Spoiler alert: this is no longer a Bihler GRM 50

WST Koradi: classic Bihler GRM 50 transformed into an EasyMachine CNC electronic stamping and bending press

WST Koradi has completed the retrofit of a classic Bihler GRM 50 bending machine, transforming it into a CNC EasyMachine electronic stamping and bending press.

This full-scale rebuild preserves the original steel/cast-iron frame of the historic GRM 50, but virtually every component has been redesigned using state-of-the-art technology. A unit that many would have considered “close to retirement” has now been completely re-engineered, featuring an electronic architecture that brings it in line with modern multi-axis systems. In other words: it may look like a GRM 50, but it no longer works like a GRM 50.

The upgrade goes far beyond simply electrifying the mechanical drives: the machine is now equipped with CNC-controlled electronic bending slides and a completely redesigned gripper-feed system. The entire rear mechanical drivetrain — including the main gear, the motor–clutch assembly, and the central rear tool drive — has been removed to make room for high-performance, independent servo motors. Each axis is now individually controlled, enabling full freedom in motion programming and highly precise synchronization of all forming and stamping operations.

Step-by-step retrofit

In place of the original main gear, seven CNC electronic motors with gearbox, double-bearing mechanical support, and a toothed gear for slide connection have been installed. Each motor drives two bending-slide anchor points, enabling independent and precise motion control. An additional CNC electronic servo motor has been added to operate the stamping unit.

The entire mechanical gripper-feed assembly has been removed and replaced with a CNC electronic gripper feed featuring adjustable stroke across the full 300 mm range and a maximum strip width of 60 mm. The new system enables multiple feeds — even with different stroke lengths — within the same 0°/360° machine cycle. The fully programmable gripper-brake unit allows either constant continuous clamping or synchronized opening to accommodate pilot pins within the stamping die.

The direct mechanical slides are equipped with CamStandard, capable of delivering a total stroke of 70 mm over 170° (2.2°/mm), featuring a smooth cam profile and constant bending force. Alternatively, CamPower (56 mm over 170°, 3°/mm) and CamExtraPower (34 mm over 170°, 5°/mm) are available. The same configuration can be applied to both right- and left-side lever slides.

Main technical features

Below is a complete overview of the technical specifications of the EasyMachine retrofit Bihler GRM 50:

• Electronic CNC gripper-feed stroke: 300 mm (multiple-feed capability)
• Maximum strip width: 60 mm (optional 120 mm)
• Maximum stroke of EasyCam axes for direct mechanical slides: 70 mm
• Maximum stroke of EasyCam axes for right/left lever mechanical slides: 70/100 mm
• Maximum stroke of EasyScrew axes for horizontal rear dies: 70 mm or 130 mm (optional)
• EasyTwist CNC axis rotation for rear spinner/spindle: 0–999 rpm per cycle (optional)
• Bending-slide force of EasyCam axes: 20–50 kN (depending on model and stroke)
• CNC double-eccentric mechanical press: 250 kN, max stroke 16 mm, centesimal BDC adjustment
• Maximum die-mounting surface: 100 × 400 mm
• Interchangeable with tooling from many traditional cam-operated bending presses of the 50 series
• Open-architecture industrial control system with digital servo drives and absolute positioning
• MULTICONTROL 2 software with 0°/360° diagram and full motion visualization
• Instant generation of each axis’s real-position graph
• Handwheel for manual operation and jog function for low-speed automatic cycling
• Standard configuration: 9 CNC axes (1 feed – 1 press – 7 bending units)
• Expandable with additional EasyScrew and EasyTwist axes
• Software expandability up to 25 axes with additional rack
• Provision for 16 inputs and 8+8 programmable outputs
• Option to integrate camera-based dimensional controls
• Centralized lubrication (optional)
  
  

Main components

Front section of the machine

1. CNC electronic gripper feed unit
2. Group of 8 pneumatic solenoid valves and 16 M12 connections (8 outputs 24VDC + 16 inputs)
3. EasyCam CNC axis for direct mechanical slide, 70 mm
4. EasyCam CNC axis for right/left lever mechanical slide, 70/100 mm
5. Pass-through window for rear-side machining operations

Rear section of the machine

1. Rear horizontal work table
2. EasyScrew CNC rear die axis
3. EasyTwist CNC rear spinner/spindle axis
4. CNC electronic motor

WST Koradi: over 60 years of specialized expertise

Founded in 2004, WST Koradi builds on more than 60 years of expertise in designing and manufacturing machines for wire and strip forming. The Bihler GRM 50 retrofit is a direct expression of this know-how, combining mechanical precision, electronic control, and multi-axis technology in a single system. The result is a machine that preserves the robustness of the original frame while delivering the performance, accuracy, and flexibility of modern CNC systems — demonstrating how even a classic bending press can remain a competitive asset in today’s production environment.