When a business decides to automate its palletizing process, there are essentially two choices: robotic or conventional. What are the differences between these two technologies? What are the advantages?
First, let’s discuss robotic palletizers. The key component in a robotic palletizer is….drum roll please….you guessed it, a robot. A robot is usually defined as an electro-mechanical machine guided by computer or electronic programming, and thus, able to do tasks on its own.
In palletizing applications, a robot can consist of a 2-axis, 3-axis, or 4-axis gantry robot. However, more often a robot consists of a 4-axis articulated arm that’s mass produced by companies such as FANUC or ABB Robotics. In some cases 5- or 6-axis articulated arms are also required should a product need to be tilted or rotated.
Other components in a robotic palletizer consist of the following:
- Infeed conveyors that deliver products to the robot
- Pallet dispensers that automatically deliver a single pallet to the robot from a stack of pallets
- Outfeed conveyors that take pallets with full stacks away from the robot
- Automatic slip sheet or tier sheet dispensers
- Safety devices such as fencing and light curtains
Another key component is the EoAT (End of Arm Tool) which is often custom-designed to handle one or more specific products.
- Typically takes up less space
- Can adapt easier to accommodating different pallet patterns and product types
- Can handle up to 1000 kg (2,200 lbs)
- Can handle many different product types, including cases, bags, pails, bottles, batteries, cubes of scrap metal, and plastic containers
- Can simultaneously handle multiple infeeds of different SKUs
- A single articulated arm can typically handle up to 4 different SKU’s. If the articulated arm attached to a moving track or a gantry style robot is utilized, 8 to 12 SKU’s can be handled simultaneously by a single robot. This of course depends on important criteria, such as pallet stacking patterns and case rates.
- Price can sometimes be less, especially when looking at four or more simultaneous infeeds.
- Palletizing rates can vary anywhere from 8 to 30 cases/min for a single robot depending on stacking patterns, requirements, and if the robot is picking a single product, rows of product, or full layer of products.
- Mixed case palletizing is possible
Now let’s look at conventional palletizers.
- Infeed conveyor
- Case turner (if case rotation is required)
- Row forming conveyor with integrated pusher
- Layer forming table with stripper plate and layer-squaring device
- Elevator that lifts full layers of products
- Pallet dispensers
- Slip/Tier sheet dispensers
- Full load pallet discharge conveyor
A conventional palletizer can be broken down into low-level and high-level palletizers. A low-level palletizer starts with products being conveyed and rotated as required by the pallet pattern. The cases then hit an end stop and back up against one another to form a row. This row is pushed onto a layer-forming table.
Rows are continually built in this manner until an entire layer is formed on the layer-forming table. The layer-forming table then raises or lowers to the correct height, and a stripper plate underneath the layer of products retracts gently depositing products onto a pallet. Layers are continuously deposited in this manner until a fully-loaded pallet is formed. The completed pallet is then discharged, an empty pallet is dispensed into the same location, and the process repeats.
A high-level palletizer operates in a similar manner to a low-level palletizer, except instead of raising and lowering full layers of cases and depositing them onto a pallet, the case layers remain stationary and the pallet is raised and lowered as required. High-level palletizers also allow products to be formed into layers at much higher speeds than low-level palletizers.
Advantages of Conventional Palletizers:
- Easier to troubleshoot, support, and operate without special training
- A single unit can handle up to 2 -3 SKU’s simultaneously
- Typically will cost less than a robotic palletizer with a single or dual infeed.
- Up to 15 cases/min for low-level palletizers
- Up to 150 cases/min for high-level palletizers
- Palletizes cases, bags, and other cube-shaped products
Which type of palletizer would you choose: Robotic or Conventional? Why?