How are manufacturing defects proven significant or trivial to the jury? How does a defendant show that the defect was created by a third party after it was shipped to the plaintiff's employer?

Design defects that result in damages almost always center around moving parts. Clearly this is an area where dynamic visuals are important, whether through animation, technical illustration, magnetics, flow charts or through the use of overlays. We frequently are asked to produce timelines that present the original design of a product and its relationship to the dates significant to the product liability case.