Simplifying CNC Automation

Mixed-part manufacturing is by definition a problem that requires the solution to be able adapt to part change quickly, easily and cost-effectively. The term Single Minute Exchange of Dies (SMED) was coined to represent the value of reducing part change-over time in Lean manufacturing. Historically, CNC automation has been anything but "Lean", requiring complex robot programming, gripper design and customized CNC workholding. Part change-over in an automated CNC production environment is typically measured in hours or even days.

The MultiGrip Automation System was created by machinists out of the frustration of using traditional grippers to automate CNC manufacturing. The team that created MultiGrip were challenged with automating over 250 part numbers. With an average batch size of less than 20 pieces, change-over needed to be measured in minutes not hours. MultiGrip began when someone asked the question, "Why can't the robot use the vise jaws as the gripper?"

Tool Exchanging Robot Gripper

Instead of using gripper fingers that bolt onto the gripper, MultiGrip Robot Grippers include an interface for picking and placing MultiGrip Tools. MultiGrip Tools include MultiGrip Fingers and MultiGrip Jaws. MultiGrip Fingers allow a MultiGrip Robot Gripper to pick and place parts like a traditional gripper but allow for more flexibility with the ability to exchange MultGrip Fingers during the automation process to better accomodate changes to the part shape. MultiGrip Jaws are a special type of CNC vise jaw that allows the robot to use the MultiGrip Jaws as a part gripper and then load the MultiGrip Jaws and part onto a MultiGrip Vise for processing. MultiGrip Gripper tools can be exchanged in seconds by an operator or automatically by the robot reducing part change-over time.

Quick Change CNC Vise System

Instead of using jaws that bolt onto the vise, MultiGrip Vises use an interface for capturing and releasing vise jaws. MultiGrip Jaws can be placed onto a MultiGrip Vise in seconds by an operator or a robot. By closing the vise, the MultiGrip Jaws and part are secured for machining with a very high level of repeatability and rigidity. With a MultiGrip Vise, part change-over time is reduced to seconds. By adding an automation system with a MultiGrip Gripper, the MultiGrip jaws are leveraged to perform the gripping function and part change-over time is reduced to seconds. A robot with a MultiGrip Gripper can even change-over from making one part to another without operator intervention.

Changing Part Shapes

A typical two operation part in a milling application will go through three different shapes: before first operation, after first operation and completed part. Using traditional grippers, picking a part as it changes shapes during the machining process is difficult at best and often disqualifies some parts from automation due to the limitations of the robot gripper.

MultiGrip leverages the CNC vise jaws to transfer parts from the infeed to the CNC machine for processing. Just like regular vise jaws, MultiGrip Jaws are easy to cut in your CNC and allow complex shapes to be held securely. Automation comes naturally to machinists using MultiGrip. Simply cut first and second operation MutliGrip Jaws for each part and your ready to automate.

The Robot Re-Grip Problem

One of the toughest challenges in automating CNC milling applications is the robot re-grip step. After the first machining operation is complete the part must be flipped over and placed in the second operation vise. Using a traditional robot gripper, this step typically cannot be performed directly because the robot is gripping the part using the same surface used by the second operation vise jaws. Using a traditional gripper, the robot will need to place the part on a fixture and re-grip the part from the opposite side. The re-grip step is often times too difficult and too expensive to accomodate in a high-mix automation environment relegating many CNC milling automation systems to single operations.

The Robot Re-Grip Solution: MultiGrip

MultiGrip allow for a direct transfer from the first machining operation into the second operation vise. By utilizing the second operation vise jaws for the part transfer, a robot using the MultiGrip Automation System is able to seamlessly transfer a part from a first operation to a second operation. With MultiGrip, automating the second operation is simple and reliable allowing for a greater level of automation.

Improving Lathe Automation

High-mix automation with robots is more common using CNC lathes than CNC milling machines. Why? Because it's easier. Lathe parts typically start as round shapes and finish as round shapes. A robot with a traidtional gripper can process most lathe parts.

Traditional lathe gripping fingers bolt on in minutes. MultiGrip Fingers snap into place on a MultiGrip Gripper in seconds. Some lathe applications may require as many as three different gripper configurations to process a lathe part. MultiGrip allows the robot to change gripper configurations during the automation process to simplify and improve the reliability of the automation process.

MultiGrip Fingers can pick parts up to 10" in diameter and up to 15 pounds allowing MultiGrip to outperform popular electric grippers. The MultiGrip Finger Tip interface allows custom 3-d printed fingertips to reliably secure the most complex part shapes during automation. By standardizing on MultiGrip, your machine shop gets the benefit of an Automation Workholding System that is optimized for both CNC mill and lathe automation.