Robot Arm Stone Machine: Types, Key Features, and How It Supports Industrial Performance

Types of Robot Arm Stone Machines

A robot arm stone machine is an advanced artificial stone-cutting system engineered to sculpt natural and engineered stone materials into precise shapes, intricate designs, and custom dimensions. These machines utilize a multi-jointed robotic arm that can be programmed to execute complex carving, cutting, and engraving operations with exceptional accuracy, consistency, and repeatability. Widely used in architectural stonework, monument creation, kitchen countertop fabrication, and artistic sculpture, robot arm stone machines have revolutionized the stone processing industry by combining automation with craftsmanship.

There are two primary categories of robot arm stone machines: robotic arm-based stone carving machines and stone cutting robotic arms. Each type serves distinct purposes and offers unique advantages depending on the application, material, and desired outcome.

Robotic Arm-Based Stone Carving Machines

Designed for artistic and decorative stonework, these machines integrate a robotic arm with interchangeable carving tools such as chisels, rotary burrs, or milling heads to shape and sculpt stone surfaces with high detail.

Advantages

• Exceptional precision for intricate designs (e.g., reliefs, inscriptions, ornamental patterns)
• High versatility with tool-changing capabilities
• Programmable for repeatable production of custom sculptures
• Ideal for artistic and heritage restoration projects
• Reduces manual labor and human error

Limitations

• Slower than high-speed cutting systems for bulk material removal
• Requires skilled programming and design input
• Higher initial investment for full-featured models

Best for: Artistic stone carving, tombstones, architectural embellishments, museum-quality reproductions

Stone Cutting Robotic Arms

Engineered for industrial precision, these robotic arms are equipped with advanced end effectors like diamond-tipped blades, waterjet cutters, or CNC routers to perform accurate linear, angular, and contour cuts in stone slabs.

Advantages

• Ultra-precise cutting for countertops, tiles, and structural elements
• Capable of high-speed multitasking (drilling, edging, polishing)
• Handles tough materials like granite, marble, quartz, and concrete
• Minimizes material waste through optimized cutting paths
• Integrates with CAD/CAM software for seamless design-to-production workflow

Limitations

• Less suited for deep 3D sculpting compared to carving machines
• Requires regular maintenance of cutting tools
• Needs robust dust extraction and cooling systems

Best for: Kitchen and bathroom countertops, flooring tiles, façade panels, prefabricated stone components

Type	Precision Level	Primary Function	Material Compatibility	Ideal Use Case
Robotic Arm-Based Stone Carving Machines	Very High (Detail-Oriented)	3D Sculpting & Engraving	Marble, Limestone, Sandstone, Soft Granite	Artistic carvings, memorials, decorative elements
Stone Cutting Robotic Arms	Extremely High (Dimensional Accuracy)	Cutting, Drilling, Shaping	Granite, Quartz, Marble, Concrete, Ceramic	Kitchen countertops, architectural panels, industrial fabrication

Expert Tip: For optimal performance, ensure your robot arm stone machine is paired with industry-specific software (such as StoneCAM or Mastercam Stone) that supports 3D modeling, toolpath simulation, and real-time error correction during operation.

Specifications and Maintenance of Robot Arm Stone Machines

Robot arm stone machines are advanced automation systems widely used in stone fabrication, carving, and processing industries. These robotic systems combine precision engineering with powerful mechanics to cut, shape, and polish natural and engineered stone materials efficiently. Understanding their key specifications ensures optimal performance, while consistent maintenance enhances reliability, safety, and equipment lifespan.

Key Technical Specifications

When selecting or operating a robot arm stone machine, several critical specifications must be evaluated to match the machine’s capabilities with your production needs. These factors directly influence efficiency, accuracy, and suitability for various stone-processing tasks.

Payload Capacity

The payload refers to the maximum weight a robot arm can safely and effectively handle during operation. In stone processing, where slabs can weigh several hundred kilograms, high payload capacity is essential. Most industrial robot arm stone machines support payloads ranging from 100 kg to over 500 kg, depending on design and application.

Choosing a robot with adequate payload ensures stable handling of heavy marble, granite, or quartz slabs without compromising precision or risking mechanical strain. Underestimating payload needs can lead to premature wear or catastrophic failure.

