Until recently, getting high precision and repeatability from production lines was difficult. But now new systems for automation are eliminating barriers associated with manual handling and assembly of high-quality product. Here we review one such option — the offering known as linear tool tray-transfer systems.
By Benedict Talan, President | LazerArc
Linear tool tray-transfer systems are often a viable option to replace rotary index tables so ubiquitous in industry. Benefits abound, as linear tool tray transfer systems serve a function much like that of 7th-axis designs. The difference is that instead of transferring the robot up and down a line (as 7th-axis designs do) linear tool tray-transfer systems move parts and fixtures past a stationary robot. What’s more, just as 7th-axis offerings, linear tool tray transfer systems can integrate with robot motors and controls to effectively communicate (and coordinate tasks) with that robot.
Related feature on sister site linearmotontips.com:
Robot-transfer unit (RTU) and other linear-transfer system considerations
The advantages of LazerArc tool tray transfer systems for plant design engineers and machine builders include direct-drive gear reducers to gear rack implements with higher accuracy and better performance with less components. In addition, robust tubular-steel construction minimizes maintenance and need for accessibility.
Before automating a plant floor, engineers should consult with solutions providers to on the production process. Then the engineering team should identify processes that automation would make most efficient.
Note that not all linear tool tray transfer systems are manufactured with the accuracy and precision necessary to handle or assemble complicated precision parts. Linear transfer systems that do rise to the challenge ensure accuracy by incorporating precision guide rails and rack-and-pinion systems, as well as closed-loop motor controls, high index speeds, and flexibility to accommodate automation challenge and quality standards. LazerArc transfer units also include machined-welded steel construction, and the transfer carriages can mount customer tooling trays and fixtures. (Local machined pads accommodate tooling trays for speedier transfer times.) Finally, the LazerArc design maintains extremely high accuracy with a low-backlash gear reducer and either an ac motor (paired with and absolute encoder) or servomotor.
Shown here is a LazerArc seventh axis. Linear tool tray-transfer systems and 7th-axis systems deliver many of similar benefits to complex plant-automation tasks … including the effective use of space on large operations and assembly tasks.
Features that help end users of LazerArc tool tray transfer systems abound as well. One of the leading features is incorporation of high-precision linear rails (guideways) and blocks. The designs also include a cable-management tray (mounted internally); hard stops on each end of transfer for over travel; and surface coatings to reduce friction and eliminate the need for external lubrication. Total axis load capacity exceeds 100,000 lb depending on the design
Shown here is a customized LazerArc tool tray transfer system. Oversized linear-bearing guideways boost load capacity; an internal cable carrier makes for a compact design. The designs also have precision rack features — including a rack that’s hardened and ground with a rack surface finish to 4.58:1; and standard DIN 6 accuracy on the gear rack — or ±0.0003in./ft.
Before purchasing a linear tool tray transfer system for a plant, engineers should partner with suppliers having experience designing, building, and installing the equipment at hand. Plant engineers should also be ready to provide specification details — including current assembly-line operations, the size and shape and weight of the parts to be moved, time for assembly, and plant-floor dimensions where available to accommodate the system.
Parameters to consider before choosing a linear tool tray transfer vendor
- Are variable frequency drives (VFD) mounted in the installation’s control panel or controlled directly through a programmable logic controller (PLC)? VFDs largely influence motor-output efficiency and performance.
- What kinds of motors are on the tool tray transfers — servomotors or asynchronous ac motors? Remember that setups equipped with servomotors and motion designs compatible with robotic operations (as in 7th-axis designs) can communicate with robotics for advanced operations and even IoT functionality. That’s especially true of setups that leverage feedback from high-quality sensors and switches.
- Can these units integrate with welding robots, tooling fixtures, and other machinery controlled with PLC logic?
LazerArc is a division of Motion Index Drives, Inc. specializing in custom engineered indexing setups. Motion Index Drives has been engineering precision indexing systems since 1970. LazerArc Tool Tray Transfer Systems are highly accurate, provide long service life, and are engineered for low maintenance. The design allows for expansion in length — to let plant engineers add tools and fixtures as needed while keeping integration costs down. The tools are interchangeable and positioning is programmable to interface with robots. Design and build time is typically 18 to 20 weeks, as each system is customized to a specific application.
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