Coil feeding is the process of transferring material from the coil into the press.
It’s paramount to an organization’s success that this process happens precisely, quickly and without damaging the material. That’s why it’s key for organizations to invest in and integrate quality feeds that meet their unique needs.
Press feeds are available in two main styles–air operated and servo driven. Both are extremely popular and have been around for decades. They each offer their own set of benefits.
Let’s take a closer look at these types of feeds.
Air vs. Servo Feeds: Which Is Best for Your Organization?
Air Feeds
As the name implies, these feeds require air pressure to operate. While different organizations offer different designs and functionality, EnSight air feeds pull air into a cable cylinder. As the cylinder draws air in and expels air out, it operates the grippers, which move the material forward with each stroke. To set the length of the stroke, the processor must crank the stop to the correct length.
Air feeds generally cost much less than servo feeds, making them ideal for organizations operating on a limited budget. And even though they cost less, they are just as accurate as most servo feeds. Once the processor has dialed in the length of the part they need, the air feed will stop at that point every time.
Getting the length set right can be a challenge, though. Because air feeds rely on a mechanical stop, most of them must be set by hand. This can result in scrap parts and downtime while the exact settings are established. For this reason, air feeds aren’t ideal for organizations who stamp different sized parts and have regular die changes. Instead, these feeds should be used on a line dedicated to one size of part, or at least a line with few die changes.
To operate, air feeds need a good supply of shop air. As feeds get larger, their required air supply increases as well. Therefore, some organizations might need to invest in a large quality air compressor if they want to ensure air feed accuracy and reliability.
In regard to materials, air feeds do really well with thicker materials. They offer a lot of gripping and pulling power, allowing them to pull heavy materials from the coil smoothly and reliably. Because air feeds use grippers, organizations should be cautious about using them for thin or sensitive-surface materials–the grippers can easily bend or mar the material while feeding it.
In addition, organizations should be aware of the maintenance requirements of air feeds. These feeds rely on everything from O-rings to springs and hoses to operate, all of which needs to be replaced on a regular basis. The schedule will change depending on the organization, but over time, the maintenance costs can add up to the cost of a servo feed.
Servo Feeds
Servo feeds generally feature two rolls–located directly on top of each other–that move the material into the press. A servo motor drives the rolls, which can have different textures or surface coatings to help them grip the material.
Servo feeds are extremely accurate, and they are programmable. The actual feed interface will determine the number of programs it will accept, but often the organization can program dozens of jobs into the system. These jobs can be recalled quickly and easily, allowing for multiple changeovers with little downtime or scrap.
Of course, with all those components, servo feeds can be significantly higher than their air-driven counterparts. This alone can cause some organizations to lean toward an air-driven feed instead. But organizations should look at more than just the initial price tag.
As discussed earlier, air feeds might cost less up front, but they will require more maintenance and upkeep over time. Those costs associated with that maintenance and downtime due to changeovers and maintenance will gradually wipe out any initial cost savings.
Servo feeds require significantly less maintenance over their lifetime. Typically, organizations can go years without having to service their servo feeds. The frequency varies by organization and depends on usage, but generally, organizations will need to resurface or replace the rolls and replace the bearings.
Servo feeds work great for thin and/or surface-sensitive materials due to the rolls being able to move the material without gripping them. They work well for heavy materials, but organizations should be aware that servo feeds can have issues with extremely thick materials due to slippage, so ensure you work with a company that can truly size the servo feed to meet your particular application.
Air vs. Servo Feeds: Which Fits Your Needs?
At EnSight Solutions, we’ve helped countless processors determine which type of feed fits their organization best, and then we’ve helped them achieve success while running those feeds. Rest assured, when you work with our sales team, you’ll be chatting with experienced individuals who will take the time to understand your products and your needs, and then help you pick the machine that fits those needs just right.
When you’re ready to learn more about our industrial press feeds and how we can help you enhance your processes, contact our industrial processing specialists.
