COMPARISON OF MODULAR SYSTEMS AND WELDED STRUCTURES IN INDUSTRIAL AUTOMATION
1 . Introduction
In industrial automation, the selection of a structural system represents one of the key technical and economic decisions in the design of production lines, conveyor systems, workstations, and safety guards.
Investors and engineers most commonly choose between two basic approaches:
- conventional welded steel structures,
- modular systems based on aluminum profiles.
Both approaches are technically justified and widely used; however, they differ significantly in terms of load capacity, flexibility, implementation speed, upgrade possibilities, and life-cycle costs.
2. Structural Concepts
2.1 Welded Structures
Welded structures are based on steel profiles, sheet metal, and tubular elements that are permanently joined by welding. After welding is completed, surface treatment follows (powder coating, painting, or galvanizing) to provide corrosion protection and an aesthetically finished appearance.
Such structures are particularly suitable for applications involving high static and dynamic loads, as well as in cases where structural requirements are long-term stable and unlikely to change.
2.2 Modular Aluminum Profile Systems
Modular systems are based on standardized aluminum profiles with slots, connection elements, and system accessories. The structure is assembled mechanically, without welding, enabling fast assembly, disassembly, and adjustments.
Modern modular systems cover a wide range of applications — from ergonomic workstations to load-bearing structures of conveyor and automated lines. The key advantage lies in the system-based design, which allows the combination of standard elements and optimization of the structure according to project requirements.
In practice, various profile series are used (e.g., 30, 40, 45, 60, 80 mm and above), allowing proper adaptation to the mechanical demands of each application. Compatibility with established industrial standards also plays an important role, as it enables greater component integration.
In development-oriented companies, modular systems are often enhanced with proprietary solutions. For example, Lipro has developed its own modular profile and component system
that maintains compatibility with established systems (e.g., Bosch Rexroth type), while allowing optimization according to specific project requirements. An additional advantage of this approach is the continuous availability of key profiles and components from stock, which further shortens delivery times and increases project responsiveness.
This combination of standardization and in-house development enables technical flexibility without being limited to a single system.
3. Mechanical Properties and Dimensioning
3.1 Load Capacity and Rigidity
Welded structures generally achieve higher absolute rigidity, especially over large spans and under concentrated loads. Due to continuous welded joints, they are less sensitive to local deformations.
In modular systems, load capacity directly depends on:
- the selected profile cross-section,
- span length,
- load distribution,
- type and quality of connection elements.
A properly dimensioned modular structure can meet most requirements in industrial automation. However, it requires a precise engineering approach and thorough knowledge of the mechanical characteristics of individual profiles and joints.
In practice, a combination of different profiles is often used to optimize weight, cost, and rigidity.
4. Flexibility and Adaptability
4.1 Changes During the Project Phase
In welded structures, any modification after fabrication requires cutting, re-welding, and renewed surface treatment. This increases costs and extends lead times.
Modular systems allow:
- quick dimensional adjustments,
- addition or removal of modules,
easy modifications without interfering with the entire structure.
In automation projects, where requirements often change during development or installation, this flexibility is extremely important.
4.2 Upgrades and Production Reorganization
Modern production lines adapt to new products, cycle time changes, and logistical requirements.
Modular systems allow:
- later expansions,
- relocation or reorganization of equipment,
- reuse of components.
The structure thus becomes a flexible platform rather than a one-time, static solution.
5. Manufacturing and Assembly Time
In modular systems, the availability of standard profiles, connectors, and accessories plays a crucial role. If key components are continuously available from stock, delivery times can be significantly shortened and the risk of project delays reduced.
In automation projects, where deadlines are often tight and requirements may change even during execution, this aspect represents an important competitive advantage.
6. Economics Throughout the Life Cycle
6.1 Investment Cost
Welded structures can be more cost-effective in very simple and static applications. Modular systems may have higher initial material costs due to high-quality profiles and system components.
It is important to emphasize that steel as a raw material is generally cheaper than aluminum; however, the base material cost does not represent the total cost of the structure. In welded steel structures, additional technological phases must be considered, such as cutting, welding, possible stress-relief annealing, machining, weld grinding, and mandatory surface protection (painting, powder coating, or galvanizing).
These operations increase labor costs, extend manufacturing time, and require additional logistics and quality control.
In practice, it often turns out that the final price of a welded structure — despite the lower cost of steel as a material — can ultimately be higher than a modular aluminum solution due to all associated processing steps and longer production time.
Therefore, any realistic comparison must consider the entire production process and not only the cost of the base material.
6.2 Total Cost of Ownership
A long-term analysis must consider:
- costs of modifications and upgrades,
- production downtime costs,
- possibility of material reuse.
Modular systems often demonstrate a lower total cost of ownership, as they allow rapid adjustments without major interventions and enable component reuse in new projects.
7. Safety, Ergonomics, and Standardization
Modular systems allow easy integration of safety fences, doors, protective elements, and ergonomic workstation adjustments.
The use of systems compatible with established industrial standards is particularly important.
This enables:
- use of a wide range of additional equipment,
- long-term component availability,
- easy integration of external systems.
At the same time, the development of proprietary modular solutions allows optimization of the structure according to actual project needs — whether in terms of load capacity, weight, cost, or specific technical requirements.
This approach combines the advantages of standardization and engineering flexibility, which is essential in modern automation.
8. Conclusion
The choice between modular systems and welded structures is not a question of absolute superiority of one approach over the other, but rather of suitability for a specific application.
In modern industrial automation, where flexibility, implementation speed, and long-term adaptability are key competitive factors, modular systems represent a technically mature and economically efficient solution.
The combination of standardized systems, compatibility with established industrial solutions, and in-house development of profiles and structural elements enables companies to achieve greater technical independence, faster project execution, and long-term optimization of production systems.
