Materials

 

Finite Element Analysis of an Injection Molding Machine Part

A plastic injection molding machine part manufacturer experienced premature failures and warranty returns of one of their most profitable products. They asked Packer Engineering metallurgical engineers to recommend a new material that would resist fatigue fracture better than their existing product. Packer, however, suspected the part geometry could be improved such that an expensive material change would not be necessary. A finite element model confirmed our suspicions and a new, optimized design was provided to the customer. The new design allowed the customer to manufacture the part at no additional cost while obtaining an order of magnitude longer part life.

Fractured Brass Fitting Analysis

A brass fitting, used in the plumbing installation for a bidet, fractured causing a large water leak while a family was out of town. The unfortunate result was a substantial amount of property damage. Metallurgical engineers from Packer Engineering analyzed the fractured brass fitting in the metallurgical laboratory utilizing both the light microscope and scanning electron microscope (SEM). Additionally, Packer personnel reviewed testimony concerning the details around the plumbing installation and the incident. The engineer’s expert testimony in deposition regarding this analysis provided the client with the leverage they needed to settle favorably with the parties involved.

Glass Panel Design Analysis

Several glass panels within a suburban office building shattered unexpectedly, prompting questions regarding glass quality, architectural design, and incidental damage. Packer architects and engineers performed a design analysis and determined that a portion of the glass installation was subject to stress that exceeded industry recommended practice. Materials engineers used high powered microscopes and chemical analysis tools to determine that some of the glass was produced with minute flaws that could cause catastrophic fracture. Field service technicians performed polarized light inspection of hundreds of glass panes in the building to identify pieces susceptible to future fracture. Ultimately, Packer’s recommendations resulted in some glass being permanently removed and many other pieces being laminated to prevent glass ejection should future fracture occur.

Chain Fracture

A ratchet chain puller being used in the rigging of a 20 ton piece of machinery experienced a chain fracture, resulting in the load swinging into and killing an employee. Mechanical and metallurgical engineers from Packer analyzed the rigging arrangement and the machinery details. We evaluated the broken chain using metallurgical laboratory equipment and techniques. A visit was made to the Japanese chain and chain puller manufacturer to establish their manufacturing practice and quality procedures. Packer’s findings proved the chain broke due to misuse and abuse of the chain puller. Packer ultimately provided expert testimony in federal court, using models and a digital video presentation, to assist in obtaining a defense verdict for the chain puller manufacturer and their insurer.

Trailer Floor Evaluation

A trucking company experienced bowed floors in many of their new trailers. They believed a steel manufacturer provided steel beams that didn’t meet the strength specifications. Packer’s metallurgical engineers determined some of the steel was below specification, but suspected a small deviation in strength should not have caused the trailer floor to deform. Research into the design specifications and analysis of the floor design confirmed these suspicions. Further investigation into the hauling schedules followed by visits to facilities where the trailers had been loaded, allowed us to uncover excessive loading conditions. This matter settled immediately after deposition testimony was provided by one of Packer’s engineers.

Particle Analysis

Packer Engineering was asked to determine the source of particles that damaged new window /sliding door units installed during remodeling of an eight story condominium. Chemical and microstructural analysis of the particles showed weld spatter was the source of the particles and the damage to the windows was caused by the molten weld spatter reacting with the glass. Analysis of the construction records indicated railings on the balconies adjacent to the damaged windows were welded in place after installation of the new windows. Packer Engineering’s analysis allowed the general contractor to recover his cost of replacing the damaged windows from the firm that had welded the railings in place without properly protecting the windows.

Rebar Tests

One of the leading manufacturers of post-tensioning rebar requires that each batch of product manufactured undergo a series of tensile tests. Mechanical engineers and technicians from Packer Engineering assisted in designing and implementing the test procedures on the rebar. The data acquired and observations made by Packer personnel during and after the testing allowed the manufacturer to assure their customers the product being supplied is fit for their design and application. With tensile loading capabilities of up to 850,000 pounds, Packer was able to provide the manufacturer with a reputable test source for their entire product range.

Tarpaulin Cover Investigation

Packer Engineering Inc. was approached by the world's largest producer of tarpaulin covers and side curtains for international freight transport regarding field performance of plastic rollers. One of the components used in side curtains was a plastic roller supplied by a third party manufacturer. The plastic roller material encountered unexpected cracking and wear during service. A dispute between multiple parties resulted regarding the material of the roller and the design of the roller. The dispute occurred because the poor service performance of rollers was observed after a change in design of the roller. A forensic investigation and testing conducted by Packer Engineering conclusively demonstrated the material of the roller was not that specified on the engineering drawing. The failure was attributed to material switch and poor manufacturing by the third party roller supplier.