These industrial internal grinding machines offer excellent versatility, high levels of quality, batch size flexibility, easy workpiece presetting, and precision handling of complex components. Engineered with heavy aged cast iron construction that is precisely machined and hand-scraped, our internal grinders deliver decades of high-accuracy, problem-free operation—further enhanced by a premium Hydro-Static lubrication system on the machine table.
Understanding the ID Grinding Process & Bore Operations
Internal Diameter (ID) grinding—often referred to as bore grinding or inside grinding—is a highly specialized machining process designed to finish the inner surfaces of cylindrical or tapered holes to strict tolerances. Unlike external grinding, an ID grinding machine requires a high-rpm wheelhead spindle engineered to rigid standards to reach inside precise cavities while completely avoiding wheel deflection.
Robbi internal grinders excel at processing complex internal components where absolute concentricity and strict roundness tolerances are mandatory. Built with exceptional structural rigidity, Robbi machines provide operators with the precise tactile feedback and intuitive control required for intricate, custom bore operations, ensuring flawless finishes without the need for overly complex, tedious programming cycles for simple components.
Technical Features & Production Advantages
In today’s competitive manufacturing landscape, versatility and precision are non-negotiable. Our lineup of European-engineered internal grinders provides job shops and high-production facilities alike with the ultimate adaptation toolkit for demanding ID grinding applications.
- Multi-Speed Workhead Flexibility: Every machine features a highly adaptable workhead configuration, offering multiple distinct work speeds alongside a variable-speed workhead control system to perfectly match your specific workpiece dynamics.
- Universal Spindle Design: Engineered with a universal spindle nose that readily accommodates either a traditional four-jaw chuck or a faceplate. This ensures your operators have the setup flexibility required to handle complex, irregular, or standard components without costly changeover downtime.
- Robust Component Protection & Clearance: Designed with removable part hoods to accommodate varying component sizes. Operators can run the machine safely with the hood intact, or remove it entirely to maximize their allowable swing clearance by several inches, depending on the model.
Common Applications & Industries Served
Our internal grinding machines are uniquely qualified to support industries requiring absolute concentricity, straightness, and micro-inch surface finishes.
- Tool & Die Shops: Perfect for grinding custom bushings, draw dies, master gages, and jig components where precise control yields unmatched precision.
- Aerospace & Defense: Ideal for processing landing gear components, specialized actuator sleeves, and aerospace valve housings.
- Automotive & Motorsports: Extensively used for reconditioning or manufacturing custom gears, collets, and heavy-duty transmission components.
- Repair & Maintenance Facilities: The rapid setup capability of the universal spindle nose makes these machines the premier choice for one-off repair jobs, shaft reclamation, and bore resizing.
Explore the Robbi Internal Grinder Lineup
Omicron IGR Series — PLC or CNC (Models: IGR 250 & IGR 600)
With excellent versatility and high-quality standards, the IGR 250 and 600 provide efficient production of small batches or single workpieces in manual or semi-automatic modes.
- Fast Machine Setup: The workpiece presetting is configured instantly on setup, allowing you to begin production immediately.
- Complex Capability: Produce quickly and precisely, even when dealing with complex components, and take advantage of more sophisticated functions with seamless machine upgrades.
Omicron IGU Series — Universal CNC (Model: IGU 400 CNC)
If your production demands high-precision, multi-axis internal grinding, the CNC IGU 400 is the ultimate solution. Featuring a motor-controlled 2-axis system with software interpolation, it allows for a wide array of customized radius adjustments to fit your specific production requirements.
Flexible X and Z Axis
Machine Model Technical Comparison Chart
| Model | Height of Centres Over Table | Workhead Rotation Speed | |
|---|---|---|---|
IGR 250 |  | ||
IGR 600 |  | ||
IGU 400 CNC |  |
Overcoming Critical Workshop Challenges
Bridging the Gap: Manual Simplicity Meets CNC Precision
If you are evaluating whether to invest in a traditional manual ID grinder or a full CNC machine, Robbi eliminates the compromise. The choice no longer requires sacrificing setup speed for advanced automation:
- Rapid Setup for Short Runs: While full CNC internal grinding machines are unmatched for high-volume production, programming them for a single piece or a small batch can bottleneck a job shop. Robbi solutions bridge this gap perfectly. With intuitive manual controls, electronic handwheels, and quick-change spindle configurations, operators can set up and finish a custom bore in a fraction of the time it takes to program a conventional CNC cycle.