Reach and Work Envelope

Reach defines the three-dimensional space within which the robot arm can operate—essentially the farthest point it can extend in any direction. This is determined by the arm’s length, joint articulation, and degrees of freedom.

A larger work envelope allows the robot to service multiple workstations, load/unload materials, and perform complex multi-axis carving. Typical reaches range from 1.5 meters to over 3 meters, making it crucial to align this specification with your workshop layout and workflow requirements.

Degree of Freedom (DoF)

The degree of freedom indicates how many independent movements the robot arm can perform—such as rotating, tilting, extending, and twisting. Most stone-processing robots feature 6 or 7 DoF, enabling human-like dexterity and access to complex angles.

Higher degrees of freedom allow for intricate sculpting, edge profiling, and undercutting that would be difficult or impossible with traditional CNC tables. This flexibility is especially valuable in artistic stone carving and custom architectural elements.

Operating Frequency & Cycle Speed

Frequency measures how many repetitive operations the robot can complete per minute, serving as a direct indicator of productivity. In high-volume stone fabrication shops, cycle speed impacts throughput and labor efficiency.

While stone cutting is generally slower than other robotic applications due to material hardness, modern systems optimize tool paths and acceleration to maximize cycles per hour. Monitoring frequency helps identify bottlenecks and plan production schedules more accurately.

Voltage Requirements

Robot arm stone machines operate on industrial power supplies, typically requiring voltages between 24V (for control systems) and up to 600V (for main motors and hydraulics). Most standard installations use 3-phase 400V or 480V AC power.

Proper voltage supply is critical to ensure smooth servo motor performance, prevent overheating, and maintain consistent torque output. Facilities must verify electrical infrastructure compatibility before installation to avoid downtime or component damage.

Power Consumption

Power consumption reflects the total energy used by the robot system, including motors, controllers, cooling systems, and auxiliary tools. Typical power ratings range from 0.6 kW for small units to 3.5 kW or higher for large, multi-axis robotic cells.

Understanding power demands helps in estimating operational costs, sizing backup generators, and ensuring circuit breakers can handle peak loads. Energy-efficient models not only reduce utility bills but also contribute to sustainable manufacturing practices.

Specification	Typical Range	Application Impact
Payload Capacity	100–500+ kg	Determines slab size and thickness the robot can handle safely
Maximum Reach	1.5–3.5 m	Affects workspace coverage and multi-station integration
Degrees of Freedom	6–7 axes	Enables complex 3D carving and precise tool orientation
Operating Voltage	24V–600V	Must match facility power supply; affects motor performance
Power Consumption	0.6–3.5+ kW	Influences energy cost and electrical load planning

Essential Maintenance Practices for Longevity and Safety

Regular and systematic maintenance is vital for robot arm stone machines due to the demanding nature of stone processing—high dust levels, vibration, and continuous operation. A well-maintained robot ensures consistent accuracy, minimizes unplanned downtime, and extends the service life of expensive components.

Follow Manufacturer Guidelines: Always consult the official user and service manual for model-specific maintenance intervals, torque settings, and recommended procedures. Deviating from these can void warranties and compromise safety.

Workplace Preparation: Before any maintenance, thoroughly clean the surrounding area. Stone dust and debris can infiltrate joints, sensors, and electronics, accelerating wear. Remove unnecessary tools and materials to create a safe, organized workspace.

Power Disconnection and Lockout: For technician safety, disconnect the machine from the main power source at the circuit breaker. Implement lockout/tagout (LOTO) procedures to prevent accidental startup during servicing—this is non-negotiable in industrial environments.

Lubrication of Moving Parts: Bearings, joints, and linear guides require regular lubrication to reduce friction and prevent metal fatigue. Use only manufacturer-approved lubricants, as improper types can attract dust or degrade seals. Schedule lubrication based on operating hours and environmental conditions.

Maintenance Scheduling and Record Keeping: Develop a preventive maintenance calendar based on usage frequency (e.g., daily, weekly, monthly). Document every inspection, part replacement, and repair. This history improves troubleshooting, supports resale value, and aids in compliance audits.

Important: Neglecting maintenance can lead to costly breakdowns, inaccurate cuts, and hazardous situations. Dust accumulation in motors or control cabinets may cause overheating or short circuits. Always prioritize safety, use OEM or certified replacement parts, and train operators in basic maintenance protocols. Proactive care not only protects your investment but also ensures consistent, high-quality stone fabrication.

