Case Study - Automotive Machine Load Cell
The Customer:
The customer for this automation is a global automotive parts supplier specializing in complex mechanisms, body hardware, suspension systems and body structures.
They recently received a contract to build components and assemblies for a pickup tailgate system. Opus received the contract to build a large-scale system to machine a key part of the assembly, an extruded aluminum component.
Cell Features
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The concept befind the machining cell is a rail mounted long-reach ABB IRB4600 robot. The rail allows a single robot to service multiple machine tools, in this case, four. Each CNC machine tool is a Doosan 3-Axis Vertical Machining Center, the DNM 750.
Guarding is designed with a central corridor for machine to machine travel and a "penalty-box" in front of each CNC. This feature uses a pneumatically driven safety gate between the robot and the face of the machine tool, creating a space that allows an operator to clean and test the machine safely while the robot services the other machines in full automatic mode.
Raw parts are loaded via a servo-controlled conveyor system, and presented accurately for pickup. Finished part are cleaned using a specially designed cleaning system in which the robot holds the part while a blow-off wand runs through the part's internal cavities to blow out most of the cutting chips remaining.
The Sequence
The DNM 750 is a direct load machine, meaning that the system does not produce while being reloaded, unlike a turntable machine tool. This means the robot must unload and reload rapidly.
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The sequence begins with a raw part preloaded in one of the nests. As soon as the machine finishes its cycle, the CNC control issues an unload call to the robot. By the time the CNC doors are open, the robot is in front of the machine and the unload sequence begins. When the robot has removed the part and cleared the machine, it signals completion of this step. The CNC closes its doors and undertakes a clean-up cycle which involves flooding the key locations on the fixture with coolant to remove all built up metal chips. While this is happening, the robot places the finished part in the empty nest and grips the raw part. Once this cleaning cycle is complete and the doors are fully opened again, the CNC issues a reload signal and the robot loads the raw part into the machine. Once clear, the robot sends a cycle-start command to the CNC and it goes back to work.
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The finished part remains in the nest for a few minutes to drain most of the coolant from the part. This coolant is recovered in the machine via a trough system. After that time expires, the robot takes the finished part to the blow-off station where chips are removed and the part is cleaned. It is then placed on the outbound conveyor.
Results
The robotic system has exceeded initial performance expectations and consistently runs quantities of parts per shift well above the maximum recorded output of human operators running the equipment.
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