Three Tier Buffer Zone Case Study
Abstract
Within 10 weeks, we were able to design and build a buffer zone cell which could hold 45 pallets within a very limited amount of real estate by way of a three tier CDLR accummulating conveyor which utilized vertical space, all while remaining cost-effective for our partners.
Challenges
This project required storage and retrieval of captive pallets with SUV hatches in a relatively small footprint.
The pallets were machined for specific hatches. 45 pallets were required to be accumulated in this cell. The pallet would be loaded via robot in one load area, would move into an accumulation cell after passing inspection. Reject station was required prior to accumulation cell.
When parts were ready to be received from this accumulation cell they were conveyed to an unload cell where they were picked up and shipped. Pallets remained captive on the cell, recirculating to repeat process.
Our challenges were to accommodate an already designed machined pallet, provide a cost effective accumulating conveyance without having to provide a separate drive per zone, it would require a vertical accumulation cell that can accommodate 45 pallets, and to top it all off, we only had 10 weeks for the entire project.
Our Solution
Special Metering Devices
The cell is designed with the two lifts and multiple lanes across three tiers. The hatchback is taken off the pallet after it comes off a lift, which is referred to as “lift #2” and is introduced to the assembly line. The pallet moves along the line until it’s loaded onto the captive aluminum pallet around the middle of the single tier conveyor. This was done by utilizing an accumulating chain driven live roller conveyor with special metering devices to accommodate loading and unloading of part onto captive pallet. To ease the process of loading, the metering device is used for repeatable escaping of one pallet and holding back the remainder of the pallets.
Last Chance Induct
After the hatchback is loaded onto the pallet in the middle of the first tier conveyor, the pallet then continues until it reaches the corner of the conveyor. The corner has a pop-up chain tranfer which takes the pallet to “lift #1” which will take the pallet up to one of the three tiers. While the pallet is on this corner, it is inspected, and if it passes inspection, it will continue up into one of the three tiers of the accumulation area. If it does not pass inspection, it goes off the opposite end at the “last chance induct”.
High Lifts
To feed and takeaway from this three tiered accumulation cell, two high lifts were required, one on each end. Lifts were equipped with chain driven live roller carriages which also had integral air operated pop up chain transfers to transfer onto the buffer lanes. Lift #1 also included and air operated cylinder stop to facilitate transfer of rejected parts onto a chain driven live roller.
To accommodate and store 45 pallets in an efficient manner, we utilized a vertical accumulating cell with three tiers.
Conclusion
We were able to meet the challenge of providing this complete project in 10 weeks from design to manufacture. We incorporated and modified our standard equipment to accommodate the captive pallets and work with the provided real estate to provide a solution for a customer that required an accumulation cell in a vertical fashion.
If you have any questions about this project, or would like to inquire about starting your own project like this one, please feel free to reach out to us anytime at info@lathrupindustries.com.
