Standardized Adhesion Testing: The Automated Tensile Tester

In the manufacturing of medical adhesive tapes, consistent raw material quality is critical for patient safety. This project introduces a custom-built, Arduino-based Tensile and Adhesion Tester designed to perform standardized tests according to international ASTM and ISO protocols. By automating the pull-rate and force measurement, the device provides a scientific baseline for factory quality control.

Engineering to International Standards

The machine is designed to accommodate various testing methodologies:

• Peel Adhesion (ASTM D3330): Measures the force required to remove a tape from a standard surface at a specific angle and speed.
• Shear Adhesion (ASTM D3654): Evaluates the ability of the adhesive to resist a constant load over time.
• T-Peel Test (ASTM D1876): Specifically designed for the "Peel Resistance" of flexible-to-flexible bonded medical materials.
• Tack Testing (ASTM D6195): Measures the "initial grab" or loop tack of the adhesive the moment it touches a surface.

High-Precision Motion and Measurement

To achieve repeatable results, the device eliminates human error through automated linear motion:

1. NEMA 17 Stepper Control: Using a 5-phase or standard high-torque stepper motor, the device moves at a constant speed (usually 300mm/min as per ASTM). This ensures the "Strain Rate" remains consistent throughout the test.
2. Load Cell & HX711: A high-precision load cell measures the force (in Newtons or Grams). The HX711 amplifier translates the minute changes in resistance into high-resolution digital data for the Arduino.
3. Nextion HMI Interface: Instead of a complex PC setup, a 7-inch Nextion TFT LCD provides a stand-alone interface. Operators can select the test type, calibrate the load cell, and view real-time force-over-distance graphs.

Industrial-Grade Fabrication

The structural integrity of a tensile tester is vital. For this project, all mechanical parts were designed specifically for high-rigidity and produced using CNC machining. This prevent "Frame Flex" from introducing errors into the force measurements. The inclusion of an Analog Joystick allows for manual positioning of the test head, making the setup of new samples quick and intuitive for factory floor workers.

I made this machine to measure adhesive and tension of medical tape, according to the procedure of ASTM standard such as:

ASTM D 3654 /D 3654M: 2011 STANDARD TESTMETHODS FOR SHEAR ADHESION OF PRESSURE-SENSITIVE TAPES (2006 R 2011)

BSI ISO 4587 : 2003 2003 ADHESIVESDETERMINATION OF TENSILE LAP-SHEAR STRENGTH OF RIGID-TO-RIGID BONDED ASSEMBLIES(W)

ASTM D 3121 : 2006 (Optional)STANDARD TEST METHODFOR TACK OF PRESSURE-SENSITIVE ADHESIVES BY ROLLING BALL R(1999)

ASTM D 6195 : 2003 STANDARD TESTMETHODS FOR LOOP TACK

ASTM D 1876 : 2008 STANDARD TESTMETHOD FOR PEEL RESISTANCE OF ADHESIVES (T-PEEL TEST)

ASTM D 3330 /D 3330M: 2010 STANDARD TESTMETHOD FORPEEL ADHESION OF PRESSURE-SENSITIVE TAPE

the device is working with 5 phase stepper motor, load cell driver, tft lcd driver, joystick and...

all mechanical part is designed by me and produced by CNC machine.