Guide · Intralogistics & Handling
AGV OR LIFTING AXIS? MOVING PARTS FROM A TO B WITHOUT HANDOVER PROBLEMS
When an automated guided vehicle with two robots is needed, and when a rail-mounted lifting axis handles the same task on its own.
In short: For fixed routes within one hall and few stations, a rail-mounted lifting axis is the simpler alternative to an AGV with two transfer robots. The Zeilhofer ZH90 lifting axis grips the part, travels along a rail and sets it down at the target station. One system instead of three, and no handover in between.
Contents:
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The real problem is the handover
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What is a rail-mounted lifting axis?
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How the rail-mounted lifting axis works
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AGV with two robots vs. lifting axis
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Automatic or manual
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Cost-effectiveness
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Three systems or one: the process at a glance
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Checklist for your route
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When an AGV remains the better choice
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Frequently asked questions
Anyone who wants to move parts automatically from one station to the next quickly ends up with a concept made of three systems: a robot places the part on an automated guided vehicle, the vehicle drives, and a second robot picks the part up again. That works. On a fixed route with few stations, however, there is often a simpler way.
This guide shows where the real difficulty lies in transporting workpieces between stations and when a rail-mounted lifting axis from Zeilhofer is the more cost-effective solution. Made in Holzkirchen, Germany, up to 1,200 kg, pendulum-free.
CHAPTER 1
The real problem is the handover, not the transport
Driving a part from station A to station B is a solved problem. It gets complicated wherever the part changes hands. In the classic solution with an automated guided vehicle (AGV) or autonomous mobile robot (AMR), this material handover happens twice:
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Robot 1 picks the part at station A.
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Handover 1: Robot 1 places the part on the vehicle. The vehicle has to stop exactly at the transfer station.
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The vehicle drives to the target station and stops there within a certain tolerance.
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Handover 2: Robot 2 has to grip the part reliably despite this tolerance, often with centering or a camera.
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Robot 2 places the part at station B.
Every transfer station brings its own requirements: positioning, centering, a safety concept for the area where vehicle and robot meet, and an interface between three controllers. Trade articles on AGV implementation therefore regularly name automated material transfer as the biggest planning effort.
CHAPTER 2
What is a rail-mounted lifting axis?
A rail-mounted lifting axis is a vertical lifting axis that travels horizontally on a rail between several stations. It lifts, transports and sets down a part in one sequence. Technically, it is a rail-guided solution for machine linking, in which the same fixture holds the part from gripping to placing.
It is based on the ZH90 lifting axis from Zeilhofer. It is mounted on a rail on the ceiling or the floor and fitted with a fixture that exactly matches the part, such as a gripper, vacuum cup or magnet. The axis lifts the part without pendulum motion, travels along the rail and sets it down at the target station with millimeter precision.
CHAPTER 3
How the rail-mounted lifting axis works
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Route as needed: The rail is designed for each project and built as long as your route requires.
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Adjustable speed: As with an automated guided vehicle, the travel speed can be adapted individually to cycle time and part.
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Up to 1,200 kg: Electric and electro-pneumatic up to 1,200 kg, pneumatic up to 800 kg, each including the fixture.
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±1 mm repeatability: The rigid, pendulum-free guidance places the part reproducibly at every station. No re-centering is needed.
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PLC connection: Electric and electro-pneumatic versions can be integrated into the existing line control.
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Sensors: Obstacle detection and predictive maintenance are possible, so faults are detected early.
CHAPTER 4
AGV with two robots or rail-mounted lifting axis
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Systems: The AGV solution needs a vehicle, fleet software, a charging station and two robots with grippers. The lifting axis is one system on a rail with a matching fixture.
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Handovers: Two with the AGV, each with centering and a safety concept. None with the lifting axis, because the part stays in the same fixture.
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Positioning: The vehicle stops within a tolerance and the robot compensates. The lifting axis achieves ±1 mm repeatability at every station.
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Route: Free and changeable via software with the AGV. Fixed with the lifting axis, and the rail is as long as needed.
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Manual takeover: Limited with the AGV, a fault stops the process. The operator can guide the lifting axis by hand at any time.
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Point of contact: With the AGV often several suppliers and controllers. With the lifting axis, axis, fixture and control all come from Zeilhofer.
CHAPTER 5
Automatic or manual: the advantage over a robot
In automatic mode, the lifting axis grips, travels and sets down parts completely without an operator. Unlike a robot, however, it can also be guided by hand at any time. An employee can set the part down manually whenever the situation requires it.
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Special parts and new variants: The operator simply places parts by hand for which no position has been taught yet.
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Ramp-up and rework: During ramp-up or rework, the process continues manually without reprogramming.
