Can You Handle It?
[caption id="attachment_6798" align="aligncenter" width="625"] This custom end of arm tool (EoAT) was designed by Bastian's robotics division for a battery recycling center. It is capable of handling 20-30 different SKUs and can palletize 16-21 batteries per minute.[/caption]
When designing a robotic material handling system
, you must evaluate the product and ask yourself, can you handle it? Every robotic system revolves around the product it handles. Knowledge is power, and product knowledge means a better designed system. Having a thorough understanding of the product allows you to utilize different technologies and methods for processing that product through the robotic system.
Below I have outlined the main areas I consider during product evaluation. These areas are analyzed during the initial design phase and considered throughout the lifecycle of the project.
10 Areas to Consider While Evaluating a Product:
- Number of Unique SKUs
- Many times the number of unique SKUs drives the variability that the system is required to handle. A slight modification to a product can cause huge ramifications throughout the system as it is processed.
- Areas to consider: styles, shape, colors, models, etc.
- Physical properties of various materials cause product to react differently when force is applied. Whether the matter is in the form of a solid, liquid, or gas, the rigidity and permeability are crucial to how it can be handled.
- Areas to consider: contact surfaces where equipment will be required to interact with the product (i.e. Is metal to metal acceptable?)
- Packaging is becoming more innovative as companies drive to reduce the cost of their product and increase marketability. As packaging trends continue to evolve, it can become a primary factor in determining the success of your system.
- Areas to consider: How is the product sealed? How does the product need to be supported throughout the system? Is product loosely or tightly packed in the packaging?
- The payload of the robot and the amount of reach within the system is driven by the weight of the product it is handling. Product weight also drives how robustly the End of Arm Tool is designed and whether bottom support is necessary while the robot is in motion.
- Areas to consider: What are the overall weight requirements for each piece of ancillary equipment? (i.e. For lightweight applications you may be able to avoid fully welding frames and select a bolt together construction.)
- As product is transported through the system, clearance of the product being handled becomes very important. The size of the product will drive the robot path and overall cycle time of the system. A formal reach study or simulation is required to determine the optimal equipment height and robot limitations.
- Areas to consider: How will the dimension of the product drive the EoAT design? Will there be enough clearance in the cell when product is located in every interaction zone?
- Porosity (Gurley Rating)
- If vacuum is going to be used to handle product, the Gurley Rating should be measured. It is important to know the porosity or air-permeability of materials where vacuum will be utilized. The benchmark is commonly referred to as "Gurley Seconds", which denotes to the time needed to pass 100cc of air through 1.0 square inch of material at standard pressure.
- Areas to consider: A Low Gurley Rating translates into high air-permeability of the paper.
- Environmental Factors
- It is very important to understand what environment the product will be handled in and what environment the product is coming from. Product can transition from solid to liquid or vice versa by transitions to different temperature environment. The environment can also affect the packaging integrity.
- Areas to consider: Wash down, foundry, corrosive, and dusty environments cause special consideration for sensors and construction of equipment.
- Flow of product through the system can be governed by product identifiers. Typical applications include barcodes, labels, and RFID. Unique SKU and system information is contained in these identifiers and can be tracked throughout the system. Many times an interface is required with a customer Warehouse Management System (WMS).
- Areas to consider: Proper care should to be taken to ensure the system is capable of sensing these identifiers and transferring that information to the control system.
- Given the variability, unique construction, size, and identifiers, the orientation of the product can be very important. It is important to understand whether the orientation of the product needs to be maintained or changed as it is processed through the system.
- Areas to consider: As the part transfers to/from a zone in the system does it need to be rotated, flipped, skewed, etc. in order to complete the next operation?
- Special Handling Requirements
- Many times products will have special handling requirements that must be defined. A fragile product will need to be handled differently than a 100lb steel product. It is important to ensure the integrity of the product is maintained throughout the system.
- Areas to consider: As marketing efforts continue to grow, many times there are cosmetic surfaces that cannot be marred as the product is processed through the system.
In order to properly handle a product, these ten areas need to be considered before you can determine the system design. Sample product during the initial phase of the project is important to allow engineers time to complete preliminary testing on different design concepts. This helps aid in the product analysis and ensures you will properly specify the right equipment for the application. The success of a system is based on adhering to the golden rule, “Know Thy Product”
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