Every coil line depends on steady movement. If the strip runs too fast or too slow, the line can jam or the material can get damaged. That is why loop control is so important. It keeps the strip flowing smoothly between machines, reducing stress on the coil and preventing costly downtime.
When you look at options for managing loops, two main choices stand out: contact loop controls and no-contact loop controls.
Each one solves the same problem in a different way, and both have unique strengths. Understanding how they work makes it easier to choose the right setup for your line.
What a “Loop” Is in a Coil Line
A loop is the extra length of strip that hangs down between the coil uncoiler and the next machine, such as a straightener or feeder. It acts like a buffer. If the press pulls more quickly, the loop gets smaller. If the press slows down, the loop grows larger. A control system watches this loop and tells the uncoiler when to speed up or slow down.
Why loops matter in coil processing lines:
- They keep tension steady, so the strip does not tear.
- They let each machine in the line run at its best speed.
- They reduce shock on the coil and help prevent jams.
In many systems, a single loop controller does the job. It measures the loop position and sends a signal to the uncoiler drive. Some setups even use a closed loop servo motor for very precise speed changes. This level of control helps when handling sensitive material like thin aluminum or shiny stainless steel.
Different coil lines need different solutions. A single-spindle adjustable-core decoiler may require basic loop sensing, while a heavy-duty multi-press line might need advanced feedback. Some companies offer specialized products—Loop Contact Solutions Inc, for example, provides tools designed for coil handling. A Loop Contact Solutions review often highlights their simple but durable gear.
At its core, the loop is the heart of smooth coil handling. Without it, each machine would fight the others. With it, the line works in harmony.
Contact Loop Controls: The Old Standby
A contact loop, often called a dancer arm, uses a roller that rests lightly on the coil strip. As the loop grows or shrinks, the arm moves up or down. That motion tells the drive to adjust coil speed.
Key features of contact loop controls:
- Mechanical feedback: The roller arm connects to a sensor, usually a potentiometer or encoder.
- Direct action: The coil line responds as the arm changes position.
- Storage effect: The dancer arm provides a small buffer of material, smoothing out sudden speed changes.
Advantages:
- Reliable and proven in many industries.
- Works on nearly all materials, including oily or perforated strip.
- Simple to install and easy to maintain.
Limitations:
- The roller touches the strip, which can risk marking delicate finishes.
- Bearings and rollers need routine inspection.
- Space is required for the arm’s movement.
Despite these limits, contact loop controls remain popular. They provide a strong, low-cost solution when durability and storage are more important than surface perfection. Many shops value their simplicity, especially when downtime is expensive.
No-Contact Loop Controls: High-Tech Eyes
No-contact loop controls use sensors to “see” the loop instead of touching it. These sensors can be ultrasonic or laser-based. They measure the distance to the strip and tell the drive how much to adjust.
How they work:
- An ultrasonic sensor sends sound waves and measures the return time.
- A laser sensor shines a beam and reads the reflection.
- The signal is turned into an output for the coil drive, similar to contact systems.
Benefits:
- No risk of marking the strip. Perfect for polished or cosmetic surfaces.
- Less wear and tear since nothing touches the material.
- Compact installation with no moving arms or rollers.
Challenges:
- Ultrasonic units may be affected by noise or airflow.
- Laser units need clear optics and proper mounting.
- Sensors require occasional cleaning and calibration.
Still, no-contact loop controls are becoming the go-to choice for high-quality materials. They are especially useful in lines where precision and surface protection are top priorities. As technology improves, their reliability continues to rise, making them a practical option for many coil processing lines.
Which Is the Right Choice for Your Coil Line?
Choosing between contact loop controls and no-contact loop controls comes down to how your coil line runs, the type of material you handle, and the level of accuracy you need. Both systems keep strip flow steady, but they do it in different ways.
Below, we’ll take things step by step so you can see which option may fit your plant the best.
1. Looking at the Basics of Performance
When you compare these two options, the first thing to think about is performance. Both systems measure the size of the loop and signal the uncoiler to change speed.
- Contact loop controls use a roller arm. As the loop grows or shrinks, the arm moves. That motion connects to a sensor, and the drive speeds up or slows down.
