Case Studies

Envelope Film

Cross-Functional Taber Team designs Rotating Sample holder to test Window Envelope Film


For companies manufacturing products not usually considered “technologically advanced”, the potential for warranty claims still exists. A supplier of clear plastic film used for standard window envelopes was faced with complaints resulting from damage to the film which occurred during their customer’s manufacturing process.Supplied in roll form, the film was often damaged as it moved through the equipment to convert it to an envelope. Rubbing against the equipment generated marring / scuffing damage that impacted the clarity of the film. Unfortunately, there was no quality check in place at the supplier’s facility to evaluate this property. And it was not uncommon for up to three months to pass before the customer put the material into production and discovered a problem. Obviously, this represents too long of a time to address any issues that might have been resolved at the time of manufacture.


The supplier initially requested information from Taber Industries regarding a “scratch tester to evaluate various formulations of thin plastic films”. Taking advantage of the “TABER-Test” program, the supplier sent in film specimens for Taber to recreate the damage. The Linear Abraser was selected as the tester, but it was not clear as to which test attachment would work best. Seven different test attachments were tried, but only one seemed to replicate the damage – the Universal Attachment. This 25mm stainless steel, flat head was rubbed back and forth over the specimen to simulate the contact the film made with the processing equipment.

taber_rotating_drum.jpgAfter reviewing data from the preliminary testing, the supplier arranged to visit Taber Industries and witness the testing. They liked the potential the Linear Abraser offered, but were not completely satisfied with the results. As they described, coating material applied to the film had a tendency to rub off and collect on the processing equipment. Reciprocating the Universal Attachment over the same spot did not adequately replicate the process / damage as seen in the field. The ideal solution would be to reposition the specimen during the test, continually exposing ‘fresh’ film to the abrading head.

Following the visit, Taber assembled a cross-functional design team to analyze the feasibility of producing a specimen holder that could ‘pull’ the sample along as the Linear Abraser test attachment moved across the specimen. Within two weeks, a prototype design was assembled and tested. A section of the supplier’s film was attached to a drum that rotated at a slow, controlled speed. This allowed the test attachment to rub the film sample in a “Z” pattern, thus meeting the supplier’s requirement to expose ‘fresh’ film.


There are many standard test procedures that reference Taber instruments, but off-the-shelf solutions do not always work for all applications. In this case, the unique requirements led to the development of a new product. Today, the film supplier utilizes the Linear Abraser and the new rotating drum sample holder to evaluate marring / scratching resistance. This customized testing solution has enabled the supplier to respond quickly if process adjustments are needed, ultimately reducing their warranty claims.