel (σ_b ≈ 450 MPa) using the standard industrial formula:

P = (650 × T² × L) / V

• P: Bending Force Required (kN)

• T: Sheet Metal Thickness (mm)

• L: Bending Length (m)

• V: Lower Die V-Opening Width (mm)

Note: For Stainless Steel, multiply the resulting force P by 1.5. For Aluminum, multiply by 0.5.

Standard Segmented Layout (835mm System)

ALAS segmented multi-V dies are precision-ground in sets to allow localized, multi-length assembly without shoulder steps:

• Full Length Block: 835 mm

• Standard Segment Breakdown (835mm Set): 100mm, 50mm, 45mm, 40mm, 35mm, 30mm, 25mm, 20mm, 15mm, 85mm, 100mm, 100mm, 190mm (Total = 835mm combined)

• Custom Lengths & Angles: Available upon request (88°, 85°, 60°, 30° critical profiles).

Frequently Asked Questions

Q1: Why choose segmented multi-V dies over continuous solid block dies?

Segmented dies allow operators to adjust the tooling length quickly to handle 4-sided box bending, deep return flanges, and varied tray sizes. Standard solid multi-V blocks cannot handle box shapes without crashing into side walls.

Q2: How does ALAS ensure center alignment accuracy across multiple segments?

Every set of ALAS segmented dies undergoes synchronized multi-axis CNC surface grinding in a single clamping setup. This guarantees that when segments are combined, center alignment tolerances remain within ≤0.02mm along the entire bed length.

Q3: What quick-clamping systems are compatible with these dies?

Our segmented multi-V lower dies feature standard precision base flanges compatible with major CNC press brake clamping systems, including Amada, Trumpf, LVD, Bystronic, and standard European/American quick-change table bases.

Q4: Can individual segments from different ALAS production batches be mixed on the same press brake bed?

It is highly discouraged to mix segments across disparate production batches if your project demands sub-millimeter angular precision. To maintain the structural center alignment within ≤0.02mm, ALAS precision-grinds every 835mm segmented multi-V die set sequentially in a single CNC clamping setup. Mixing batches may introduce microscopic cumulative errors in height and centerline tracking.

Q5: What is the maximum recommended tensile strength threshold for the 42CrMo multi-slot lower block?

The ALAS 42CrMo structural matrix is rated to continuously withstand high-tensile loads up to 1100+ MPa. When utilizing the standard air bending calculation (P = (650 × T² × L) / V), ensure that high-yield alloys such as Hardox, Weldox, or heavy spring steels do not spike localized pressures beyond the pre-calculated shoulder load limits.

Critical Engineering Operational Limits & Safety Warning

• Strict Fragment Seating: Never mix segmented fractional blocks (e.g., 20mm, 45mm segments) on a clamping table that has accumulated microscopic sheet debris or metallic slag. An underlying particle as small as 0.05mm will tilt the alignment plane, causing sharp localized shoulder wear or part angular distortion.

• Symmetric Load Balancing: Avoid executing high-tonnage short-length bending operations on isolated small segments (such as the 10mm or 15mm blocks) while utilizing the max rated tonnage of the hydraulic cylinders. Off-center hydraulic stroke pressure can induce severe localized stress risers, potentially fracturing the lower die table or splitting the die carrier.

• Tonnage De-rating for Radius Shifts: When bending high-elastic stainless steel sheets, the theoretical bending force P must be multiplied by a mandatory safety coefficient of 1.5. Failure to de-rate your CNC controller's automatic tonnage stroke will permanently compress the multi-V groove's top ground radius edges.