There are several different types of palletiser grippers and each has its own uses and benefits. The type of gripper you will need to automatically palletise your product will depend on the products attributes. Below we have explained the most commonly used gripper types and the types of product they are most suited to. However, to be sure that the gripper specified for your application is appropriate for your product we would recommend you book a palletiser trial to try your product on the palletiser before you commit to the investment.
Foam Vacuum Gripper
Foam vacuum grippers are typically used where the product you are palletising has a flat top surface and the item can be vacuum picked from the top. The types of product that a vacuum gripper is typically used for include boxes, display boxes, cartons and some types of packed products and bags.
There are several different styles of vacuum gripper available, but the most commonly used one for palletising product is a flat foam head vacuum gripper.
A vacuum gripper can also be used to pick and place empty pallets onto the conveyor ready for palletising, and to pick and place cardboard slip sheets between layers.
Bag Gripper
A bag gripper is usually only used for bags and sacks of various sizes. The bag gripper will usually also be able to pick and place empty pallets.
A bag gripper has positioning pins, lifting pins and a centre clamp which provides extra support as the product is moved. Due to the unique way in which the gripper works this results in a very neatly stacked pallet.
Typically, when a bag gripper is used, the robot will need to pick off a purpose manufactured sack pick conveyor to allow the pins to wrap round under the bag before lifting. The gripper closes the positioning pins and lifting pins around the product and clamps the centre clamp as it lifts the product off the conveyor. Once the robot has moved the bag to the correct position for stacking, the lifting pins release and the positioning pins guide the bag into place.
Underneath Gripper
Underneath grippers are suitable for a wide variety of different applications and are often used where the product cannot be picked by a foam vacuum gripper due to the nature of the product. Product that usually require an underneath gripper include: open top plastic or cardboard crates, open top boxes, boxes that are not strong enough to be lifted with a vacuum gripper, shrink wrapped items such as packs of bottles, etc.
An underneath gripper has tines that slides underneath the product, and an arm that goes across the top of the item and clamps down onto it to hold it in place. Once the product has been placed in the desired location on the pallet, the top clamp is released and the gripper tines are withdrawn from under the product. An underneath gripper also has an integrated vacuum gripper that is used to pick and place empty pallets onto the conveyor, and also to pick and place slip sheets if they are required.
Parallel Gripper
A parallel gripper is usually only used for boxes, and other products that are regular in shape but are not suitable for vacuum gripping such as shrink-wrapped trays of goods.
A parallel gripper has two side plates that close parallel to each other onto the two sides of the product and then lift it. Once the product has been placed into the correct position on the pallet, the gripper then releases.
Row Gripper Option
The row gripping option extends the length of any of the grippers so it is able to pick and place multiple items at once. This increases the cycle speed and is typically used on high speed production lines. Depending on the stacking pattern bump turn conveyors may be required to orientate the product as it come off the production line before it is picked by the gripper.
With the speed of a row gripper palletising system, you will often be able to palletise different types of products off more than one line. A system like this can help to reduce your capital expenditure requirements as you will only require one palletising cell for multiple lines, rather than a palletising system for each production line.
Bespoke Gripper
A bespoke gripper would usually only be used when the product is not suited to being lifted by any of the above gripers. Items that may require a bespoke gripper include: drums, cans, bottles, irregular shaped items, large or heavy items, etc.
A bespoke gripper would also typically be designed to be able to pick and place empty pallets and to pick and place slip sheets as required.
If you would like to know more about which gripper will be best suited to your product and application, feel free to give us a call on 01223 499488 or contact us at helpline@granta-automation.co.uk. We will also be very happy to arrange a free trial of your product on a palletiser if you require this.
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