How to Boost Efficiency and Cut Costs with Quick Change Systems

What Are Quick Change Pallet Systems?

A Quick Change System is a modular quick-change pallet system that enables fixtures, workpieces or other equipment to be changed very fast on the machine during the initial part setup on machining centers.

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The common practice of changing fixtures within a machining center without a Quick Change System consists of:

• Removing the fasteners that are holding the fixture to the machine table;
• Cleaning the table free of debris;
• Stoning the surface of the machine table to remove any high spots so that the next fixture can sit flat on the machine table;
• Applying the next fixture and lining it square to the machine table before fastening;
• Finding the new co-ordinates to teach the machine the position of the new fixture in both x-axis and y-axis;
• Touching off the spindle to teach the machine the new position for the height in z-axis;
• Doing a dry run to make sure that the machine is safe to cycle through at full speed.

This process can sometimes take up to 30 minutes on average or more!

Changing a fixture with a Quick Change Pallet System consists of:

• Applying air to the base fixture to open the clamping mechanism;
• Removing the existing pallet;
• Blowing any debris away and a quick wipe of the base plate location;
• Placing the next fixture on the base plate;
• Releasing the air to engage the clamping mechanism;
• Cycle start!

This process can take as little as 3-5 minutes and due to the accuracy of the system you do not have to teach the machine any co-ordinates, just use the same as you did last time!

Schunk VERO-S: Adding Quick Change Systems to your Operation

The VERO-S Quick Change System from Schunk Inc. is a zero-point clamping system that can drastically improve a machine shop’s efficiency by reducing setup time.

The VERO-S clamps workpieces, pallets, clamping stations, existing fixtures, and tombstones with one or more clamping pins. The radial aligned clamping slides of the quick-change pallet system pulls in the clamping pin and locks it. Exact positioning is accomplished via a short taper, and radial location is done via a diamond pin, which assures a repeat accuracy of at least 5µm (0.″).

With the VERO-S Quick Change System, machine set-up times can be reduced by up to 90 percent.

Additionally, all functional components of the new module from Schunk Inc. are made of hardened Stainless Steel. Pull-in force of the new module is up to 9,000 lbs thanks to the patented dual clamping stroke and the integrated turbo function.

The rigidity of the clamping system benefits from this higher force — as a result, considerably higher cutting forces are possible with the VERO-S. Even extremely high shear forces can be absorbed reliably. The VERO-S is paving the way to more precision, efficiency, process reliability, and set up reduction in metal cutting.

This is Part 1 in a 4 part series on Quick-Change Workholding. Stay tuned each week for additional articles.

General Considerations for Quick Change Workholding

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Traditionally, in the metalworking industry, machinists were prized for their ability to achieve precision results through their creative fixture construction and their ability to maximize output. One of the shortcomings of this approach was the very individualized results achieved this way. This methodology had numerous limitations including the need to build the fixturing each time the job was run, resulting in variations in output and quality. Setup time was a serious limitation in overall productivity, as well. With the growth in the popularity of CNC machines, much of the variability was removed; however, setup was still a serious concern. 

In recent years, a new approach to fixture construction and change out has been developed. Quick-Change fixturing  takes advantage of the features of the machine tools, such as extreme accuracy and high speeds/high forces, and the increased emphasis on maximizing spindle utilization to dramatically improve productivity Quick-Change Systems allows fixture change out to be completed in minutes rather than hours, since the location of the fixture within the machine is known. This setup reduction becomes very powerful in maximizing machine utilization as well as facilitating smaller run quantities to aid in creating a lean environment. 

To provide for this certainty of location Quick-Change systems have two roles; locating and retention. The system must provide accurate location of the tool and then it must have some provision for the retention of that tool once in that location. Different systems types have different approaches to resolving these issues and each has specific strengths and weaknesses.  

Quick-Change System Types 

Quick-Change systems primarily consist of two types: Mechanical and Power. Mechanical systems use hand operated tools, like an Allen wrench, to engage and disengage the system while Power types use some power supply, like hydraulics, for actuation.  

In Quick-Change Workholding, Time is Money 

Typically, systems that have the “slowest” quick change time and accuracy have the lowest cost of acquisition and implementation. Systems that can be fully automated typically carry the highest acquisition costs. Determining the appropriate system for your application will depend greatly on the number for fixture changes in a given period. The more changes the greater need for speed and accuracy.  

Best Practices for Quick Change Workholding 

Design for Interoperability 

Not only amongst like operations (i.e. – all VMC fixtures are interchangeable) but also for downstream operations. This reduces the need for additional clamping/positioning operations, improves flexibility creating improved Manufacturing Planning. 

Understand your Costs Beyond System Costs

Do not discount the interruption to production during any transition period. It is also easy to forget to include fixture modification cost in your ROI. 

If you are looking for more details, kindly visit Quick Change Fixturing Solutions.