Choosing a PLC Control System for Roll Forming Machines: Complete Guide

Choosing a PLC Control System

The PLC (Programmable Logic Controller) is the brain of a roll forming machine.

👉 It controls:

Machine speed
Length cutting
Feeding systems
Punching operations
Safety systems

👉 The key principle:

A good PLC system = reliable, accurate, and scalable production

1. What Does a PLC Do in Roll Forming?

A PLC system manages:

Encoder signals (length control)
Motor speed (VFD / servo control)
Shear timing (especially flying shear)
Punching synchronization
Operator interface (HMI screen)

👉 Without a proper PLC, the machine cannot run accurately

2. Types of PLC Systems Used

Basic PLC Systems

Simple controls
Limited automation
Manual parameter setup

Mid-Level PLC Systems

Standard automation
Touchscreen interface (HMI)
Multiple product recipes

Advanced PLC Systems

Full automation
Servo integration
Remote diagnostics
Data logging

👉 Most modern machines use mid to advanced PLC systems

3. Most Common PLC Brands

Delta (Very Popular)

✔ Cost-effective
✔ Reliable
✔ Easy to use

👉 Best for:
Startups and standard machines

Siemens (Premium)

✔ High performance
✔ Advanced features
✔ Global support

👉 Best for:
High-end, large-scale production

Mitsubishi

✔ High reliability
✔ Strong performance
✔ Widely used

👉 Best for:
Industrial-grade systems

Omron

✔ Precision control
✔ Stable performance

👉 Best for:
Specialized automation

👉 Brand choice affects support, reliability, and integration

4. HMI (Human Machine Interface)

The HMI is the touchscreen interface.

Functions:

Set product length
Adjust speed
Select profiles
Monitor production

👉 A good HMI improves usability and reduces errors

5. Key Features to Look For

1. Length Accuracy Control

Encoder-based measurement
Precise cut length

2. Recipe Storage

Save multiple product settings
Quick changeovers

3. Speed Control Integration

Works with VFD or servo motors

4. Fault Detection

Alerts for errors
Safety shutdowns

5. Expandability

Ability to add features later

👉 These features are essential for modern production

6. Servo vs VFD Integration

VFD (Variable Frequency Drive):

Basic speed control
Lower cost

Servo Systems:

High precision
Required for flying shear and punching

👉 Advanced PLC systems support servo integration

7. Automation Level

Low Automation:

Manual adjustments
Basic controls

High Automation:

Fully synchronized systems
Minimal operator input

👉 Automation improves efficiency and consistency

8. Remote Access & Diagnostics

Modern PLC systems can include:

Remote troubleshooting
Online monitoring
Data tracking

👉 This is becoming standard in advanced machines

9. Cost Comparison

PLC Type

Cost

Capability

Basic

Low

Limited

Mid-level

Medium

Standard

Advanced

High

Full automation

👉 PLC cost is small compared to machine impact

10. Reliability & Support

Choosing the right PLC brand ensures:

✔ Spare parts availability
✔ Technical support
✔ Easy troubleshooting

👉 Avoid unknown or unsupported brands

11. Common Beginner Mistakes

❌ Choosing cheapest PLC
❌ Ignoring future expansion
❌ Not considering spare parts
❌ Overcomplicating simple machines

👉 PLC choice should match your machine and business

12. Best PLC for Startups

👉 Recommended setup:

Delta PLC + HMI
Encoder-based length control
VFD integration

👉 Balanced cost and performance

13. Best PLC for High-End Production

👉 Recommended setup:

Siemens or Mitsubishi PLC
Servo system integration
Full automation

👉 Ideal for large-scale operations

14. Real-World Example

Scenario: Roofing panel machine

Startup setup:

Delta PLC
VFD motor
Basic HMI

Advanced setup:

Siemens PLC
Servo feeding
Flying shear

👉 Result: higher speed and precision

15. Expert Rule (VERY IMPORTANT)

👉 If your machine includes:

Flying shear
Servo feeding
Punching system

➡️ You need a high-quality PLC system

16. Quick Decision Checklist

Before choosing:

✔ Machine type defined
✔ Automation level required
✔ Budget confirmed
✔ Support availability checked
✔ Future upgrades considered

👉 This ensures the right choice

FAQ – PLC Systems

What is the best PLC brand?

👉 Siemens (premium), Delta (best value)

Is PLC important?

👉 Yes—it controls the entire machine

Can I upgrade later?

👉 Yes—but costly and complex

Do I need servo integration?

👉 Only for high-speed or precision systems

What is the biggest mistake?

👉 Choosing a low-quality or unsupported PLC

FINAL THOUGHT

The PLC system is the control center of your machine.

👉 A good PLC ensures:

Accuracy
Reliability
Scalability

👉 The right approach:

Choose a system that matches your current needs—
but can support your future growth