Key Criteria for Selecting Industrial Manipulator Before Investment

Today, industrial manipulators are no longer merely auxiliary devices to reduce physical labour for workers; they are a strategic engineering investment that directly impacts safety, productivity, and long-term operating costs.

This article summarises the core criteria that must be evaluated before investing in an industrial manipulator, helping businesses choose the right solution that fits their actual needs and long-term usage orientation.

1. Defining the Actual Handling Task

The most common mistake when selecting a manipulator is starting with the load capacity instead of the actual handling method in production. In reality, two applications lifting the same 40–50kg weight may require two completely different manipulator configurations.

The process requires the manipulator

• Is it simple vertical lifting, or does it require horizontal movement, rotation, or tilting of the part?
• Is it a basic operation or an assembly task requiring high precision?
• Is the load moved in an open space, or must it reach deep into a machine, mould, or obstructed area?

Characteristics of the load

• Actual working weight: Includes the workpiece plus the end-effector/gripper.
• Shape and dimensions: Compact, long, wide, or asymmetrical.
• Centre of Gravity (CoG): Is it near the axis or offset far from the manipulator arm?

Note: In many cases, the load moment generated by an offset centre of gravity is the deciding factor for the manipulator’s structure, balance, and stability, not the "kg" figure listed in the catalogue.

Working intensity

• Number of lifting cycles per shift/day.
• Continuous operation time.
• Number of operators and the degree of reliance on manual control "feel."

Describing the handling task correctly from the start helps the supplier select the right operating principle and structural design, avoiding situations where the manipulator has excess power but is hard to use, or has sufficient capacity but lacks stability.

In other words, an industrial manipulator should not be selected based on the maximum load, but rather on the most complex operation it must perform. This is the foundation for all subsequent technical criteria.

2. Motion Trajectory & Actual Workspace

After defining the handling task, the next criterion is to clarify how the manipulator will move within the actual workspace. This factor is often overlooked but directly affects usability and long-term efficiency.

Primary motion trajectory

• Does the manipulator only lift vertically, or must it move across multiple axes?
• Is there a requirement to rotate or flip the part (90°, 180°) during the process?
• Is the movement continuous, or does it involve specific stop points?

Unlike traditional lifting equipment, manipulators often work in 3D space where the load not only moves but also changes direction, acceleration, and balance. These movements generate inertia and oscillation, requiring the system to be stable enough to safely and precisely control the load.

Workspace Scope

• Maximum reach radius.
• Effective working height.
• Limitations caused by the factory ceiling, columns, machinery, or surrounding conveyors.

In many projects, the manipulator has sufficient load capacity but cannot reach the final position or hits factory structures when fully extended. In such cases, the device is forced to operate in an "avoidance" mode, reducing productivity and increasing handling risks.

Stability when stopping

• Can the manipulator dampen oscillation when stopping mid-travel?
• Does it maintain precise positioning when the operator releases their hand?

These requirements are critical in assembly processes, loading workpieces into CNC machines, or operations close to the operator.

3. Selecting the Right Drive Technology

Drive technology is the core technical factor determining how the manipulator reacts to the operator, its precision, stability, and operating costs over its lifecycle.

Pneumatic Manipulators – The common solution for standard tasks

Pneumatic manipulators operate based on the elasticity of compressed air, creating a feeling of weightlessness and natural floating.

• Pros: Low initial investment cost; safe operation (especially in explosion-prone environments); simple structure, easy maintenance.
• Cons: Air's compressibility limits stopping precision, especially for tasks requiring exact positioning.
• Energy costs and losses due to air leaks in the long term must be considered.

Hydraulic Manipulators – When high force is required

Hydraulic technology fits high-load applications requiring a high lifting force within a compact device size.

Incompressible hydraulic fluid helps hold loads more stably than pneumatic systems.

• Cons: In modern production, hydraulic manipulators are less preferred due to oil leakage risks, high maintenance costs, and unsuitability for food, pharmaceutical, or electronics industries.

Electric Manipulators – High precision and control

Electric manipulators use servo motors combined with force sensors to assist operations in real-time.

• Pros: Precise control of position, speed, and acceleration; stable load holding at any position in space; high energy efficiency and low long-term operating costs; easy integration with smart manufacturing systems.
• Cons: Higher initial investment cost, requiring a long-term view on Total Cost of Ownership (TCO).

4. Precision & Control Feel During Operation

In many industrial applications, a manipulator must not only make lifting easier but also replace human hands in tasks requiring delicate control. Therefore, precision and motion control are non-negotiable criteria, especially for assembly, machine loading, or close-proximity work.

Defining required precision

• Does the manipulator need to stop at any point in its travel?
• Must the stop position be repeatable between cycles?
• Is stable load holding required when the operator releases the handle?

In well-controlled systems, the load remains stationary at a specific position without drifting, dropping, or oscillating, allowing the operator to work safely and accurately.

Vibration dampening upon stopping

When moving in 3D space, inertia forces can cause shaking, especially with heavy loads or offset centres of gravity. If the system is not well-designed, residual oscillation will reduce assembly accuracy, increase collision risks with surrounding machinery, and cause fatigue or lack of confidence for the operator.

Control Feel

• How much force is required to move the load?
• Does the manipulator respond smoothly and uniformly to hand movements?
• Can the operator easily "feel" the load during manipulation?