Applications of Robotic Arm Stone Engraving Machines

Robotic arm stone engraving machines have revolutionized the way natural stone is processed across multiple industries. Combining advanced automation with high-precision motion control, these machines offer unmatched versatility in cutting, carving, polishing, and engraving stone materials. From intricate artistic designs to large-scale construction components, robotic arms enable efficient, repeatable, and highly accurate stone processing. Below are the key industries and real-world applications where robotic stone machines deliver significant value.

Stone Industry

Robotic arms are a cornerstone of modern stone processing, enabling full automation of complex tasks such as cutting, engraving, polishing, grinding, drilling, and sandblasting. Their multi-axis flexibility allows them to handle irregularly shaped and heavy stone blocks with ease, ensuring consistent quality across large production runs.

• Capable of processing granite, limestone, travertine, and other dense materials with minimal human intervention
• Equipped with interchangeable tool heads for seamless transitions between operations (e.g., switching from engraving to polishing)
• Integrated CNC programming allows for replication of detailed patterns across multiple slabs
• Reduces labor costs and workplace injuries by automating physically demanding tasks

Key advantage: High repeatability and precision for mass production of stone components

Monument-Making Industry

In the production of tombstones, memorial walls, and commemorative plaques, robotic engraving machines provide exceptional detail and consistency. These systems can automate the entire workflow—from initial slab cutting to final lettering and decorative engraving—while maintaining the dignity and craftsmanship expected in memorial products.

• Engraves names, dates, religious symbols, and portraits with micron-level accuracy
• Supports both serif and script fonts, including multilingual characters and custom calligraphy
• Reduces production time from days to hours without sacrificing quality
• Enables digital templating for remote customer design approval

Pro insight: Integration with design software allows families to preview engravings before production

Construction & Architecture

Robotic stone machines are increasingly used in architectural projects requiring custom stonework, such as façades, columns, flooring, and interior detailing. Their ability to execute complex 3D carvings makes them ideal for both modern and heritage-style buildings.

• Produces ornate cornices, moldings, and relief carvings for luxury developments
• Automates the cutting of interlocking stone panels for cladding systems
• Ensures tight tolerances for seamless on-site assembly
• Supports BIM (Building Information Modeling) integration for precise component matching

Innovation highlight: Robotic arms can carve load-bearing stone elements with structural integrity

Art & Design Studios

Artists and designers leverage robotic arms to bring intricate sculptures and custom installations to life. These machines bridge the gap between digital design and physical creation, allowing creators to experiment with forms that would be nearly impossible to achieve manually.

• Translates 3D digital models into large-scale stone sculptures with high fidelity
• Enables mixed-media integration, such as inlaying metal or glass into carved stone
• Ideal for public art installations, fountains, and bespoke interior décor
• Supports experimental textures and surface finishes (e.g., stippling, fluting, rough-hewn looks)

Creative benefit: Expands artistic possibilities while reducing production time

Restoration & Renovation

In heritage conservation, robotic arms perform delicate stone restoration with minimal invasive contact. Their precision allows for accurate replication of damaged or missing architectural elements, preserving historical authenticity.

• Scans and duplicates eroded carvings, balustrades, and capitals using 3D scanning technology
• Carves replacement stones that match original craftsmanship in texture and detail
• Minimizes risk to fragile structures by reducing manual handling
• Used in museums, churches, and historic government buildings

Critical use case: Faithful reproduction of heritage elements without altering original artifacts

Granite & Marble Fabrication

Robotic systems are essential in high-volume granite and marble workshops, where consistency, speed, and finish quality are paramount. From kitchen countertops to luxury flooring, robots handle everything from rough cutting to mirror polishing.

• Processes large slabs with automated loading and positioning systems
• Applies consistent polish across surfaces for uniform sheen
• Executes complex edge profiles (bullnose, ogee, bevel) with zero variation
• Integrates water-cooled tools to prevent thermal cracking in sensitive stones

Efficiency gain: Up to 70% faster processing compared to manual methods

Industry Insight: The integration of AI-driven path planning and real-time feedback sensors is pushing the boundaries of robotic stone machining. Future systems will adapt to stone grain and hardness variations during operation, further improving cut quality and tool life. For businesses investing in this technology, the return on investment comes not only from labor savings but also from the ability to offer premium, customizable stone products at scale.