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Automation failure: If automatic mode fails, the line does not stop. The axis continues to be operated manually.
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Collaborative operation: People and axis share the workspace without a safety fence, up to 300 kg load.
CHAPTER 6
Cost-effectiveness: what the lifting axis eliminates
In an AGV project, the vehicle price is only part of the bill. Market overviews put integration, fleet software, charging infrastructure and safety validation at an additional 30 to 60 percent. Two transfer robots add grippers, programming and safety equipment.
With a rail-mounted lifting axis, you no longer need the vehicle, fleet software and charging stations, two robots including programming, two transfer stations with centering, the safety technology for the handover areas, the interfaces between three controllers and the coordination between several suppliers.
A rail-mounted, automated lifting axis is a custom solution whose price depends on route length, load capacity and fixture. Complex lifting axis solutions from Zeilhofer cost up to around €150,000. What the individual systems cost is explained in the guide What does a manipulator cost?. The system can also be financed through leasing or hire purchase.
CHAPTER 7
Three systems or one: the process at a glance
The rail-mounted lifting axis grips the part at station A, travels on a rail to station B and sets it down there. There is no vehicle, no second robot and no handover in between. The graphic compares both processes.
CHAPTER 8
Checklist: Is a rail-mounted lifting axis right for your route?
The more questions you answer with yes, the more likely the lifting axis is the more cost-effective solution:
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Are start and destination in the same hall?
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Is the route between the stations always the same?
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Are there only a few stations along the route?
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Is the part heavy or sensitive, so that every handover is a risk?
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Should an employee be able to intervene manually when needed?
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Is ceiling mounting or a floor rail possible in the layout?
CHAPTER 9
When an AGV remains the better choice
A lifting axis is bound to its rail. An automated guided vehicle plays to its strengths where routes are long, changing or branched. Both approaches can also be combined: the vehicle brings material into the area, and the lifting axis transfers it precisely between the stations.
Long routes or routes across halls
When parts shuttle between buildings, warehouse and production, a vehicle is more flexible than any rail.
Many frequently changing destinations
If stations and routes change constantly, an AGV can be adapted via software. If a fleet is already running in the plant, expanding it can make sense.
High transport volume
A vehicle fleet handles many simultaneous transports across several shifts better than a single axis.
FAQ / Q&A
FREQUENTLY ASKED QUESTIONS
01 What is a rail-mounted lifting axis?
A rail-mounted lifting axis is a vertical lifting axis that travels on a rail between several stations. The Zeilhofer ZH90 lifts, transports and sets down a part in one sequence, mounted on the ceiling or the floor.
02 What is an alternative to an AGV for short routes?
For fixed routes with few stations, a rail-mounted lifting axis is an alternative. The Zeilhofer ZH90 grips the part at station A, travels on a rail to station B and sets it down there. The vehicle and transfer robots are no longer needed.
03 Why is the handover between AGV and robot so complex?
The vehicle stops at the station within a certain tolerance. The robot has to compensate for it, often with centering or a camera. On top of that come a safety concept for the transfer area and interfaces between several controllers.
04 How long and how fast can a rail-mounted lifting axis travel?
The route is designed for each project: Zeilhofer builds the rail as long as the route requires, on the ceiling or the floor. As with an automated guided vehicle, the travel speed is individually adjustable and adapted to cycle time and part.
05 Does the lifting axis work completely without an operator?
Yes. In automatic mode, the Zeilhofer ZH90 grips, travels and sets down parts completely without an operator. If needed, an employee can take over at any time and place the part manually. This is a major advantage over a robot.
06 What loads can a rail-mounted lifting axis move?
The Zeilhofer ZH90 moves up to 1,200 kg in electric and electro-pneumatic versions and up to 800 kg in the pneumatic version, each including the fixture. In collaborative operation without a safety fence, the limit is 300 kg.
07 How much does a rail-mounted lifting axis cost?
The price depends on route length, load capacity and fixture, as every rail-mounted lifting axis is a custom solution. Complex lifting axis solutions from Zeilhofer cost up to around €150,000. In return, the vehicle, fleet software and two transfer robots are no longer needed.
08 When is an AGV still the better solution?
For long routes or routes across halls, many changing destinations and high transport volumes, an AGV is more flexible. Both solutions can also be combined.
READ MORE
FURTHER GUIDES ON THIS TOPIC
In-depth guides on related topics in handling technology.
COMPARISON
Manual, collaborative or automated load handling compared, including the ZH90 as a collaborative lifting axis.
LEVEL OF AUTOMATION
When a manual manipulator is enough, when semi-automation pays off and when a robot does.
PRODUCT
Lifts pendulum-free up to 1,200 kg, mounted on the ceiling or floor and traversable on a rail.