Robotic Assembly

What is Robotic Assembly?

Industrial robots can be used to automate the tasks involved with putting together a product, such as automotive assemblies, furniture, machinery, or electronics components. This can often be done using a 4- to 6-axis robot that is capable of human-like levels of dexterity. Specialized tooling or grippers attached to end of the arm work with the axes of the robot to manipulate and attach parts. Robot vision components are often integrated into an assembly automation system to identify and sort parts, ensure proper placement and inspect the finished product.

Types of Automated Assembly Tasks

Assembly applications typically consist of multiple operations. While the operations vary with the application, we’ve listed several of the most common operations below.

• Part Identification
• Part Sortation
• Flexible Feeding
• Bowl Feeding
• Bin Picking
• End-Effectors
• Tool Changing
• Force Sensing
• Part Fastening or Joining
• Visual Inspection
• Results

Bowl Feeding

Typically uses a vibratory motion to advance parts from a bulk hopper. Parts are advanced from the hopper onto a rail (or into a groove) that orients the part and presents it to the robot. Bowl feeders are typically designed and built based on the part geometry and mass. Bowl feeders are well suited for applications where the part shape or size does not change. Bowl feeders are not recommended for applications where the part is expected to change.
 

Bin Picking

Automating the distribution of a broad and varied mix of parts or SKUs is no longer a challenge. Advances in 3D vision robotics are improving both speed and accuracy in identifying and sorting nearly any mix of parts presented in bins, totes, cases or cartons. MotoSight 3D BinPick is an ideal solution for manfuacturing facilities that must process parts presented from bins.
 

End-Effectors

End-effectors (or end-of-arm-tooling) are how the robot grips the parts. Complex and advanced assembly operations require the robot to accurately and precisely locate and grip the parts. Often a base actuator (often pneumatic and sometimes electric) is used to perform the open and close motion. Custom gripper fingers are attached to the actuator to ensure proper gripping of the parts. When a variety of part types and sizes are used, end-effectors can become complex.

Some operations necessitate compliance built into the end-effector. This can be done at the gripper fingers or where the end-effector attaches to the robot.
 

Tool Changing

Tool changing is often required for automated assembly operations. As different part types and sizes are needed, multiple gripper configurations might be required. Tool changers provide the flexibility to automatically change end-effectors or other peripheral tooling.

Adaptive grippers are capable of grasping multiple part types and sizes and can be used in some robotic assembly applications.
 

Force Sensing

Force sensing is often needed for insertion or tightening operations. A force sensor provides feedback to the robot control system and can measure forces and torques being applied at the end-effector. MotoFit force control assembly tool alters the robot’s position based on the force encountered to align or assemble parts. (During normal robot operation, robot is setup for positional control; the robot moves to or retains position even when external forces are applied, provided that forces do not exceed limits that would cause an error.)

Part Fastening or Joining

Part fastening/joining is a critical part of many assembly operations. After all, the nature of assembly is bringing multiple parts together. The fastening and joining methods can vary greatly and depend upon the part types being assembled. Typical fastening methods include screwdriving, dispensing glues and adhesives, ultrasonic welding and inserting clips.