Industry	Primary Applications	Key Benefits	Typical Materials Processed
Stone Processing	Cutting, engraving, polishing, drilling	High throughput, consistent quality	Granite, basalt, quartzite
Monument Making	Tombstone engraving, memorial walls	Precision lettering, fast turnaround	Marble, limestone, slate
Construction	Architectural stone, façades, flooring	Complex 3D shaping, BIM compatibility	Sandstone, travertine, engineered stone
Art & Design	Sculptures, custom décor, installations	Digital-to-physical translation	All natural and composite stones
Restoration	Historic stone replication, repairs	Non-invasive precision, authenticity	Weathered stone, heritage marble
Marble/Granite	Countertops, inlays, edge profiling	Flawless finish, minimal waste	Polished marble, exotic granite

Emerging Trends & Future Outlook

• Smart Tooling: Self-diagnosing cutting heads that adjust pressure and speed based on material resistance
• Digital Twin Integration: Virtual simulation of stone processing to optimize tool paths and reduce errors
• Hybrid Workflows: Combining robotic arms with human artisans for "assisted craftsmanship" models
• Sustainability: Water recycling systems and dust extraction reduce environmental impact
• Cloud-Based Design: Remote access to engraving templates and customer customization portals

How to Choose a Robot Arm Stone Machine: A Comprehensive Buyer’s Guide

Selecting the right robotic arm stone machine is a critical decision for stone fabrication businesses aiming to enhance precision, efficiency, and automation. With a wide variety of models and configurations available, buyers must carefully evaluate several key factors to ensure optimal performance and return on investment. This guide outlines the essential considerations when purchasing a robotic arm for stone processing, from application analysis to system integration and human collaboration.

Important Note: The performance and longevity of a robotic arm stone machine depend heavily on proper selection and integration. Rushing the decision-making process can lead to compatibility issues, reduced productivity, and increased maintenance costs. Take time to assess your specific needs and consult with technical experts when necessary.

Key Factors to Consider When Choosing a Robotic Arm Stone Machine

1. Application Requirements Analysis

   Begin by conducting a thorough analysis of your stone processing needs. Identify the types of materials you work with—such as granite, marble, quartz, or limestone—as each has different hardness levels and machining characteristics. Consider the typical dimensions, weight, and shapes of the stone pieces being processed.

   Determine the primary tasks the robot will perform: cutting, carving, engraving, edge profiling, drilling, or polishing. Define the required precision (tolerance levels), processing speed (cycles per hour), and flexibility (ability to handle diverse job types). This foundational assessment ensures the machine aligns with your production goals and workflow demands.

2. Robot Arm Configuration

   The mechanical design of the robotic arm must match your operational requirements. Evaluate the following parameters:

   • Load Capacity: Ensure the arm can safely handle the heaviest stone block or slab you plan to process, including tooling weight.
   • Reach (Work Envelope): Choose an arm with sufficient horizontal and vertical reach to access all areas of your worktable or production line.
   • Degree of Freedom (DOF): Most stone robots use 6-axis arms for maximum flexibility. More axes allow complex 3D movements, essential for intricate carving and contouring.
   • Repeatability and Accuracy: Look for high repeatability (±0.02 mm or better) to maintain consistent quality across batches.
   • Speed and Acceleration: Balance speed with stability—faster arms improve throughput but require robust structural support.
3. End Effector Matching

   The end effector is the tool that directly interacts with the stone. Selecting the right one is crucial for achieving desired results:

   • Saw Blades: For straight or curved cuts; choose diamond-tipped blades for hard stones.
   • Milling Cutters/Router Bits: Ideal for carving, edge detailing, and shaping.
   • Polishing Heads: Use multi-stage pads (from coarse to fine) for mirror finishes.
   • Drilling Attachments: For sinkholes, faucet holes, or decorative patterns.

   Ensure the robotic arm supports tool changers (if multiple operations are needed) and that the end effector interfaces seamlessly with the arm’s mounting system and power supply (pneumatic, electric, or hydraulic).

