Spindles for brushing without compliance by Mannesmann Demag for your robot

Rigid Spindles for Brushing by Mannesmann Demag for Your Robot

Rigid robot spindles from Mannesmann Demag are specifically designed for highly repeatable brushing processes at robot workstations. They combine robust mechanics with vibration-damping construction, precise bearing, and thermal stability, ensuring constant speeds, reproducible contact forces, and reduced cycle times in series production. These spindles are designed for direct clamping of brushing tools and are optimized for mechanical processing of weld seams, deburring, surface finishing, and removal of oxide layers on steel, aluminum, or stainless steel.

Structure and Materials

The housing of rigid spindles typically consists of hardened steel or aluminum alloy with an enhanced surface coating for corrosion and abrasion resistance. Inside, precision-ground rolling bearings or ceramic bearing pairs ensure high concentricity and long service life, even at high speeds. The shaft is heat-treated and balanced to prevent imbalance and excessive vibration transmission to the robot arm. Seals are designed as multi-stage labyrinth or V-ring solutions, often combined with dust protection rings and optional air purging to keep abrasive brush debris away from the bearing area. Materials for shaft seals and bearing seals are chemically resistant elastomers (e.g., NBR, FKM) or PTFE-filled materials when chemical resistance to cleaning media is required.

Designs and Dimensions

Rigid spindles are available in compact cylindrical designs and flange-mounted variants. Compact designs reduce mass inertia and allow for more dynamic robot movements, while flange variants enable easy mounting on robot flanges or intermediate plates. Available output diameters and shaft designs are matched to common brush holders: standard bushings, taper mounts (e.g., ISO30/ISO40 for larger tools), or special collets for cylindrical brushing tools. The length of the spindle and axial offset are chosen to allow both internal and external brushing without collision risk with the robot flange or workpiece.

Connections, Interfaces, and Control

Electrical connections comply with industrial standards: 3-phase DC or AC motors with integrated encoders or resolvers for position and speed feedback. Interfaces for control and safety are typically M12 connectors for motor current, encoder feedback, and optional sensors (tachometer, temperature, torque). The motor housing can accommodate integrated brakes or clutches to ensure safe rest positions during tool changes. Pneumatic or hydraulic interfaces are installed for clamping systems or air purging of the bearings; quick connectors with standardized threads are provided for this purpose. For connection to robot controllers, CANopen, EtherCAT, or analog signals are supported to control speed profiles, ramps, and emergency stop behavior directly from the robot application.

Seals, Maintenance, and Service Life

The sealing concepts are designed for abrasive brushing media: external dirt-repellent seals combined with internal cleanroom labyrinth simulation seals significantly extend bearing service life. Maintenance intervals depend on operating parameters; for dry brushing in dusty environments, cyclic cleaning and re-lubrication intervals for the bearings are necessary at short intervals, while with air purging, longer intervals are possible. Replaceable sealing units and modularized bearing housings enable quick repair directly on the machine. Typical service life estimates, depending on load and cleaning regimen, range from several thousand operating hours to over 20,000 hours with optimal application.

Application Areas and Process Integration

In manufacturing environments, rigid brushing spindles are primarily used where defined surface conditions are required without tool flexibility. Typical applications include post-processing of weld seams on body components, deburring and edge processing after punching or laser cutting, and surface preparation before painting or coating. The rigid design creates constant contact conditions between the brush and the workpiece, ensuring a reproducible roughness curve and low dispersion of contact force. In automated cells, robots handle path guidance, while the spindle performs tool-supported processing; this combination allows for high cycle times with consistent quality.

Practical Examples

Example 1: In a welding cell, a rigid spindle with a nylon brush plate in a 6-axis robot application removes weld spatter along butt seams on vehicle cross members. The spindle is configured with cleanly sealed bearings and air purging to keep welding fumes and spatter away from the bearing area. An encoder reports constant speed, and the robot path is programmed to create a defined overlap of brush strokes through contact pressure and path guidance, resulting in a homogeneous finish. Example 2: For deburring stamped sheets, a flange-mounted spindle with steel and brass brushes is used. The spindle is integrated into the plant control system via EtherCAT, which synchronizes speed and feed. Sealing units with FKM material protect the bearings against chip flight, and the modular design allows quick replacement after wear without disassembling the robot flange plate. Example 3: In aluminum profile processing, PTFE-supported seals combined with ceramic bearings are used to tolerate chemically aggressive cleaning media during cycle changes. The rigid spindle works with fine brush combinations to remove oxide layers before bonding or anodizing. The control system regulates a slow start-up curve to avoid shock loads on the bearing.

Selection Criteria and Integration Recommendation

Select a rigid spindle based on the following criteria: workpiece material and surface requirements define brush material and hardness; operating speed and contact pressure determine bearing and shaft design; environmental conditions (dust, chips, cleaning concentrates) influence the sealing concept and the need for air purging; mounting variants and interfaces decide on flange or cylindrical design as well as electrical/pneumatic connection. For retrofit or new integration into existing robot cells, the mechanical interface dimensions, mass inertia, and dynamic behavior must be checked against existing robot entries to avoid path deviations. Detailed information on compatible motor types, encoder designs, and connection cables can be found on our technical page: https://maku-industrie.de/technik. Practical examples and application cases with specific machine specifications are documented here: https://maku-industrie.de/anwendungsbeispiele.

Economic Efficiency and Safety

Rigid spindles reduce downtime through easier handling and predictable wear intervals. Standardized interfaces and modular installation dimensions minimize setup times. In terms of safety, integrated emergency stop and braking functions, as well as encoder-based speed monitoring, are essential to stop immediately in case of tool breakage or blockage and to avoid collisions. Explicit documentation on inertia values and follow-up torques helps in selecting the robot axis for optimal cycle times.

FAQs

* Which brush materials are best suited for rigid spindles? Nylon and brass brushes cover most applications; steel brushes for robust deburring and special fiber types for sensitive surfaces or chemical resistance. * How are rigid spindles protected against dust and abrasion? A combination of multi-stage labyrinth seals, V-ring seals, and optional air purging, as well as replaceable sealing inserts, extend bearing life. * Which interfaces are necessary for robot integration? Standard electrical M12 connectors for motor and encoder, communication interfaces such as EtherCAT or CANopen, and optional pneumatic connections for clamping and purging systems.