- No-contact loop controls use sensors like ultrasonic or laser. They “see” the loop and measure its distance without touching the strip.
Both do the job, but the level of response is slightly different. A dancer arm gives a small buffer of strip. That makes the line steadier when there are sudden speed changes. A sensor-based system reacts quickly but has no extra storage. If your line has lots of sudden pull changes, contact control may handle that better.
2. Considering Your Material
The type of material is another big factor.
- Strong and common steels: Contact systems work fine. They are rugged and don’t usually mark the surface.
- Polished, coated, or cosmetic surfaces: No-contact sensors are safer. Because nothing touches the strip, you avoid scratches and dents.
- Oily or perforated material: Contact rollers can slip, but they still work. Ultrasonic sensors may sometimes struggle if the surface gives odd echoes. In those cases, laser sensors tend to be more reliable.
If surface finish is important to your customers, no-contact may be the safer choice.
3. Installation and Maintenance
Setup and upkeep also play a big role in the decision.
- Contact loop systems need room for the arm to move. They also have bearings and rollers that require checks and lubrication.
- No-contact systems take up less space and have no moving arms. Maintenance usually means keeping the sensor lens or face clean.
Neither system is overly complex, but the mechanical parts of a contact system do add long-term upkeep.
4. Matching Control to Your Equipment
Your choice may depend on the drives and controllers you already use.
- A single loop controller is common in basic coil lines. It connects to the loop sensor and adjusts the uncoiler drive.
- More advanced lines may tie into a closed loop servo motor for precise, high-speed changes. This setup can be very accurate, but it costs more and requires a skilled setup.
If your line already uses a servo drive, no-contact sensors may give you the best results. If your line is older and uses simple motors, a dancer arm may be easier to integrate.
5. Thinking About Cost
Price is always part of the decision. Contact systems are usually less expensive up front. No-contact systems cost more, but they may save money if they prevent surface damage. A scratched or dented strip can mean scrap or returns, which adds up quickly.
6. Real-World Examples and Feedback
Many coil shops share reviews of their experiences. For instance, companies like Loop Contact Solutions Inc supply gear for coil handling. A Loop Contact Solutions review often notes that their products are simple, tough, and designed to last.
On the other hand, shops that handle premium metals often talk about the value of laser sensors. They cost more at first but pay off by protecting material.
7. Making the Call
When you line up all the points, here’s a simple way to think about it:
- Choose contact loop controls if:
- You need rugged, low-cost solutions.
- Your line handles standard material with no special finish.
- You want the benefit of loop storage for smoother operation.
- You need rugged, low-cost solutions.
- Choose no-contact loop controls if:
- You work with sensitive, polished, or coated material.
- You need compact installation without moving parts.
- You want high accuracy in a modern, sensor-driven line.
- You work with sensitive, polished, or coated material.
Both systems can be paired with advanced drives and a single loop controller, so the choice often comes down to material and finish quality.
Conclusion
Contact loop controls and no-contact loop controls both keep coil lines running smoothly. The right choice depends on your material, speed, and surface needs.
At the end of the day, both contact and no-contact loop systems are proven in coil processing.
Contact systems are like the tough workhorses—reliable, low-cost, and steady. No-contact systems are the precision specialists—clean, safe, and protective.
By weighing your materials, budget, and performance needs, you can make a clear, confident choice for your coil line.
For expert equipment and support, reach out to Durant Tool Company today and keep your coil processing line moving with confidence.
Frequently Asked Questions
How do loop controls help prevent coil jams?
They adjust coil feed speed so the loop stays steady, reducing tension spikes that can cause jams.
What makes a contact loop control reliable?
It uses a simple roller and arm design that works with many materials and needs little upkeep.
Can no-contact loop controls handle oily strip?
Yes, laser sensors often perform well on shiny or oily surfaces without marking them.
Do I need a single loop controller for every machine?
No, one controller can manage the loop between two machines, keeping flow balanced.
What kind of maintenance do loop sensors need?
Mostly cleaning and checking alignment. No-contact sensors need lens care, while contact rollers need bearing checks.