PAPER

Problem Solving

Paper

The following examples illustrate some of our contributions to this business sector:

• Evaluation of the in-service failure of a suction roll head was performed to determine the type of material used for fabrication and the reason for the failure. The investigation performed found that the failure was the result of corrosion fatigue cracking of the area of a 4″ fillet radius in the journal. Nothing unusual was found about the head in terms of material used for fabrication or the actual manufacture of the piece except that the metal was carbon steel. The solution was to use either a corrosion resistant alloy or protective cladding. Detailed recommendations were offered.
• A major container manufacturer asked Touchstone to assist them in determining the best coating material for their chime bands ­ the metal flange at the top of a cardboard “barrel”. Chime bands coated with a new material were tested for corrosion resistance along with electrogalvanized and hot-dip galvanized steel chime bands. Neutral salt-spray and humidity tests were also performed. The results helped the manufacturer develop a superior product.
• A manufacturer of cardboard trivets asked Touchstone to provide them with the maximum useful temperature for their product. The maximum useful temperature was determined by attaching thermocouples to trivets, placing them onto hot plates, and observing any change in physical characteristics as temperatures were increased.
• A manufacturer of plastic household products had a problem with blistering after lamination of their plastic-coated placemats. A gas chromatograph/mass spectrometer (GCMS) evaluation of the card stock from a new supplier found a silicone compound present on the surface which volatilized at or below the temperature used to seal the placements. A change in the card stock eliminated the problem.
• Two samples of MICR ribbon were compared to understand why a one product performed better than another in a check writer when the ribbon was run through the machine multiple times. Evaluations included abrasion resistance, density, GC/MS and scanning electron microscopy of ink surface. Significant differences between the two products in terms of composition, morphology and abrasion resistance were found.
• Touchstone was asked to determine the cause of the crack in a steel roll, which failed in use in a paper mill. The crack was found to be due to contact fatigue from sleeve weld. The roll had been clad with stainless steel to provide corrosion resistance. The sleeve had been resistance welded from SS sheet, but the weld bead was not scarfed or ground from the inside. Repeated contact with the steel roll caused contact fatigue cracks to develop which propagated into the roll resulting in the final catastrophic failure.
• Three grade B-7, dryer bolts were evaluated to determine the cause of failure of a broken bolt. The cause was found to be tool marks and/or cracks left during machining of the threads which propagated to failure under operating stresses. The use of grade 8 bolts was recommended, with threads rolled after heat treatment, to prevent problem.
• 3 roll scale samples were examined using a scanning electron microscope equipped with X-ray microanalysis to identify their source. No evidence of an unusual corrosive agent was identified. The scale was found to be iron rust and the condition was attributed to aggressive paper mill conditions.

The above examples are only a sample of our work in this area. We would be pleased to provide any additional information you may require. We also invite you to review examples on our website of work that we have performed in support of other business sectors.