Automotive rivet assembly and inspection

On automotive rivet assembly and inspection lines where multiple robots work in coordination, scattered workstations, complex wiring, and demanding pneumatic response are common control challenges. This article shares a real-world application of Point Technology's C3 Valve Terminal on such a line—by deploying I/O modules and the Valve Terminal close to the workstations, wiring is simplified and pneumatic response speed is improved.

Point Technology products used in this case study

XBF4-PN04

(Discrete PROFINET coupler)

XBF5A-1616B

(Digital 16-channel input, NPN/PNP compatible, 16-channel output PNP)

XBF5A-0032B

(Digital 32-channel output PNP)

C3 Valve Terminal configured with Point Technology's own solenoid valves

I. Device and process

The automotive rivet assembly and inspection line is a key part of automotive component manufacturing that integrates assembly and quality inspection. The entire line consists of an automatic feeding unit, a multi-station turntable, a conveying system, a pneumatic/servo riveting unit, an online inspection unit, and an automatic sorting mechanism, enabling the full process from workpiece positioning to quality judgment.

The overall process flow of the line mainly covers the following four steps:

II. I/O communication pain points

This automotive rivet assembly and inspection line uses multiple devices working together to execute riveting, assembly, and inspection processes, forming an overall line-type layout. In terms of automation control, it mainly faces three pain points:

Pain point 1: Scattered workstations, complex signal wiring

Industrial robots, sensors, and actuators are distributed along the line. Traditional I/O modules require cables to be routed from the main cabinet to the end points, resulting in long, tangled cables that are difficult to install and maintain. Long-distance wiring also weakens pneumatic response, and hard wiring limits further expansion of the production line.

Pain point 2: High response requirements for pneumatic actuators

During production, the Valve Terminal must switch direction quickly to ensure synchronization and consistency of equipment actions. Signal delay or jitter may cause workpiece position deviation or riveting quality defects, affecting product yield.

Pain point 3: Complex site environment, high protection rating requirements

The Valve Terminal needs to be installed close to the workstation where space is limited, requiring a specific protection rating. In addition, equipment vibration affects the long-term stable operation of the Valve Terminal's communication.

III. Shidian Technology C3 Valve Terminal Solution

This solution uses Shidian Technology's C3 Discrete Valve Terminal, paired with discrete I/O modules, connected to a Siemens S7-1500 PLC via PROFINET bus:

Control layer:

The Siemens S7-1500 PLC acts as the core Controller, responsible for overall line logic scheduling, data processing, and signal interaction with the robot Controller.

Information layer:

Shidian Technology's discrete I/O modules are deployed together with the C3 Valve Terminal, installed in a distributed manner at each station Node, effectively reducing signal Cable Length and simplifying the overall wiring structure.

Execution layer:

The C3 Discrete Valve Terminal is deployed at the station's air source, receiving control commands through discrete I/O modules to directly drive actuating elements such as pneumatic fixtures, riveting cylinders, and air-blow cleaning, enabling proximal centralized control of the pneumatic unit.

IV. Shidian Technology C3 Valve Terminal

Shidian Technology's C3 Valve Terminal supports up to 24-position Double Solenoid Valve configurations, with an IP65 Protection rating; featuring an in-house Solenoid valve brand, a lifespan > 50 million cycles, low power consumption design, and support for Online Firmware Upgrade. It is widely used in demanding scenarios such as automotive manufacturing, 3C electronics, and lithium battery production.