In modern systems, good motion control allows the operator to move heavy objects with very little force while maintaining stability and precision throughout the path.

5. End-Effectors (Tooling) & Customisation

In many projects, the manipulator has the correct load rating and drive technology, yet fails to perform effectively. The cause usually lies not in the arm, but in the end-effector (gripper)—the part directly contacting the product. First, analyse the workpiece characteristics:

• Shape: Flat, round, long, asymmetrical.
• Surface: Smooth, rough, porous, or non-porous.
• Hardness: Ability to withstand clamping force.

Vacuum grippers: Common for sheet materials or flat surfaces. Note: Non-porous materials (steel plates, glass, hard plastic) require deep vacuum; porous materials (paper bags, cartons) require high flow rates to compensate for leakage.

Mechanical clamps: Mandatory for complex shapes or surfaces unsuitable for vacuum. Note: Clamping force must be sufficient but not deform the product; the mechanism must be stable during rotation/flipping; force sensors or limiters should be integrated for sensitive products.

Magnetic grippers: High speed for steel plates or metal blanks. However, safety is paramount, especially regarding power loss scenarios.

Future flexibility should also be considered: Is it easy to change the gripper for different sizes? Can one gripper serve multiple product lines? Is changing the tooling time-consuming or costly?

6. Safety & Compliance with Vietnamese Standards

Since manipulators work directly with humans, safety is a mandatory condition. A smooth-running system lacking proper safety mechanisms poses significant risks.

Considering potential loss-of-control scenarios

• Sudden loss of power or compressed air.
• Operator releasing the handle mid-air.
• Overloading due to an error or a product change.

The manipulator must be equipped with passive and active safety mechanisms: anti-drop devices (check valves, mechanical brakes, or controlled lowering systems), travel limits, overload limits, and easily accessible Emergency Stop (E-stop) buttons.

Compliance with Vietnam Standards (TCVN/QCVN)

Manipulators fall under lifting equipment; thus, they must meet regulations such as TCVN 4244 (Design, manufacturing, and safety inspection) and QCVN 07 (Occupational safety for lifting equipment), including initial and periodic inspections. Ignoring inspection leads to accident risks and legal liabilities affecting production.

Specific Environment Considerations

• Explosion risks, dust, or flammable vapours.
• Food/Pharma requiring clean, washable materials.
• Crowded areas require specific safety zones.

7. Installation Infrastructure & Foundation

Even a well-designed manipulator cannot function effectively if the infrastructure is unsuitable.

• Foundation & Load Bearing: When reaching far with heavy loads, the force on the floor includes not just static weight but also overturning moments and dynamic forces. Check concrete thickness, strength, anchor bolt capacity, and floor stability. If the current floor is insufficient, foundation reinforcement or independent footing must be budgeted for.
• Installation Method: Floor-mounted (column), Overhead rail system (for extended range), or Mobile base. The choice depends on layout, machine density, and future expansion needs.
• Integration: Does the manipulator block aisles or safety zones? Does it hinder machine maintenance? Can it be relocated if the line layout changes?

8. Total Cost of Ownership (TCO)

Many businesses misjudge investment efficiency by only looking at the initial purchase price. TCO includes:

• Initial equipment and installation costs.
• Energy costs (electricity or compressed air).
• Maintenance and consumables.
• Costs of downtime due to incidents or unplanned maintenance.

Pneumatic manipulators: Low initial cost, but higher operating costs due to low energy efficiency and air leaks.

Electric manipulators: Higher initial cost, but high energy efficiency, fewer consumables, and reduced maintenance/downtime.

Indirect costs: Impact on productivity, operator fatigue, safety risks, and reusability. Over a 5–10 year cycle, solutions that seem expensive initially often prove more economical.

9. Supplier & Technical Support Capability

Manipulators are not "plug-and-play" shelf items; they are engineering solutions requiring customisation.

• Approach: Does the supplier survey the actual site or just sell from a catalogue? Do they ask about trajectories and environments? A professional supplier starts by understanding the production problem, not by quoting a price.
• Design & Customisation: Is the device designed for your specific product and layout? Is the end-effector tested before delivery?
• After-sales Service: Response time, spare parts availability, maintenance support, inspection assistance, and training.
• Partnership: Can they support upgrades or layout changes later? Do they have a local technical team or rely on third parties?

VIETMANI - Genuine Industrial Manipulator Manufacturer in Vietnam

VIETMANI – Vietnam Manipulator Joint Stock Company is one of the rare entities in Vietnam that directly researches, designs, and manufactures industrial manipulators, rather than merely distributing or assembling them.

Established in 2019, VIETMANI has a clear focus on industrial manipulators and lifting assist devices, with a product ecosystem including:

• Pneumatic Industrial Manipulators (HA series)
• Pneumatic Cable Manipulator (HAS series)
• Vacuum lifter
• Overhead Rail Systems
• Customised lifting solutions

A key advantage of VIETMANI is our comprehensive turnkey capability: Site survey and task analysis => Solution design fitting the layout and process => Manufacturing => Installation => Operator training & Inspection support => Long-term domestic maintenance and technical support.

Contact Vietmani for a free consultation and site survey.

Hotline: 0931 782 489