Multi-operation parts are challenging for CNC milling automation, requiring the automation system to flip the part over for the CNC to produce a finished part. The challenges of multi-operation parts constrain manufacturers to specific negative effects that limit the productivity and practicality of automating multi-operation parts using traditional robot grippers. Versabuilt’s MultiGrip Gripper solves the multi-operation challenge. In this article, we will explore the challenges of multi-operation parts with traditional grippers and a brief discussion on the benefits of MultiGrip.
The Challenges of Multi-Operation Parts with Traditional Grippers
Traditional grippers are a good option for parts with simple geometry, rounds and rectangles, and when the part doesn’t need to be flipped over for a second operation. However, when used with multi-operation parts or parts with complex geometry, traditional grippers struggle due to the specific challenges posed by these types of parts. The limitations of traditional grippers lead to some adverse effects of which manufacturers should be aware.
Practicality
One major challenge of multi-operation parts with traditional grippers is that automating both operations simultaneously is not always practical. This is because the gripper typically must grip the part where the part needs to be held for the next operation. This is known as the robot re-grip problem. Although it can often be overcome with a separate re-grip robot processing step, implementing a re-grip step is part specific and typically requires a re-grip station specific to each part geometry. In high-mix CNC manufacturing, implementing a re-grip step is usually not practical. In some cases a two operation part can be completed as a series of two one-operation automation jobs, employing the operator to flip the parts between automation jobs.
Another problem with traditional grippers is that the shape of the part after each operation can be challenging to grip if the part geometry is complex after machining. The gripper used to load the raw material in the CNC machine may not be able to unload a part with complex geometry after it has been machined.
Unattended Infeed Processing Time
One of the benefits of automation is the ability of the automation system to process part for long periods of time without operator intervention. However, if a traditional gripper limits most parts to processing most multi-operation parts one operation at a time, the automation system’s unattended infeed processing time will be cut in half vs an automation system that can process both operations. An automation system with multi-operation processing has significant benefits.
Operator Labor and the Automation System
Traditional grippers may exclude some parts with complex geometries from being automated. In other cases, a traditional gripper will result in a multi-operation part being processed in single op batches. In both cases, additional operator labor is required to complete the parts reducing the effectiveness of the automation system. The increased labor means each part has a higher labor cost. Additionally, the added attention from the operator could be pulling them away from other tasks. This trade-off often leads to increased costs, reduced profitability, and limits overall productivity for all the machines or tasks the operator could have been overseeing.
How MultiGrip Solves the Multi-Operation Problem
MultiGrip solves the challenges of multi-operation parts in CNC milling machines by using an innovative concept where the robot grips the vise jaws that hold the part instead of gripping the part directly. This allows a single gripper to handle the part through multiple operations as it is machined, eliminating the need for additional manual handling or difficult-to-implement re-grip steps. The MultiGrip Gripper excels in high-mix environments consisting of multi-operation parts.
During the first operation, the robot uses the first operation vise jaws to grip the part from the infeed and place it in the MultiGrip first operation vise to be machined. Once the first operation is complete, the robot uses the second operation vise jaws to remove the half-completed part from the first operation vise and load the second operation jaws and part, and place it in the MultiGrip second operation vise to be machined. You can see a demonstration of the MultiGrip op1 to op2 pipeline here.
The Benefits Provided by MultiGrip
There are several benefits to using the MultiGrip Gripper in machining multi-operation parts. You can gain significant competitive advantages by leveraging the MultiGrip system for your automated CNC system.
Part Workholding
One of the primary benefits is that MultiGrip eliminates the need to duplicate part workholding for both the robot gripper and the CNC machine. This can significantly reduce the time and effort required to initally integrate a new part for automation and the time it takes to change over the automation and machining process when switching between parts to be machined. This results in increased CNC machine efficiency and productivity in a high-mix environment.
Labor Reduction
One of the key benefits of the MultiGrip Gripper is that it can significantly reduce the labor required from operators in the machining process. This is because the gripper can handle both the first and second operations, eliminating the need for operators to handle the parts directly for one or both operations. Additionally, for parts with complex geometries that may be difficult to grip after machining, the MultiGrip gripper can grip virtually any part geometry that can be held by a vise. By reducing the need for manual intervention, manufacturers can reduce operators’ workload, improve overall efficiency, and reduce applied labor costs.
Quality Control
Quality control is a significant problem for manufacturers producing multi-operation parts. MultiGrip does this through its precise gripping mechanism, which can maintain a secure hold on the part, even those characterized by complex geometries. Operators and robots with standard grippers are more susceptible to errors due to the extra handling required to move from op 1 to op 2. The MultiGrip enables manufacturers to eliminate many variables leading to defects and quality problems; this leads to higher-quality parts and reduced waste.
Increased Infeed Time
Infeed time is a significant consideration for any automation system. An automation system equipped with MultiGrip will typically have twice the average infeed time of an automation system that process parts one operation at a time. The increased infeed time reduces operator labor and provides greater opportunity for lights-out manufacturing.
Ease of Creating New Workholding
Another benefit of MultiGrip is that it allows machinists to create optimal part workholding easily. This can help improve the accuracy and quality of the finished parts and reduce the risk of errors and downtime due to tooling issues. Additionally, this makes rapid deployment of new parts into the automation system possible–critical for high-mix machine shops.
For most manufacturers, multi-op CNC milling processing with traditional grippers will limit the potential of the automation system. Single-op processing, limited part geometries, and longer part integration times all conspire to limit the capability of the automation system. Traditional grippers are limited and inflexible for high-mix environments. As costs balloon, productivity is limited, and the workforce is stretched thin, many manufacturers need an alternative.
Are you tired of struggling with the challenges of multi-operation parts in your CNC milling process? Take control of your machining process today with MultiGrip Workholding. Contact us to learn more and get started on your journey to improved profitability and productivity.