4. Control System Selection

   A reliable and user-friendly control system is the brain of the robotic arm. Key considerations include:

   • Programming Interface: Opt for systems with intuitive software (e.g., teach pendants, offline programming, or CAD/CAM integration) that allow easy job setup and modification.
   • Software Compatibility: Ensure compatibility with common design formats like DXF, DWG, or STL for direct import of cutting paths.
   • Customization & Automation: Look for open-architecture controllers that support custom scripts or integration with factory management systems (MES/ERP).
   • Learning Curve: Evaluate training requirements for operators—some systems offer simulation modes to reduce setup errors.

   Advanced control systems may include AI-based path optimization or real-time monitoring for predictive maintenance.

5. Machine Compatibility and Integration

   To maximize efficiency, the robotic arm should integrate smoothly into your existing production line. Assess:

   • Communication Protocols: Ensure compatibility with other equipment using standard industrial protocols such as Modbus, Profibus, Ethernet/IP, or OPC UA.
   • Physical Integration: Verify space requirements, mounting options, and alignment with conveyors, CNC tables, or polishing stations.
   • Data Exchange: The robot should be able to receive job data from upstream systems and send status updates downstream.
   • Automation Level: For fully automated lines, consider robots with vision systems or sensors for automatic workpiece recognition and alignment.

   Proper integration enables seamless material flow, reduces manual handling, and supports lights-out manufacturing.

6. Cooperation with Human Workers

   Even in automated environments, human-robot collaboration (HRC) is often necessary for loading, inspection, or maintenance. Consider:

   • Safety Features: Look for robots with built-in safety sensors, emergency stops, and optional collaborative modes (if applicable).
   • Workstation Layout: Design the workspace to allow safe access for operators while minimizing interference with robot motion paths.
   • Ease of Operation: Choose systems with clear status indicators, simple error recovery, and multilingual interfaces.
   • Flexibility: Robots that can be quickly reprogrammed or manually guided (via teach mode) improve adaptability for small-batch or custom jobs.

   A well-designed collaborative environment boosts productivity while maintaining a safe working atmosphere.

Selection Factor	Critical Parameters	Recommended Minimum Standards	Common Mistakes to Avoid
Application Requirements	Material type, task type, precision, throughput	Clear definition of top 3 use cases	Overlooking future scalability or niche tasks
Robot Arm Configuration	Load capacity, reach, DOF, repeatability	6-axis, ≥10 kg payload, ±0.05 mm repeatability	Underestimating weight or workspace needs
End Effector	Tool type, power source, interchangeability	Diamond tools for hard stone, quick-change mounts	Mismatched tooling or inadequate cooling
Control System	Programming ease, software support, connectivity	CAD/CAM import, teach pendant, USB/Ethernet	Choosing closed systems with no API access
Machine Compatibility	Communication protocols, physical fit, data flow	Support for Modbus or Ethernet/IP	Ignoring integration costs or retrofit challenges
Human Collaboration	Safety, ergonomics, operator training	Emergency stop, clear workspace zones	Poor layout leading to bottlenecks or hazards

Expert Tip: Before finalizing your purchase, request a live demonstration using your actual stone materials and job profiles. This allows you to evaluate real-world performance, software usability, and integration potential—helping avoid costly surprises after installation.

Additional Recommendations for Long-Term Success

• Partner with suppliers who offer comprehensive training, technical support, and spare parts availability.
• Consider service contracts or preventive maintenance plans to minimize downtime.
• Plan for dust extraction and cooling systems, as stone processing generates significant debris and heat.
• Document all configurations and programs for easy replication and troubleshooting.
• Stay updated on new technologies like AI-assisted path planning or IoT-enabled monitoring for predictive maintenance.

Investing in a robotic arm stone machine is not just about automation—it's about transforming your production capabilities. By carefully evaluating your needs across all six key areas, you can select a system that delivers precision, reliability, and scalability for years to come. When in doubt, consult with experienced integrators or request trial installations to make an informed, confident decision.

Robot Arm Stone Machine FAQs: Trends, Capabilities & Market Outlook

Q1: What are the latest trends in stone cutting robot arms?