- The Power of Hybrid Control: Many Robbi models feature conversational control options (such as Siemens TP 700 touch screens). This allows you to run the machine in a manual or semi-automatic mode for quick one-off repair jobs, or leverage PLC/CNC capabilities for automated, multi-step batch production. You get sub-micron precision and ultimate flexibility without the massive capital investment or steep learning curve of a dedicated production-only CNC.
Addressing Combined ID/OD Grinding Requirements
In many precision manufacturing and repair environments, workpieces require exact finishes on both their internal bores and external diameters. While our lineup features dedicated internal grinders, Robbi’s specialized engineering excels at universal, multi-operation workflows.
For facilities that frequently require simultaneous internal and external grinding on a single setup, Robbi offers advanced multi-spindle configurations (such as the Robbi Omicron IGU series). Featuring a rotating turret that can house multiple internal and external spindles, these machines allow operators to achieve absolute concentric alignment across multiple ID and OD surfaces without removing the workpiece.
Upgrading Legacy Equipment: A Modern Alternative to Remanufacturing
For decades, vintage machines like the classic Heald 273A internal grinder have been the staple workhorses of precision machine shops. Today, however, facilities face soaring costs, long lead times, and scarce replacement parts when trying to rebuild or remanufacture these obsolete brands.
Investing in a brand-new Robbi internal grinder from Ecotech Machine Tool provides a far superior return on investment compared to rebuilding outdated equipment. Robbi machines deliver modern structural rigidity, hydrostatic lubrication systems, advanced roller linear guides, and state-of-the-art electronics backed by full factory support. Skip the uncertainties and limitations of the used or remanufactured market, and step up to a modern, heavy-duty production asset built to the highest European manufacturing standards.
General Information
Internal Grinding Components
Measures and Control
Grinding Dressing Wheel
Operator Panel
Tailstock
Wheelhead
Workhead
Internal Grinding Spindle
About The Robbi Group
Robbi is an industrial machine manufacturer based out of Italy and since 1936. Robbi uses materials and high-quality components to deliver the utmost precision. Most of their mechanical components are created in their machine shop.
Their company mission is to design and manufacture precision machine tools, technologically advanced, reliable, safe, easy to use, and “tailor-made” for each customer.
What are the benefits of PLC-controlled grinding machines compared to fully CNC systems?
A PLC-controlled (Programmable Logic Controller) grinding machine bridges the gap between manual operation and full CNC automation. The primary benefits of a PLC system compared to a fully CNC alternative include:
- Simpler Programming & Faster Setup: CNC systems require complex G-code programming and multi-axis interpolation, which can bottleneck short production runs. PLC-controlled grinders (like the Robbi Omicron IGR series) utilize intuitive, conversational touch screens (such as the Siemens TP 700). Operators can input basic dimensional parameters for plunge or pass grinding without any programming knowledge.
- Lower Capital Investment: PLC machines deliver the exact same sub-micron precision and rigidity as a full CNC machine but at a fraction of the initial cost, making them highly cost-effective for job shops and maintenance facilities.
- Automated Consistency for Small Batches: While simpler to operate than a CNC, a PLC system still automates critical accuracy-driving tasks. It handles automatic wheel dressing, automatic dimensional compensation, and can manage up to 12 different diameters in a single cycle.
What applications and materials require precision internal bore grinding?
Precision internal bore grinding (ID grinding) is mandatory for any cylindrical or tapered cavity that requires absolute concentricity, strict roundness tolerances, and micro-inch surface finishes.
- Critical Applications: Common use cases include high-stress components such as aerospace landing gear, actuator sleeves, valve housings, custom bushings, draw dies, master gages, heavy-duty automotive gears, collets, shaft reclamation, and high-precision industrial steel piping or hydraulic cylinders.
