The other way to identify the lot the bag is from is to stamp the information onto the bag using a labeler. These labelers may be automatic and included in the automated bagging and sealing system. Either way, it is important to identify what lot of product is in the bag. This information also may be used for inventory control and product location in the warehouse.
The bag used needs to be fully filled and shaped when sealed. This is extremely important if the bags are to be palletized and or stacked. As the bags are discharged from the packing line, they must be handled either manually or by a mechanized system such as a robotic arm.
In earlier times, the removal of bags from a packing line and stacking or putting them on pallets was done manually or by installing an expensive and complicated bag conveying belt. It fed the bags into a palletizer that was totally automatic or required a person to turn the bags so they could be positioned to form a tier of bags to fit the pallet. Today’s use of automated high speed bagging equipment may be followed by a robotic bag handling system that may place empty pallets in a specific spot and orientation so that each bag may be picked up and placed on the pallet in a pattern. It eliminates human handling. The robotic bag handler may be programmed to do the work needed and is much more accurate than a person trying to do the same thing.
A common size pallet measures 42 inches wide by 48 inches long. Figure 1 shows a pallet with a five-bag tier pattern on each level. The tiers are alternated by turning every second tier 180 degrees so the bags from each tier interlock with the other tiers.
A ton of 50-pound bags will need 40 bags. Using a five-bag pattern for each tier on a pallet, eight tiers would be needed for the pallet to hold a ton. The bags on a full pallet also may be automatically wrapped in shrink wrap to hold the bags in place when handling a full pallet.
A 42-inches-wide pallet is used so that a double row of pallets may be placed in a box truck or semi-trailer, which are limited to a maximum of eight feet wide on the outside. Some new trailers and changes in state motor vehicle regulations now allow outside widths of 8 feet, 6 inches. The walls of the trailers are two to three inches thick so the net width inside is 90 inches or less. The semi-trailer will hold 24 pallets in a 2 x 12 layout. A second layer of 24 pallets might be added if height limits and allowable load capacity of the trailer are not exceeded.
Once the product is loaded on a pallet, a forklift truck is used to move the pallet to its location. Locating the pallets sensibly may make a huge difference in the number of forklift trucks required to place and retrieve the pallet and the product on it. I personally know a feed company that sold most of their products in 50-pound bags. Pallets of product were placed in any location in the warehouse there was space. This required the forklift trucks to travel many miles to place and retrieve product from wherever it was put in the warehouse to fill a shipment. This company served large customers with single product shipments as well as small feed stores and outlets resulting in mixed bags of product on the same pallet. The company analyzed their shipments and redesigned their warehouse so truck loads were staged near the truck loading area. The large usage product pallets also were located as close to the loading area as possible. The less or seldom-used product pallets were put farther back in the warehouse. By making these changes, the company reduced the number of forklifts required from five to two and cut the forklift mileage in half. This resulted in a major cost savings in handling product.
||| Next page: Warehouse design |||
Warehouse design
When laying out a warehouse, several things need to be considered. First, determine the shortest distance from the bagging operation to the point where the pallets are loaded for shipment. Product made for immediate shipment should be staged near the loading point. Additional area for staging mixed loads should also be available near the loading point. Second, store highly used products as close to the loading area as possible. Thirdly, place pallets of low shipped product in other areas of the warehouse.
Pallets placed at the walls in a warehouse should be kept at least 18 inches from the wall and allow six inches of clearance between adjacent pallets. Rows of pallets more than one pallet deep should be avoided as the key is to use the oldest product before using the newer product. This means that all the newer pallets of product should be moved in and out to get to the oldest product. Bags of good product can easily be damaged each time the pallets are moved to reach the rear pallet of older product.
It doesn’t make sense to design a warehouse so all product is placed on the floor only. But you also don’t want to stack pallets of product one on top of the other as this causes damage to bags when placing or removing pallets. To avoid stacking pallets of product on top of one another, a rack system may be used to stack the pallets off the floor. Pallet storage rack systems are available from many sources.
My recommendation for storing multiple pallets of the same product is to use a pallet rack system. These racks should not be placed near the walls, but an aisle at least 12 feet wide should be used on both ends of the pallet rack so the oldest product is at one end of the storage racks and the new product is at the other end.
Pallet storage racks may be supplied with rollers to allow the pallets to be easily moved along the storage rack to the other end.
Aisles where forklifts travel but do not access the pallets should be eight feet wide to allow forklift passing. Aisles where forklifts turn into to place or remove pallets should be at least 12 feet wide.
I have devoted this article to manual or automatic packing lines handling large 50- to 100-pound bags. Smaller bag sizes also may be automatically filled and sealed by using rotary scaling pockets that fill, check-weigh, seal and discharge the product.
The small filled bags are often placed in cardboard boxes that hold 12 to 25 bags. The box filling may be done by hand or again the whole operation may be done using totally automatic filling and sealing and stacking operations.
In summary
To summarize the articles in this two-part series, filling, sealing and placement of bags on pallets may be done manually or automatically. Fully automated bagging, sealing and robotic stacking of product on to pallets is faster, minimizes human health problems due to handling bags, and may keep product from contact with foreign materials.
Warehouses for bagged storage should be designed so that any pallets stored next to the wall should never be more than one pallet deep.
Pallet storage systems should be used for multiple pallets of like product. These storage racks (systems) should have forklift access at both ends of a row of product for “first in/first out” use that allows the oldest product be used first.
Placement of pallets and racks of pallets should be as close to the shipping area as possible to minimize the number of forklift trucks needed and the miles traveled to handle the pallets of product.
Provide adequate floor area in the warehouse near the loadout doors for staging of loads prior to shipment. Smart planning and system design can save significant costs in bagging, storage and shipping operations while minimizing contamination and human labor requirements.