The stone processing industry is undergoing a technological transformation, with robotic automation at the forefront. The latest trends in stone cutting robot arms reflect advancements in both hardware and software, aimed at increasing precision, efficiency, and adaptability:

• Compact and Modular Designs: Modern robot arms are being engineered to occupy less floor space while maintaining high payload capacity and reach. This makes them ideal for small-to-medium-sized fabrication shops where space is limited.
• Enhanced Software Integration: Advanced CAD/CAM and AI-powered programming software now allow for intuitive 3D modeling, real-time simulation, and automatic toolpath generation. This reduces setup time and enables complex designs to be executed with minimal manual input.
• Improved Precision and Speed: High-torque servomotors and advanced motion control systems enable faster cutting speeds without sacrificing accuracy, even on intricate patterns or large slabs.
• IoT and Remote Monitoring: Many new systems come equipped with Internet of Things (IoT) connectivity, allowing operators to monitor machine performance, receive maintenance alerts, and optimize workflows remotely.
• Sustainability Features: Energy-efficient motors, water recycling systems, and dust extraction integration are becoming standard, supporting eco-friendly manufacturing practices.

These innovations are making robotic stone cutting more accessible, reliable, and cost-effective across diverse market segments.

Q2: What are the potentials of the robot stone cutting market?

The global robot stone cutting market is poised for significant growth, driven by rising demand for automation in construction, architecture, and interior design industries. Key factors contributing to this expansion include:

• Increasing Labor Costs: As skilled labor becomes more expensive and harder to find, manufacturers are turning to robotics to maintain productivity and reduce dependency on manual workers.
• Demand for Customization: Consumers increasingly seek unique, personalized stone elements (e.g., custom countertops, artistic engravings), which robotic systems can produce efficiently and consistently.
• Global Infrastructure Development: Rapid urbanization in emerging economies is fueling demand for high-quality stone products in residential and commercial projects.
• Technological Advancements: Falling costs of robotics and improved ease of use are lowering entry barriers for smaller fabricators.
• Market Projections: Industry analysts predict a compound annual growth rate (CAGR) of 6–8% over the next five years, with particular growth in Asia-Pacific and Latin American regions.

As integration with digital design platforms and smart factory systems improves, robot arm stone machines are expected to become central components in next-generation stone fabrication facilities.

Q3: Can a robot arm stone machine handle different types of stone materials?

Yes, one of the key advantages of modern robot arm stone machines is their versatility in handling a wide variety of natural and engineered stone materials. These systems are designed with adjustable parameters—such as spindle speed, feed rate, and tool selection—that can be optimized for each material type:

• Granite: A dense, hard stone requiring high-power cutting tools and slower feed rates. Robots can precisely manage these settings to avoid chipping or overheating.
• Marble: Softer than granite but more prone to scratching and cracking. Robotic systems apply gentle, controlled force and use fine polishing tools for flawless finishes.
• Quartzite: Extremely durable and abrasive, necessitating diamond-tipped tools and robust machine calibration, which robots can maintain consistently.
• Limestone: A softer sedimentary stone that benefits from low-speed cutting and careful dust management to preserve surface integrity.
• Engineered Stone (e.g., Quartz): Uniform composition allows for highly predictable machining, making it ideal for automated robotic processing.

With proper tooling and programming, a single robot arm can seamlessly switch between materials, enabling flexible production lines that cater to diverse customer needs.

Q4: What stone machining tasks can a robot arm perform?

Robot arm stone machines are highly versatile and capable of executing a comprehensive range of machining operations, often within a single setup. This multi-functionality enhances workflow efficiency and reduces the need for multiple specialized machines:

Task	Description	Tools Used
Cutting	Precise slicing of stone slabs into custom sizes and shapes using water-cooled diamond blades or wire saws.	Diamond circular blades, diamond wire saws
Carving	Creating 3D reliefs, decorative edges, and sculptural elements with micron-level accuracy.	Rotary carving bits, ball-nose end mills
Engraving	Inscribing text, logos, or intricate patterns onto stone surfaces for signage or artistic purposes.	Fine-point diamond or carbide engraving tools
Polishing	Smoothing and shining surfaces to achieve glossy, satin, or honed finishes.	Polishing pads (resin, diamond-impregnated)
Drilling	Creating precise holes for sinks, faucets, or mounting hardware.	Diamond core drills, CNC drill bits
Assembling & Handling	Some advanced systems integrate robotic arms with suction grippers to move, position, or assemble stone components automatically.	Vacuum lifters, articulated grippers

By combining these capabilities, robot arm stone machines offer a complete end-to-end solution for modern stone fabrication, from raw slab to finished product, with minimal human intervention and maximum repeatability.