- Demanding Materials: ID grinding is an abrasive machining process used when materials are too hard or brittle for standard milling or turning tools. Robbi internal grinders excel at processing:
- Hardened Tool Steels (case-hardened, nitrided, or heat-treated alloys)
- High-Strength Aerospace Alloys (such as Titanium, Inconel, and cobalt-based alloys)
- Tungsten Carbide & Industrial Ceramics
- Surface-Treated Components (such as parts featuring hard chrome plating or high-velocity oxygen fuel [HVOF] thermal spray coatings)
What is an ID (internal diameter) grinding machine and how does it work?
An ID (internal diameter) grinding machine—commonly referred to as a bore grinder or inside diameter grinder—is a highly specialized machine tool designed to finish the inner surfaces of cylindrical or tapered holes to tight tolerances. It works by utilizing a high-RPM wheelhead spindle that enters the internal cavity of a rotating workpiece. Because the grinding wheel must be small enough to fit inside the bore, ID grinding machines require exceptional structural rigidity and precision engineering to maintain strict roundness and absolute concentricity while completely eliminating wheel deflection.
What is the difference between a manual ID grinder and a CNC ID grinding machine?
The primary difference comes down to volume capacity, setup times, and operator control. CNC ID grinding machines are unmatched for high-volume, repetitive production batches, but programming and fixturing a full CNC cycle for a single piece or a small run can severely bottleneck a shop. Manual and hybrid ID grinders feature manual handwheels and quick-change universal spindle noses, allowing operators to set up and finish a custom bore in a fraction of the time it takes to code a CNC run. The Robbi lineup bridges this gap by offering conversational touch screens that provide manual simplicity for quick turnarounds alongside automated capabilities for batch consistency.
What are the primary applications of an internal cylindrical grinding machine?
Internal cylindrical grinding machines are primarily used in high-precision industries where components demand micro-inch surface finishes, absolute straightness, and strict roundness tolerances. Key applications include manufacturing and reconditioning aerospace landing gear components, specialized actuator sleeves, valve housings, custom tool & die bushings, draw dies, master gages, heavy-duty automotive transmission gears, collets, hydraulic cylinders, and industrial precision steel piping.
Can an ID grinding machine also perform OD (outer diameter) grinding?
Yes, depending on the machine configuration. While dedicated internal grinders focus exclusively on internal bores, universal multi-operation machines like the Robbi Omicron IGU series are explicitly designed to handle both. These advanced machines feature an automatic rotating turret that can house up to four spindles—typically three configuration styles for internal grinding and one dedicated spindle for external (OD) grinding. This multi-spindle configuration allows operators to grind both the internal diameter and external surfaces of a workpiece in a single setup, guaranteeing absolute concentric alignment.
Deep Dive: The Robbi Omicron IGR 250 Internal Grinder
If you are looking to upgrade an inefficient, outdated internal grinding setup, the Robbi Omicron IGR 250 is designed to transform your manufacturing operations by delivering unparalleled precision, efficiency, and control.
Equipped with a Siemens TP 700 touchscreen control, this machine equips operators with an intuitive, conversational user experience over all internal grinding operations, supporting both plunge and pass modes across up to 12 different diameters in a single cycle.
Key Performance Specifications of the IGR 250:
- Impressive Grinding Capacity: Offers a maximum internal grinding diameter capacity of 250mm (9.80”) and a center height over the table of 180/230mm, allowing you to tackle a wide range of workpieces with ease.
- High-RPM Belt-Driven Spindle: Equipped with a powerful belt-driven internal grinding spindle that achieves up to 27,000 RPM, ensuring fast, precise cycle times and flawless surface finishes.
- Flexible Operational Control: Supports automatic grinding wheel dressing with automatic dimensional compensation, as well as manual grinding cycles with diameter-based physical stops for rapid one-off prototyping.
- Advanced In-Process Options: Can be configured with optional in-process measuring gauges and gap control systems to further automate and enhance production accuracy.
- Comprehensive Safety Features: Built with fully protective enclosures, emergency stop buttons, and intelligent fault detection systems to ensure a secure operating environment.
